Bisphosphonates may protect against breast cancer

Investigators searched the medical literature through June 2011 for studies of the association between bisphosphonate use and breast cancer risk that included, or allowed the calculation of, relative risks (RRs) and 95% confidence intervals (CIs). Four studies were ultimately used for data extraction and synthesis. Risk was evaluated for any use of bisphosphonates and per 1-year increase in bisphosphonate use compared with nonusers.

The publications were 2 cohort studies and 2 retrospective case-control studies from 2010 and 2011 that included a total of 15,363 breast cancer patients and 84,931 bisphosphonate users. Among the 3 studies that listed the relevant medications, alendronate was the most common bisphosphonate (52% to 90%).

Bisphosphonates therefore appear to reduce risk of any breast cancer diagnosis and, in particular, risk of invasive tumors. The authors acknowledge the limitations of meta-analyses and state that randomized controlled trials are needed before bisphosphonates can be prescribed for prevention of breast cancer.

Liu Y, Zhao S, Chen W, et al. Bisphosphonate use and the risk of breast cancer: a meta-analysis of published literature. Clin Breast Cancer. 2012;12(4):276-281.