Opportunities For Improvement in The Administration of Neoadjuvant Chemotherapy For T4 Breast Cancer: A Comparison of The United States and Nigeria

Neoadjuvant chemotherapy (NAC) is an integral component of T4 breast cancer (BCa) treatment. We compared response to NAC for T4 BCa in the U.S. and Nigeria to direct future interventions. Cross-sectional retrospective analysis included all non-metastatic T4 BCa patients treated from 2010-2016 at Memorial Sloan Kettering Cancer Center (New York, U.S.) and Obafemi Awolowo University Teaching Hospitals Complex (Ile Ife, Nigeria). Pathologic complete response (pCR) and survival were compared and factors contributing to disparities evaluated. 308 patients met inclusion criteria: 157 (51%) in the U.S. and 151 (49%) in Nigeria. All U.S. patients received NAC and surgery compared with 93 (62%) Nigerian patients. 56/93 (60%) Nigerian patients completed their prescribed course of NAC. In Nigeria, older age and higher socioeconomic status were associated with treatment receipt. Fewer patients in Nigeria had immunohistochemistry performed (100% U.S. vs. 18% Nigeria). Of those with available receptor subtype, 18% (28/157) of U.S. patients were triple negative vs. 39% (9/23) of Nigerian patients. Overall pCR was seen in 27% (42/155) of U.S. patients and 5% (4/76) of Nigerian patients. Five-year survival was significantly shorter in Nigeria vs. the U.S. (61% vs. 72%). However, among the subset of patients who received multimodality therapy, including NAC and surgery with curative intent, 5-year survival (67% vs. 72%) and 5-year recurrence-free survival (48% vs. 61%) did not significantly differ between countries. Addressing health system, socioeconomic, and psychosocial barriers is necessary for administration of complete NAC to improve BCa outcomes in Nigeria. This cross-sectional retrospective analysis of T4 breast cancer patients in Nigeria and the U.S. found a significant difference in pathologic complete response to neoadjuvant chemotherapy (5% Nigeria vs. 27% U.S.). Five-year survival was shorter in Nigeria, but in patients receiving multimodality treatment, including neoadjuvant chemotherapy and surgery with curative intent, 5-year overall and recurrence-free survival did not differ between countries. Capacity-building efforts in Nigeria should focus on access to pathology services to direct systemic therapy, and promoting receipt of complete chemotherapy to improve outcomes.