Adverse Event Management of mTOR Inhibitors During Treatment of Hormone Receptor–Positive Advanced Breast Cancer: Considerations for Oncologists

Breast cancer (BC) is diagnosed in nearly 1 in 3 women with cancer in the United States; one third of these patients have regional lymph node metastases at the time of diagnosis. The 5-year survival rate of patients with metastatic BC is very low, and approximately 40,000 women were expected to die of the disease in 2013. About 75% of patients with BC have hormone receptor–positive (HR+) disease, which is often managed with endocrine therapy; however, most patients eventually have resistance to these therapies. Recently, the mammalian target of rapamycin (mTOR) inhibitor everolimus, in combination with exemestane, improved progression-free survival (PFS) of patients with advanced BC, leading to its approval by the US Food and Drug Administration. Because adverse events (AEs) associated with everolimus might differ from AEs that oncologists who treat patients with BC are more familiar with, everolimus AEs and their effective management are reviewed in this article. Possible dose adjustments of everolimus for patients with renal or hepatic impairment and strategies for minimizing potential interactions of everolimus with other drugs and food are also discussed.