Unraveling the South African Breast Cancer Story: The Relationship of Patients, Delay to Diagnosis, and Tumor Biology With Stage at Presentation in an Urban Setting.

BACKGROUND: Adverse outcomes from breast cancer disproportionately affect women in sub-Saharan Africa, with delay the most studied contribution to advanced stage at presentation. However, tumor molecular biology and its contribution to advanced stage are yet to be explored. MATERIALS AND METHODS: Patients newly diagnosed with breast cancer in a South African tertiary breast center completed a questionnaire and file review concerning socioeconomics, delay to care, stage at presentation, and molecular characteristics. Logistic regression was done to determine the relative risk of advanced stage presentation. RESULTS: Advanced stage was present in 70.1% (n = 162) of the 231 participants, with 55.8% stage III (n = 129) and 32% (n = 72) having a T4 tumor. The median age was 56 y with 21.6% (n = 47) aged <45 y. Most common subtype was luminal B (57.7%, n = 128) followed by luminal A (21.6%, n = 48), triple negative (13.9%, n = 31), and HER2 positive (6.7%, n = 15). Lobular cancer (incidence risk ratio [IRR], 1.29; 95% confidence interval [CI], 1.03-1.62), high grade and intermediate grade tumors (IRR, 1.90; 95% CI, 1.15-3.13 and IRR, 1.95; 95% CI, 1.18-3.22, respectively), high Ki67 proliferation index (IRR, 1.30; 95% CI, 1.02-1.66), and HER2 overexpression (IRR, 1.32; 95% CI, 1.12-1.55) were more likely to present with advanced disease, as were luminal B (HER2+) cancers (adjusted IRR [aIRR], 1.46; 95% CI, 1.10-1.95). Although on univariate analysis Black and young participants were both more likely to have advanced stage (IRR, 1.23; 95% CI, 1.01-1.49 and IRR, 1.25; 95% CI, 1.04-1.51, respectively), in multivariate analysis controlling for tumor biology and delay, these were no longer significant (aIRR, 1.12; 95% CI, 0.91-1.37 and aIRR, 1.17; 95% CI, 0.94-1.48, respectively). CONCLUSIONS: Tumor biology has a compelling role in the etiology of advanced-stage disease irrespective of socioeconomic factors. Accurate pathologic assessment is important in planning breast cancer care in Africa.