Colorectal Cancer
Colorectal cancer refers to cancers that begin in the colon or rectum, which together make up the large intestine, the final part of the digestive tract. Most colorectal cancers start as small, noncancerous (benign) clumps of cells called polyps that form on the inner lining of the colon or rectum. Over time, some of these polyps can develop into cancer. Colorectal cancer is the third most commonly diagnosed cancer worldwide, but with early screening and detection, it is highly treatable and often preventable. Regular screenings can identify and remove precancerous polyps before they develop into cancer, making colorectal cancer one of the most preventable types of cancer.
Causes
- Age - Risk increases significantly after age 50, with most cases diagnosed in people over 65, though incidence in younger adults is rising.
- Personal history of polyps - Having adenomatous polyps, especially large ones or multiple polyps, increases risk of developing colorectal cancer.
- Inflammatory bowel disease - Chronic inflammatory conditions such as Crohn's disease or ulcerative colitis increase risk, particularly with longer duration and greater extent of colon involvement.
- Inherited syndromes - Genetic conditions such as familial adenomatous polyposis (FAP) and Lynch syndrome (hereditary non-polyposis colorectal cancer) significantly increase lifetime risk.
- Family history - Having a first-degree relative (parent, sibling, child) with colorectal cancer increases risk, especially if they were diagnosed before age 60.
- Lifestyle factors - Sedentary lifestyle, low-fiber and high-fat diet, obesity, smoking, and moderate to heavy alcohol consumption all contribute to increased risk.
- Diabetes - People with type 2 diabetes have an increased risk of colorectal cancer and a less favorable prognosis after diagnosis.
- Radiation therapy - Previous radiation therapy directed at the abdomen to treat previous cancers increases the risk of colorectal cancer.
- Race and ethnicity - African Americans have the highest colorectal cancer incidence and mortality rates of all racial groups in the US.
- Microbiome imbalance - Emerging research suggests that imbalances in gut bacteria may contribute to colorectal cancer development.
Signs and Symptoms
- Change in bowel habits - Persistent diarrhea, constipation, or narrowing of the stool that lasts for more than a few days
- Rectal bleeding - Bright red blood in stool or dark, tarry stools
- Persistent abdominal discomfort - Cramps, gas, pain, or feeling that the bowel doesn't empty completely
- Weakness or fatigue - Can be caused by bleeding from the cancer leading to anemia
- Unexplained weight loss - Losing weight without trying
- Feeling that bowel doesn't empty completely - Sensation after bowel movements
- Iron deficiency anemia - Due to chronic blood loss from the tumor
- Pelvic pain - Particularly in rectal cancer
- Change in stool caliber - "Pencil-thin" stools
- Nausea or vomiting - When cancer causes a bowel obstruction
- Many people with early colorectal cancer have no symptoms, which is why screening is crucial
Diagnosis
Colonoscopy
The gold standard for diagnosing colorectal cancer, this procedure allows visualization of the entire colon and rectum using a flexible tube with a camera. During colonoscopy, suspicious areas can be biopsied, and polyps can be removed entirely. It requires bowel preparation beforehand to clean the colon.
Sigmoidoscopy
Similar to colonoscopy but examines only the rectum and lower (sigmoid) colon. It requires less bowel preparation but misses potential issues in the upper colon. If abnormalities are found, a full colonoscopy is typically recommended.
Stool-Based Tests
These include fecal immunochemical tests (FIT) and stool DNA tests that check for hidden blood or altered DNA in stool that might indicate cancer or large polyps. These are less invasive screening options, but positive results require follow-up with colonoscopy.
Imaging Tests
CT colonography (virtual colonoscopy) uses CT scanning to create detailed images of the colon. Barium enema with X-ray can also visualize the colon outline. If suspicious areas are found with these methods, conventional colonoscopy is needed for biopsy or polyp removal.
Biopsy and Pathology
Tissue samples from suspicious areas are examined under a microscope to confirm cancer diagnosis, determine cancer type, and check for specific genetic mutations that may guide treatment. This definitive diagnosis is typically obtained during colonoscopy.
Staging Tests
Once cancer is diagnosed, additional tests help determine its stage (extent of spread). These may include CT scans of the chest, abdomen, and pelvis; MRI, particularly for rectal cancer; PET scan to check for distant spread; and blood tests for tumor markers like CEA (carcinoembryonic antigen).
Treatment Options
Surgery
The primary treatment for most colorectal cancers. For early-stage cancers, minimally invasive approaches (laparoscopic or robotic surgery) may be used. Procedures range from polypectomy (polyp removal during colonoscopy) for very early cancers, to partial colectomy (removing the affected section of colon), to more extensive surgeries for advanced disease. Rectal cancer may require special approaches to preserve sphincter function. Temporary or permanent colostomy (external bag for stool) may be necessary in some cases.
Radiation Therapy
Uses high-energy rays to kill cancer cells. More commonly used for rectal cancer than colon cancer, often in combination with chemotherapy (chemoradiation). May be given before surgery (neoadjuvant) to shrink tumors and make them easier to remove, or after surgery (adjuvant) to kill remaining cancer cells. Advanced techniques like intensity-modulated radiation therapy (IMRT) target the tumor while minimizing damage to surrounding healthy tissue.
