Mapping the Prevalence of BRCA1 and BRCA2 Mutations in Hereditary Breast and Ovarian Cancer Across Africa: A Systematic Review and Meta-Analysis.

Prevalence of germline pathogenic BRCA1 and BRCA2 variants in African individuals with breast or ovarian cancer.

This PRISMA-compliant systematic review and meta-analysis searched PubMed, Scopus, Web of Science and Embase for studies published between January 2000 and June 2024 reporting germline BRCA1 or BRCA2 data in African individuals with breast and/or ovarian cancer. Fifty-two studies from 19 African countries were included, mainly from Morocco (28.4%), Tunisia (18.9%), South Africa (14.7%) and Nigeria (11.6%), predominantly cross-sectional in design (68.4%), with Sanger sequencing in 45.3% and next-generation sequencing in 31.6%. The pooled prevalence of pathogenic BRCA1/BRCA2 variants was 9.0% (95% CI 7.7-10.4%), higher for BRCA1 (10.5%; 8.3-13.0%) than for BRCA2 (5.5%; 4.9-6.1%). More than half the studies did not distinguish between the two genes, and gaps in geographic coverage suggest the true burden is underestimated.

Synthesis written by Geno'X. For the full original abstract, please refer to the source publication.

A pooled prevalence of 9% looks high, but it aggregates predominantly cross-sectional and selected series, more than half of which do not even distinguish BRCA1 from BRCA2: the estimate tells us more about the cohorts tested than about African populations. Choosing a fixed-effects model for a prevalence expected to differ between Morocco and Nigeria is questionable and pulls towards illusory precision. What remains solid, and useful, is the mapping of the gap: 19 countries represented, four of which supply close to three quarters of the data.

Analysis by Dr Thibaut Benquey