Recent trends in hereditary breast cancer incidence by race and age in KwaZulu-Natal, South Africa: An 11-year single-centre retrospective study (2011-2021)

Abstract

Breast cancer incidence has increased globally in the last decade, especially in low- and middle-income countries. In Sub-Saharan Africa, breast cancer trends have been described only in a few populations owing to the scarcity of population-specific data. Using data collected between 2011 and 2021 at Inkosi Albert Luthuli Central Hospital, this retrospective study describes demographic and genetic trends for hereditary breast cancer patients in the KwaZulu-Natal province, South Africa. Six hundred and forty-five patients were included, of whom 44.3% were Black, 36.8% Indian, 15.6% White and 3.2% Coloured. The number of annual new cases increased from eight in 2011 to 145 in 2021, with a notable increase among Blacks. The mean onset age was 46 years, and Black patients were diagnosed ~10 years earlier than White and Indian patients. Triple-negative breast cancers accounted for 20.3% of hereditary cases, and 51.1% of them were Black. Bilateral and recurrent breast cancers constituted 7.4%, while pathogenic sequence variants in BRCA1/2 were reported in 10.4% of all patients, and the majority were Blacks and Indians. Overall, the KwaZulu-Natal province has seen an increase in hereditary breast cancer incidence in the past decade. Despite testing negative for pathogenic sequence variants, Black women frequently presented with breast cancers that are BRCA1-like, while Indians presented with extensive family history. This suggests that South African patients may require unique approaches to interventions, such as early detection and awareness programs among Blacks and increased genetic screening among Indians.