Application of sentinel node biopsy in breast cancer patients with clinically negative and positive axilla and role of axillary ultrasound examination to select patients for sentinel node biopsy

Purpose: To evaluate the identification rate and the false-negative (FN) rate of sentinel lymph node biopsy (SLNB) using preoperative axillary ultrasound (AU) in patients with clinically negative and positive axilla and to prove that SLNB could also be performed in clinically axillary positive patients. Methods: Three hundred and fifty seven consecutive T1-2 invasive breast cancer patients with clinically negative or positive axilla were enrolled in our Institution between 2006 and 2011. All patients had preoperative AU, and underwent SLNB followed by breast conserving surgery or mastectomy with level 1, 2 axillary dissection. SLNB was performed using 5 mL of 1% methylene blue. The identification (ID) rate and the FN rate of SLNB were calculated for patients with clinically negative and positive axilla, and for patients with negative AU. Results: Two hundred thirty two patients (65%) were clinically axillary-negative and 125 (35%) were clinically axillary-positive. The ID rates of SLNB were 91 and 89% and the FN rates were 7 and 9%, respectively, in patients with clinically negative and positive axilla. The ID rate of SLNB increased to 94% and the FN rate decreased to 4% after the exclusion of 85 patients (24%) with metastatic lymph nodes on AU. Conclusion: SLNB can be safely applied to T1 tumors regardless of the clinical status of the axilla. Use of AU before SLNB significantly increases the ID rate and decreases the FN rate of SLNB in clinically axillary negative as well as in positive patients.