Sentinel lymph node biopsy validation for large tumors.

Background: Sentinel lymph node biopsy (SLNB) remains under discussion for large size tumors. The aim of this work has been to study the false negative rate (FNR) of SLNB for large tumors and predictive factors of false negative (FN).

Materials And Methods: A study of a multicentric cohort, involved patients presenting N0 breast cancer with a SLNB eventually completed by complementary axillary lymph node dissection (cALND). The main criteria were the FNR and the predictive factors of FN.

Results: 12.415 patients were included: 748 with tumors ≥30 mm, 1101 with tumors >20 and < 30 mm and 10.566 with tumors ≤20 mm, with a cALND respectively for 501 patients (67%), 523 (62.1%) and 2775 (26.3%). The FNR were respectively: 3.05% (IC95%: 1.3-4.8) for tumors ≥30 mm*, 3.5% (1.8-5.2) for tumors >20 and < 30 mm*, 1.8% (1-2.4) for tumors ≤20 mm (p < 0.05) (*Not significant). At multivariate analysis, SN number harvested ≤2 (OR:2.0, p = 0.023) and tumor size >20 and < 30 mm (OR:2.07, p = 0.017) were significant predictive factors of FN, without significant value for tumor size ≥30 mm (OR:1.83, p = 0.073).

Conclusion: The FNR of SLNB was not higher amongst large size tumors compared to tumors of a smaller size. These results support the validation of SNLB for tumors up to 50 mm.