diagnosis of colorectal cancer

Last edited 02/2020


Diagnosis of colorectal cancer in a patient may be made after the patient presents with symptoms or as a result of a screening programme (1).

  • less than 10% of patients with clinical features suspicious of symptomatic colorectal cancer are found to have colorectal cancer when reviewed in NHS outpatient clinics (1).
  • choice of diagnostic intervention depends on the co-morbidities (which may increase the risk of complications)

Several diagnostic investigations have been used to detect colorectal caner though the optimum diagnostic method is yet to be identified (1)

  • these interventions include - colonoscopy, barium enema/flexible sigmoidoscopy and CT colonography
  • all initial diagnostic investigations require rigorous bowel cleaning preparation (1)

With the aim of maximising the benefit of diagnostic intervention, the initial clinical consultation of patients with symptoms suspicious of colorectal cancer should include the following:

  • accurate recording of the nature and duration of symptoms
  • with the patient’s consent, thorough digital examination of the rectum and palpation of the abdomen
  • accurate recording of significant co-morbidities which may increase the risks arising from investigative procedures
  • explanation of the investigations which may be offered, including the morbidity, risks and benefits
  • discussion of the patient's preferences (2)

Molecular biomarkers to guide systemic anti-cancer therapy (3)

  • test for RAS and BRAF V600E mutations in all people with metastatic colorectal cancer suitable for systemic anti-cancer treatment