Colorectal Cancer

Colorectal cancer is one of the most prevalent cancer types, affecting the colon, rectum, and appendix. It typically develops from precancerous polyps that form on the inner intestinal lining and undergo malignant transformation. Symptoms can include changes in bowel habits, abdominal pain, rectal bleeding, and unexplained weight loss. Colorectal cancer is strongly linked to lifestyle factors like obesity, smoking, and red meat consumption as well as age and family history. If detected early, it has high cure rates through surgical removal of tumors along with chemotherapy and/or radiation. However, colorectal cancer becomes increasingly deadly at later stages, highlighting the importance of the recommended screening tests. Here we will provide an in-depth look at colorectal cancer causes, risk factors, pathogenesis, diagnosis, treatment, and prevention strategies.

Executive Summary

  • Colorectal cancer is a serious condition characterized by abnormal cell growth in the colon or rectum. In 2023, it's projected that 82,290 US adults will be diagnosed with colorectal cancer, with a significant gender disparity - 62,420 cases in men and 19,870 in women. This difference raises concerns and calls for further investigation into the underlying factors contributing to this disparity.

  • The main risk factors for colorectal cancer include cigarette smoking, chemical exposures (like aromatic amines and aniline dyes), genetic mutations, chronic urinary tract infections, and certain inherited conditions. Smokers are three times more likely to develop colorectal cancer compared to non-smokers. Recent research has shown a link between cigarette smoke extract and increased platelet-activating factor accumulation in bladder cancer cells.

  • Colorectal cancer is classified and staged based on the extent of tumor invasion. Low-grade tumors are typically non-invasive with a high risk of recurrence but low likelihood of progression. High-grade tumors are more aggressive, often invading deeper layers of the colon wall and having a poorer prognosis.

  • Common symptoms of colorectal cancer include blood in stool, changes in bowel habits, and symptoms of irritation. However, these symptoms can also be caused by other conditions like UTIs or inflammatory bowel diseases, so it's important to get them checked by a doctor. Early detection and proper diagnosis are crucial for effective treatment and management of the disease.

  • Diagnosis of colorectal cancer involves various tests including colonoscopy, biopsy, and imaging studies like CT scans or MRIs. Colonoscopy is considered the most sensitive technique for detecting colorectal tumors, while transurethral resection (TURBT) is used for determining tumor stage and grade. Genetic counseling and tumor biomarker testing may also be recommended in some cases.

  • Treatment options for colorectal cancer include surgery, radiation therapy, chemotherapy, immunotherapy, and targeted therapy. The choice of treatment depends on the cancer stage, grade, and individual patient factors. Surgery options range from local excision to partial or total colectomy, while systemic therapies are often used for more advanced stages.

  • Surgical procedures for colorectal cancer include polypectomy, local excision, and various types of colectomies. The specific type of surgery depends on the tumor location and extent. Lymph node removal is also a crucial part of colorectal cancer surgery to determine if the cancer has spread beyond the colon.

  • Chemotherapy drugs commonly used for colorectal cancer include 5-Fluorouracil (5-FU), Capecitabine, Irinotecan, and Oxaliplatin. These drugs work by interfering with cancer cell division and growth. Side effects can include fatigue, nausea, hair loss, and increased risk of infection, but these can often be managed with supportive care.

  • Immunotherapy, particularly immune checkpoint inhibitors like Pembrolizumab and Nivolumab, has shown effectiveness in treating certain types of colorectal cancer. These drugs work by helping the immune system recognize and attack cancer cells. They are particularly effective in cancers with specific genetic characteristics like microsatellite instability-high (MSI-H) or mismatch repair deficient (dMMR).

  • Targeted therapies for colorectal cancer include anti-EGFR drugs, anti-angiogenesis drugs, and kinase inhibitors. These therapies are designed to interfere with specific molecules involved in cancer growth and spread. The choice of targeted therapy often depends on the specific genetic characteristics of the tumor.

  • Complementary approaches, including Traditional Chinese Medicine and acupuncture, are being explored as adjuncts to standard treatments. While some studies show potential benefits, more research is needed to establish their efficacy. It's important for patients to discuss any complementary treatments with their healthcare team to ensure safety and avoid potential interactions.

  • Follow-up care and recurrence monitoring are crucial aspects of colorectal cancer management. Regular surveillance through colonoscopy, imaging studies, and blood tests is recommended, with the frequency depending on the patient's risk level. The American Society of Clinical Oncology provides guidelines for follow-up schedules based on the risk stratification of the cancer.

  • Future directions in colorectal cancer management include the use of artificial intelligence for diagnostics and prognostics, development of better biomarkers for recurrence monitoring, and exploration of new treatment combinations. There's also a focus on improving patient quality of life and reducing the financial burden of treatment through more targeted and effective therapies.

  • Prevention plays a key role in combating colorectal cancer. Regular screening, starting at age 45 for average-risk individuals, can help detect and remove precancerous polyps. Lifestyle factors such as maintaining a healthy diet, regular exercise, limiting alcohol consumption, and avoiding smoking can also help reduce the risk of developing colorectal cancer.

  • The emotional and psychological impact of colorectal cancer shouldn't be underestimated. Support from family, friends, and cancer survivor communities can be crucial throughout the journey. Patients are encouraged to stay informed, communicate openly with their healthcare team, and never give up hope in the fight against this disease.

Colorectal cancer is also known as colon or rectal cancer and refers to the growth of malignant tumors in the colon or rectum which are parts of the large intestine. This is one of the most common types of cancer worldwide. This cancer typically begins as small, non-cancerous groups of cells called polyps on the inner lining of the colon or rectum. Overtime, some of these polyps can develop into cancerous tumors. There are two main types of polyps that can lead to colorectal cancer. The first is adenomatous polyps and the other are serrated polyps. Regular screening tests can help to prevent colorectal cancer by identifying polyps before they become cancerous.

Adenomatous polyps are the most common type and have the most potential to become cancerous. Serrated polyps on the other hand, less common but can also progress to cancer. Not all polyps will turn into cancer, removing them early can significantly reduce the risk. This makes colonoscopies a significant way to avoid potentially difficult cancers later on.

At the cellular level, cancer is usually the result of mutations that cause polyp cells to undergo unregulated cell growth. When the body's normal maintenance mechanisms fail, have normal cells begin to multiply and form a tumor. Certain gene mutations can increase the risk of colorectal cancer. For instance, the APC genes are very common colorectal cancer. The APC gene normally suppresses tumors by controlling cell growth and division, but a mutation in this gene can contribute to the development of cancer.

The exact causes of colorectal cancer are not fully understood, several risk factors have been identified. These include:

  1. Age: The risk of developing colorectal cancer increases with age particularly after the age of 50.

  2. Personal or family history: People who have previously had colorectal cancer or have a family history of the disease are at a higher risk.

  3. Inflammatory bowel disease: Chronic conditions such as ulcerative colitis or Crohn's disease increase the risk.

  4. Genetic syndromes: Certain inherited gene mutations such as familial adenomatous polyposis or Lynch syndrome predispose individuals to correct all cancer.

