April 2020 – Breast cancer incidence in sub-Saharan Africa is increasing, and the region has the highest age-standardized breast cancer mortality rate worldwide. In a setting where breast cancer data are limited, our findings indicate that late stage presentation, HER2-enriched and triple-negative subtypes, and HIV coinfection were associated with mortality and were more prevalent in our cohort compared to resource-rich settings.
Outcomes and Prognostic Factors for Women With Breast Cancer in Malawi
VM Youngblood, R Nyirenda, R Nyasosela, T Zuze, Y Yang, E Kudowa, A Moses, J Kincaid, C Kajombo, C Kampani, F Chimzimu, M Mulenga, C Chilima, GK Ellis, R Seguin, M Chagomerana, R Maine, S Jordan, A Charles, C Lee, S Gopal, T Tomoka
Cancer Causes and Control
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Abstract
BACKGROUND: Breast cancer incidence in sub-Saharan Africa (SSA) is increasing, and SSA has the highest age-standardized breast cancer mortality rate worldwide. However, high-quality breast cancer data are limited in SSA.
MATERIALS AND METHODS: We examined breast cancer patient and tumor characteristics among women in Lilongwe, Malawi and evaluated risk factor associations with patient outcomes. We consecutively enrolled 100 women ≥ 18 years with newly diagnosed, pathologically confirmed breast cancer into a prospective longitudinal cohort with systematically assessed demographic data, HIV status, and clinical characteristics. Tumor subtypes were further determined by immunohistochemistry, overall survival (OS) was estimated using Kaplan-Meier methods, and hazards ratios (HR) were calculated by Cox proportional hazard analyses.
RESULTS: Of the 100 participants, median age was 49 years, 19 were HIV-positive, and 75 presented with late stage (III/IV) disease. HER2-enriched and triple-negative/basal-like subtypes represented 17% and 25% tumors, respectively. One-year OS for the cohort was 74% (95% CI 62-83%). Multivariable analyses revealed mortality was associated with HIV (HR, 5.15; 95% CI 1.58-16.76; p = 0.006), stage IV disease (HR, 8.86; 95% CI 1.07-73.25; p = 0.043), and HER2-enriched (HR, 7.46; 95% CI 1.21-46.07; p = 0.031), and triple-negative subtypes (HR, 7.80; 95% CI 1.39-43.69; p = 0.020).
CONCLUSION: Late stage presentation, HER2-enriched and triple-negative subtypes, and HIV coinfection were overrepresented in our cohort relative to resource-rich settings and were associated with mortality. These findings highlight robust opportunities for population- and patient-level interventions across the entire cascade of care to improve breast cancer outcomes in low-income countries in SSA.