Colorectal cancers are common, and early detection improves prognosis. See separate article Colorectal Adenocarcinoma.

Why is early detection important?

Early detection is important because:

• Colorectal cancer is common and has significant mortality:
  • In the UK, bowel cancer is the second most common cause of cancer mortality.
  • Each year 34,900 people are diagnosed (about 1 per GP) - 63% in the colon and 37% in the rectum.
  • It causes 16,100 deaths per year.
  • The lifetime risk is about 5%.
• Early detection improves outcome.
• Early diagnosis may reduce morbidity.
• It is achievable and is cost-effective.

Early detection can be achieved by:

• Identifying those at risk. For example, the risk of colorectal cancer increases with age. 85% of cases occur in people aged over 60. 10% have a first-degree relative with the disease, and 6% have a genetic cause (e.g. familial adenomatous polyposis (FAP) and hereditary non-polyposis colon cancer (HNPCC)) and these patients tend to present at a younger age.¹
• Case recognition through clinical awareness of the disease, including knowledge of those at risk, clinical presentations and when and how to refer.
• Screening programmes. Screening involves a national screening programme for patients without symptoms, and normal population risk,² and targeted surveillance programmes for those who are at special risk (e.g. inflammatory bowel disease or a strong family history).³

National screening programme for the general population²

A national call and recall system has now been rolled out across the UK (a system of local hubs).

Patients are sent faecal occult blood (FOB) test kits, and local screening centres analyse samples, despatch results, provide endoscopy investigation services, specialist screening nurse clinics and, if necessary, referral to a local hospital multidisciplinary team (MDT) for people with abnormal results.

Men and women are screened every two years between the ages of 60 to 69. People aged over 70 can request a screening kit by calling the freephone helpline 0800 707 6060. Some English areas are extending the screening age to between 60 and 75, although full roll-out across the UK is still uncertain. Scotland screens all patients between 50 and 74 years,⁴ Wales between 60 and 71 years⁵ and Northern Ireland between 60 and 69 years.⁶

Results from the pilots indicate that on average 1.9% of tests are positive (rates are slighter higher as age increases, in men and in Scotland). Cancer was identified in 1.62 per 1,000 people screened; of these, 48% were Dukes' stage A, and only 1% were found to have metastasised at diagnosis. Of those with a positive initial test, 10.9% will have a cancer and 35% an adenoma. Results are now becoming available from individual screening hubs.⁷

In addition to the FOB test above, the NHS plans to offer an additional one-off flexible sigmoidoscopy screening to men and women aged 55-59. Full details of its implementation are not yet known.⁸

Identifying moderate-risk and high-risk patients

These are more targeted screening programmes and protocols which select out sectors of the population at particularly high risk of colorectal carcinoma.³ High-risk groups include patients with:

• Previous resection of a colorectal cancer - see separate Colorectal Adenocarcinoma article.
• Previous colorectal adenomatous polyps (see below).
• Inflammatory bowel disease (see below).
• Ureterosigmoidostomy - annual flexible sigmoidoscopy beginning 10 years after the original operation.
• Acromegaly - regular colonoscopic screening from age 40 years.
  • Patients with an adenoma at first screening or elevated IGF-1 level should be offered 3-yearly screening.
  • The remainder should be offered screening colonoscopy ever 5-10 years.
• Family history of colorectal cancer. Patients with a personal or close family history (first-degree relative) consistent with an autosomal dominant cancer syndrome or a characterised polyposis syndrome should be referred for assessment, genetic counselling and mutation analysis. High-risk patients are first-degree relatives (where the patient developed cancer aged <50). These genetic conditions are:³
  • Hereditary non-polyposis colon cancer (HNPCC, or Lynch's syndrome) - colonoscopy every two years from the age of 25 until the number of polyps make prophylactic colectomy advisable. Upper gastrointestinal (GI) endoscopy every two years from the age of 50.
  • Familial adenomatous polyposis (FAP) - usually requires prophylactic colectomy between the ages of 16 and 25 years. Upper GI endoscopy surveillance 3-yearly from the age of 30 years.
  • MUTYH-associated polyposis (MAP) - colonoscopy every 2-3 years from age 25, upper GI endoscopy every 3-5 years from age 30.
  • Juvenile polyposis - colonoscopy every 18-24 months from age 18 (or earlier if there are any symptoms) and upper GI endoscopy every 1-2 years from age 25.³
  • Peutz-Jeghers syndrome - 2-yearly colonoscopy and upper GI endoscopy from age 25.

