Molecular diagnostics to reduce inequity in breast cancer diagnosis.

Abstract

548 Background: Modern management of breast cancer requires proper subtyping of the breast tumor to guide appropriate treatment and prognostication. However, there are barriers to availability of this resource in low- and middle-income countries (LMIC) which contributes to global inequalities in breast cancer management and outcomes. The non-availability is due to high cost, and lack of personnel and infrastructure required for immunohistochemistry (IHC), the current gold standard for subtyping. IHC results are affected by pre-analytic and analytic handling and are subjective. Alternative methods that are more objective, cost less and require less infrastructure and skilled personnel will improve access and reduce disparities. Methods: In the AFBRECANE Project, we compared the results of ER and PR subtyping of 1,000 breast cancer tumors from patients recruited from 5 clinical sites in Nigeria using IHC and Cepheid GeneXpert RNA STRAT4 biomarker assay at ACCME Lab in Nigeria and University of Maryland. Results: For ER, the sensitivities, specificities, and agreement between IHC and STRAT4 ranged from 50.0%, 71.4% and 59.4% to 77.1%, 80.0% and 78.5% while for PR, they ranged from 58.1%, 66.7% and 62.5% to 84.6%, 84.2% and 84.4%. Conclusions: The wide range of sensitivities, specificities, and agreement between IHC and STRAT4 in this study confirms the challenges of molecular subtyping of breast cancer in LMICs like Nigeria. Sustainable objective methods are sorely needed to improve diagnosis, treatment and prognostication, and reduce global disparities.