Five years of endocrine therapy with an aromatase inhibitor (AI) is highly effective in reducing the risk of recurrence of hormone-receptor-positive breast cancer; however, the risk continues beyond the five years of treatment. Researchers analyzed the combined results of 12 clinical trials involving 24,912 postmenopausal women with estrogen-receptor-positive disease to determine if there is a benefit to taking endocrine therapy for more than five years. All of the women in the trials had at least five years of endocrine therapy; with either tamoxifen alone, tamoxifen followed by AI, or AI alone. The study authors compared the outcomes of patients who received five additional years of AI to those who received no further therapy. Overall, they found extended therapy resulted in a quarter reduction in local recurrence (in the breast), a modest reduction in distant recurrence, and a very modest reduction in breast cancer mortality. The study authors noted that the follow-up period needs to be extended to truly evaluate the effect of extended AI therapy on breast cancer mortality. The beneficial effect of extended AI therapy differed by the type of prior endocrine therapy received, with a larger benefit for women who took five years of prior tamoxifen. Importantly, the benefit of extended therapy was greater for patients with positive lymph nodes. In women with four or more positive nodes, there was a 7.7% absolute risk reduction in local or distant recurrence. Patients with negative lymph nodes had a marginal benefit of 1.1% risk reduction. Risk of bone fracture increased by approximately 25% with prolonged AI therapy. The meta-analysis did not assess additional side effects and impact of AIs on quality of life.
Highlights from the 2018 San Antonio Breast Cancer Symposium
By Anh Diep, VMD, PhD Candidate, and Erika Bell, PhD, Manager of Medical Information, Bay Area Cancer Connections
In early December 2018, thousands of researchers from across the world convened in San Antonio, Texas, for the 41st Annual San Antonio Breast Cancer Symposium. This five-day symposium brought together experts in basic, translational, and clinical research; clinicians; and patient advocates to present and discuss advances in breast cancer research and treatment. As progress in breast cancer continues, the challenges remain: to personalize treatment based on characteristics of the cancer, to minimize over- and under-treatment, and to maximize quality of life. This article highlights several of the talks from the 2018 symposium that are most likely to have a direct impact on the clinical care of breast cancer patients. For access to complete symposium resources, including abstracts, posters, and presentations, visit sabcs.org.