Chemotherapy
Anti-cancer drugs that kill rapidly dividing cells throughout the body. May be given before surgery (neoadjuvant), after surgery (adjuvant), or as the main treatment for metastatic disease. Common regimens include FOLFOX (5-FU, leucovorin, and oxaliplatin), FOLFIRI (5-FU, leucovorin, and irinotecan), and CAPOX (capecitabine and oxaliplatin). Side effects can include nausea, hair loss, fatigue, and increased risk of infection.
Targeted Therapy and Immunotherapy
Newer treatments that target specific abnormalities in cancer cells or help the immune system fight cancer. Targeted therapies include anti-angiogenic drugs (bevacizumab) that block tumor blood vessel formation, EGFR inhibitors (cetuximab, panitumumab) for certain gene-normal tumors, and BRAF inhibitors for tumors with BRAF mutations. Immunotherapy drugs like pembrolizumab or nivolumab may be used for metastatic colorectal cancers with specific genetic features (MSI-high or dMMR).
Home Remedies
Nutrition During Treatment
Focus on easily digestible, nutrient-rich foods. Small, frequent meals may be better tolerated than large ones. Stay hydrated and consider liquid nutritional supplements if eating is difficult. Avoid spicy, greasy, or gas-producing foods if they cause discomfort. Work with a dietitian who specializes in oncology nutrition for personalized advice.
Physical Activity
Gentle exercise can help manage fatigue, maintain strength, and improve mood during treatment. Walking, swimming, or light yoga are good options. Start slowly and gradually increase activity as tolerated. Always consult your healthcare team before beginning an exercise program during cancer treatment.
Stoma Care
If you have a temporary or permanent colostomy or ileostomy, proper care is essential. Keep the skin around the stoma clean and dry, change the appliance regularly, and watch for signs of irritation or infection. Ostomy nurses can provide invaluable guidance on managing your specific type of stoma.
Bowel Management
Treatment may affect bowel function. For diarrhea, maintain hydration, eat low-fiber foods temporarily, and use prescribed anti-diarrheal medications as directed. For constipation, gradually increase fiber intake, stay hydrated, and use stool softeners if recommended. Keep a food diary to identify foods that worsen symptoms.
Stress Reduction
Techniques such as deep breathing, meditation, guided imagery, or progressive muscle relaxation can help manage the emotional impact of diagnosis and treatment. Support groups, either in-person or online, provide connection with others who understand your experience. Professional counseling may also be beneficial.
Preventive Care
- Follow recommended screening guidelines for colorectal cancer, typically starting at age 45 for average-risk individuals.
- Maintain a healthy weight through balanced nutrition and regular physical activity.
- Eat a diet rich in fruits, vegetables, and whole grains while limiting red meat and processed meats.
- Stay physically active with at least 150 minutes of moderate exercise per week.
- Limit alcohol consumption to no more than one drink daily for women and two for men.
- Avoid tobacco in all forms, as smoking increases risk of many cancers including colorectal.
- Know your family history and discuss earlier or more frequent screening with your doctor if you have affected relatives.
- Consider genetic counseling if you have a strong family history or if relatives had colorectal cancer at a young age.
- Take aspirin daily only if recommended by your doctor, as it may reduce risk but also has potential side effects.
- Manage other health conditions like diabetes and inflammatory bowel disease with proper medical care.
- Recognize and promptly report potential symptoms like changes in bowel habits or rectal bleeding.
Surgical Options
Polypectomy and Local Excision
For very early-stage colorectal cancers or precancerous polyps, removal during colonoscopy may be sufficient. Techniques include snare polypectomy (using a wire loop to remove polyps), endoscopic mucosal resection (removing larger areas of the innermost lining), and transanal excision (removing rectal tumors through the anus without an abdominal incision).
Learn More About This ProcedureColectomy
Surgical removal of all or part of the colon containing the cancer, along with nearby lymph nodes. Types include right hemicolectomy, left hemicolectomy, sigmoid colectomy, or transverse colectomy, depending on tumor location. The remaining healthy sections are reconnected to maintain normal bowel function. Can be performed through traditional open surgery or minimally invasive approaches (laparoscopic or robotic).
Learn More About This ProcedureLow Anterior Resection
For rectal cancer, this procedure removes the affected portion of the rectum along with surrounding tissue and lymph nodes. The remaining rectum is typically reconnected to the colon to preserve normal bowel function. For very low rectal tumors, special techniques may be used to create a new reservoir (J-pouch) to improve bowel function.
Learn More About This ProcedureAbdominoperineal Resection (APR)
For cancers very low in the rectum that cannot be removed while preserving the anal sphincter, this procedure removes the rectum, anus, and surrounding tissues. A permanent colostomy is created, where the end of the remaining colon is brought through the abdominal wall to form a stoma (opening) for waste elimination into an external bag.
Learn More About This ProcedureSurgery for Metastatic Disease
When colorectal cancer has spread to other organs, surgical removal of metastases may be beneficial in selected cases. This is most common for liver metastases, where partial hepatectomy (liver resection) or ablation techniques may be used. Lung metastases may also be surgically removed in some cases. These procedures are typically part of a comprehensive treatment plan that includes systemic therapies.
Learn More About This ProcedureSchedule a Consultation
If you're experiencing symptoms of colorectal cancer, our expert team is here to help you find the right treatment approach for your specific needs.