Review: Aspirin reduces colorectal cancer incidence and mortality in patients at average risk.

Questions In patients eligible for primary prevention of cardiovascular disease (CVD), does aspirin reduce risk for incident cancer and cancer mortality? In patients at average risk for colorectal cancer (CRC), does aspirin reduce risk for incident CRC and CRC mortality? Review scope Included studies compared oral aspirin (≥75 mg at least every other day) with placebo or no treatment for ≥1 year for any indication in adults ≥40 years of age. Total cancer : Studies that included chemopreventive or other thrombotic agents or patients with previous cancer or a high prevalence of familial cancer syndromes were excluded. Outcomes were cancer mortality and incidence.

CRC :

Studies of patients with previous CRC were excluded. Outcomes were CRC mortality and incident CRC. Review methods Total cancer : PubMed, MEDLINE, and Cochrane Central Register of Controlled Trials (2011 to Jan 2015), and reference lists of US Preventive Services Task Force (USPSTF) reviews and other reviews were searched for English-language, randomized, controlled trials (RCTs) and controlled clinical trials of fair or good quality from countries with a very high Human Development Index in 2013. 11 RCTs (mean age 47 to 65 y, 0 to 100% women) and 2 individual-patient data (IPD) meta-analyses of RCTs met the selection criteria.

CRC :

MEDLINE and Cochrane Central Register of Controlled Trials (2004 to Jan 2015), studies included in a 2007 USPSTF review, and reference lists were searched for RCTs published in English. Data were primarily from 3 IPD meta-analyses (<75% men). Main results Total cancer : Meta-analysis showed that aspirin did not reduce cancer mortality or incident cancer in CVD primary prevention trials (Table).

CRC :

Meta-analysis showed that aspirin reduced CRC mortality at a median 18 years and incident CRC at 10 to 19 years, but not at 0 to 12 years, in primary and secondary prevention trials (Table). Conclusions In patients eligible for primary prevention for cardiovascular disease, aspirin does not reduce risk for cancer mortality or incident cancer. In patients at average risk for colorectal cancer (CRC), aspirin reduces risk for CRC mortality and long-term incident CRC. Evidence-based guideline associated with this review: Bibbins-Domingo K; U.S. Preventive Services Task Force. Aspirin use for the primary prevention of cardiovascular disease and colorectal cancer: U.S. Preventive Services Task Force recommendation statement. Ann Intern Med. 2016;164:836-45. 27064677