Predicting postoperative malignancy upgrading in B1-B3 breast lesions: combined utility of conventional ultrasound and contrast-enhanced ultrasound features.

[BACKGROUND] While conventional ultrasound (US)-guided core needle biopsy (CNB) is routinely used for preoperative diagnosis of breast lesions, it is susceptible to false negatives and underestimation, especially in B1-B3 categories, making accurate diagnosis a significant clinical challenge. This study aimed to explore the conventional US and contrast-enhanced ultrasound (CEUS) features that predict postoperative malignancy upgrading of category B1-B3 breast lesions diagnosed by CEUS-guided CNB.

[METHODS] A total of 84 breast lesions that underwent US, CEUS, CEUS-guided CNB and surgery were collected from February 2023 to February 2025, retrospectively. The malignancy upgrading was defined as CNB showing a B1-B3 classification, but surgical pathology showing a B5 classification. Uni-variable analysis compared US and CEUS features between non-upgrading and upgrading groups, and significant features were entered into multi-variable logistic regression. The performances of each independent predictor and their combinations were evaluated using receiver operating characteristic curve analysis.

[RESULTS] Thirteen B1-B3 lesions were upgraded to B5 lesions. The multivariate analysis showed that size >20 mm on conventional US [odds ratio (OR) =5.85; 95% confidence interval (CI): 1.49-22.92; P=0.011], and enlarged enhancement range on CEUS (OR =17.44; 95% CI: 2.03-150.02; P=0.009) were independent predictors. The multi-variable model incorporating these two features yielded an area under the curve (AUC) of 0.83 and showed significantly higher predictive efficiency than size >20 mm (AUC =0.68) and enlarged enhancement range (AUC =0.74) (P=0.027 and P=0.013, respectively).

[CONCLUSIONS] Both conventional US and CEUS can provide useful information for postoperative malignancy upgrading in B1-B3 lesions. The integration of them improved the predictive performance.