Estrogen receptor negative breast cancer incidence rates are similar in Ghanaian and Non-Hispanic Black women in the USA

Age-standardized incidence rates of estrogen receptor negative (ERN) breast cancers in the US are higher among Non-Hispanic Black (NHB) compared to Non-Hispanic White (NHW) women. We aimed to determine if incidence rates were similar between NHB and Ghanaians, given that a high proportion of NHB share West African genetic ancestry. We compared US rates (per 100,000 women) to those in Ghana, using data from US SEER, the Ghanaian census, and the Ghana Breast Health Study (GBHS), a population-based case-control study conducted between 2013-2015 in Accra and Kumasi. ERN age-standardized rates were similar among Ghanaian (40.7) and US NHB women (43.1), and both were higher compared to US NHW (24.0). Estrogen receptor-positive (ERP) rates were lower in Ghanaian (43.7) than US NHB (84.4), and highest in US NHW (128.5). Our data support higher ERN rates among women in Ghana similar to US NHB suggesting shared putative risk factors that require investigation.