  5. Diet and lifestyle: A diet high in red meat or processed meat, low fiber intake, sedentary lifestyle, obesity, smoking and excessive alcohol consumption can increase the risk.

Early detection plays a very crucial role in the successful treatment of colorectal cancer. Several screening methods are available to detect precancerous polyps or early-stage cancers. These include:

  1. Colorectal cancer remains one of the most common and deadly cancers, but education and awareness about the disease can truly make a difference in fighting it. It starts with understanding the key risk factors, like age, family history, inflammatory diseases, smoking, obesity, and diet and lifestyle habits. Knowing your personal risk empowers you to get screened at the appropriate time. Catching precancerous polyps early via colonoscopy allows them to be removed before they ever become cancerous.

  2. Paying attention to concerning digestive symptoms is also critical, as early diagnosis leads to far better outcomes. Persistent changes in bowel habits, rectal bleeding, abdominal pain, fatigue and unintended weight loss should prompt a timely evaluation. Don't assume complaints will just go away.

  3. If faced with a colorectal cancer diagnosis, take the time to understand your specific tumor characteristics, stage, and treatment options. Ask your oncology team thoughtful questions. Localized early stage disease can often be cured with surgery alone. More advanced cancers may require multi-modality approaches like chemotherapy, radiation, targeted therapies, or immunotherapy on top of surgery. Seeking a second opinion is perfectly acceptable.

  4. Throughout treatment, listen to your body and speak up about side effects. Don't try to power through pain or discomfort alone. Your care team has tools to help manage symptoms and provide emotional support. After treatment, commit to regular follow-up visits for monitoring and surveillance.

  5. Prevention is also key. Making positive lifestyle changes like eating a healthy plant-based diet, exercising regularly, maintaining a healthy weight, minimizing alcohol intake, and not smoking can all lower colorectal cancer risk.

  6. Most importantly, remember you are not alone on this journey. Lean on family, friends, counselors, and cancer survivor communities for inspiration and hope. Arm yourself with information. Stay vigilant about your health. And never give up the fight against this disease.

Overview of colonoscopy for colorectal cancer screening:

Colonoscopy is considered the gold standard screening test for colorectal cancer. During this procedure, the entire length of the colon and rectum is visually examined using a thin, flexible, lighted tube called a colonoscope.

Key points about the preparation required for a colonoscopy:

The colon must be thoroughly cleansed before a colonoscopy in order for the doctor to clearly visualize the colon lining. Any stool present can obscure the visibility.

  • The preparation typically involves restricting one's diet to clear liquids only starting 1-2 days before the colonoscopy.

  • A strong laxative solution is also prescribed, usually either polyethylene glycol or sodium phosphate. This must be consumed in a large volume the evening before the exam.

  • The laxative stimulates forceful bowel movements to flush out the colon contents before the procedure. People often need to stay near a toilet once they start drinking the laxative prep.

  • Abdominal cramping and bloating are common side effects of the laxative prep, but symptoms improve once the bowels are emptied.

  • The preparation can be uncomfortable, but is a necessary step. Poor preparation may lead to a failed colonoscopy or the need to repeat it sooner.

  • Drinking clear broths, electrolyte solutions, and staying well hydrated can help ease the prep process. Medications can treat nausea or pain if needed.

  • The doctor will ask about your prep to ensure your colon was sufficiently cleansed before starting the colonoscopy. Be sure to follow all prep instructions carefully for best results.

Though not particularly pleasant, properly preparing with diet restrictions and laxative solutions helps ensure a successful colonoscopy procedure and optimal colorectal cancer screening.

The colonoscope contains a tiny camera on one end that allows the gastroenterologist to closely inspect the lining of the entire large intestine on a video monitor. Using the colonoscope, the doctor can see any abnormalities in the colon and rectum, including inflammation, ulcers, and most importantly, polyps.

Polyps are small clumps of cells that form on the lining of the colon and can sometimes become cancerous over time. The key advantage of colonoscopy is that if any suspicious polyps are found, they can often be removed immediately during the same colonoscopy procedure. Removing precancerous polyps interrupts the progression to colorectal cancer.

Colonoscopy has several benefits over other screening tests:

  • It visualizes the entire length of the colon, rather than just portions.

  • It has very high accuracy for polyp and cancer detection.

  • Precancerous polyps can be removed on the spot.

  • If cancer is found, biopsies can be taken for analysis.

  • A high level of bowel preparation is needed prior to ensure the colon lining is clearly seen.

Overall, colonoscopy every 10 years beginning at age 45 is the recommended screening approach for average-risk individuals, as it provides the most comprehensive colorectal cancer prevention by allowing both cancer detection and polyp removal.

Overview of the fecal occult blood test for colorectal cancer screening:

The fecal occult blood test (FOBT) checks stool samples for the presence of tiny amounts of blood that cannot be seen with the naked eye, known as occult blood. This test can be performed at home using a test kit provided by your healthcare provider.

To complete the FOBT, small samples from two or three different bowel movements are smeared onto test cards. The cards are then sent back to the doctor's office or lab to be checked for any sign of blood.

Finding blood in the stool could be an indication of colorectal polyps or cancer. As polyps or cancer grow in the colon, they can sometimes bleed or leak small amounts of blood. However, other conditions like hemorrhoids can also cause occult stool blood.

If blood is detected by the FOBT, further testing like colonoscopy is needed to investigate the cause. Around 5% of FOBT screenings return a positive result for blood in the stool.

The main advantages of the FOBT are that it is noninvasive, inexpensive, and convenient to complete at home. However, its accuracy is relatively low compared to other screening methods. Small polyps and early stage cancers may bleed intermittently or not at all, leading to false negative results.

The recommended screening frequency is once a year. The high rate of false negatives means FOBT should not be relied on as the sole screening modality. But used in conjunction with colonoscopy, it provides a regular monitoring interval for colorectal cancer screening

Overview of flexible sigmoidoscopy for colorectal cancer screening:

Flexible sigmoidoscopy is a screening procedure that allows direct visualization of the rectum and lower third of the colon using a slim, bendable, lighted tube called a sigmoidoscope.

Similar to colonoscopy, this tube has a small camera on one end that feeds images to a video monitor. The doctor slowly advances the sigmoidoscope through the anus into the rectum, and then into the descending colon and sigmoid colon.

The sigmoid colon is the S-shaped portion of the large intestine before the splenic flexure, which represents about the lower 35-40 cm of the colon. Any abnormal growths like polyps seen in the rectum or sigmoid colon can be biopsied or removed through the sigmoidoscope during the procedure.

If concerning lesions are found, the patient will likely be referred for a full colonoscopy at a later date. This allows examination of the entire colon, as flexible sigmoidoscopy only views the distal portion.

Advantages of flexible sigmoidoscopy include shorter procedure time, no sedation required, and quicker recovery compared to colonoscopy. It also has lower bowel preparation requirements.

Disadvantages are that it misses lesions located in portions of the colon beyond the sigmoid. And any polyps found cannot be removed endoscopically during the sigmoidoscopy itself.

