Does The Tumor Location Affect The Accuracy of Sentinel Lymph Node Biopsy In Breast Cancer? A Single Institute Experience

Background: Sentinel lymph node biopsy (SLNB) can give an idea about the nodal status with high accuracy. Objective: To assess the effect of breast cancer location on SLNB accuracy regarding identification rate (IR), accuracy rate and false negativity rate (FNR). Methods: Breast cancer patients with positive axilla who were scheduled for axillary lymph node dissection (ALND) were included. They were randomly allocated into two groups: Group I (G I) included patients with laterally located breast cancer while Group II (G II) included patients with medially located breast cancer. Four ml of Methylene blue (1%) was injected in the peritumoral tissue. SLNB was taken for histopathological examination while ALND was completed in all cases. SLN IR, FNR and accuracy rate were assessed in both groups. Results: This study included 104 female patients; 63 (60.6%) in GI whereas 41(39.4%) in GII. SLN identification was done successfully in 92% in G I and 87.8% in G II with no significant difference. In G I; Out of the 58 patients in whom SLN was identified; SLN was positive in 54 (93.1%) cases and negative in 4(6.9%) cases while in G II; SLN was positive in 31 out of 36 (86.1%) cases and negative in 5 (13.9%) cases with no significant difference regarding SLN accuracy or FNR. Conclusion: The tumor location doesn’t affect axillary SLNB regarding identification rate, accuracy rate and false negativity rate. Methylene blue alone is still efficacious in SLNB lymphatic mapping especially in developing countries because of its low cost.