Visual Counting and Automated Image-analytic Assessment of Ki-67 and their Prognostic Value in Synovial Sarcoma

Abstract

BACKGROUND: Ki-67 is a widely used proliferation marker reflecting prognosis in various tumors. However, visual assessment and scoring of Ki-67 suffers from marked inter-observer and intra-observer variability. We aimed to assess the concordance of manual counting and automated image-analytic scoring methods for Ki-67 in synovial sarcoma.PATIENTS AND METHODS: Tissue microarrays from 34 patients with synovial sarcoma were immunostained for Ki-67 and scored both visually and with 3DHistech QuantCenter.RESULTS: The automated assessment of Ki-67 expression was in good agreement with the visually counted Ki-67 (r Pearson =0.96, p<0.001). In a Cox regression model automated [hazard ratio (HR)=1.047, p=0.024], but not visual (HR=1.063, p=0.053) assessment method associated high Ki-67 scores with worse overall survival.CONCLUSION: The automated Ki-67 assessment method appears to be comparable to the visual method in synovial sarcoma and had a significant association to overall survival.