An investigation to identify the factors for negative sentinel lymph node metastasis in early breast cancer cases.

BACKGROUND: Sentinel Lymph Node Biopsy (SLNB) in breast cancer (BC) is a standard procedure. Omission of SLNB in BC is an evolving area in clinical practice and a reasonable option. A retrospective study was conducted to identify cases of negative SLNs. METHODS: A total of 1,956 patients who underwent SLNB for cN0 invasive BC and who did not undergo preoperative chemotherapy were included in this retrospective study. Pathological diagnosis using frozen sections or the OSNA method was used for the diagnosis of SLNs. A multivariate analysis of factors for negative SLNs was performed using logistic regression analysis. RESULTS: Metastasis to SLNs was observed in 379 cases (19.4%). SLN metastasis was not associated with ER, PgR, and HER2 status. A multivariate analysis revealed that the significant factors for negative SLNs were age > 50 years, tumor size ≤ 2 cm and HG of 1. The incidence of SLN metastasis in Luminal B type was significantly higher than the other subtypes, and cases with breast conserving surgery had a significantly lower metastatic rate than total mastectomy. The disease-free survival rate of cases with the above-mentioned factors was favorable regardless of the SLN status. CONCLUSION: Metastasis to SLNs was found in 19.4% of cN0 BC cases. Factors related to negative SLNs were age > 50 years, tumor size ≤ 2cm, and HG of 1, and a positive SLN rate was significantly higher in the Luminal B subtype. The DFS for cases with the above factors was highly favorable. Therefore, conducting SLNB will depend on the above-mentioned characteristics.