Colorectal Cancer

Understanding Colorectal Cancer

Colorectal cancer is cancer that begins in the large intestine — the colon — or in the rectum, the final section of the bowel. It usually starts as a small, non-cancerous growth on the inner lining called a polyp. Over time, some polyps undergo changes and become cancerous.

Because this process is often slow, removing polyps before they turn cancerous can prevent the disease altogether. When cancer does develop, catching it while it is still confined to the bowel wall makes treatment far more effective. This is why screening — even when you feel completely well — is so valuable.

Symptoms

• A lasting change in bowel habit — diarrhoea, constipation or narrower stools
• Blood in the stool, or bleeding from the back passage
• A feeling that the bowel does not empty completely
• Persistent abdominal cramps, bloating or discomfort
• Unexplained weight loss and loss of appetite
• Tiredness or weakness from low blood count (anaemia)

Causes & risk factors

• Age over 50, though cases in younger adults are rising
• A personal or family history of colorectal cancer or polyps
• Long-standing inflammatory bowel disease (ulcerative colitis or Crohn's)
• A diet high in red or processed meat and low in fibre
• Smoking, heavy alcohol use and physical inactivity
• Being overweight or having type 2 diabetes
• Certain inherited genetic conditions (such as Lynch syndrome)

Possible complications

• Bowel obstruction if a tumour blocks the passage of stool
• Bleeding leading to anaemia and weakness
• A hole (perforation) in the bowel wall, which is a surgical emergency
• Spread of cancer to nearby lymph nodes, the liver or the lungs

How it is diagnosed

The most reliable way to diagnose colorectal cancer is colonoscopy — a thin, flexible camera that examines the entire large bowel and allows the doctor to take a small tissue sample (biopsy) or remove polyps at the same time. Simple stool tests can flag hidden blood and prompt further investigation. If cancer is confirmed, CT or MRI scans are used to check the exact location and whether it has spread, so that treatment can be planned precisely.

Treatment options

Treatment is tailored to the type, position and stage of the cancer, and is usually planned by a team of specialists. Very early cancers within a polyp can sometimes be cured by removing the polyp alone during colonoscopy. Most colorectal cancers, however, are best treated by surgery to remove the affected segment of bowel, sometimes combined with chemotherapy or radiotherapy to improve the chance of long-term cure.

Surgical treatment

Surgery is the cornerstone of curative treatment. The affected part of the colon or rectum is removed along with nearby lymph nodes, and the healthy ends of the bowel are re-joined so that normal function is restored wherever possible. Dr. Sujan Shrestha performs colorectal cancer surgery using minimally invasive (laparoscopic) and surgeon-powered robotic techniques where suitable, which allow precise removal of the tumour through small incisions.

Compared with traditional open surgery, the keyhole approach generally means less pain, smaller scars, a shorter hospital stay and a faster return to normal life — while maintaining the same cancer-clearance goals.

Recovery & aftercare

Recovery depends on the extent of surgery and the individual, but minimally invasive techniques often shorten hospital stay and speed the return to eating and walking. Most patients gradually resume normal activity over a few weeks. After treatment, regular follow-up — including scans, blood tests and colonoscopy — helps confirm that you stay well and catches any change early.

When to see a doctor

See a doctor if you notice a persistent change in bowel habit, blood in your stool, unexplained weight loss or ongoing tiredness. These symptoms are often caused by harmless conditions, but they should always be checked. If you are over 50 or have a family history, ask about screening even when you feel completely well — early detection saves lives.