PIK3CA mutation, aspirin use after diagnosis, and colorectal cancer survival: A systematic review and meta-analysis of epidemiological studies.

e12594 Background: Regular aspirin (ASA) use has been associated with inhibition of the whole spectrum of colorectal carcinogenesis, including prevention of metastases and reduced total mortality in colorectal cancer (CRC). Preclinical data have demonstrated that ASA down-regulates PI3K signaling activity through COX2 inhibition leading to the hypothesis that the effect of ASA might be different according to PIK3CA mutational status, but epidemiological studies have led to conflicting results. We performed a systematic review and meta-analysis to evaluate the interaction between PIK3CA status and efficacy of post-diagnosis ASA use. Methods: We searched PubMed, ISI Web Science, Embase and Cochrane library electronic databases to identify studies that compared the efficacy of post-diagnosis ASA in CRC patients identified by PIK3CA status. Log HRs for OS were meta-analyzed according to PIK3CA status by inverse variance weighting. A pooled test for treatment by PIK3CA status interaction was performed by weigh...