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

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.

Figure 1.

Breast cancer incidence rate by race and ethnicity for women aged 20–49 years diagnosed with stage I–III breast cancer, 2000–2015, SEER 18 registries. A) Women ages 20–29 years. B) Women ages 30–39 years. C) Women ages 40–49 years. Rates were calculated using the analytic sample. Women with breast cancer ascertained by the Alaska Native registry were excluded from incidence estimations for the Hispanic group because this registry only ascertains patients from the Native American and Alaska Native populations within the state. SEER = Surveillance, Epidemiology, and End Results.

Figure 2.

Breast cancer incidence rate by stage and HR status and grade for women aged 20–49 years diagnosed with stage I–III breast cancer, 2000–2015, SEER 18 registries. A) Women ages 20–29 years. B) Women ages 30–39 years. C) Women ages 40–49 years. D) Women ages 20–29 years. E) Women ages 30–39 years. F) Women ages 40–49 years. Rates for (A, B, and C) were calculated using the analytic sample; rates for (D, E, and F) were calculated using the analytic subsample. HR = hormone receptor; SEER = Surveillance, Epidemiology, and End Results.

Figure 3.

Ten-year survival by race and ethnicity for women aged 20–49 years diagnosed with stage I–III breast cancer, 2000–2014, SEER 18 registries. A) Women ages 20–29 years. B) Women ages 30–39 years. C) Women ages 40–49 years. Survival was calculated using the analytic sample. Numbers of patients at risk are given below the x-axis. SEER = Surveillance, Epidemiology, and End Results.

Figure 4.

Ten-year survival by stage and HR status and grade for women aged 20–49 years diagnosed with stage I–III breast cancer, 2000–2014, SEER 18 registries. A) Women ages 20–29 years. B) Women ages 30–39 years. C) Women ages 40–49 years. D) Women ages 20–29 years. E) Women ages 30–39 years. F) Women ages 40–49 years. Survival for (A, B, and C) was calculated using the analytic sample; survival for (D, E, and F) was calculated using the analytic subsample. Numbers of patients at risk are given below the x-axis. HR = hormone receptor; SEER = Surveillance, Epidemiology, and End Results.