Incidence and Survival Among Young Women With Stage I–III Breast Cancer: SEER 2000–2015

Abstract

Abstract Background Although recent findings suggest that de novo stage IV breast cancer is increasing in premenopausal women in the United States, contemporary incidence and survival data are lacking for stage I–III cancer. Methods Women aged 20–29 (n = 3826), 30–39 (n = 34 585), and 40–49 (n = 126 552) years who were diagnosed with stage I–III breast cancer from 2000 to 2015 were identified from the Surveillance, Epidemiology, and End Results 18 registries database. Age-adjusted, average annual percentage changes in incidence and 5- and 10-year Kaplan-Meier survival curves were estimated by race and ethnicity, stage, and hormone receptor (HR) status and grade (low to well and moderately differentiated; high to poorly and undifferentiated) for each age decade. Results The average annual percentage change in incidence was positive for each age decade and was highest among women aged 20–29 years. Increased incidence was driven largely by HR+ cancer, particularly HR+ low-grade cancer in women aged 20–29 and 40–49 years. By 2015, incidence of HR+ low- and high-grade cancer each independently exceeded incidence of HR− cancer in each age decade. Survival for HR+ low- and high-grade cancer decreased with decreasing age; survival for HR− cancer was similar across age decades. Among all women aged 20–29 years, 10-year survival for HR+ high-grade cancer was lower than that for HR+ low-grade or HR− cancer. Among women aged 20–29 years with stage I cancer, 10-year survival was lowest for HR+ high-grade cancer. Conclusions HR+ breast cancer is increasing in incidence among premenopausal women, and HR+ high-grade cancer was associated with reduced survival among women aged 20–29 years. Our findings can help guide further evaluation of preventive, diagnostic, and therapeutic strategies for breast cancer among premenopausal women.