Sigmoidoscopy every 5 years plus FOBT is considered an acceptable screening strategy, but colonoscopy remains the single most thorough screening test for colorectal cancer available.

Overview of stool DNA testing for colorectal cancer screening:

Stool DNA testing is a non-invasive screening approach that analyzes a sample of stool for biomarkers associated with colorectal cancer or precancerous polyps. Several stool DNA tests have been developed.

These tests screen for abnormal DNA mutations that can arise in colorectal tumor cells, such as mutations in the KRAS or APC genes. Testing the stool DNA for the presence of these cancer-associated mutations can detect colorectal cancer or polyps without requiring a colonoscopy.

In addition to analyzing DNA, stool DNA tests also use an immunochemical assay to check for occult blood in the stool sample, similar to a traditional fecal occult blood test.

To perform stool DNA testing, patients collect an entire bowel movement using a collection kit sent from the lab, and ship the sample back for analysis. Advanced technologies like quantitative molecular assays and digital PCR enable the lab to detect minute amounts of tumor DNA in the stool.

Compared to other non-invasive tests like FOBT, stool DNA testing has higher single-test sensitivity for both cancer and precancerous lesions, detecting over 90% of colorectal cancers. However, specificity can be lower leading to more false positive results.

If a stool DNA test is positive, proceeding to colonoscopy is recommended to confirm findings. The recommended interval for screening with stool DNA tests is every 3 years, assuming negative findings. But compared to colonoscopy, stool DNA testing must be repeated more frequently.

Overview of CT colonography for colorectal cancer screening:

CT colonography, also known as virtual colonoscopy, uses X-ray computed tomography (CT) to generate cross-sectional images of the entire colon and rectum.

During the procedure, a small tube is inserted into the rectum and the colon is inflated with air in order to better visualize the bowel wall. No sedation is required. The patient lies on their back and stomach while CT scans are performed.

The CT scanner takes multiple images as it rotates around the body. A computer then compiles these images into detailed 2D and 3D reconstructions of the interior lining of the colon.

Like colonoscopy, CT colonography requires a full bowel prep to cleanse the colon beforehand. But the procedure itself is much less invasive, since no scope needs to be passed into the bowel.

The radiologist can digitally "fly through" the images of the colon to look for any polyps or cancerous lesions. If abnormalities are found, colonoscopy will still be needed for biopsy or removal.

Advantages of CT colonography are that it is quicker, non-invasive, and does not require sedation. Disadvantages are exposure to radiation, inability to take biopsies/remove polyps, and lower accuracy which may miss some smaller polyps.

CT colonography every 5 years is a reasonable screening option for those who wish to avoid colonoscopy. But colonoscopy remains the single best screening test for colorectal cancer detection and prevention.

However, suspicious areas are seen, a traditional colonoscopy still need to be performed to remove or biopsy those polyps. This test is typically done every 5 years. 

If colorectal cancer is detected, further tests, such as biopsies and imaging scans may be performed to determine the stage in the extent of the disease. Treatment options for colorectal cancer include surgery, navigation therapy, targeted therapies and immunotherapy. The choice of treatment depends on various factors including the stage of the cancer and the individuals overall health.

Remember, the best screening test is the one that gets done. Regular screenings, starting at the age of 50, for most people, is essential for detecting and preventing colorectal cancer. Consult with your healthcare provider to choose the best screening method for you based on your risk factors and your overall health.

Symptoms to watch for of potential colorectal cancer include changes in bowel habits such as diarrhea constipation or narrowing of the stools that last for more than a few days. It can also include the feeling that your bowel doesn't empty completely, the presence of blood in your stool, persistent cramps, or pain, unexplained weight loss, or fatigue.

Staging for Colorectal Cancer:

Cancer staging describes the severity and spread of the disease. For colorectal cancer, earlier stage tumors are located only in the innermost layers of the colon or rectum, while higher stage tumors have grown deeper into the colon wall or spread to other organs.

Stage 0 means abnormal cancer cells are present but have not grown beyond the colon surface lining. In Stage I, the cancer has grown into the next tissue layer under the surface but no deeper.

In Stage II, the tumor extends into the muscle layer of the colon wall, which is deeper but still localized. Stage III cancer has spread to nearby lymph nodes but not yet other organs.

Stage IV is the most advanced stage where the cancer has metastasized and spread to distant sites like the liver or lungs.

Doctors use the stage along with other factors to estimate prognosis and guide treatment choices. For example, early Stage I and II cancers are often curable with surgery alone to remove the tumor.

But Stage III and especially Stage IV cancers have a higher chance of coming back after initial treatment. So chemotherapy may be given after surgery to try to eliminate any stray cancer cells still circulating in the body.

In general, finding colorectal cancer early, when it is Stage I or II, provides the best chance for successful treatment. Later stage cancers are more complicated to treat and have a greater risk of recurrence. Knowing the stage helps patients understand their prognosis and make informed decisions.

Adenocarcinomas:

Adenocarcinomasare a type of cancer that start in the cells that form glands making and secreting mucus and other substances. About 95% of colorectal cancers are adenocarcinomas, the most common type of colorectal cancer. Adenocarcinomas of the colon may begin as a growth on the inner lining of the colon or rectum called a polyp as we've mentioned before. These polyps may be flat or raised and they typically take many years to develop into cancer.

At the cellular level, the transition from normal cells to polyps and ultimately to cancer involves a series of mutations. We've already mentioned the mutation of the APC gene as an example. Over time additional mutations and other genes may occur, in the cells to become increasingly abnormal which then eventually become cancerous.

Prevention: One prevention strategy against colorectal adenocarcinoma is regular screening particularly for individuals over 50 and those with additional risk factors. More fundamentally, we need to address lifestyle changes, maintaining a healthy diet and weight, your exercise, limiting alcohol intake and quitting smoking. We also need to consider, as we have mentioned elsewhere, avoiding environmental factors. These environmental factors include doing our best to get clean air, clean water and foods that are as free as possible from toxins such as pesticides, herbicides, other pollutants and in as unprocessed a state as possible. Please check our website for a very complete overview of how to manage these environmental issues and support your fundamental health as much as possible.

There are two main types of colorectal adenocarcinoma:

  1. Tubular adenocarcinoma: This is the most common type, 50 to 60% of colorectal adenocarcinomas. These cancers have a tubular pattern when viewed under the microscope. They're often well differentiated, meaning they closely resemble normal tissue.

  2. Mucinous adenocarcinoma: This type accounts for 10 to 15% of correct all adenocarcinomas. These cancers have more than a 50% extracellular mucin, which is a protein that gives mucus its gel-like properties. These are often more aggressive than tubular adenocarcinomas.  

The symptoms of colorectal adenocarcinoma are similar to those of other types of colorectal cancer, including changes in bowel habits, operating, abdominal discomfort, ongoing fatigue and unexplained weight loss. Diagnosis typically involves a colonoscopy to examine the colon and the rectum and to sample the suspicious area or polyp so that it can be tested to see if there are cancerous cells. This biopsy will give your doctor a great deal of information about the condition of your colon and if there is cancer, it will enable them to determine exactly what type it is. Imaging tests may also be used to determine the stage of the cancer and if it has spread to other areas of the body. Most commonly, this is done either through a CT or CAT scan with contrast, or with a PET scan. 

