Colorectal Cancer

December 2, 2022
by Hannah Farrell, co-authored by Mr Abhiram Sharma (Consultant Colorectal Surgeon)

The lower gastrointestinal tract is comprised of the ascending colon, transverse colon, descending colon, caecum, rectum, and anus. It functions to extract water from our faeces, before facilitating the excretion from the body.

Colorectal cancer is the fourth most common cancer diagnosed in the United Kingdom. The earlier colorectal cancer is diagnosed, the more favourable the outcome. Therefore, it is vital that the symptoms of colorectal cancer are recognised and investigated in a timely manner.

What are the signs and symptoms of colorectal cancer?
The most common signs and symptoms of colorectal cancer include:

  • Blood in the stool (occult bleeding)
  • Persistent change in bowel habit
  • Iron-deficiency anaemia
  • Persistent lower abdominal pain, bloating, or discomfort
  • Unexplained weight loss
  • Abdominal mass

How is colorectal cancer diagnosed?

All patients suspected of colorectal cancer should be referred to secondary care on a two-week cancer pathway. Upon referral, the individual should undergo a colonoscopy or a virtual CT colonoscopy with a biopsy of any suspicious lesions sent for histology.

Upon diagnosis, the individual should undergo a contrast-enhanced CT scan of chest, abdomen and pelvis in order to stage the disease and an MRI scan should be performed in patients with rectal cancer.
The Duke’s staging classification or TNM classification is used to identify how advanced the disease is i.e., size/depth of tumour, whether it has spread to lymph nodes, whether there are metastases. The cancer can also be graded to indicate how differentiated (abnormal) the cancerous cells are. Both staging and grading will be used to decide how best to treat the patient.

How is colorectal cancer treated?

Treatment options include:

  • Curative surgical resection
  • Symptom-alleviating surgery
  • Radiotherapy
  • Chemotherapy

What are the risk factors for colorectal cancer?

  • Family history of colorectal neoplasia
    • Lynch syndrome (HNPCC) – genetic condition whereby an individual is predisposed to various cancers, including colorectal cancer. Unlike other hereditary predisposition to colorectal cancer, this syndrome is not associated with bowel polyps.
    • Familial adenomatous polyposis (FAP) – genetic condition whereby there is a large number of polyps lining the bowel.
    • MUTYH-associated polyposis – a genetic condition where individuals are prone to developing multiple adenomatous colon polyps that are susceptible to becoming cancerous.
    • Other unrecognised familial predisposition to Colorectal cancer
  • Previous history of colorectal cancer
  • Inflammatory bowel disease i.e., Crohn’s disease or ulcerative colitis
  • Unhealthy lifestyle: obesity, smoking, high alcohol intake.
  • Type 2 diabetes

Types of colorectal cancer

  • Adenocarcinoma: the majority of colorectal cancers, starting in the mucus-producing gland cells in the lining of the bowel wall.
  • Squamous cell: cancer starting in the cells comprising the bowel lining.
  • Carcinoid: a neuroendocrine tumour that grows in hormone-producing tissue.
  • Sarcoma
  • Melanoma: presenting as anal cancer.

Colorectal cancer screening
In the UK, everyone between the ages 60 to 74 are offered colorectal cancer screening every two years. This is a simple, non-invasive test which can be performed at home, whereby a stool sample is collected and sent off to the laboratory; this test is known as a faecal immunochemical test (FIT). At the laboratory, the stool sample is tested for occult (hidden) blood. Blood in the stool is an indicator of cancer or polyps, which can become cancerous. Should blood be detected, the individual will be invited for a colonoscopy whereby a tube is passed into the bowel and used to observe for signs of cancer.

Our expert witnesses in colorectal surgery specialise in the care of individuals who suffer from colorectal cancer. If you are concerned about bowel cancer and how it may affect you, we would recommend you contacting your GP.