Validation of an Algorithm for the Diagnosis of Serous Tubal Intraepithelial Carcinoma

TLDR

Diagnosis of serous tubal intraepithelial carcinoma (STIC) based solely on histology is poorly reproducible, and the algorithm must be evaluated by general surgical pathologists before routine clinical use. The study aimed to validate the diagnostic algorithm by having six gynecologic pathologists, trained via a dedicated website, apply it to a set of cases. After training, the six pathologists independently reviewed 41 microscopic slides of fallopian tube mucosal lesions. The algorithm achieved 93 % consensus for STIC versus non‑STIC with a κ of 0.67, confirming its reproducibility and supporting its use in research.

Abstract

It has been reported that the diagnosis of serous tubal intraepithelial carcinoma (STIC) is not optimally reproducible on the basis of only histologic assessment. Recently, we reported that the use of a diagnostic algorithm that combines histologic features and coordinate immunohistochemical expression of p53 and Ki-67 substantially improves reproducibility of the diagnosis. The goal of the current study was to validate this algorithm by testing a group of 6 gynecologic pathologists who had not participated in the development of the algorithm (3 faculty and 3 fellows) but who were trained in its use by referring to a website designed for the purpose. They then reviewed a set of microscopic slides, which contained 41 mucosal lesions of the fallopian tube. Overall consensus (≥4 of 6 pathologists) for the 4 categories of STIC, serous tubal intraepithelial lesion (our atypical intermediate category), p53 signature, and normal/reactive was achieved in 76% of the lesions, with no consensus in 24%. Combining diagnoses into 2 categories (STIC versus non-STIC) resulted in an overall consensus of 93% and no consensus in 7%. The κ value for STIC versus non-STIC among all 6 observers was also high at 0.67 and did not significantly differ, whether for faculty (κ=0.66) or fellows (κ=0.60). These findings confirm the reproducibility of this algorithm by a group of gynecologic pathologists who were trained on a website for that purpose. Accordingly, we recommend its use in research studies. Before applying it to routine clinical practice, the algorithm should be evaluated by general surgical pathologists in a community setting.