AGA Issues Best Practice Advice for Chemoprevention of CRC

For patients younger than 70 years of age at average risk of colorectal cancer (CRC), gastroenterologists should advise the use of low-dose aspirin for chemoprevention of neoplasia, the American Gastroenterological Association (AGA) advises in an expert review.

The review was developed to outline best practices in prescribing of medication to prevent colorectal neoplasia—specifically cancerous and precancerous lesions, including adenomas and sessile serrated lesions. It did not include advisory statements relating to high-risk patients, including those with inflammatory bowel disease, or dietary factors.

Patients with a life expectancy of at least 10 years; a 10-year cardiovascular disease risk of at least 10%; not at high risk for bleeding; and who are also under age 70 years and at average risk of CRC are good candidates for low-dose aspirin use to reduce the risk of mortality and neoplasia, according to the best practice statement. Aspirin is also advised for patients with a history of CRC.

Due to “the substantial risk of cardiovascular and gastrointestinal adverse events,” physicians are advised not to use nonsteroidal anti-inflammatory drugs (NSAIDS) other than aspirin.

For patients with type 2 diabetes, the best practice advises that clinicians consider using metformin to prevent colorectal neoplasia and to reduce mortality. However, the authors stated, “Among existing evidence gaps is the need for more robust trial data on metformin.”

They also noted that future studies may clarify the effect of vitamin D on the incidence of CRC and on mortality. Based on existing evidence, however, the best practice statements suggest that clinicians should not use calcium, vitamin D, folic acid, or stains to prevent colorectal neoplasia and in patients with a history of CRC, statins are not recommended to prevent mortality.

“The ideal chemopreventive agent should be inexpensive, effective, and safe when used on a population level. Few medications meet all these criteria,” the authors wrote. “There is strong evidence to support the use of aspirin for the chemoprevention of colorectal neoplasia for individuals who are younger, at risk for cardiovascular disease, and not at high risk for bleeding.”

The authors added, “Additional trials evaluating the combination of multiple medications should be pursued because they may uncover synergistic effects.”

—Rebecca Mashaw

Reference:

Liang PS, Shaukat A, Crockett SD. AGA clinical practice update on chemoprevention for colorectal neoplasia: expert review. Clin Gastroenterol Hepatol. 2021;19(7):1327–1336