[Sentinel lymph node biopsy in breast cancer: a validation study and preliminary results].

Introduction: Sentinel lymph node biopsy (SLNB) has been recently proven to be an accurate staging method for breast cancer, replacing axillary lymph node dissection (ALND) in selected cases. We present our initial experience and the process of introduction and implementation of SLNB in a University Hospital setting.
Material and Methods: 46 SLNB were performed in 42 consecutive female patients with invasive breast cancer. Treatment included 0.4mCi-2mCi of Tc-99m rhenium colloid injected either 2 hours before surgery (0.4 mCi) or the night before surgery (2 mCi). Four milliliters of Patent Blue V were injected peritumoral 10 minutes prior to skin incision in all patients. Following SLNB all women underwent subsequent ALND. Sentinel nodes were processed both with multiple (10-15) H&E sections and immunohistochemistry with cytokeratin antibodies stain.
Results: Blue dye, isotope or the combination of both identified 43/46 (93%) of the sentinel lymph nodes. ALND was performed only unilaterally in 4 patients with bilateral breast cancer bringing the total evaluable SLNB to 39. In the 39 patients in whom the sentinel node was successfully identified and underwent ALND, the SLNB was true positive (TP) in 17/39 (44%) true negative (TN) in 20/39 (51%) and false negative in 2/39 [(5%), both T2 lesions] with overall accuracy of 95%. In the last 10 cases all sentinel nodes were successfully identified with 70% TP and 30% TN.
Conclusions: Experience with at least 30-40 consecutive cases for safe implementation of SLNB in clinical practice. Specific training and dedication is required for the entire team involved, including surgeons, nuclear medicine physicians and technicians and pathologists.