Screening

Screening recommendations for average-risk patients

In the US, guidelines for screening of average-risk men and women aged 45 years and older for colorectal cancer (CRC) and adenomatous polyps emphasise the prevention of CRC through the detection of pre-malignant polyps.[1][46][47]​ Average-risk men and women are defined as those without a personal or family history of colorectal neoplasia (CRC or neoplastic colorectal polyps) and without clinical features of CRC.[46][48]​ Screening for such individuals should start at the age of 45 years.[48]​ For individuals aged >75 years, screening decisions should be individualised, taking into account risks, benefits, screening history, and comorbidities.[48]​ The American Gastroenterological Association (AGA) is clear that a national approach to CRC screening including both colonoscopy and non-invasive tests would reduce the burden of disease and improve disease mortality.[49] Similar guidelines have been generated for Asia.[50]

The US Multi-Society Task Force on Colorectal Cancer (MSTF) recommends colonoscopy or faecal immunochemical testing (FIT) as the tests of choice to screen average-risk patients for CRC.[1] The sensitivity of colonoscopy is 89% to 95% for adenomas ≥10 mm, and 75% to 93% for adenomas ≥6 mm. FIT has a pooled sensitivity of 74% and pooled specificity of 94% to detect CRC compared with colonoscopy.[51]​ The National Institute for Health and Care Excellence (NICE) recommends offering FIT in primary care settings to detect people likely to have CRC, so as to prioritise them for referral to secondary care.[52] If FIT value is ≥10 micrograms haemoglobin/g of faeces, urgent referral to secondary care is recommended. Based on FIT results, investigations such as colonoscopy can be avoided in people who are less likely to have CRC, thus making the resources available to those who need them the most.[52]​ FIT has been found to be superior to guaiac-based faecal occult blood tests in detecting advanced neoplasia and colorectal cancer in average risk individuals.[53]

If colonoscopy or FIT are unsuitable or declined, MSTF recommends second-line screening tests of computed tomography colonography, flexible sigmoidoscopy, or FIT-faecal DNA testing.[1] However, the US National Comprehensive Cancer Network (NCCN) guidelines comment that the choice of screening modality should be individualised, taking into account patient preference and resource availability.[47]

Public Health England recommends that bowel cancer screening is offered every 2 years to men and women from ages 60 to 74 years using the home faecal immunochemical test kit provided by the National Health Service (NHS). People older than 74 years can request a screening test if they wish to continue to be screened. Anyone with an abnormal screening test result should be offered a colonoscopy.[54]

Screening recommendations for high-risk patients

The US MSTF on CRC recommends screening colonoscopy for patients with:[1]

  • Two or more first-degree relatives with CRC diagnosed at any age, or

  • A single first-degree relative with colon cancer or adenomatous polyps diagnosed when the patient was younger than 60 years.

The AGA advises using colonoscopy as the screening strategy for individuals at increased CRC risk.[48]​ Colonoscopy should begin at 40 years of age, or 10 years younger than the earliest diagnosis in the family, whichever comes first, and should be repeated every 5 years.[1][47][48]​ People with a single first-degree relative diagnosed at or over 60 years of age should be offered average-risk screening options, beginning at 40 years of age.[1]

UK guidelines recommend that screening starts at 50 years of age (55 years for lower-risk individuals) in patients with a family history of CRC in a first-degree relative.

Use of this content is subject to our disclaimer