Chemotherapy for colorectal cancer involves the use of drugs to kill cancer cells. It's often used after surgery to kill any cancer cells that might remain or before surgery to shrink cancers and to make them easier to remove. Chemotherapy may also be used in patients with advanced stage disease to help shrink tumors, to slow the progression of the disease and to relieve symptoms. As we have described elsewhere, chemotherapy, although useful and often necessary, can have a tremendous impact on the overall health and well-being of the person receiving it. Please look at our exploration of this consideration elsewhere on our website.

Overview of the Main Surgical Options for Treating Colorectal Cancer:

Overview of polypectomy:

Polypectomy is the removal of precancerous polyps in the colon before they have a chance to turn into cancer. This procedure is typically done during a screening colonoscopy.

Polyps are abnormal tissue growths that arise from the lining of the colon. While most will never become cancerous, some polyps can gradually transform into colorectal cancer over the course of around 10-15 years.

Finding and removing precancerous polyps through polypectomy is one of the primary cancer prevention benefits of colonoscopy screening.

When a polyp is identified during colonoscopy, the doctor passes a wire loop or cautery device through the colonoscope to snip the polyp off at its stalk or burn it off. The polyp can then be retrieved and sent to pathology to analyze the tissue.

If it is an adenomatous (precancerous) polyp, the patient will likely need more frequent colonoscopy surveillance to check for recurrence. Different recommendations exist based on number, size, and histology of polyps found.

Polypectomy is very safe and most patients have no side effects. On rare occasions, bleeding or perforation can occur. Larger or harder to reach polyps may require a second procedure for complete removal.

By removing precancerous polyps before they can develop into colorectal cancer, polypectomy allows colonoscopy to serve as both a screening and preventive technique. This interruption of the adenoma-carcinoma sequence prevents cancer development.

Overview of local excision for early stage rectal cancer:

Local excision is typically considered for T1N0 rectal cancers that meet specific criteria:

  • Tumor size is generally less than 3-4 cm

  • Cancer has not grown deeper than the submucosa (T1 stage)

  • No lymph node involvement or distant spread on imaging

  • Cancer is within 8 cm of the anal verge

  • No obstruction or significant bowel symptoms

Certain favorable tumor characteristics like well-differentiated histology, lack of lymphovascular invasion, and precursor lesions like an adenoma component also support local excision.

The two main local excision techniques are:

  1. Transanal excision: The tumor is removed through the anus using long instruments. This has the advantage of being low-cost and accessible. It is good for smaller lesions but harder for higher tumors. Risk of poor visualization and margin clearance.

  2. TEMS (transanal endoscopic microsurgery): Done with a specialized scope that allows magnified visualization and precise excision. TEMS can successfully remove larger and higher rectal lesions while sparing healthy tissue. But it requires expensive specialized equipment and expertise.

After local excision, the patient needs very close endoscopic surveillance every 3-6 months to watch for recurrence. Additional surgery or chemoradiation may still be required if margins were positive or high-risk features present.

While local excision can be curative for the earliest T1 rectal lesions, cancers that recur locally have a poorer prognosis. Patients considering this approach must understand the risks and need for diligent follow-up compared to radical resection. But for well-selected early cancers, local excision is a reasonable minimally invasive option.

Overview of the various types of colectomies performed for colorectal cancer:

  • Right hemicolectomy: Removes the cecum, ascending colon, and proximal transverse colon. Reconnects the remaining transverse colon to the ileum. Done for right-sided colon cancers.

  • Extended right hemicolectomy: Removes a larger portion of transverse colon for tumors located near the hepatic flexure.

  • Left hemicolectomy: Removes the descending colon and sigmoid colon. Reconnects the transverse colon to the rectum/upper sigmoid. For left-sided colon tumors.

  • Sigmoid colectomy: Removes only the sigmoid colon portion, reconnecting descending colon to rectum. Indicated for sigmoid colon cancer.

  • Low anterior resection: For upper rectal cancers. Removes sigmoid colon and upper rectum, reconnecting the remaining rectum to the colon with an anastomosis. May require temporary ileostomy.

  • Abdominoperineal resection: Removes the anus, rectum, sigmoid colon and desc. colon. Permanent colostomy needed since the anus is removed. Done for very low rectal Cancers.

  • Total colectomy: Removal of the entire colon. Usually done urgently for things like colonic volvulus. May be indicated electively for some advanced cancers.

  • Proctocolectomy: Removal of rectum and entire colon. Often done for inflammatory bowel disease.

More detail on the processes and potential consequences of different types of colectomies:

Right Hemicolectomy

  • Incision in right abdomen to access cecum, ascending colon, proximal transverse colon

  • Mobilize and resection colon sections

  • Lymph node dissection near major vessels

  • Anastomose ileum to remaining transverse colon

  • Can result in increased stool frequency after resection

Low Anterior Resection

  • Access rectum transanally or via abdomen

  • Distal colon mobilization and rectal transection

  • Lymphadenectomy in mesorectum

  • Anastomose colon to remaining rectum

  • Risk includes anastomotic leak, stricture, incontinence

Left Hemicolectomy

  • Incision in left abdomen to access descending colon, sigmoid colon

  • Mobilize and resect colon

  • Lymph node dissection near vessels

  • Anastomose transverse colon to rectum/sigmoid

  • May have looser stools due to loss of sigmoid reservoir

Abdominoperineal Resection

  • Access abdomen and perineum separately

  • Remove entire rectum, anus, distal colon

  • Permanent colostomy needed

  • Higher risk of complications like infection

  • Major impact on bowel function and body image

Sigmoid Colectomy

  • Resect sigmoid colon portion only

  • Preserves descending colon

  • Manage mesentery carefully to avoid vasculature

  • Usually minimally invasive

  • Lowest risk of bowel habit changes

The goal is cancer removal with minimal impact on quality of life. But consequences vary depending on the location and extent of resection required for each patient's unique cancer.

For all resections, nearby lymph nodes are also removed (lymphadenectomy) and analyzed for cancer spread. The goal is to achieve negative margins and adequate lymph node resection. Minimally invasive/laparoscopic techniques can allow faster recovery when appropriate. The type of colectomy depends on the specific tumor location and stage.

Overview of right and left hemicolectomies:

Right Hemicolectomy

This procedure removes the cecum, ascending colon, and proximal part of the transverse colon. It is typically performed for cancer located in the cecum, ascending colon, or hepatic flexure.

During right hemicolectomy, the surgeon makes an incision in the abdomen to access the right colon. The blood vessels supplying the affected sections are ligated and the colon is mobilized. The ileocecal valve and portions of colon containing the tumor are resected. Nearby lymph nodes are also removed.

Finally, the remaining healthy transverse colon is connected to the ileum (ileotransverse anastomosis) to restore intestinal continuity. The anatomy is different after a right colectomy, which can lead to increased stool frequency.

Left Hemicolectomy

This procedure removes the descending colon and sigmoid colon. It is done for cancers in the left colon.

