Clin Breast Cancer

Background: Young, premenopausal women with breast cancer often experience more aggressive disease biology and poorer survival than older women. Diagnostic and therapeutic advances, including human epidermal growth factor receptor-2 (HER2)-directed therapy, may lessen treatment burden and improve survival for these young women, but contemporary incidence and survival data by HER2 status are limited. Patients and Methods: We identified women aged 20–49 years (n=68,530) diagnosed with stage I-III breast cancer during 2010–2016 from the United States Surveillance, Epidemiology and End Results 18 registries database. Age-adjusted, average annual percentage changes in incidence (diagnosis 2010–2016) and five-year Kaplan-Meier survival curves (diagnosis 2010–2015) were estimated by HER2 and hormone receptor (HR) status and stratified independently by cancer stage and race/ethnicity. Results: With increasing age decade, proportions of HER2−/HR+ cancer increased, whereas proportions of HER2+/HR+, HER2+/HR−, and HER2−/HR− decreased. The greatest increases in incidence during 2010–2016 were observed for HER2+ among women 20–49 and HER2−/HR− among women 20–29. Incidence decreased for HER2−/HR− among women 40–49. Five-year survival was lowest for HER2−/HR− status compared to other receptor-based subtypes among women 20–49. HER2+ status was more beneficial for five-year survival than HR+ status among women 20–29, with the opposite observed among women 30–49, particularly those 40–49. Conclusions: HER2+ breast cancer increased among premenopausal women and was also associated with higher early survival within each HR status. HER2−/HR− cancer also increased among women 20–29 and was associated with lower early survival. Our contemporary data provide important insights to help inform preventive and therapeutic strategies for premenopausal women.

32278642

PMC7398833

Journal Article

CDC Public Access