ObjectiveTo explore the risk factors affecting sentinel lymph node (SLN) metastasis in patients with early-stage (N0) breast cancer and establish a predictive model for SLN metastasis, so as to assist in decision-making of axillary surgery in clinical practice. MethodsThe unilateral early-stage breast cancer patients who underwent surgical treatment and SLN biopsy at the Affiliated Hospital of Southwest Medical University from September 2020 to December 2023 were selected as the study subjects. The univariate and multivariable logistic regression analyses were adopted to analyze the relevant risk factors of SLN metastasis, then a predictive model evaluating the risk of SLN metastasis was constructed. The area under receiver operating characteristic curve (AUC) was used to assess the distinguishing ability of risk factors for SLN metastasis. ResultsA total of 351 patients with early-stage breast cancer patients who met the inclusion criteria were enrolled, 136 of whom with SLN metastasis, the SLN metastasis rate was 38.7%. The results of the multivariate logistic regression analysis showed that the maximum tumor diameter >2.5 cm, estrogen receptor (ER) positive, Ki-67 >20%, and vascular invasion were the risk factors affecting SLN metastasis [maximum tumor diameter: OR(95%CI)=1.897(1.186, 3.034), P=0.008; ER positive: OR(95%CI)=2.721(1.491, 4.967), P=0.001; Ki-67 >20%: OR(95%CI)=1.825(1.125, 2.960), P=0.015; vascular invasion: OR(95%CI)=2.858(1.641, 4.976), P<0.001]. The AUC for the SLN metastasis by these four factors was 0.693(0.637, 0.749), with a sensitivity and specificity of 70.59% and 57.21%, respectively. ConclusionsThe results from this study suggest that SLN biopsy is recommended to guide postoperative adjuvant treatment strategies for cN0 early-stage breast cancer patients with a maximum tumor diameter >2.5 cm, ER positivity, Ki-67>20%, and vascular invasion. However, the predictive model constructed based on these four factors in this study has a general ability to distinguish the occurrence of SLN metastasis, then the reasons can be further analyzed in the future.