Incremental Value of C-Reactive Protein Combined with O-RADS US v2022 for Preoperative Adnexal Mass Assessment

To evaluate whether C-reactive protein (CRP) provides incremental diagnostic value when combined with the O-RADS US v2022 system for preoperative discrimination of benign and malignant adnexal masses.

This retrospective study included 570 patients with adnexal masses (138 benign and 432 malignant) between January 2019 and February 2024. Independent predictors of malignancy were identified through univariate and multivariate logistic regression analyses. Model performance was compared via receiver operating characteristic (ROC) curve analysis, with differences in the area under the curve (AUC) assessed using the DeLong test, followed by Bonferroni correction for multiple comparisons.

Multivariate analysis identified the O-RADS US v2022 score (OR 16.538, 95% CI: 8.397 - 32.569, p < 0.001), elevated CRP (≥ 3 mg/L) (OR 4.560, 95% CI: 1.896 - 10.969, p < 0.001), and age (OR 1.044, 95% CI: 1.009 - 1.080, p = 0.014) as independent predictors of malignancy. The combined model (O-RADS US v2022 + CRP) achieved a significantly higher AUC of 0.964 (95% CI: 0.945-0.983) than O-RADS US v2022 alone (AUC = 0.943, 95% CI: 0.918-0.967; p_adj = 0.0198), and itself demonstrated high sensitivity (93.1%) and specificity (91.0%). However, adding age to the combined model (O-RADS US v2022 + CRP + Age) did not significantly improve the AUC (0.964 vs. 0.964, p_adj = 1).

CRP is an independent predictor of malignancy in adnexal masses. Integrating CRP with O-RADS US v2022 significantly enhances diagnostic value, improving preoperative risk stratification for adnexal masses. However, because this study was performed at a tertiary oncology center with a high malignancy prevalence (76%), the specificity estimates may be overestimated and require validation in lower-prevalence community settings before widespread application.