Comparative Study of Ki-67 Labeling Index Quantification by Eye-rolling, Manual Count, and Digital Image Analysis; An Approach with Caution

An accurate Ki-67 labeling index assessment is critical for managing a few tumors, like breast carcinomas and neuroendocrine tumors. We aimed to determine the degree of agreement between digital image analysis (DIA) & eye-rolling assessment (EE) and DIA & manual count (MC) for Ki-67 LI scoring.

A total of 120 cases (Both tru-cut biopsies and resected specimens) were selected during the study period from the institutional database wherein the Ki-67 labeling index was performed. The selected cases were divided into two groups, i.e., breast neoplasms and other neoplasms. The correlation between DIA & EE and DIA & MC for Ki-67 LI scoring was calculated in both groups.

A total of 113 cases were analyzed for Ki-67 LI by three different methods (EE, MC, & DIA); 7 cases were rejected because of poor image quality. Ki-67 LI scoring by DIA & EE was highly correlated in both the study groups with a Spearman's rank correlation coefficient of 0.809 (P=0.01) and 0.904 (P=0.01), respectively. Correlation between DIA & MC methods was also found to be almost perfect in both study groups with a Spearman's rank correlation coefficient of 0.974 (P=0.01) and 0.955 (P=0.01), respectively.

ImmunoRatio is a free web-based digital image analysis application that can be used for Ki-67 LI assessment with considerable reliability and reproducibility. Yet, it carries a few limitations and demands a careful approach and final confirmation by an expert.