Estrogen Receptor-Negative Breast Cancer Trends Vary by Location, Race, and Ethnicity
, by DCEG Staff
For the first time, researchers examined incidence of estrogen receptor (ER)-negative breast cancer by age, race and ethnicity, and geographic location simultaneously, discovering substantial variation between subgroups despite an overall decline in incidence within the U.S. population since 1992. The findings were published September 11, 2021, in the Journal of the National Cancer Institute.
Gretchen Gierach, Ph.D., M.P.H, senior investigator and Chief of the Integrative Tumor Epidemiology Branch, and Philip S. Rosenberg, Ph.D., senior investigator in the Biostatistics Branch, analyzed data from 1992 through 2016 from 17 cancer registries in the NCI Surveillance, Epidemiology and End Results (SEER) Program, using SEER registry as a proxy for location. In order to complete this comprehensive analysis, the investigators used hierarchical age-period-cohort models that stabilized estimates across groups.
An overall decline in ER-negative breast cancer incidence at the U.S. population level masked considerable variability when the investigators looked by SEER registry, race and ethnicity, and age. They reported greater variability among non-Hispanic Black and Hispanic White women, compared with non-Hispanic White women, across all registries. For example, non-Hispanic White women experienced declining incidence in all age groups and across all registries. In contrast, older non-Hispanic Black women showed slower declines or even slight increases in ER-negative breast cancer incidence within registries in the southeastern U.S. and California. Age was a contributing factor in trend patterns across race and ethnicity: trends among younger Hispanic White women were similar to younger non-Hispanic White women, whereas trends among older HW women were similar to older non-Hispanic Black women. Within registries, the magnitude of differences over time generally increased with age among non-Hispanic Black women and Hispanic white women but decreased with age or remained constant for non-Hispanic White women.
These trends may reflect prevalence of risk factors by region. For example, registries in the southeast with the slowest declines in ER-negative breast cancer incidence are also those with high rates of obesity. Further studies in racially and ethnically diverse populations are needed to investigate the possible mechanisms behind these disparities, including the role of societal determinants of health.
Davis Lynn, B.C., et al. Decreasing Incidence of Estrogen Receptor-Negative Breast Cancer in the United States: Trends by Race and Region. J Natl Cancer Inst. 2021.