First-degree relatives of patients who develop cancer aged <50 years are high-risk and will be screened as above unless they are shown not to have the appropriate mutation.

Patients with a moderate risk are generally offered screening, e.g. members of a family connected by first-degree kinship with three cases of colorectal cancer, aged >50, or two cases, with a mean age of <60 years, might be offered 5-yearly colonoscopy from age 50 to 75. Recommendations are pragmatic and complex - see the British Society of Gastroenterology (BSG) guideline.³

Colonoscopic surveillance for prevention of colorectal cancer in people with ulcerative colitis, Crohn's disease or adenomas⁹

Adenomas

• Low risk (one or two adenomas smaller than 10 mm):
  • Consider colonoscopy after five years.
• Intermediate risk (three or four adenomas smaller than 10 mm, or one or two adenomas if one is 10 mm or larger):
  • Offer colonoscopy after three years.
• High risk (five or more adenomas smaller than 10 mm or three or more adenomas if one is 10 mm or larger):
  • Offer colonoscopy after one year.

Inflammatory bowel disease

• Colonoscopic surveillance should be offered to people whose symptoms started 10 years ago and who have ulcerative colitis (but not proctitis alone) or Crohn's colitis involving more than one segment of colon.
• Offer a baseline colonoscopy with chromoscopy and targeted biopsy of any abnormal areas to determine the risk of developing colorectal cancer.
  • Low risk (left-sided ulcerative colitis or Crohn's colitis, or extensive but quiescent ulcerative colitis or extensive but quiescent Crohn's colitis):
    • Offer further colonoscopy with chromoscopy after five years.
  • Intermediate risk (extensive ulcerative or Crohn's colitis with mild active inflammation confirmed endoscopically or histologically, or post-inflammatory polyps, or family history of colorectal cancer in a first-degree relative aged 50 or over):
    • Offer further colonoscopy with chromoscopy after three years.
  • High risk (extensive ulcerative or Crohn's colitis with moderate or severe active inflammation confirmed endoscopically or histologically, or primary sclerosing cholangitis (including after liver transplant), or colonic stricture in the preceding five years, or any grade of dysplasia in the preceding five years, or family history of colorectal cancer in a first-degree relative aged under 50):
    • Offer further colonoscopy with chromoscopy after one year.

Document references

1. Bowel cancer statistics - UK, Cancer Research UK
2. Bowel Cancer Screening.; NHS; Bowel Cancer Screening Programme: Detail and progress from NHS website
3. Guidelines for colorectal cancer screening and surveillance in moderate and high risk groups, British Society of Gastroenterology (May 2010 update from 2002)
4. Scottish Bowel Cancer Screening Programme Website
5. Bowel Screening Wales Website
6. Bowel Screening in Northern Ireland Website
7. Gupta S, Saunders BP, Fraser C, et al; The first Three years of National Bowel Cancer Screening at a single UK Tertiary Colorectal Dis. 2011 Jan 25. doi: 10.1111/j.1463-1318.2011.02567.x. [abstract]
8. Flexible Sigmoidoscopy Bowel Cancer Screening
9. Colonoscopic surveillance for prevention of colorectal cancer in people with ulcerative colitis, Crohn's disease or adenomas, NICE Clinical Guideline (March 2011)

Internet and further reading

• Cunningham D, Atkin W, Lenz HJ, et al; Colorectal cancer. Lancet. 2010 Mar 20;375(9719):1030-47. [abstract]