Measuring the WHO Global Breast Cancer Initiative Pillars' key performance indicators in Sub-Saharan Africa: experience in the African Breast Cancer-Disparities in Outcomes hospital-based cohort study.

Background: The World Health Organization Global Breast Cancer Initiative aims to reduce breast cancer (BC) mortality through three pillars, whose key performance indicators (KPIs) and benchmarks are: (KPI-1) ≥60% BC diagnosed at early stage (I/II), (KPI-2) all suspected BC diagnosed ≤60 days from health system presentation, and (KPI-3) ≥80% of BC patients completing recommended treatment. We aimed to inform measurement of these KPIs in the context of a multi-country hospital-based study. Methods: We included all women who participated to the African Breast Cancer-Disparities in Outcomes (ABC-DO) prospective cohort study (excluding South Africa), recruited between 2014 and 2017, across five population-race groups spanning low to high survival: Nigeria, Uganda, Zambia, Namibian black and Namibian non-black women. Follow-up was up to five years post-diagnosis. For each KPI, we reported challenges, assumptions and consistencies in measuring them; completeness and group-level estimations of each KPI were assessed using descriptive analyses. To evaluate their discriminatory ability, we assessed group-level correlations between KPI estimates and five-year net survival. Findings: KPI-1 was extracted from study or medical records for 1389/1473 (94%). KPI-2 relied upon the woman's recall of her date of first contact with the healthcare system and a pathology date, both of which were available for 1222/1473 (83%) but inconsistent for 114/1222 (9.3%). KPI-3, estimated using dates of receipt of multiple therapies from medical records and patient interviews over 12 months, was estimated for 1129/1188 (95%), but uncertain in 113/1129 (10%). For each population group, KPIs achievements were similar for KPI-1 and KPI-2, at 22-49%, and lowest for KPI-3 (<30%). Highest KPIs values were observed in Namibian non-black women who had the highest survival. Interpretation: Data collection systems specifically set up for prospective hospital-based studies can be used to collect the necessary data to measure these three GBCI KPIs. Funding: National Cancer Institute (United States).