Bowel cancer

Bowel cancer is a general term for cancer that develops in the large bowel, which includes the colon and rectum. It can be further classified as colon cancer or rectal cancer, depending on where the cancer originates.

 

Function of the large bowel

Your digestive system consists of the oesophagus, stomach, duodenum, small bowel, and large bowel.

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• The colon (first six feet of the large bowel) absorbs water from bowel contents to form solid stools

• The rectum (last six inches of the large bowel) stores stool until it is expelled as a bowel movement

 

Bowel cancer develops when cells lining the inside of the bowel become cancerous (also known as malignant cells). Cancer in the colon or rectum is referred to as bowel cancer or colorectal cancer.

 

What causes bowel cancer?

Bowel cancer often starts from pre-cancerous growths called polyps. While most polyps are non-cancerous, some may develop into cancer if left untreated.

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Although the exact cause of bowel cancer is unknown, several risk factors can increase your chances of developing the disease:

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• Age – Most cases occur in people over 50 years old

• Diet – A diet high in fat, red or processed meat and low in fruit and vegetables increases risk

• Lifestyle – An inactive lifestyle and being overweight contribute to bowel cancer risk

• Family history – If a first-degree relative (parent, sibling, or child) has had bowel, breast, or ovarian cancer, your risk increases. Regular bowel cancer screening should be considered

• Previous cancer diagnosis – If you have had ovarian cancer, breast cancer, or colon polyps, you may be at a higher risk

• Inflammatory bowel disease – Conditions like ulcerative colitis or Crohn’s disease increase the risk

 

Symptoms of bowel cancer

Early detection is key to better treatment outcomes. Common symptoms of bowel cancer include:

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• Changes in bowel habit, such as diarrhoea or constipation

• Blood in the stools, which may appear bright red or very dark

• A feeling of incomplete emptying after a bowel movement

• Abdominal pain, bloating, or discomfort

• Loss of appetite

• Fatigue and breathlessness, which may be due to anaemia

• Unexplained weight loss

 

Unfortunately, many bowel cancers do not cause symptoms until they are advanced, making regular screening crucial.

 

How is bowel cancer investigated?

If you have symptoms of bowel cancer, your doctor may recommend:

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• Clinical examination of the abdomen and rectum

• Flexible sigmoidoscopy to examine the rectum and lower colon

• Colonoscopy to assess the entire colon and rectum

• CT scan or CT colonography (virtual colonoscopy) to get detailed images of the bowel

 

If an abnormality is found, a biopsy may be taken. A histopathologist will examine the sample to confirm whether cancer is present.

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If bowel cancer is diagnosed, further tests (such as CT scans, MRI scans, PET scans, or endoscopic ultrasound) may be required to determine the stage of the cancer and whether it has spread.

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Bowel cancer treatment

Once diagnosed, specialists including colorectal surgeons, radiologists, histopathologists, and oncologists will review your case and determine the best treatment approach.

 

How is bowel cancer staged?

Bowel cancer is staged using the TNM (Tumour, Node, Metastasis) system, which assesses:

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• How deep the cancer has spread within the bowel

• Whether it has spread to lymph nodes

• If it has spread to other parts of the body, such as the liver or lungs

 

Treatment options for bowel cancer

The main treatment for bowel cancer is surgery, often combined with chemotherapy or radiotherapy, depending on the stage of the cancer.

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• Surgery – Involves removing the affected section of the bowel and surrounding lymph nodes

• Chemotherapy or radiotherapy – Used before or after surgery to shrink the tumour or reduce the risk of recurrence

• Early-stage cancer – If detected early, a small tumour may be treated with surgical excision alone

 

Specialist bowel cancer surgery

At the Rapid Access Bowel Clinic, we offer advanced colorectal surgery for bowel cancer, including:

 

• Right hemicolectomy

• Extended right hemicolectomy 

• Left hemicolectomy 

• Sigmoid colectomy 

• Anterior resection 

• Hartmann’s procedure 

• Abdomino-perineal excision of the rectum (APER) 

• Pan-proctocolectomy