The surgeon accesses the left colon through an abdominal incision. After mobilization and ligation of the blood vessels, the descending and sigmoid colon are resected along with associated lymph nodes. The remaining transverse colon is then connected to the rectum or upper sigmoid (transverse-sigmoid or transverse-rectal anastomosis).

Since the left hemicolectomy preserves the right colon, including the ileocecal valve, the impact on bowel function is less than a right hemicolectomy. But resection of the sigmoid colon reservoir can still result in looser stools.

Overview of transverse colectomy:

A transverse colectomy involves surgically removing the transverse colon, which is the portion that crosses horizontally across the abdomen. This procedure may be done for tumors located in the transverse colon itself.

During a transverse colectomy, the surgeon makes an abdominal incision to access the transverse colon. The blood supply to the transverse colon is ligated and the colon mobilized. The transverse colon is then transected at both its right and left ends, allowing resection of the entire transverse portion.

The remaining ends of the right and left colon must then be connected (anastomosed) to restore bowel continuity. This can be done in either order:

  • Right hemicolon to left hemicolon anastomosis

  • Left hemicolon to right hemicolon anastomosis

Nearby lymph nodes associated with the transverse colon arterial supply are also removed and examined for any cancer spread.

Removing the entire transverse colon is a more challenging resection than a hemicolectomy. It can result in disrupted motility leading to abdominal pain, constipation or diarrhea. Patients may also experience malabsorption of nutrients like iron due to the shortened colon. Careful follow-up is needed to monitor for complications and adjust to new bowel patterns after transverse colectomy.

Overview of sigmoid colectomy (sigmoidectomy):

A sigmoid colectomy is the surgical removal of the sigmoid colon. The sigmoid colon is the S-shaped portion of the large intestine that connects the descending colon to the rectum.

This procedure is typically performed for cancers or polyps located within the sigmoid colon itself.

During a sigmoid colectomy, the surgeon makes an incision in the lower abdomen to access the sigmoid colon. The blood vessels supplying the sigmoid colon are ligated. The sigmoid colon is freed from its attachments and resected. Nearby lymph nodes are also removed.

The remaining descending colon is then connected to the rectum or upper sigmoid colon. This new anastomosis restores intestinal continuity.

Advantages of removing just the sigmoid colon include:

  • Less bowel resection than a full left hemicolectomy

  • May be done laparoscopically with faster recovery

  • Lowest risk of causing changes in bowel habits

Sigmoid colectomy preserves the descending and transverse colon. This maintains the ileocecal valve and length of the colon for absorption. Patients usually have relatively normal bowel function after sigmoid colon resection.

Overview of low anterior resection (LAR) for rectal cancer:

A low anterior resection is performed for upper to mid rectal cancers. The goal is to remove the cancerous portion of rectum while preserving anal sphincter function.

During an LAR, the surgeon accesses the rectum either transanally or via the abdomen. The upper rectum, distal sigmoid colon, and associated mesorectum are mobilized and then transected below the tumor. Nearby lymph nodes are also dissected.

The remaining colon is then connected to the rectal stump above the anus using an anastomosis technique. This preserves continued stool passage via the anus.

Sometimes a temporary diverting ileostomy is also created to allow the new anastomosis to heal before restorative flow.

Advantages of LAR include colon preservation and avoidance of permanent colostomy. Risks include anastomotic leak, stricture, impaired rectal function, and cancer recurrence if margins are involved.

Close follow-up is needed after LAR to monitor for recurrence and manage any changes in bowel habits, urgency, or incontinence that can occur after rectal resection. Radiation therapy may be recommended to lower local recurrence risk.

Overview of lymph node removal during colorectal cancer surgery:

In addition to removing the primary tumor, an important part of colorectal cancer surgery is resection of regional lymph nodes near the site of the tumor.

Lymph nodes are small immune tissue masses that drain fluid from tissues. Cancer can spread through lymph drainage pathways.

To determine if the cancer has moved beyond the bowel into the lymphatic system, the surgeon performs a systematic lymphadenectomy. This involves removing and analyzing the lymph nodes around the arteries that supply the section of colon with cancer.

For example, in a right colectomy for ascending colon cancer, the lymph nodes around the ileocolic, right colic, and middle colic arteries would be dissected.

The removed lymph nodes are sent to pathology to detect micrometastasis - small deposits of cancer cells that have spread to the node. Finding cancer in the lymph nodes means the tumor has grown beyond the colon itself.

The number of lymph nodes involved and presence of extracapsular extension affects staging and prognosis. More nodes involved indicates wider spread.

Adequate lymph node resection and analysis is a critical part of colorectal cancer surgery to understand the true extent of disease spread. This guides decisions about additional treatments like chemotherapy that may be indicated.

Surgery forms the foundation of todays treatment for most colorectal cancers. The specific type of resection performed depends on the location of the primary tumor within the colon or rectum. Early stage cancers can often be excised completely through limited surgeries like polypectomy, local excision, or segmental resections. More advanced disease requires lobectomies or total colectomies with lymph node dissection.

In all cases, the principles guiding colorectal cancer surgery are:

  • Achieving clear margins and adequate lymph node resection to accurately stage the disease

  • Removing all detectable cancer while preserving as much noninvolved bowel as possible

  • Maintaining sphincter function and avoiding permanent stoma when feasible

  • Allowing intestinal continuity to be restored

While surgery often offers the best chance at definitive treatment, colorectal cancer excision can still have major impacts on quality of life. Patients require close follow-up to monitor for recurrence and manage long-term effects on bowel, urinary, and sexual function. Continued advances in surgical techniques aim to optimize cancer control while minimizing morbidity.

Overview of abdominoperineal resection (APR) for low rectal cancer:

An abdominoperineal resection is an extensive surgery done for tumor located very low in the rectum, especially when the cancer is involving or close to the anal sphincter complex.

During an APR, the surgeon makes both an abdominal incision and a perineal incision. The rectum, anus, and distal sigmoid colon are completely resected through these two approaches. A permanent colostomy is created on the abdominal wall.

Specifically, the steps involve:

  • Accessing the abdomen and pelvis to mobilize the rectum, sigmoid colon and anus

  • Ligating the colon blood supply

  • Removing the entire rectum and anus through the perineal incision

  • Performing a lymph node dissection around the vessels

  • Bringing the remaining colon up as an end colostomy

This extensive surgery removes the rectum and anus entirely since the cancer is too low to allow preservation of anal function. Because the anus is gone, stool must exit through the abdominal colostomy permanently.

APR carries significant risks including perineal wound infection, abscess, bleeding, and impacts to quality of life from colostomy. But it is required for very low rectal adenocarcinomas not amenable to sphincter-preserving resection.

Overview of pelvic exenteration surgery:

A pelvic exenteration is an extensive, life-altering surgery that removes all organs of the pelvic cavity in cases where rectal cancer has advanced locally and spread to adjacent structures.

