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What is the added value of digital image analysis of HER 2 immunohistochemistry in breast cancer in clinical practice? A study with multiple platforms
Author(s) -
Koopman Timco,
Buikema Henk J,
Hollema Harry,
Bock Geertruida H,
Vegt Bert
Publication year - 2019
Publication title -
histopathology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.626
H-Index - 124
eISSN - 1365-2559
pISSN - 0309-0167
DOI - 10.1111/his.13812
Subject(s) - immunohistochemistry , medicine , breast cancer , human epidermal growth factor receptor 2 , gold standard (test) , digital image analysis , predictive value , breast carcinoma , cancer , oncology , pathology , computer science , computer vision
Aims We aimed to compare digital image analysis ( DIA ) of human epidermal growth factor receptor 2 ( HER 2) immunohistochemistry ( IHC ) in breast cancer by two platforms: (i) to validate DIA against standard diagnostics; and (ii) to evaluate the added value of DIA in clinical practice. Methods and results HER 2 IHC and in‐situ hybridisation ( ISH ) were performed on 152 consecutive invasive breast carcinomas. IHC scores were determined with DIA using two independent platforms. Manual scoring was performed by two independent observers. HER 2 status was considered positive in 3+ and ISH ‐positive 2+ cases. HER 2 status using DIA was compared to HER 2 status with standard diagnostics (manual scoring with ISH in 2+ cases). Interplatform agreement of IHC scores was ‘moderate’ (linear weighted κ = 0.58), agreement between manual scoring and platform A was ‘moderate’ (κ = 0.60) and between manual scoring and platform B ‘almost perfect’ (κ = 0.85). Compared to manual scoring, DIA resulted in a reduction of 2+ cases from 17.1 to 1.3% with platform A and from 17.1 to 15.8% with platform B. However, compared to standard diagnostics, there were three false‐negative cases with DIA using platform A [81.3% sensitivity, 100% specificity, 100% positive predictive value ( PPV ), 97.8% negative predictive value ( NPV )]. Sensitivity, specificity, PPV and NPV were 100% with DIA using platform B. Conclusions DIA of HER 2 IHC is a valid tool in determining HER 2 status in breast carcinoma. Algorithms in different platforms can behave differently, and optimal calibration is essential. In clinical practice, DIA offers an objective alternative to manual scoring, but a reduction in 2+ cases could result in loss of sensitivity.