THE CHANGING IMMUNOHISTOCHEMICAL PROFILE OF BREAST CARCINOMAS IN NNEWI, SOUTH-EAST NIGERIA: OUR EXPERIENCE

Abstract

Introduction: GLOBOCAN statistics has shown a rising incidence of breast cancers (BCs) in Nigeria, with previous studies in our region showing predominance of triple negative category. The molecular classification of BCs, as refined in 2015 by the St. Gallen’s consensus, will help prognosticate and better personalize treatment even in resource limited countries. Objective: The aim of this study was to evaluate immunohistochemically (IHC) status of BCs diagnosed in Nnewi, southeast Nigeria. Materials and Methods: We analysed all the morphologically diagnosed cases of BCs that were evaluated IHC for hormone receptors (HR) status, HER2 and Ki67 from two histopathology laboratories serving Nnewi and environs over a 6 year period using SPSS software, version 20. Results: A total of 13275 surgical specimens were received, 2888 of which were solid malignancies and 2485 were breast tissue specimens (974 (39.20%) of which were BCs). BCs accounted for 33.73% of all solid cancers. Only 142 had IHC done on the tissue blocks. The age ranged from 21 to 80 years with modal age in the 5th decade and mean age of 49.90±12.1 years. Majority (59.2%) of the BCs were HR positive and only 17.1% of BCs in women ≤40years were triple negative (TN). HER2 BCs and triple negative breast cancers (TNBCs) were commoner in women aged > 40 years. Conclusion: There is higher proportion of hormone receptor positive breast cancers in this study compared to previous study in our locality and other parts of the country. The higher proportion of triple negative breast cancers in other studies may be due to pre-analytic factors.