Low-dose aspirin promotes secondary prevention of adenomas
In a Cochrane review evaluating the effects of aspirin on CRA, pooled data from 3 RCTs with a total of 1839 subjects (1322 with a history of CRA and 517 with a history of CRC) showed that aspirin in a daily dose of 81 mg is effective for secondary prevention of sporadic CRA over a 1- to 3-year follow-up period (RR=0.77; 95% CI, 0.61-0.96; number needed to treat=12.5). The outcome measured in these 3 trials was an intermediate clinical finding, CRA, and not the more relevant end point of CRC.3
Recommendations
The USPSTF recommends against routine use of aspirin and nonsteroidal anti-inflammatory drugs to prevent colorectal cancer in people at average risk (grade D recommendation: ineffective or harm outweighs benefits).4
The American Gastroenterological Association (AGA) doesn’t recommend aspirin for primary CRC prevention, but acknowledges a possible role in secondary prevention. Aspirin should be considered for patients with a personal history of CRC, advanced CRA, or a strong family history but no history of peptic ulcer disease or hemorrhagic stroke. The AGA notes that 1 in 100 people taking aspirin for 2 years will develop significant GI bleeding.5