At the 2014 American Society of Clinical Oncology® meeting in Chicago, researchers reported that women with early stage hormone receptor-negative (HR-negative) breast cancer who were treated with Zoladex® (goserelin) had a reduced rate of ovarian failure at 2 years. In addition, the Zoladex group had higher rates of patients becoming pregnant, patients giving birth, and patients with one or more deliveries (or still pregnant).
HR-negative breast cancer is a type of breast cancer that does not respond to hormonal therapy, treatment that lowers the amount of estrogen in the body or blocks its action. A problem associated with the chemotherapy used to treat HR-negative breast cancer is ovarian failure (loss of function before the age of 40).
In this study conducted with multiple research groups, premenopausal women with early stage HR-negative breast cancer were enrolled and treated with a regimen of cyclophosphamide-containing chemotherapy. Patients were then randomized to take either additional Zoladex or just chemotherapy alone.
Researchers reported that at two years only 8% of the Zoladex patients encountered ovarian failure as compared to 22% in the chemotherapy-alone group. Other fertility measures improved as well, including pregnancies (21% versus 11%), births (15% versus 7%), and patients with one or more deliveries or still pregnant (18% versus 9%).
In addition, the Zoladex group showed better 2-year disease-free survival and overall survival rates (89% versus 78% and 92% versus 82%, respectively). The authors of the paper, however, did not present a hypothesis as to why the survival rates might have improved with the Zoladex.
Reference: Moore et al. Phase III trial (Prevention of Early Menopause Study [POEMS]-SWOG S0230) of LHRH analog during chemotherapy to reduce ovarian failure in early-stage, hormone receptor-negative breast cancer: An international intergroup trial of SWOG, IBCSG, ECOG, and CALGB. ASCO 2014; Abstract LBA505.