Equity impact and cost-effectiveness of a community health worker breast cancer educational programme in rural South Africa: a modelling study

Introduction: Breast cancer is a leading cause of cancer-related death among women. Women with lower income, those living in rural areas and women of Black ethnicity are more likely to be diagnosed at advanced stages and have poorer survival outcomes. Reducing these inequities is an important public health priority. This study aimed to identify a cost-effective strategy for reducing breast cancer-related inequities and to evaluate the equity impact of the intervention across population subgroups.

Methods: We developed a novel individual-level microsimulation model to assess both the equity impact and cost-effectiveness of a community health worker-led education intervention in rural areas. The model, with annual cycles, simulated rural and urban breast cancer populations in South Africa using data from national and regional cancer datasets and followed individuals over a lifetime horizon. Costs were estimated from the provider perspective and outcomes included life-years, quality-adjusted life-years (QALYs), and incremental cost-effectiveness ratios (ICERs) compared with three willingness-to-pay thresholds (ZAR 58 018/ZAR 109 468/ZAR 328 408). Parameter uncertainty was explored using probabilistic sensitivity analysis. Equity impact was evaluated by estimating changes in age-standardised all-cause mortality across subgroups defined by place of residence (rural vs urban) and ethnicity (Black vs non-Black), using both absolute (rate differences) and relative (rate ratios) measures.

Results: The intervention generated average gains of 0.35 life-years and 0.31 QALYs per patient across the breast cancer population. Inequities by residence decreased, with an absolute reduction of 229.65 per 1000 patients with breast cancer in the age-standardised mortality rate difference, and a relative reduction in the rate ratio of 0.80. By ethnicity, absolute and relative reductions of 110.26 per 1000 patients and 0.27, respectively, were observed between Black and non-Black populations. The intervention was cost-effective, with an ICER of ZAR 44 124 (I$6036) per QALY gained, which is below all three willingness-to-pay thresholds considered.

Conclusions: Community health worker programmes represent a cost-effective strategy to reduce breast cancer-related inequities. Their integration into national cancer control plans in low-income and middle-income countries should be prioritised and supported.