Diagnostic accuracy of Ovarian-Adnexal Reporting and Data System, IOTA Simple Rules and Pediatric Risk of Malignancy Index for pediatric adnexal lesions: comparative study.

OBJECTIVE

Many risk stratification models have been developed to improve the accuracy of sonographic evaluation of adnexal lesions. Although these models have been validated across various adult populations, their accuracy in the pediatric population remains underexplored. This study aimed to evaluate and compare the diagnostic accuracy of three sonography-based risk models in assessing pediatric adnexal lesions.

METHODS

This was a single-center retrospective diagnostic accuracy study conducted at a tertiary hospital in China, which included consecutive patients aged 17 years or younger with adnexal lesions managed either surgically or conservatively between January 2015 and January 2024. Each adnexal lesion was assessed using the Ovarian-Adnexal Reporting and Data System (O-RADS) ultrasound risk stratification and management tool, the International Ovarian Tumor Analysis (IOTA) Simple Rules (SR) followed by expert assessment for inconclusive cases in a two-step strategy and the Pediatric Risk of Malignancy Index (PRMI) model. The reference standard was either surgical intervention or conservative management with ultrasound surveillance. The accuracy of the different sonography-based risk models was evaluated using the area under the receiver-operating-characteristics curve (AUC), sensitivity, specificity and positive and negative predictive values. The clinical utility of each model was evaluated using decision-curve analysis.

RESULTS

This study included 364 patients with a total of 375 adnexal lesions. The median age of the patients was 15.0 (interquartile range, 14.0-17.0) years, with a malignancy rate of 2.1% (8/375). The AUC for the O-RADS tool, IOTA two-step strategy and the PRMI model were 0.989 (95% CI, 0.980-0.999), 0.992 (95% CI, 0.985-0.998) and 0.806 (95% CI, 0.626-0.985), respectively. The IOTA two-step strategy demonstrated the highest accuracy and provided the greatest net benefits at malignancy risk thresholds between 1% and 30% compared with the other two models.

CONCLUSIONS

In this retrospective pediatric cohort, the O-RADS ultrasound model and the IOTA-SR followed by expert assessment for inconclusive cases in a two-step strategy exhibited high diagnostic accuracy in characterizing adnexal lesions, comparable to that observed in adults. These results support the applicability of both of these risk-stratification methods to the pediatric population. The PRMI scoring system showed lower discriminative capacity compared with the other models; therefore, it is not recommended to serve as a standalone diagnostic tool. © 2025 International Society of Ultrasound in Obstetrics and Gynecology.