Colorectal Cancer Screening Guidelines Are Primarily Based on Low-Moderate-Quality Evidence

Background: Owning to colorectal cancer's (CRC) high mortality, multiple societies developed screening guidelines.

Aims: We aimed to assess the overall quality of CRC screening guidelines.

Methods: A systematic search was performed to review CRC screening guidelines for conflicts of interest (COI), recommendation quality and strength, external document review, use of patient representative, and recommendation age-as per Institute of Medicine (IOM) standards. In addition, recommendations were compared between guidelines/societies. Statistical analysis was conducted using R.

Results: Twelve manuscripts were included in final analysis. Not all guidelines reported on COI, provided a grading method, underwent external review, or included patient representation. 14.5%, 34.2%, and 51.3% of recommendations were based on high-, moderate-, and low-quality evidence, respectively. 27.8%, 54.6%, and 17.5% of recommendations were strong, weak/conditional, and did not provide a strength, respectively. The proportion of high-quality evidence and strong recommendations did not significantly differ across societies, nor were significant associations between publication year and evidence quality seen (P = 0.4).

Conclusions: While the majority of the CRC guidelines contain aspects of the standards set forth by the IOM, there is an overall lack of adherence. As over 85% of recommendations are based on low-moderate quality evidence, further studies on CRC screening are warranted to improve the overall quality of evidence.