Validation of the IOTA ADNEX Model Among Japanese Women Performed by Gynecology Trainees and Ultrasound Specialists: A Retrospective Diagnostic Accuracy Study.

Objectives: This study aimed to validate the diagnostic accuracy of the International Ovarian Tumor Analysis (IOTA) Assessment of Different NEoplasias in the adneXa (ADNEX) model in Japanese women, population with a distinct adnexal mass distribution compared with European women, and to evaluate the model's utility by gynecology trainees and ultrasound specialists.

Methods: This single-center, retrospective study analyzed ultrasound data from January 2017 to March 2020 of 206 women with adnexal masses. Patients who underwent ultrasonography and serum CA-125 measurement and received postsurgery histological diagnosis were included. The ADNEX model's diagnostic performance was evaluated by two trainees and two specialists using the area under the receiver operating characteristic curve (AUC) and measures of accuracy, sensitivity, specificity, and predictive values for overall performance and each examiner.

Results: Of the 206 included Japanese women, the prevalence of malignancy was 30.1%, including borderline cases. The overall AUC for distinguishing malignancy was 0.848 (95% confidence interval [CI]: 0.817-0.880). The AUC for each examiner ranged from 0.791 to 0.898, with Specialist 2 showing the highest accuracy and sensitivity varying between 0.677 and 0.839. A moderate degree of agreement was noted among the four examiners (Fleiss' kappa was 0.586). The performance of trainees and specialists differed significantly in evaluating the solid tissue and the papillary projections in both malignant and benign groups (P < .001).

Conclusions: The IOTA ADNEX model effectively differentiates benign and malignant adnexal masses in Japanese women. Although the accuracy matched up moderately among the four examiners, better accuracy is expected with training in evaluating solid tissue and papillary projections.