Association of regular aspirin use and breast cancer risk

Of the limited number of epidemiological investigations on aspirin ( and other nonsteroidal anti-inflammatory drugs) and breast cancer, the majority observe a protective role, yet only a few report dose-response effects for frequency or duration of use. We studied aspirin use among 1,478 breast cancer patients diagnosed from 1982 to 1998, and 3,383 cancer-free hospital controls at the Roswell Park Cancer Institute. Adjusted odds ratios (ORs) and 95% confidence intervals (CIs) were estimated using unconditional logistic regression. Compared to never use, both regular ( 6 1 tablet per week for 6 1 year) and occasional use were inversely associated with breast cancer ( adjusted OR = 0.84, 95% CI 0.64 - 0.97; adjusted OR = 0.80, 95% CI 0.67 - 0.96, respectively). Among regular users, an inverse trend was found for number of tablets consumed per week ( 1, 2 - 6, or 6 7) with corresponding ORs of 0.95, 0.80, and 0.74 ( P trend = 0.01). Daily use spanning 10 or more years was associated with a more pronounced reduction in risk ( P trend = 0.005). Our findings corroborate the growing body of observational evidence that regular aspirin use may be associated with reduced risk of breast cancer. Copyright (C) 2005 S. Karger AG, Basel.