Tumor size of breast invasive ductal cancer measured with contrast-enhanced ultrasound predicts regional lymph node metastasis and N stage

Purpose: This study aimed to determine the role of breast invasive ductal cancer (BIDC) size measured with Contrast-enhanced Ultrasound (CEUS) in the prediction of regional lymph node metastasis (LNM) and N stage. Methods: One hundred and six consecutive patients with breast lesions underwent ultrasound imaging within 2 weeks before mastectomy and axillary lymph node dissection. The largest transverse (width) and anteroposterior (depth) diameter were measured under CEUS by using calipers. The correlation between tumor size and regional LNM metastasis and N stage was evaluated. Results: Univariate analysis showed the diameters measured with CEUS were associated with lymph node metastasis (P < 0.05). The tumor size could distinguish grouped N stage (all P < 0.05). Tumor area (TA) might be an indicator that can differentiate No BIDC from N1-3 BIDC (cutoff = 5.37 cm²), N0-1 BIDC from N2-3 BIDC (cutoff = 6.48 cm²), and N0-2 BIDC from N3 BIDC (cutoff = 8.23 cm²) with the sensitivity of 71%, 72% and 83%, respectively, and the specificity of 79%, 68% and 84%, respectively. Conclusions: The TA of BIDC measured with CEUS may be a predictor of regional LNM and N stage.