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Abstract
Introduction/Background High-grade serous ovarian carcinoma is characterised by four gene expression-based subtypes: mesenchymal, immunoreactive, differentiated, and proliferative, with suggested distinct prognoses and treatment responses. Murakami (MK) translated these into histopathological subtypes, showing differences in survival outcomes. Miyagawa (MG) refined the histopathological criteria to improve concordance rates. In this study, we evaluated the inter-observer variability and prognostic differences of the histopathologic subtypes using MK and MG criteria.
Methodology In this retrospective cohort study, 208 high-grade serous ovarian carcinoma cases were analysed. The mesenchymal subtype was categorised first, followed by the immunoreactive subtype. Non-conforming cases were categorised as solid and proliferative or papilloglandular, mirroring the gene expression-based proliferative and differentiated subtypes, respectively.
Results The mesenchymal subtype was identified in 122 patients (58.7%) for both criteria. Using MK criteria, 10 cases (4.8%) were immunoreactive, 26 (12.5%) solid and proliferative, and 50 (24%) papilloglandular, with a concordance rate of 62.5% (κ=0.34, p<.001). Using MG criteria, 23 cases (11%) were immunoreactive, 20 (9.6%) solid and proliferative, and 43 (20.7%) papilloglandular. The median progression-free survival was 17.8 months, while the median overall survival was 41.5 months. No differences in progression-free and overall survival were observed between the subtypes.
Conclusion The fair reproducibility of histopathological subtype classification of high-grade serous ovarian carcinoma and the lack of survival differences among these subtypes indicate the need for further refinement of the criteria and exploration of their correlation with overall survival outcomes before clinical application.
Disclosures The authors have no disclosures to declare that are relevant to the content of this study.
