Use of Aspirin postdiagnosis improves survival for colon cancer patients

BACKGROUND: The preventive role of non-steroid anti-inflammatory drugs (NSAIDs) and aspirin, in particular, on colorectal cancer is well established. More recently, it has been suggested that aspirin may also have a therapeutic role. Aim of the present observational population-based study was to assess the therapeutic effect on overall survival of aspirin/NSAIDs as adjuvant treatment used after the diagnosis of colorectal cancer patients. METHODS: Data concerning prescriptions were obtained from PHARMO record linkage systems and all patients diagnosed with colorectal cancer (1998-2007) were selected from the Eindhoven Cancer Registry (population-based cancer registry). Aspirin/NSAID use was classified as none, prediagnosis and postdiagnosis and only postdiagnosis. Patients were defined as non-user of aspirin/NSAIDs from the date of diagnosis of the colorectal cancer to the date of first use of aspirin or NSAIDs and user from first use to the end of follow-up. Poisson regression was performed with user status as time-varying exposure. RESULTS: In total, 1176 (26%) patients were non-users, 2086 (47%) were prediagnosis and postdiagnosis users and 1219 (27%) were only postdiagnosis users (total n = 4481). Compared with non-users, a survival gain was observed for aspirin users; the adjusted rate ratio (RR) was 0.77 (95% confidence interval (CI) 0.63-0.95; P = 0.015). Stratified for colon and rectal, the survival gain was only present in colon cancer (adjusted RR 0.65 (95% CI 0.50-0.84; P = 0.001)). For frequent users survival gain was larger (adjusted RR = 0.61 (95% CI 0.46-0.81; P = 0.001). In rectal cancer, aspirin use was not associated with survival (adjusted RR 1.10 (95% CI 0.79-1.54; P = 0.6). The NSAIDs use was associated with decreased survival (adjusted RR 1.93 (95% CI 1.70-2.20; P < 0.001). CONCLUSION: Aspirin use initiated or continued after diagnosis of colon cancer is associated with a lower risk of overall mortality. These findings strongly support initiation of a placebo-controlled trial that investigates the role of aspirin as adjuvant treatment in colon cancer patients. British Journal of Cancer (2012) 106, 1564-1570. doi:10.1038/bjc.2012.101 www.bjcancer.com Published online 27 March 2012 (C) 2012 Cancer Research UK