Colorectal Cancer

Colorectal cancer is cancer that starts in the colon (large intestine) or rectum (the last section before the anus). Together, the colon and rectum make up the large intestine, which absorbs water and forms solid waste. Most colorectal cancers begin as small, benign (non-cancerous) growths called polyps on the inner lining of the colon or rectum. Over several years, some polyps become cancerous. If not removed early, the cancer can grow through the bowel wall and spread to the lymph nodes and then to the liver, lungs, or other organs.

Colorectal cancer may cause no symptoms in early stages. See a doctor if you notice:

Colonoscopy is the gold-standard test — a flexible camera is passed into the colon to visualise polyps or tumours, and biopsies can be taken at the same time. Sigmoidoscopy examines only the lower colon and rectum. Stool tests (faecal occult blood test) detect hidden blood in the stool. Digital rectal examination (DRE) can detect rectal tumours. CT colonography (virtual colonoscopy) provides images of the entire colon. Blood tests including CEA (carcinoembryonic antigen) may help monitor treatment response, though they are not used alone for diagnosis.

Stage I: Cancer is in the inner layers of the colon wall only. Stage II: Cancer has grown through the bowel wall but has not spread to lymph nodes. Stage III: Cancer has spread to nearby lymph nodes but not to distant organs. Stage IV: Cancer has spread to distant organs — most commonly the liver or lungs. About 20% of patients in Ethiopia present with Stage IV disease (metastatic), underscoring the importance of earlier presentation.

According to NCCN Guidelines, treatment is determined by the stage and location of the cancer:

Risk-reducing strategies: eat a high-fibre diet rich in whole grains, vegetables, and legumes; limit red meat (especially processed meat) to no more than 2–3 times per week; maintain a healthy body weight; be physically active for at least 30 minutes on most days; avoid tobacco and limit alcohol. Screening: NCCN recommends that average-risk adults begin colorectal cancer screening at age 45 — earlier if there is a family history of colorectal cancer or polyps. Finding and removing polyps during colonoscopy prevents cancer.

Recovery from surgery may take 4–6 weeks. Patients with a colostomy will work with a stoma nurse to learn to manage the appliance — most patients adapt well and live full, active lives. A diet rich in fibre and fluids supports bowel health after surgery. Follow-up colonoscopy is recommended one year after surgery to check for recurrence or new polyps. CEA blood tests and CT scans are performed regularly during the first 3–5 years.