Purpose: To discuss trends in breast and prostate cancer prevalence and survival; risk factors for bone loss, osteoporosis, and fractures and the approach to risk assessment in patients with these malignancies; established and investigational drug therapies for managing cancer treatment-induced bone loss and osteoporosis; and the role of health-system pharmacists in promoting bone health in patients with breast or prostate cancer.
Summary: Breast cancer and prostate cancer are common, deadly diseases, but many survivors are alive today because of improvements in early detection and treatment over the past 10-15 years. Cancer chemotherapy, corticosteroids, hormone-ablation therapy, and other common risk factors place patients with breast or prostate cancer at high risk for bone loss, osteoporosis, and fractures. Most patients with breast or prostate cancer should undergo assessment of risk for bone loss and osteoporosis that involves a bone-related history and physical examination, dual-energy X-ray absorptiometry scanning, and the FRAX fracture risk assessment tool from the World Health Organization. A recent National Comprehensive Cancer Network task force report on bone health in cancer care provides recommendations for considering the use of pharmacologic therapy on the basis of the results of this assessment. Bisphosphonates are useful for slowing or preventing bone loss associated with hormone-ablation therapy in women with breast cancer and men with prostate cancer, although fracture data are limited in women and not available in men. The usefulness of other therapies (selective estrogen receptor modulators, teriparatide, calcitonin salmon, and estrogens) is limited by adverse effects, a lack of experience with the drugs in these patient populations, or both. Various drug therapies are in development for managing cancer treatment-induced bone loss and osteoporosis. The agent closest to approval by the Food and Drug Administration, denosumab, has been shown to improve bone mineral density in women and men receiving hormone-ablation therapy for breast or prostate cancer, but additional data are needed to dispel safety concerns that could limit the use of this drug in these patient populations. Health-system pharmacists play an important role in screening patients with a history of breast or prostate cancer for bone loss or osteoporosis, making drug therapy recommendations to address the problem, and counseling patients on modifiable risk factors for osteoporosis and proper use of drug therapies to improve bone health.
Conclusion: Health-system pharmacists can improve the detection and management of cancer treatment-induced bone loss and osteoporosis in patients receiving systemic therapy for breast or prostate cancer.