Colorectal Cancer

Colorectal cancer is a cancer that develops in the colon or rectum, usually starting as a small growth (polyp) that can, over years, become cancerous if not removed. Screening and early detection significantly improve outcomes.

• Change in bowel habits, such as new or worsening diarrhoea, constipation, or a change in stool consistency lasting more than a few weeks
• Blood in the stool, or blood mixed with stool rather than just on the surface
• Unexplained weight loss
• Abdominal pain or cramping
• Fatigue related to anaemia from chronic, unnoticed blood loss
• A feeling of incomplete emptying after a bowel movement

• Most colorectal cancers develop from a pre-cancerous polyp that grows slowly over years before becoming cancerous.
• Risk is increased by older age, a diet low in fibre and high in processed or red meat, obesity, smoking, excessive alcohol use, physical inactivity, and a family history of colorectal cancer or certain inherited conditions.
• Chronic inflammatory bowel conditions also increase risk over time.

• Suspected based on the symptoms above, particularly persistent change in bowel habit, rectal bleeding, or unexplained weight loss, especially in older adults.
• Colonoscopy is the key diagnostic test, allowing direct visualisation of the colon and rectum along with biopsy of any suspicious areas.
• Blood tests may show anaemia from chronic blood loss, and further imaging is used for staging if cancer is confirmed.

Surgical removal of the affected part of the colon or rectum is the main treatment for localised colorectal cancer and is often curative when the cancer is caught at an early stage.

Chemotherapy, and sometimes radiotherapy (particularly for rectal cancer), may be used alongside surgery depending on the stage and location of the cancer.

More advanced disease that has spread requires a combination of treatments coordinated at a specialised cancer centre, aimed at controlling the disease and relieving symptoms.

Regular follow-up after treatment monitors for recurrence.

Anyone with persistent change in bowel habit, rectal bleeding, or unexplained weight loss should be assessed promptly, as earlier-stage cancer has significantly better outcomes.

• Eat a diet high in fibre, fruits, and vegetables, and limit processed and red meat.
• Maintain a healthy weight and engage in regular physical activity.
• Avoid smoking and limit alcohol intake.
• Where colorectal cancer screening is available, attend according to recommended guidelines, particularly from age 45–50 or earlier with relevant risk factors.
• Seek prompt medical assessment for persistent changes in bowel habit or rectal bleeding rather than assuming it is due to piles or diet alone.