As reported in The British Medical Journal (BMJ) by Lise M. Helsingen, MD, PhD, and colleagues, a clinical practice guideline on colorectal cancer screening published as a BMJ Rapid Recommendations guideline indicates that previously unscreened individuals aged 50 to 79 years old with 15-year colorectal cancer risk of ≥ 3% should undergo screening with fecal immunochemical test every 1 or 2 years, single sigmoidoscopy, or single colonoscopy.
Lise M. Helsingen, MD, PhD
BMJ Rapid Recommendations represent a collaborative effort between the MAGIC group and BMJ. The BMJ article provides a summary of the clinical practice guideline; the full version including decision aids can be found on the MAGICapp.
The guideline panel formulating the recommendations included patients, clinicians, content experts, and methodologists using the GRADE approach to assess quality of evidence. Linked systematic review of colorectal cancer screening trials and microsimulation modeling were conducted to ascertain 15-year screening benefits and harms, with the panel also reviewing practical issues and burdens of screening methods. The panel estimated the magnitude of benefit typical members of the population would value to opt for screening and used the benefit thresholds to inform the recommendations.
The panel considered screening options of fecal immunochemical test every year, fecal immunochemical test every 2 years, a single sigmoidoscopy, or a single colonoscopy over 15 years in adults aged 50 to 79 years old with no prior screening, no symptoms of colorectal cancer, and life-expectancy of 15 years or more. The recommendations do not apply to individuals with prior screening, history of polyps or colorectal cancer, inflammatory bowel disease, or hereditary syndromes that increase risk of colorectal cancer (eg, Lynch syndrome and familial adenomatous polyposis).
Overall, there was substantial uncertainty (low certainty evidence) regarding the 15-year benefits, burdens, and harms of screening.
For individuals with estimated 15-year colorectal cancer risk of < 3%, no screening is recommended (weak recommendation).
For individuals with estimated 15-year risk of ≥ 3%, screening with one of the four screening options is suggested: fecal immunochemical test every year, fecal immunochemical test every 2 years, a single sigmoidoscopy, or a single colonoscopy (weak recommendation).
Best estimates indicated that all four screening options resulted in similar colorectal cancer mortality reductions.
For effect on colorectal cancer incidence, fecal immunochemical test every 2 years may have little or no effect on incidence over 15 years; fecal immunochemical test every year, sigmoidoscopy, and colonoscopy may reduce cancer incidence, although the incidence reduction with fecal immunochemical test is small compared with sigmoidoscopy and colonoscopy.
Screening-related serious gastrointestinal and cardiovascular adverse events are rare.
The magnitude of the benefits of screening is dependent on the individual risk, whereas harms and burdens are less strongly associated with cancer risk.
The authors stated: “Based on benefits, harms, and burdens of screening, the panel inferred that most informed individuals with a 15-year risk of colorectal cancer of 3% or higher are likely to choose screening, and most individuals with a risk of below 3% are likely to decline screening. Given varying values and preferences, optimal care will require shared decision-making.”
Helsingen LM et al: BMJ. October 2, 2019 (early release online). ■