Colorectal cancer
Also called: Bowel cancer, Colon cancer, Rectal cancer
Cancer of the large bowel, usually developing slowly from a benign polyp over 10 years or more. Screening finds and removes polyps before they turn cancerous.
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The third most common cancer worldwide (about 1.9 million cases a year).
What happens in the body
Stepwise mutations (APC, KRAS, TP53) turn normal lining into an adenoma and then an invasive adenocarcinoma.
Causes
- Accumulated genetic mutations in colonic cells
Risk factors
- Age over 50 (rising in younger adults)
- Family history; Lynch syndrome and familial adenomatous polyposis
- Red and processed meat
- Low fibre
- Obesity and inactivity
- Smoking and alcohol
- Inflammatory bowel disease
Symptoms
- Change in bowel habit
- Blood in stools
- Abdominal pain or lump
- Unexplained weight loss
- Iron-deficiency anaemia and tiredness
Diagnosis — tests and examinations
- Faecal immunochemical test (FIT)
- Colonoscopy with biopsy
- CT colonography
- CT chest/abdomen/pelvis and MRI (rectal) for staging
- CEA tumour marker
Treatment
Medicines and medical treatment
- Chemotherapy (FOLFOX, CAPOX) after surgery for node-positive disease
- Targeted therapy (bevacizumab, cetuximab/panitumumab for RAS wild-type)
- Immunotherapy for mismatch-repair-deficient tumours
- Radiotherapy/chemoradiotherapy for rectal cancer
Operations and procedures
- Polyp removal at colonoscopy
- Surgical resection (hemicolectomy, anterior resection, total mesorectal excision)
- Stoma where needed
- Resection of liver or lung metastases in selected patients
Self-care, home remedies and lifestyle
- Attend screening
- High-fibre diet, less processed meat
- Physical activity
Possible complications
- Bowel obstruction or perforation
- Spread to liver, lungs and peritoneum
Prevention
- Screening from 45–50 (FIT or colonoscopy)
- Healthy diet, exercise, not smoking, moderate alcohol
- Surveillance for high-risk families
Outlook
Over 90% five-year survival when found early; screening saves lives.
When to see a doctor
See a doctor for blood in stools, a change in bowel habit lasting weeks, weight loss or anaemia.
Sources and further reading
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