Abstract

Introduction: Ki-67 proliferation index is used as a prognostic-predictive marker in breast carcinoma and determined using visual hotspots or global counts methods. We studied analytical objectivity and reproducibility using the two methods.
Material and Method: 56 cases of carcinoma breast with Ki-67 (MIB-1antibody) staining on same sections were evaluated by two equally experienced pathologists, blinded to each other using both methods. The values obtained were classified into low, intermediate and high categories and statistical analysis was done using SPSS ver21.0 software.
Result: The mean value of hotspot method was higher whereas global method showed better interobserver reliability.
Conclusion: We recommend global method of Ki-67 evaluation as it has better reproducibility and inter-observer agreement as compared to visual hot spot method. The latter which has a higher mean value may result in change in categorization of Ki-67 index especially at higher end of cut-off in intermediate category, thereby affecting treatment protocols.