Low-Dose Aspirin Linked with Reduced Risk of Common Type of Breast Cancer

Taking an 81-mg dose of aspirin appears to be linked to a 20% reduction in risk of developing hormone-receptor positive, HER2 negative breast cancer. The finding comes from analysis of data from the California Teachers Study, a prospective study that enrolled 133,000 active and retired women educators in 1998. In 2005, more than 57,000 of these participants provided information on medications they used regularly. In this group, 1,457 women developed invasive breast cancer before 2013. The researchers found that developing breast cancer was inversely associated with taking three or more low-dose aspirin per week. This reduction was not seen with regular-dose aspirin or other nonsteroidal anti-inflammatory drugs. However, the study does not establish a causal relationship. A 20% reduction in risk is considered a moderate reduction. 

Clarke CA, Conchola AJ, Neuhausen SL, et al.: Regular and low-dose aspirin, other non-steroidal anti-inflammatory medications and prospective risk of HER2-defined breast cancer: the California Teachers Study. Breast Cancer Res. 2017; 19:52.