Objective The accurate preoperative differentiation of benign and malignant adnexal masses, especially those with complex ultrasound morphology, remains a great challenge for junior sonographers. The purpose of this study was to develop and validate a nomogram based on the Ovarian-Adnexal Reporting and Data System (O-RADS) for predicting the malignancy risk of adnexal masses with complex ultrasound morphology. Methods A total of 243 patients with data on adnexal masses with complex ultrasound morphology from January 2019 to December 2020 were selected to establish the training cohort, while 106 patients with data from January 2021 to December 2021 served as the validation cohort. Univariate and multivariate analyses were used to determine independent risk factors for malignant tumors in the training cohort. Subsequently, a predictive nomogram model was developed and validated in the validation cohort. The calibration, discrimination, and clinical net benefit of the nomogram model were assessed separately by calibration curves, receiver operating characteristic (ROC) curves, and decision curve analysis (DCA). Finally, we compared this model to the O-RADS. Results The O-RADS category, an elevated CA125 level, acoustic shadowing and a papillary projection with color Doppler flow were the independent predictors and were incorporated into the nomogram model. The area under the ROC curve (AUC) of the nomogram model was 0.958 (95% CI, 0.932–0.984) in the training cohort. The specificity and sensitivity were 0.939 and 0.893, respectively. This nomogram also showed good discrimination in the validation cohort (AUC = 0.940, 95% CI, 0.899–0.981), with a sensitivity of 0.915 and specificity of 0.797. In addition, the nomogram model showed good calibration efficiency in both the training and validation cohorts. DCA indicated that the nomogram was clinically useful. Furthermore, the nomogram model had higher AUC and net benefit than the O-RADS. Conclusion The nomogram based on the O-RADS showed a good predictive ability for the malignancy risk of adnexal masses with complex ultrasound morphology and could provide help for junior sonographers.

Objective: Since the promulgation of the International Ovarian Tumor Analysis (IOTA) Simple Rules (SR) and the American College of Radiology (ACR) Ovarian-Adnexal Reporting and Data System (O-RADS) , many studies have verified their diagnostic performance successively. But the low accuracy of masses of O-RADS 4 and SR inconclusive still perplex sonographers, thus this study aimed to settle this problem by combining Cancer Antigen 125 (CA125) with those masses, and to assess diagnostic added-value of CA125 on O-RADS and SR in discrimination benign and malignant adnexal masses. Methods: Data of women with adnexal masses recruited from a tertiary center between January 2019 and September 2021 were included in this study. All patients underwent transvaginal or transabdominal ultrasound examination as well as had complete ultrasound images and clinical data. Firstly, the masses were classified retrospectively using O-RADS and SR by two less experienced sonographers according to the corresponding criteria. Then, the masses of O-RADS 4 and SR inconclusive were reclassified according to the level of CA125,that is, the combination of O-RADS and SR with CA125. And analyzed the differences in diagnostic efficacy of the above methods for menopause status. Finally, receiver operating characteristic (ROC) curves were plotted to evaluate the diagnostic performance of CA125,O-RADS, SR, CA125 combine with O-RADS, and CA125 combine with SR, and calculate the area under the curve (AUC), sensitivity, specificity. Results: Of the 403 patients (143 premenopausal and 260 postmenopausal), 269 had benign lesions, and 134 had malignant tumors. The AUCs of CA125, O-RADS, SR, O-RADS combined with CA125, SR, SR combined with CA125,and CA125 in the whole study group were 0.842, 0.939, 0.963, 0.884, and 0.944, respectively. The findings showed that the AUCs of O-RADS and SR combined with CA125 were significantly higher than O-RADS and SR alone severally (p <0.05). The accuracy of O-RADS 4 and SR inconclusive masses were only 0.438 and 0.534, however, their accuracy has been improved to 0.829 and 0.814 when combined with CA125. Furthermore, the addition of CA125 into O-RADS and SR significantly increased the AUC to 0.930 (0.930 vs 0.712, p <0.001) and 0.931 (0.931 vs 0.774, p <0.001) separately in women with amenorrhea. Conclusions: CA125 can markedly improve the accuracy of O-RADS 4 and SR inconclusive masses, thereby improving the overall diagnostic efficiency of the O-RADS and SR classification system, especially for menopause women.