Abstract OT2-1-01: Feasibility of sentinel node detection after neoadjuvant chemotherapy for patient with proved axillary lymph node involvement: the French prospective multiinstitutional GANEA 2 ongoing trial
Authors: Classe J-M , Bordes V , Gimbergues P , Tunon de Lara C , Faure C , Belichard C , Houpeau J-L , Raro P , Dupré P-F , Houvenaeghel G , Barranger E , Marchal F , Deblay P , Rouanet P , Lefebvre C , Bourcier C , Alran S 
Published: August 2014

Abstract
Background: Half of the patient treated with neoadjuvant chemotherapy (NAC) for a large operable breast cancer have no axillary lymph node involvement at the time of surgery. Sentinel lymph node detection (SLND), performed after NAC, would select patient who might be spared of an axillary lymphadenectomy (AL). In a previous study, we assessed the feasibility of SLND after NAC in the case of patients without axillary involvement1. Previous published series have shown that, for patients with an axillary lymph node involvement before treatment, SLND after NAC bring a low detection rate and a high false negative rate (FNR), making this technique contra indicated in this situation.
The aim of GAEA 2 study is to assess the FNR of SLND after NAC in the particular case of patients with a proven axillary lymph node involvement before NAC.
Patients and Method: Prospective study validated by scientific and ethical National boards.
Inclusion criteria: FIGO stage T2-T3 infiltrating breast carcinoma, indication of NAC, surgery (radical or conservative) after NAC and signature of the consent form,
Exclusion criteria: locally advanced, inflammatory breast cancer, local relapse, previous surgical removal of the tumour, mental disorder, pregnancy or no contraceptive method, contra-indication to NAC, NAC interrupted due to progressive disease.
Design of the study: Indication to plan a NAC, control of inclusion and exclusion criteria, consent form signature, axillary sonography before NAC to select the patient in group 1 (patient with a proven lymph node involvement treated with SLND and complementary AL) or 2 (no involvement proven treated with SLND + AL only if detection failure or involvement). Surgery, breast and axilla, performed 4 to 6 weeks after NAC.
Pathological procedure: No intraoperative histopathological examination. Pathological analysis, of sentinel and non sentinel nodes, carried out according to standard methods and classified according the last American Joint Committee staging system and Sataloff classification.
FNR is defined as the ratio of patients with a false negative case of SLNB to the patients with at least one involved node, SLN or not, among patients with SLN detected.
The hypothesis: Taking into account results of lymph node involvement rate found in GANEA 1, to estimate our hypothesis of a FNR between 10 and 15% with a 95% confidence interval will require to include 858 patients in order to obtain 260 patient with a proven axillary lymph node involvement (group 1).
A standard follow up is planned for each patient, with a clinical breast and axillary examination two times/ year and an annual mammography, for five years. In case of clinical axillary relapse a fine needle aspiration must be performed guided with sonography.
Results: On May 31, 2012, 341 patients were included from 16 French institutions; 130 patients with a proven SLN involvement before NAC and 211 with SLN free of metastasis.
1Classe JM, Bordes V, et al. Sentinel lymph node biopsy after neoadjuvant chemotherapy for advanced breast cancer: results of Ganglion Sentinelle et Chimiotherapie Neoadjuvante, a French prospective multicentric study. J Clin Oncol. 2009 Feb.
Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr OT2-1-01.