Breast Cancer Treatment (PDQ®): Treatment - Health Professional Information [NCI] - Stage IIIB, Inoperable IIIC, IV, Recurrent, and Metastatic Breast Cancer
Premenopausal women should undergo oophorectomy (surgically, with external-beam radiation therapy or with an LHRH agonist). Patients with lymphangitic pulmonary metastases, major liver involvement, and/or central nervous system involvement should not receive hormone therapy as a single modality. Patients with structural compromise of weight-bearing bones should be considered for surgical intervention and/or radiation in addition to systemic therapy. Patients with vertebral body involvement should be evaluated for impending cord compression even in the absence of neurologic symptoms. Increasing bone pain and increasing alkaline phosphatase within the first several weeks of hormone therapy does not necessarily imply disease progression. Patients with extensive bony disease are at risk for the development of symptomatic hypercalcemia early in the course of hormone therapy. Early failure (e.g., <6 months) on hormone therapy suggests that cytotoxic chemotherapy should be the next modality employed.
Endocrine therapy is recommended for patients with metastatic hormone receptor-positive (HR+) disease. However, patients inevitably develop resistance to endocrine therapy. Preclinical models and clinical studies suggest that mammalian target of rapamycin (mTOR) inhibitors might enhance the efficacy of endocrine therapies.
BOLERO-2 [NCT00863655], is a randomized, phase III, placebo-controlled trial, of randomly assigned patients with HR+ metastatic breast cancer resistant to nonsteroidal aromatase inhibition who received the mTOR inhibitor everolimus plus exemestane versus placebo plus exemestane.[Level of Evidence: 1iDiii]. At the interim analysis, median PFS was 6.9 months for everolimus plus exemestane and 2.8 months for placebo plus exemestane (HR, 0.43; 95% CI, 0.35-0.54; P < .001). The addition of everolimus to exemestane was more toxic with the most common grade 3 or 4 adverse events (AEs) being stomatitis (8% vs. 1%), anemia (6% vs. <1%), dyspnea (4% vs. 1%), hyperglycemia (4% vs. <1%), fatigue (4% vs. 1%), and pneumonitis (3% vs. 0%). The results of this study report a benefit in PFS with the addition of an mTOR inhibitor to endocrine therapy but there were more side effects. Final overall survival (OS) outcomes on this trial are awaited.