Feasibility of sentinel node biopsy in patients with locally advanced breast cancer after neoadjuvant therapy: A pilot study.

Abstract

1120 Background: Sentinel lymph node biopsy (SLNB) is a widely used staging method for patients with early breast cancer. Neoadjuvant Therapy (NT) modifies the anatomical conditions in the breast and axilla, and thus reliability of SLNB after NT remains controversial. The aim of this study is to prospectively evaluate the feasibility and accuracy of this procedure in this particular group of patients. Methods: Between December 2007-2011, 69 patients (mean age 56 years) with locally advanced breast cancer (LABC) were prospectively studied. Patients were T1-4, N0-1, M0. Prior to surgery, 61 patients received chemotherapy (CT) (adryamicin/cyclophosphamide followed by docetaxel) and 8 patients endocrine therapy (ET). Thirty nine patients were initially node-negative (cN0) and 30 patients had clinical/ultrasound node-positive confirmed by cytology (cN1) at presentation. All patients were clinical and ultrasound node-negative after NT. The study contained two groups of patients: group A (validation) included the first 29, associated with an axillary lymph node dissection (ALND) after NT, in order to validate the study, and group B included the last 40, only associated with an ALND when SLNB was positive or not found. Results: Whole SLNB identification rate was 89.9%, and no significant differences were found between patients initially cN0 (92%; 36/39) and initially cN1 (87%; 26/30). Four of 7 patients in whom SLNB was not found had residual nodal metastasis after NT (3 of them were initially cN1). Sentinel lymph nodes were successfully identified in 87% (7/8) of patients after ET and in 90% (55/61) of patients after CT. There was one false negative (FN) case after CT in group A (9% of overall false negative rate, initially cN0) and there were no FN cases after ET. Positive SLNB were higher in initially cN1 group (53%; 16/30) than in initially cN0 group (18%; 7/39). Conclusions: SLNB after NT (CT or ET) is safe and feasible in patients with LABC, not only in initially cN0 but also in initially cN1. It accurately predicts the status of the axilla and avoids unnecessary ALND.