External Validation of the IOTA Two-Step Strategy for Pre-operative Characterization of Adnexal Masses: Comparison...

To externally validate the International Ovarian Tumor Analysis two-step strategy, using modified Benign Descriptors followed by the Assessment of Different Neoplasias in the Adnexa model, in a single-center, surgically managed tertiary-center cohort and to compare its diagnostic performance with that of Assessment of Different Neoplasias in the Adnexa, the Ovarian-Adnexal Reporting and Data System and Simple Rules followed by Assessment of Different Neoplasias in the Adnexa for the pre-operative characterization of adnexal masses.

This retrospective diagnostic accuracy study included consecutive women who underwent trans-vaginal ultrasound within 6 months before surgery for an adnexal mass between January 1, 2022, and May 31, 2025, at a tertiary gynecologic oncology center. Histopathology was used as the reference standard. Ultrasound examinations adhered to International Ovarian Tumor Analysis terminology. Risk assessment was performed using Assessment of Different Neoplasias in the Adnexa, Ovarian-Adnexal Reporting and Data System, the International Ovarian Tumor Analysis two-step strategy, and Simple Rules followed by Assessment of Different Neoplasias in the Adnexa. Diagnostic performance was evaluated using the area under the receiver operating characteristic curve, sensitivity, specificity, and predictive values. Statistical comparisons were performed using 95% confidence intervals.

A total of 432 women were included (median age, 52 years [interquartile range 44-63]; 225/432, 52.1% post-menopausal). Histopathology showed benign tumors in 288/432 women (66.7%), borderline tumors in 21/432 (4.9%) and malignant tumors in 123/432 (28.5%). All models demonstrated excellent discrimination (area under the receiver operating characteristic curve >0.90). Assessment of Different Neoplasias in the Adnexa and the International Ovarian Tumor Analysis two-step strategy showed the highest performance (area under the receiver operating characteristic curve ≥0.94; sensitivity>93%; specificity, 83%-85%). Ovarian-Adnexal Reporting and Data System showed comparable discrimination (area under the receiver operating characteristic curve, 0.929; sensitivity, 91.7%; specificity, 81.6%). Simple Rules followed by Assessment of Different Neoplasias in the Adnexa achieved the highest specificity (90.3%) with lower sensitivity (86.1%).

The International Ovarian Tumor Analysis two-step strategy showed high diagnostic performance for the pre-operative characterization of adnexal masses, with results comparable to those of Assessment of Different Neoplasias in the Adnexa alone and Ovarian-Adnexal Reporting and Data System. Sequential strategies provided different sensitivity-specificity trade-offs, supporting their role as structured diagnostic approaches for expert ultrasound-based assessment of surgically managed adnexal masses.