Decreased risk of breast cancer associated with oral bisphosphonate therapy

Abstract

Preclinical studies and adjuvant trials using bisphosphonates have found them to have an antitumor effect. Although major advances have been made in chemoprevention strategies with selective estrogen receptor modulators and aromatase inhibitors, their use has been fraught with significant adverse effects such as venous thromboembolic events and an increased risk for endometrial cancer. In this context, several recent observational studies have investigated a chemoprevention role for oral bisphosphonates in decreasing risk for breast cancer. This review will aim to summarize these studies and present a critical evaluation of the association between oral bisphosphonate use and breast cancer risk reduction.

Keywords: alendronate; chemoprophylaxis; incidence; risk reduction; zoledronate.

Figure 1

Potential confounding role of low bone mineral density in the relationship between bisphosphonate use and breast cancer incidence. Notes: Low bone mineral density could result in bisphosphonate use. It is also known that low bone mineral density is associated with a decreased incidence of breast cancer. Therefore, the relationship between bisphosphonate use and breast cancer risk could be influenced by confounding with low bone mineral density.