Breast cancer subtypes among Eastern‐African–born black women and other black women in the United States

Abstract

BACKGROUND:A previous study reported that Eastern-African-born black women in the United States had lower prevalence of estrogen receptor-negative breast cancer than those in US-born and Western-African-born black women, among whom the prevalence was similar. It is unknown whether the prevalence of triple-negative breast cancer (negative for estrogen receptor, progesterone receptor, and human epidermal growth factor 2 receptor) among black women in the United States differs similarly by birthplace. METHODS: In the National Program of Cancer Registries and US Cancer Statistics, the authors identified 65,211 non-Hispanic black women who were diagnosed with invasive breast cancer from 2010 through 2015 and were recorded as being born in the United States, East Africa, West Africa, or the Caribbean. The prevalence of triple-negative and hormone receptor-negative breast cancer (negative for estrogen receptor and progesterone receptor) among each group of foreign-born black women was compared with that among US-born black women and was expressed as the adjusted prevalence rate ratio, accounting for sociodemographic and tumor characteristics. Analyses were stratified by Census region, and region-specific estimates were summarized using random-effects meta-analyses. RESULTS: Compared with US-born black women, the prevalence rate ratio of triple-negative breast cancer was 0.92 (95% CI, 0.81-1.04) among Western-African-born, 0.87 (95% CI, 0.78-0.98) among Caribbean-born, and 0.53 (95% CI, 0.37-0.77) among Eastern-African-born black women. Patterns for hormone receptor-negative tumors were generally similar, although the differences between populations were attenuated. The test for heterogeneity by Census region was not significant in any of the comparisons (all P for heterogeneity >.05). CONCLUSIONS: The prevalence of triple-negative breast cancer among black women in the United States varied significantly by birthplace, particularly among Eastern-African-born black women. These findings underscore the importance of considering geographic origin in studies characterizing breast cancer among women of African descent in the United States and elsewhere. Cancer 2019;125:3401-3411.

Breast cancer statistics, 2019

“…For example, a recent study reported that the prevalence of the triple-negative subtype in black women in the United States varied substantially by country of birth; compared with US-born blacks, the prevalence was 47% lower in women born in countries in Eastern Africa but only 8% lower in Western Africa-born blacks. 21 In another study of women in California, those of Korean, Filipina, Chinese, and Southeast Asian descent had a higher risk of HER2-positive breast cancers compared with white women, whereas those of Japanese and Asian Indian descent had a lower risk. 22 Differences in breast cancer subtype within and between racial/ethnic groups likely reflect variations in the prevalence of breast cancer risk factors 23 and mammography use, 24 but may also be related to genetic variations.…”

“…Importantly, studies suggest that the distribution of breast cancer subtypes varies within broadly defined racial/ethnic groups. For example, a recent study reported that the prevalence of the triple‐negative subtype in black women in the United States varied substantially by country of birth; compared with US‐born blacks, the prevalence was 47% lower in women born in countries in Eastern Africa but only 8% lower in Western Africa‐born blacks . In another study of women in California, those of Korean, Filipina, Chinese, and Southeast Asian descent had a higher risk of HER2‐positive breast cancers compared with white women, whereas those of Japanese and Asian Indian descent had a lower risk .…”

“…In another study of women in California, those of Korean, Filipina, Chinese, and Southeast Asian descent had a higher risk of HER2‐positive breast cancers compared with white women, whereas those of Japanese and Asian Indian descent had a lower risk . Differences in breast cancer subtype within and between racial/ethnic groups likely reflect variations in the prevalence of breast cancer risk factors and mammography use, but may also be related to genetic variations …”

“…22 Differences in breast cancer subtype within and between racial/ethnic groups likely reflect variations in the prevalence of breast cancer risk factors 23 and mammography use, 24 but may also be related to genetic variations. 21,[25][26][27] Temporal Trends in Incidence and Mortality Incidence Much of the historic increase in breast cancer incidence rates reflects changes in reproductive patterns, such as delayed childbearing and fewer births, associated with increased breast cancer risk. 28 During the 1980s and 1990s, incidence rates of DCIS and invasive breast cancer rose rapidly, particularly among women aged ≥50 years (Fig.…”

High triple‐negative breast cancer prevalence and aggressive prognostic factors in Barbadian women with breast cancer

“…NHBs have a high prevalence of the very aggressive and clinically challenging BCa subtype called triple‐negative breast cancer (TNBC), which is characterized by the absence of 3 therapeutically relevant BCa biomarkers: estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER2) . Currently, TNBC patients are treated with a combination of nontargeted chemotherapies, radiotherapy, and surgery .…”