During a total pelvic exenteration:

  • The rectum, anus, distal colon are removed, as in an abdominoperineal resection

  • For women, the uterus, ovaries, and vagina are also removed

  • For men, the prostate and seminal vesicles are removed

  • For either gender, the bladder may be removed entirely (cystectomy) or partially resected

This extensive demolition surgery is only done when the cancer has infiltrated these other pelvic organs to a point where it is not possible to remove the rectal primary tumor without resection of the involved organs.

After recovery, patients require reconstruction of digestive and urinary tracts, as well as insertion of colostomy and urostomy pouches. There is major impact on quality of life.

Pelvic exenteration is used as a last resort when less extensive surgeries cannot clear this locally invasive rectal cancer. But even then, outcomes are poor due to high risk of complications and recurrence.

Chemotherapy Drugs for Colorectal Cancer:

(See our in-depth article on chemotherapies here)

5-Fluorouracil (5FU):

This is one of the most common chemotherapy drugs used to treat colorectal cancer. It interferes with the production of DNA and RNA, preventing the division and growth of cancer cells. It is often given alongside leucovorin to enhance the drug's effectiveness.

Bevacizumab (Avastin), Ramucirumab (Cyramza), and Aflibercept (Zaltrap):

This drug belongs to a class of drugs known as Platinum based compounds. It works by binding to the DNA in cancer cells, causing DNA damage and preventing cells from dividing. It is often used in combination with 5-FU and leucovorin in a regimen that is called FOLFOX.

Oxaliplatin (Eloxatin):

This drug belongs to a class of drugs known as Platinum based compounds. It works by binding to the DNA in cancer cells, causing DNA damage and preventing cells from dividing. It is often used in combination with 5-FU and leucovorin in a regimen that is called FOLFOX.

Capecitabine (Xeloda):

This is a pro-drug, since it is inactive when taken but converted into 5-fu by the body's own enzymes. It can be taken orally, making it more convenient for some patients. It also interferes with DNA and RNA production, leading to cell death.

Trifluidine and Tipiracil (Lonsurf):

This combination drug includes trifluridine, a nucleoside metabolic inhibitor that gets incorporated into DNA, causing DNA damage. It also contains tipiracil, which helps maintain higher levels of trifluridine in the bloodstream by inhibiting its breakdown. This drug is typically used for advanced colorectal cancer that has stopped responding to other treatments.

The choice of chemotherapy drug or combination often depends on the specific characteristics of the cancer, is the stage and the location, patient’s overall health and preferences and how well the cancer is expected to respond to the particular drug. Once again, side effects of each drug also need to be considered, and have a significant impact on the patient's quality of life.

Irinotecan (Camptosar):

This drug is a topoisomerase inhibitor, which works by interfering with the enzymes that help cancer cells divide and grow. It is often used when cancer has spread or if the cancer has recurred after the initial treatment. Topoisomerases are enzymes that help to relieve strain in the DNA helix during replication and transcription. This drug creates a temporary single-strand in the DNA to relieve this strain. It works by binding to the topoisomerase DNA complex, leading to the relegation of the DNA strand and results in double strand DNA damage that triggers cell death.

Regorafenib (Stivarga):

Regorafenib is a type of medication known as a multi-kinase inhibitor. It functions by blocking the activity of proteins known as kinases that play a key role in various cellular processes, including signaling pathways responsible for cell growth and division. By inhibiting these kinases, regorafenib can disrupt the growth and proliferation of cancer cells, and even induce their death. Regorafenib is primarily used for the treatment of metastatic colorectal cancer, specifically when other treatment options have been unsuccessful

Chemotherapy drugs for colorectal cancer

There are several chemotherapy drugs that might be used to treat colorectal cancer. This is a list of the more commonly used chemotherapy drugs:

Pembrolizumab (Keytruda) and Nivolumab (Opdivo)

Both of these drugs are known as immune checkpoint Inhibitors. They specifically Target a protein called pd-1 on the surface of immune cells. Normally, d-1 to another protein called pd- l1 which is often over Express in cancer cells. When pd-1 and pd- find, they create a checkpoint that helps cancer cells evade immune detection. These two drugs work by blocking the interaction between pd-1 - L1 allowing the immune system to recognize and attack cancer cells. These drugs are commonly used in patients with advanced colorectal cancer.

Bevacizumab (Avastin) , Ramucirumab (Cyramza) , and Aflibercept (Zaltrap)

These are immunotherapies that target vascular endothelial growth factor, that helps tumors form new blood vessels to get nutrients. This process is known as angiogenesis. By blocking this vegf growth factor, these drugs can starve the tumor of nutrients. Drugs are typically used in combination with chemotherapy for treatment of advanced colorectal cancer.

Ipilimumab (Yervoy)

This is another checkpoint inhibitor, it targets a different protein: Ctla-4. Ctla- protein on the surface of the immune cells that act as a break or checkpoint on the immune response. By blocking this protein, this drug can boost the immune response against cancer cells. Sometimes used in combination with nivolumab for treatment of metastatic colorectal cancers.

Which of these treatments is used can depend on a variety of factors, the specifics of the patient's cancer (such as its molecular characteristics or the presence of certain mutations), the patient's overall health, and how well the cancers are expected to respond to the particular therapy. Immunotherapy is an area that is rapidly developing with a great deal of research being engaged in.

Cittuximab (Erbitux) and Panitumumab (Vectibix)

These are monoclonal antibodies that target a protein on the surface of cancer cells called epidermal growth factor receptors. By binding to egfr, these drugs block the signal that tells cancer cells to grow and divide. These drugs are typically used in patients with advanced colorectal cancer whose tumors do not have mutations in the Kraf, Nras, or Bras genes, these tumors are more likely to respond to this type of therapy.

Choosing a treatment regimen for an individual patient involves a complex decision making the considers many factors. This process is usually guided by evidence from clinical trials, clinical guidelines, and the healthcare providers own clinical judgment. Your healthcare provider will take into consideration the potential side effects of the medication being considered for use and how that will play given your state of health.

Immunotherapies

Immunotherapies are treatments that use the body's own immune system to fight cancer. They are being increasingly used in the treatment of colorectal cancer and other cancers, often for patients whose cancer is Advanced or has metastasized. Here are some of the key immunotherapies used in treating colorectal cancer.

Anti-EGFR Drugs:

Epidermal growth factor receptor (EGFR) is a protein on the surface of cells that helps them grow and divide. Some colorectal cancers have too much EGFR, and drugs that target EGFR can be used to treat these cancers.

Cetuximab (Erbitux) and Panitumumab (Vectibix) are monoclonal antibodies (man-made versions of immune system proteins) that attach to EGFR and stop it from working. These drugs can be used in metastatic colorectal cancer that has specific mutations in the RAS gene.

Anti-angiogenesis Drugs:

These drugs work by stopping the process of angiogenesis, the formation of new blood vessels that tumors need to grow and spread.

Bevacizumab (Avastin) is a monoclonal antibody that targets a protein called vascular endothelial growth factor (VEGF). This protein helps cancers form new blood vessels (a process known as angiogenesis) to get nutrients they need to grow. By blocking VEGF, bevacizumab can "starve" the tumor.

