What is colorectal cancer?
Colorectal cancer is malignancy developing in the colon or rectum. It typically begins as small, non-cancerous growths called polyps, which can gradually turn into cancer over time.
What are the risk factors?
- Age: most cases occur in people over 50.
- Family history: increases risk significantly.
- Lifestyle: high red and processed meat consumption, obesity, smoking and heavy alcohol use.
- Medical conditions: inflammatory bowel disease and genetic syndromes such as Lynch syndrome or familial adenomatous polyposis.
What are the symptoms?
Early-stage colorectal cancer often has no symptoms at all, which is what makes regular screening essential.
When symptoms are present, they include:
- Changes in bowel habit lasting weeks.
- Rectal bleeding or blood in the stool.
- Persistent abdominal pain or cramping.
- Unexplained weight loss.
- Fatigue or weakness from anaemia.
How is it diagnosed?
- Colonoscopy: camera examination allowing polyp removal and biopsy.
- Biopsy: tissue analysis confirming the cancer.
- Imaging: CT, MRI or PET scans to assess extent.
- Blood tests, including carcinoembryonic antigen (CEA).
Guidelines recommend screening beginning at age 45, or earlier where risk factors are present.
What are the treatment options?
- Surgery: polypectomy, partial colectomy or abdominoperineal resection.
- Chemotherapy: before or after surgery in advanced stages.
- Radiation therapy: combined with chemotherapy for rectal cancers.
- Targeted therapy: drugs directed at cancer cells specifically.
- Immunotherapy: for certain genetic subtypes.
What is recovery like?
- Hospital stays typically last 3–7 days after surgery, with full recovery taking 4–6 weeks.
- Dietary adjustment beginning with soft or low-fibre foods is often necessary.
- Chemotherapy or radiation involves multiple sessions, with side effects that can include fatigue and nausea.
- Regular follow-up monitors for recurrence.
Can it be prevented?
- Regular colonoscopy, detecting and removing polyps.
- A diet emphasising whole grains, fruit, vegetables and lean protein.
- Maintaining a healthy weight.
- Regular exercise.
- Avoiding smoking and limiting alcohol.
What is the prognosis?
Early-stage cancers have a high survival rate, with up to 90% of patients surviving five years or more after treatment.
More on the colon and rectum
Related conditions handled by the same team.
This page is general information about a condition we treat. It is not a diagnosis and does not replace an in-person consultation. Bring your reports — they change the answer more than the symptoms do.