US breast cancer mortality trends in young women according to race

Abstract

Background: Young age at diagnosis has a negative prognostic impact on outcome in patients with breast cancer (BC). In the current study, the authors sought to determine whether there is a differential effect of race and examined mortality trends according to race and age.

Methods: The Surveillance, Epidemiology, and End Results program was used to identify women aged <50 years with invasive BC diagnosed between 1990 and 2009. Multivariate regression analyses were performed to determine the risk-adjusted likelihood of survival for white and black patients. Annual hazards of BC death according to race and calendar period and adjusted relative hazards of death for white and black women stratified by age were computed.

Results: A total of 162,976 women were identified, 126,573 of whom were white, 20,405 of whom were black, and 15,998 of whom were of other races. At a median follow-up of 85 months, the 5-year disease specific survival rates were 90.1% for white patients and 79.3% for black patients. Annual hazards of death in white patients decreased by 26% at 5 years after diagnosis in contrast to the hazards in black patients, which decreased by only 19%. With 1990 as the referent year, the adjusted relative hazards of death in women aged <40 years in 2005 were 0.55 (95% confidence interval [95% CI], 0.46-0.66) and 0.68 (95% CI, 0.49-0.93), respectively, for white and black women. In women aged 40 to 49 years, adjusted hazards of death were 0.53 (95% CI, 0.47-0.60) and 0.78 (95% CI, 0.61-0.99), respectively, for white and black women.

Conclusions: Among young women diagnosed with BC, black patients have a worse outcome compared with white patients. Mortality declines have been observed over time in both groups, although more rapid gains have been reported to occur in white women. Emphasis should be placed on improving outcomes for young patients with BC.

Keywords: breast cancer; survival; trends; young age.

Figure 1

Patients with breast cancer included in the analytical cohort. Consort diagram showing number of patients with breast cancer diagnosed between 1990 and 2009 that were included or excluded from the analytical cohort

Figure 2

Kaplan-Meier survival curves showing estimates of overall survival by race for all patients included in the analytical cohort

Figure 3

Smoothed Annual Hazard Rates of Breast Cancer Death according to Race and Calendar Period. Curves show absolute death rates at a stated time period after diagnosis.

Figure 4

Relative Risk of Breast Cancer Death according to Race and Age at Diagnosis. RR are adjusted for stage, ER, PR, histology, age, diagnosis year, tumor size, nodal status, and grade.