Abstract: Objective To investigate the correlation between tumor-infiltrating lymphocyte (TIL) and lymph node metastasis in patients with cT1N0M0 breast cancer and the value of TIL density in predicting sentinel lymph node metastasis (SLNM). Methods The clinical data of patients with cT1N0M0 breast cancer who underwent surgery in our hospital from January 2008 to December 2016 were retrospectively analyzed. The histopathological assessment of TIL density was performed in the biopsy specimens before surgery. The multivariable logistic regression and the receiver operating characteristic (ROC) curve were used to analyze the value of TIL in predicting SLNM. Results A total of 153 patients with cT1N0M0 stage breast cancer were included in the analysis, of which 30 patients (19.6%) developed SLNM. The TIL density was related to estrogen receptor (ER) status (P<0.001), progesterone receptor (PgR) status (P=0.003), human epidermal growth factor receptor 2 (HER2) status (P=0.029), Ki67 expression (P=0.025), and nuclear grade (P=0.026). Multivariable logistic regression showed that TIL density (OR=1.40, 95%CI: 1.15-1.71, P=0.001) was an independent factor affecting SLNM in cT1N0M0 breast cancer , and its area under the ROC curve (AUC) was 0.755 (95%CI: 0.680-0.830, P<0.001). Conclusions TIL density is closely related to SLNM in cT1N0M0 breast cancer and may be a potential predictor of SLNM.

Key words: Breast cancer, Lymph node metastasis, Tumor infiltrating lymphocyte, Predictive value