Ramucirumab (Cyramza) is a monoclonal antibody that can be used in combination with chemotherapy for treatment of metastatic colorectal cancer that has progressed on first-line therapy. It blocks a protein called VEGFR-2 to prevent the tumor from forming new blood vessels.

Kinase Inhibitors:

Regorafenib (Stivarga) and Lenvatinib (Lenvima) are drugs known as kinase inhibitors. Kinases are proteins on or near the surface of cells that send important signals to the cell’s control center. By blocking these proteins, these drugs can stop cancer cells from growing. These drugs can be used if colorectal cancer is still growing despite treatment with other therapies.

Targeted therapies that may be used to treat colorectal cancer:

Side Effects of Targeted Therapy:

Because targeted therapy drugs work differently from standard chemotherapy drugs, they have different side effects. Common side effects can include:

  • Diarrhea

  • Skin problems (dry skin, rash, nail changes)

  • High blood pressure

  • Problems with wound healing

  • Tiredness

  • Loss of appetite or weight loss

Some targeted therapy drugs can cause more specific side effects. For instance, EGFR inhibitors can often lead to skin problems like an acne-like rash on the face and chest. Anti-angiogenesis drugs can sometimes lead to high blood pressure and kidney problems.

It's important to note that not all patients will experience all side effects, and patients can experience side effects to different degrees. Side effects can often be managed with the help of your healthcare team.

Precision Medicine

One important point to mention is the rise of precision medicine in treating cancers like colorectal cancer. Precision medicine (also known as personalized medicine) is an approach to patient care that allows doctors to select treatments most likely to help patients based on a genetic understanding of their disease. This could be selecting targeted therapies based on specific genes and proteins that are involved in the growth and development of the cancer.

As always, it's important to have detailed conversations with your healthcare team to understand your treatment options, including the possible side effects and how they can be managed.

Immunotherapy is a type of cancer treatment that helps your immune system fight cancer. It's a promising area of cancer treatment that has been successful in treating some types of cancer, including certain cases of colorectal cancer.

Two types of immunotherapy can be used in colorectal cancer:

Immune Checkpoint Inhibitors:

One of the main types of immunotherapy used in treating colorectal cancer is called immune checkpoint inhibitors. Our immune system cells have certain "checks" in place to prevent them from attacking our own body cells. These "checks" are proteins on immune cells called "checkpoints". Some cancer cells can hijack these checkpoints to avoid being attacked by the immune system. Immune checkpoint inhibitors work by targeting these checkpoints, blocking the cancer cells from using them, and enabling the immune cells to attack the cancer cells.

Two checkpoint inhibitors have been shown to be particularly effective in treating colorectal cancer:

  • Pembrolizumab (Keytruda): This drug targets the PD-1 checkpoint. It has been shown to be effective in treating colorectal cancers that are microsatellite instability-high (MSI-H) or mismatch repair deficient (dMMR). These cancers make up about 15% of colorectal cancers and have genetic characteristics that make them more susceptible to immunotherapy.

  • Nivolumab (Opdivo): This is another PD-1 inhibitor. It can be used alone or in combination with a CTLA-4 inhibitor called ipilimumab (Yervoy) for MSI-H/dMMR colorectal cancers that have grown or spread to other parts of the body.

Cancer Vaccines:

Another type of immunotherapy is a cancer vaccine that can help the immune system fight cancer. For example, the Sipuleucel-T (Provenge) vaccine has been used to treat prostate cancer. In the case of colorectal cancer, vaccines are generally considered experimental and are mostly available through clinical trials.

There are currently no vaccines approved specifically for colorectal cancer treatment.

Vaccines in Clinical Trials

  • GVAX: Engineered vaccine using patient's tumor cells combined with immune-stimulating bacterial components. Being tested in combination with checkpoint inhibitors.

  • CEA/MUC-1/Brachyury vaccines: Target specific tumor antigens. Designed to boost immune response against cancer cells expressing these antigens.

  • DCVAC: Uses activated dendritic cells loaded with tumor antigens to activate the immune system. Being studied in CRC after liver metastasis resection.

  • Personalized neoantigen vaccines: Uses next-generation sequencing of a patient's tumor DNA to predict tumor-specific neoantigens and create a customized vaccine. Very early phase testing.

Peptide/Protein Vaccines

  • Use short peptide sequences or full-length proteins from tumor-associated antigens like CEA, MUC-1, and Brachyury to elicit T cell responses when administered with an adjuvant.

  • Potential to induce robust CD8+ cytotoxic T lymphocyte responses against cancer cells expressing the target antigen.

  • Limitations include HLA restriction, short peptide half-life, and need for right adjuvant to boost immunogenicity.

DNA/RNA Vaccines

  • Directly introduce DNA or mRNA encoding tumor antigens into patient tissues. This causes in vivo expression and immune activation.

  • Simplicity of manufacture and administration benefits DNA/RNA vaccines.- Durability of response and optimal delivery methods remain challenges.

Vector-based Vaccines

  • Use viral vectors like poxviruses engineered to express tumor antigen genes. This causes antigen expression in patient cells to stimulate immune attack.

  • Viruses can generate strong CD8+ T cell responses. Their natural immunogenicity provides built-in adjuvant effect.

  • Safety concerns exist over possible reversion to virulence. Anti-vector immunity may also limit repeat dosing.

In summary, vaccine strategies for colorectal cancer remain in early clinical development. Most aim to boost immune recognition of tumor cells by targeting shared or personalized tumor antigens. Combining vaccines with checkpoint inhibitors to enhance efficacy is a promising direction.

Dendritic Cell Vaccines

  • Patient DCs loaded with tumor peptides, proteins, mRNA or fused to tumor cells can activate antigen-specific T cell immunity.

  • Natural DC biology allows both CD4+ and CD8+ T cell priming.

  • Complex ex vivo DC manipulation is often required. Optimization of antigen loading being explored.

Key Vaccine Approaches

Here are more details on the key vaccine approaches being explored for colorectal cancer:

Peptide/Protein vaccines

  • Injection site reactions - pain, swelling, redness

  • Flu-like symptoms - fever, chills, fatigue

  • Autoimmune reactions possible if vaccine elicits response against normal tissues

DNA/RNA vaccines

  • Injection site pain

  • Muscle damage with intramuscular delivery

  • Potential increased autoimmunity risk

  • Theoretical concern mRNA could integrate into genome

Vector-based vaccines

  • Flu-like symptoms

  • Injection site reactions

  • Allergic reactions to vaccine components

  • Low risk of actual viral infection from attenuated vectors

Overall, vaccines are designed to have reasonable safety profiles, especially compared to cytotoxic chemotherapy. Mild injection site reactions, flu-like symptoms, fatigue, and low-grade fevers are commonly reported. Autoimmunity and long-term safety will require ongoing monitoring. Combining vaccines with other immunotherapies may increase immune-related adverse events.

Dendritic cell vaccines

  • Low overall toxicity as uses patient's own cells

  • Autoimmunity risk if dendritic cells present normal antigens

  • Post-leukapheresis symptoms - fatigue, dizziness, nausea

Side Effects of Immunotherapy:

Here are some of the potential side effects associated with experimental colorectal cancer vaccine approaches:

Importance of Genetic Testing:

Here are some key points on the role of genetic testing in guiding immunotherapy decisions for colorectal cancer:

  • Genetic testing of the tumor can identify specific biomarkers that predict increased likelihood of response to immunotherapy.

