Abstract
PURPOSE: Evaluating the role of preoperative axillary ultrasound (US) in early-stage, clinically node-negative breast cancer, focusing on its ability to predict nodal metastasis and long-term recurrence. METHODS: This retrospective study included patients with T1-T2 clinically node-negative breast cancer who underwent preoperative axillary US and surgery between January and December 2009. Based on US findings, patients were classified as US-positive (presence of suspicious nodes, such as cortical thickening or absent fatty hilum) or US-negative. Clinicopathological features and recurrence outcomes were analyzed using the χ² test, Cox proportional hazards regression, and Kaplan-Meier survival analysis. RESULTS: Among 878 women (mean age, 49 ± 9 years), 234 were US-positive and 644 were US-negative; 283 patients were pathologic node-positive (pN ≥ 1) and 595 were node-negative (pN0). Preoperative axillary US demonstrated a sensitivity of 42.4% (95% confidence interval [CI], 36.8-48.2); specificity, 80.8% (95% CI, 77.5-83.8); positive predictive value, 51.3% (95% CI, 44.9-57.6); and negative predictive value, 74.7% (95% CI, 71.2-77.9). The US-positive group had a higher rate of axillary lymph node dissection (62.8% vs. 32.8%), greater mean number of metastatic nodes (2.6 vs. 0.5), and higher proportion of macrometastasis (94.2% vs. 71.8%) compared with the US-negative group (all p < 0.001). The 10-year recurrence-free survival was lowest in the pN-positive/US-positive group (90.3%; 95% CI, 82.7-94.7), intermediate in the pN-positive/US-negative group (92.4%; 95% CI, 86.7-95.7), and highest in the pN-negative group (97.4%; 95% CI, 95.4-98.5) (log-rank p < 0.001). CONCLUSION: Preoperative axillary US might help assess lymph node metastasis in clinically node-negative patients. Moreover, US positivity was associated with an increased risk of long-term recurrence.