Predictors of sentinel lymph node metastasis in Chinese women with clinical T1-T2 N0 breast cancer and a normal axillary ultrasound

Background The clinicopathological predictors of sentinel lymph node (SLN) metastasis in clinical T1-T2 N0 (cT1-T2 N0) patients with a normal axillary ultrasound (AUS) are unclear. Purpose To assess the association between clinicopathological characteristics of a primary tumor and SLN metastasis in cT1-T2 N0 patients with a normal AUS. Material and Methods Patients who were diagnosed with cT1-T2 N0 invasive breast cancer and who obtained normal AUS results between October 2016 and September 2018 in a single hospital were included. Clinicopathological data were collected to explore the predictors of SLN metastasis using a multivariate logistic regression model. Results SLN metastasis occurred in 26 patients (18.4%) among 141 AUS-normal patients, of which 24 cases (17.0%) had one or two nodal involvements. In the univariate analysis, tumor location, estrogen receptor (ER) status, progesterone receptor (PR) status, and lymphovascular invasion (LVI) were significantly associated with SLN metastasis (P < 0.05). The multivariate analysis showed that tumor location in the upper outer quadrant (odds ratio [OR] = 4.49, 95% confidence interval [CI] = 1.63-12.37; P = 0.004), positive PR status (OR = 13.35, 95% CI = 1.60-111.39; P = 0.017), and positive LVI (OR = 8.66, 95% CI = 2.20-34.18; P = 0.002) were independent high-risk factors for SLN metastasis. The area under the receiver operating characteristic curve of the regression model was 0.787 (95% CI = 0.694-0.881; P < 0.001). Conclusion Tumor location in the upper outer quadrant, positive PR, and LVI status were found to be significantly high-risk factors for SLN metastasis among cT1-T2 N0 breast cancer patients with a normal AUS result.