  • The main markers are mismatch repair deficiency (dMMR) and microsatellite instability-high (MSI-H). These are found in about 5% of metastatic colorectal cancers.

  • dMMR/MSI-H tumors have very high mutation loads and express abundant neoantigens, making them more susceptible to immune checkpoint inhibitors.

  • Testing for dMMR is typically done first by immunohistochemistry for mismatch repair proteins MLH1, MSH2, MSH6, and PMS2. Absence of staining indicates dMMR.

  • MSI testing confirms this finding by identifying frequent insertions/deletions in repetitive DNA sequences from high mutation burden.

  • The FDA has approved two checkpoint inhibitor immunotherapies, pembrolizumab and nivolumab, specifically for dMMR/MSI-H metastatic colorectal cancers.

  • So genetic testing of the tumor at diagnosis of advanced or metastatic CRC is critical to identify this biomarker and guide potential immunotherapy use.

  • Genetic counseling may also be recommended to assess for Lynch syndrome which frequently underlies dMMR/MSI-H.

Upfront tumor genomic profiling, especially mismatch repair and microsatellite instability testing, plays a vital role in determining if immunotherapies are likely to benefit an individual colorectal cancer patient.

Deciding which treatment to use

Here is a generalized decision tree or process that your healthcare provider might follow. Do understand that the specifics of this will vary greatly from one patient to another:

Step 1: Diagnosis and staging

Your doctor will confirm the diagnosis of colorectal cancer and determine the stage of the disease. This typically involves procedures such as what we've talked about before, as in colonoscopy, biopsy and imaging studies.

Step 2: Assessment of the patient's characteristics and condition

Your healthcare provider will evaluate your overall health status, age and performance status and your ability to carry out daily activities), comorbid conditions and the potential for surgical intervention. They will also conduct laboratory test to ascertain organ function to make sure that you can deal with the treatment as best possible.

Step 3: Molecular testing

Your provider will likely perform molecular tests on the tumor sample to detect specific genetic mutations and biomarkers that could guide your therapy.

Step 4: Formulating a treatment plan

Based on the results of the above assessments, your healthcare provider will formulate a treatment plan. This might involve any one of the above treatments or a combination. This can include surgery, chemotherapy, radiation therapy, targeted therapy, or immunotherapy or a combination of these. This is where the choice of chemotherapy can come into play:

For localized colorectal cancer (Stage I-III) surgery is usually the first line of treatment, followed by adjuvant chemotherapy to kill any remaining cancer cells and reduce the risk of reoccurrence. At times, your surgeon will be quite confident in having gotten all the cancerous cells and may recommend forgoing chemotherapy.

For metastatic colorectal cancer (Stage IV), systemic therapy is typically used, include chemotherapy, therapy or immunotherapy.

Step 5. Monitor the response and adjust the treatment plan

Once the treatment has started, your responses will be monitored through imaging studies and often blood tests. The treatment plan might need to be adjusted based on the patient's response and any side effects that they are experiencing.

This decisions tree is a very simplified version of the actual decision-making says, which faceted and personalized for each patient. Furthermore this process may need to be revisited over time as the patient's situation changes.

When considering outcomes of colorectal cancer treatments, it is important to note that success rates can be measured in a number of ways: overall survival (how long patients live without their disease getting worse), and response rates (the percentage of patients whose tumors shrink or disappear after treatment). Success rates can also depend heavily on the stage of the disease, ones overall health as well as other factors. One would have to speak with their physician to get the more accurate likely outcomes for their particular case as all the factors that can be at play.

The side effects of chemotherapy depend on the type and dose of drugs given and the length of time they are used. These side effects can include:

  • Fatigue

  • Nausea and vomiting

  • Loss of appetite

  • Diarrhea

  • Mouth sores

  • Hair loss

  • An increased risk of infection (due to a lowered white blood cell count)

  • Easy bruising or bleeding (due to a decreased platelet count)

  • Anemia (from a shortage of red blood cells), which can cause fatigue, shortness of breath, and other symptoms

The side effects of oxaliplatin and other platinum drugs can include nerve damage (neuropathy). This can lead to symptoms like numbness, tingling, or even pain in the hands and feet. This often gets better over time, but it might not go away completely in some people.

Not everyone gets every side effect, and some people get few, if any. The severity of side effects (how bad they are) varies greatly from person to person. Be sure to talk to your cancer care team about which side effects are most common with your chemo, how long they might last, how bad they might get, and when you should call the doctors office about them.

Managing Side Effects

Your healthcare team can suggest ways to manage these side effects, such as prescribing medications to prevent or control nausea and vomiting, or suggesting dietary modifications to manage digestive issues. There are also many effective ways to prevent and manage other side effects like hair loss, mouth sores, and fatigue.

Also, remember that everyone is different and side effects vary from person to person. Some people may experience minimal side effects while others may find the side effects more challenging. Your healthcare team is your best source of information about your health and your treatment. Always consult with them for personalized advice and care.

Targeted therapies are drugs or other substances that block the growth and spread of cancer by interfering with specific molecules that are involved in the growth, progression, and spread of cancer. Unlike traditional chemotherapy drugs that act on all rapidly dividing cells, targeted therapies act on specific molecular targets that are associated with cancer.

Final Thoughts

Colorectal cancer remains one of the most common and deadly cancers, but education and awareness about the disease can truly make a difference in fighting it.

It starts with understanding the key risk factors, like age, family history, inflammatory diseases, smoking, obesity, and diet and lifestyle habits. Knowing your personal risk empowers you to get screened at the appropriate time. Catching precancerous polyps early via colonoscopy allows them to be removed before they ever become cancer.

Paying attention to concerning digestive symptoms is also critical, as early diagnosis leads to far better outcomes. Persistent changes in bowel habits, rectal bleeding, abdominal pain, fatigue and unintended weight loss should prompt a timely evaluation. Don't assume complaints will just go away.

If faced with a colorectal cancer diagnosis, take the time to understand your specific tumor characteristics, stage, and treatment options. Ask your oncology team thoughtful questions. Localized early stage disease can often be cured with surgery alone. More advanced cancers may require multi-modality approaches like chemotherapy, radiation, targeted therapies, or immunotherapy on top of surgery. Seeking a second opinion is perfectly acceptable.

Throughout treatment, listen to your body and speak up about side effects. Don't try to power through pain or discomfort alone. Your care team has tools to help manage symptoms and provide emotional support. After treatment, commit to regular follow-up visits for monitoring and surveillance.

Prevention is also key. Making positive lifestyle changes like eating a healthy plant-based diet, exercising regularly, maintaining a healthy weight, minimizing alcohol intake, and not smoking can all lower colorectal cancer risk.

Most importantly, remember you are not alone on this journey. Lean on family, friends, counselors, and cancer survivor communities for inspiration and hope. Arm yourself with information. Stay vigilant about your health. And never give up the fight against this disease.