Low-dose Aspirin and Cancer Mortality: A Meta-analysis of Randomized Trials
American Journal of Medicine, 05/25/2012
Mills EJ et al. – Nonvascular deaths, including cancer deaths, are reduced with low–dose aspirin. Methods The authors conducted a comprehensive search of 10 electronic databases up to December 2011. The authors conducted a meta–analysis using data from all randomized clinical trials evaluating low–dose (75–325 mg) daily aspirin. The authors extracted data on non–cardiovascular disease mortality and cancer mortality. The authors e pooled studies using a random–effects model and conducted a meta–regression. The authors supplemented this with a cumulative meta–analysis and trial sequential monitoring analysis. Results
Twenty–three randomized studies reported on nonvascular death. There were 944 nonvascular deaths of 41,398 (2.28%) patients receiving low–dose aspirin and 1074 nonvascular deaths of 41,470 (2.58%) patients not receiving aspirin therapy. The relative risk of nonvascular death was 0.88 (95% confidence interval [CI], 0.81–0.96, I2 = 0%). Eleven trials included data evaluating cancer mortality involving 16,066 patients. There were 162 of 7998 (2.02%) and 210 of 8068 (2.60%) cancer deaths among low–dose aspirin users versus non–aspirin users, respectively, reported over an average follow–up of 2.8 years. The relative risk of cancer mortality was 0.77 (95% CI, 0.63–0.95, I2 = 0%). Studies demonstrated a significant treatment effect after approximately 4 years of follow–up. The optimal information size analysis showed that a sufficient number of patients had been randomized to provide convincing evidence of a preventive role of low–dose aspirin in nonvascular deaths.