Purpose: To evaluate sonographic signs for predicting of breast cancer in small breast masses (≤ 10 mm).
Material and Methods: 190 breast masses (≤ 10 mm) underwent breast US were retrospectively analyzed their sonographic findings by two radiologists according to the Breast Imaging Reporting and Data System. The results were compared with histopathological findings (both biopsy and surgery) or serial breast US at least 24 months. By using fisher extract test, P-value, odds ratio and 95% CI of sonographic features were reported. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and accuracy of breast US was calculated.
Results: 130 of 190 masses were proven by histopathological reports (46 malignant and 84 benign). 60 of these were stable on serial US at least 2 years, representing presumed benign masses. The sonographic features of shape, wall margin, posterior shadowing, thick hyperechoic halo, and width/ AP ratio ≤ 1.4 of the mass were statistically significant features in differentiating benign from malignant. The sensitivity, specificity, PPV, NPV and accuracy of breast US in differentiating benign from malignant tumor were 98%, 70.6%, 51.1%, 99% and 76.3%, respectively.
Conclusion: Our study provides further evidence to suggest that ill-defined margin, irregular shape, posterior shadowing, thick hyperechoic halo, and width/AP ratio ≤ 1.4 are predictive signs of malignancy in small breast masses (≤10mm). US also plays an important role in guiding interventional procedures in small BI-RADS 4 and BIRADS 5 masses. For small BI-RADS 3 lesions, the serial breast US is reasonable approach to avoid unnecessary biopsy.