Physicians should screen for colorectal cancer in average-risk adults who do not have symptoms between the ages of 50 and 75, the American College of Physicians (ACP) states in a new evidence-based guidance statement published in Annals of Internal Medicine. In ‘Screening for Colorectal Cancer in Asymptomatic Average Risk Adults’, ACP reviewed guidelines from the American College of Radiology, the Canadian Task Force on Preventive Health Care, the US Preventive Services Task Force, the American Cancer Society, the Scottish Intercollegiate Guidelines Network and US Multi-Society Task Force on Colorectal Cancer.
The frequency of screening depends upon the screening approach selected. ACP suggests any one of the following screening strategies:
- Faecal immunochemical test (FIT) or high sensitivity guaiac-based faecal occult blood test (gFOBT) every two years
- Colonoscopy every ten years
- Flexible sigmoidoscopy every ten years plus FIT every two years
"Not enough people in the United States get screened for colorectal cancer," said ACP President, Dr Robert M McLean. "Physicians should perform an individualized risk assessment for colorectal cancer in all adults. Doctors and patients should select the screening test based on a discussion of the benefits, harms, costs, availability, frequency, and patient preferences."
ACP's guidance statement is for adults at average risk for colorectal cancer who do not have symptoms. It does not apply to adults with a family history of colorectal cancer, a long-standing history of inflammatory bowel disease, genetic syndromes such as familial cancerous polyps, a personal history of previous colorectal cancer or benign polyps, or other risk factors.
Although the median age for colorectal cancer diagnosis is 67 years, and individuals aged 65 to 75 years derive the most direct benefit from colorectal cancer screening, screening in adults ages 50 to 75 also has benefit, ACP found.
All colorectal cancer-screening tests - like all tests and procedures - have both potential benefits and potential harms. The harms and burdens vary by person and screening strategy. Harms may include bleeding, perforation, cardiopulmonary complications, and radiation exposure.
The age to start and stop screening, screening intervals, and the recommended screening test differ among organisations, who often have different criteria for evaluating or assessing the quality and certainty of evidence, follow different processes for creating clinical recommendations, and can interpret the evidence differently.
Rather than developing a new clinical practice guideline in such circumstances ACP instead prepares and releases guidance statements that rely on evidence presented or referenced in selected guidelines and accompanying evidence reports. ACP guidance statements do not include new reviews or searches of the literature outside the body of evidence referenced by the reviewed guidelines.
"Several organizations offer evidence-based guidelines for CRC [colorectal cancer] screening, but recommendations sometimes differ,” write Dr Michael Pignone, in an accompanying editorial. “The evidence that supports the various guidelines, including randomised controlled trials that document reductions in CRC mortality with screening, also supports ACP's guidance."
ACP is member of the Guidelines International Network, whose mission is to lead, strengthen, and support collaboration in guideline development, Cochrane, a global leader and resource in evidence-informed health decision-making, has officially recognised ACP as a Cochrane US Network Affiliate. To receive such a designation, Affiliates must show a proven record of supporting evidence-based practice and expertise and competencies in systematic reviewing and evidenced-informed health practice and policy.