Oral Bisphosphonates and Risk of Cancer

Bisphosphonates are currently widely used in the treatment and prevention of osteoporosis, as well as in patients with cancer metastases to bone or multiple myeloma. With a 75 million people affected by osteoporosis in the US, Europe and Japan, this represents a significant population being treated with these medications [1]. The benefits conferred by bisphosphonates in terms of reduced mortality and morbidity as a result of fracture reduction are well known, as are some of the adverse side effects such as esophagitis and osteonecrosis of the jaw. However, following a recent report by the US Food and Drug Administration of esophageal cancer in bisphosphonate users, investigators have began looking at the relationship between the use of oral bisphosphonates and various cancers, especially cancers of the gastrointestinal tract, and have produced varying results [2]. A number of studies [3-5] as well as a meta-analysis [6] of all available studies to date showed a positive relationship with esophageal cancer, which is perhaps not entirely surprising considering the association of oral bisphosphonates with esophagitis. Perhaps less expected is the reduced risk of colorectal cancer and breast cancer associated with bisphosphonate use reported by several investigators. Considering, the wide use of bisphosphonates [7-10], the possibility of an association with cancer development, especially the potential for a protective effect is intriguing.