Vitamin D in the Prevention of Aromatase Inhibitor–Induced Musculoskeletal Symptoms: Is It Ready for Practice?

© 2012 Harborside Press® B reast cancer is the most common malignancy in women. In 2012, approximately 226,870 new cases of breast cancer will be diagnosed in the United States (American Cancer Society, 2012). Depending on tumor characteristics and stage of disease, breast cancer treatment includes surgery, radiation therapy, chemotherapy, biologic therapy, and hormonal therapy. Aromatase inhibitors (AIs), one type of hormonal therapy, are indicated in the treatment of estrogen receptor– positive breast cancer in postmenopausal women (National Comprehensive Cancer Network, 2012). Although tamoxifen was traditionally used in the treatment of hormone receptor– positive breast cancer, the randomized controlled ATAC (Arimidex, Tamoxifen, Alone or in Combination) trial (N = 9,366) comparing tamoxifen with anastrozole (an AI) plus tamoxifen indicated that anastrozole reduced the risk of tumor recurrence in postmenopausal women with localized breast cancer by 40%. Unfortunately, the use of anastrozole and other AIs is associated with musculoskeletal symptoms, including an increased risk of bone fractures and musculoskeletal pain (Howell et al., 2005). Symptoms can affect both adherence and quality of life (Chlebowski, 2009). A recent study by Rastelli and colleagues (2011) suggests that vitamin D supplementation can decrease aromatase inhibitor–induced musculoskeletal symptoms (AIMSS). This article will discuss the problem of musculoskeletal symptoms with AI use, treatment strategies currently suggested in the literature, recent results of the vitamin D study by Rastelli and colleagues, and implications for advanced practitioners.