Calcium and vitamin D supplements do not prevent loss of bone mineral density in women undergoing therapy for breast cancer

Abstract

Women with breast cancer (BC) are at an increased risk of osteoporosis due to accelerated bone loss caused by BC therapies. Since calcium &/or vitamin D (Ca±D) are frequently recommended for osteoporosis prevention & management to women undergoing BC therapy, we examined the effects of Ca±D supplements in preventing bone loss in these women. We reviewed guidelines for Ca±D supplementation in women with BC & conducted a systematic review of Ca±D supplementation trials in maintaining skeletal health in women with BC. We used the “before‐after” data from the comparison groups of trials that evaluated the effect of drugs such as bisphosphonates on bone mineral density (BMD) in which Ca±D were used as the comparison group. The effect of Ca±D supplements on BMD in women with BC undergoing BC therapy has not been tested against an unsupplemented control group. However, results from 15 trials of “before‐after” comparison indicate that supplements of 500 – 1500 mg calcium & 200 – 1000 IU vitamin D were inadequate to prevent loss of BMD in women with BC. Mean loss of BMD at the lumbar spine in pre‐ & postmenopausal women was −5.6% & −2.3%. Additionally, other evidence indicates that both BC therapies & calcium supplements may increase the risk of cardiovascular disease. Because cardiovascular disease is the main cause of mortality in women with BC, future trials should evaluate the safety & efficacy of Ca±D supplementation in these women.Grant Funding Source: Dr. Datta is supported by the Comprehensive Cancer Center of Wake Forest University Cancer Control Traineeship – NCI/NIH Grant# #R25CA122061