Elderly patients with hormone-sensitive breast cancer (HSBC): Are they receiving optimal treatment?

Abstract

20638 Background: Breast cancer incidence, prevalence, and mortality increase with age. About 50% of women with breast cancer are older than 65, yet this population is often underrepresented in clinical trials. This study explores the benefits of adjuvant hormone treatment of breast cancer, including selective estrogen receptor modulators (SERMs) and aromatase inhibitors (AIs), in older women. Methods: Trials evaluating tamoxifen (TAM) and AIs in postmenopausal women with HSBC were reviewed to examine their effects on elderly women (EBCTCG, ATAC, BIG 1–98, IES, MA.17, etc). Results: The EBCTCG analysis showed a similar reduction in recurrence risk with adjuvant TAM therapy for younger (<40 y) and older (≥70 y) women, but many older women discontinue TAM due to tolerability issues. Also, SSRIs are being prescribed more frequently to treat depression in elderly patients, and the concomitant use of SSRIs with TAM decreases TAM efficacy. In clinical trials comparing AIs and TAM (BIG-1, ATAC, IES), AIs were superior to TAM in patients of all ages. In the BIG 1–98 study, letrozole (LET) provided a 21% reduction in the risk of recurrence in patients >65 years old (n=2867) that reached statistical significance (HR=0.79; P=0.02). LET showed a significant benefit regardless of age in the extended adjuvant setting following 5 years of TAM in the MA.17 trial, and disease-free survival (DFS) and distant DFS were significantly improved in all patients receiving LET vs placebo. Conclusions: Many elderly women with HSBC may not receive optimal therapy. TAM offers less protection against relapse than the AIs and has diminished efficacy in women taking SSRIs. The AIs appear superior to SERMs in terms of DFS and safety for women of all ages and should be the adjuvant hormone treatment of choice in older women. Author Disclosure Employment or Leadership Consultant or Advisory Role Stock Ownership Honoraria Research Expert Testimony Other Remuneration Amgen, Novartis, Ortho, Pfizer, sanofi-aventis, Speaker Bureau