Association of Axillary Dissection With Systemic Therapy in Patients With Clinically Node-Positive Breast Cancer
Authors: Weber Walter P. , Matrai Zoltan , Hayoz Stefanie , Tausch Christoph , Henke Guido , Zimmermann Frank , Montagna Giacomo , Fitzal Florian , Gnant Michael , Ruhstaller Thomas , Muenst Simone , Mueller Andreas , Lelièvre Loïc , Heil Jörg , Knauer Michael , Egle Daniel , Sávolt Ákos , Heidinger Martin , Kurzeder Christian ,   TAXIS Study Writing Group, Zwahlen Daniel R. , Gruber Günther , Ackerknecht Markus , Kuemmel Sherko , Bjelic-Radisic Vesna , Smanykó Viktor , Vrieling Conny , Satler Rok , Hagen Daniela , Becciolini Charles , Bucher Susanne , Simonson Colin , Fehr Peter M. , Gabriel Natalie , Maráz Robert , Sarlos Dimitri , Dedes Konstantin J. , Leo Cornelia , Berclaz Gilles , Fansa Hisham , Hager Christopher , Reisenberger Klaus , Singer Christian F. , Loibl Sibylle , Winkler Jelena , Lam Giang Thanh , Fehr Mathias K. , Kohlik Magdalena , Clerc Karine , Ostapenko Valerijus , Maggi Nadia , Schulz Alexandra , Andreozzi Mariacarla , Goldschmidt Maite , Saccilotto Ramon , Markellou Pagona 
Published: July 2023

ImportanceThe role of axillary lymph node dissection (ALND) to determine nodal burden to inform systemic therapy recommendations in patients with clinically node (cN)–positive breast cancer (BC) is currently unknown.ObjectiveTo address the association of ALND with systemic therapy in cN-positive BC in the upfront surgery setting and after neoadjuvant chemotherapy (NACT).Design, Setting, and ParticipantsThis was a prospective, observational, cohort study conducted from August 2018 to June 2022. This was a preplanned study within the phase 3 randomized clinical OPBC-03/TAXIS trial. Included were patients with confirmed cN-positive BC from 44 private, public, and academic breast centers in 6 European countries. After NACT, residual nodal disease was mandatory, and a minimum follow-up of 2 months was required.ExposuresAll patients underwent tailored axillary surgery (TAS) followed by ALND or axillary radiotherapy (ART) according to TAXIS randomization. TAS removed suspicious palpable and sentinel nodes, whereas imaging-guidance was optional. Systemic therapy recommendations were at the discretion of the local investigators.ResultsA total of 500 patients (median [IQR] age, 57 [48-69] years; 487 female [97.4%]) were included in the study. In the upfront surgery setting, 296 of 335 patients (88.4%) had hormone receptor (HR)–positive and Erb-B2 receptor tyrosine kinase 2 (ERBB2; formerly HER2 or HER2/neu)–negative disease: 145 (49.0%) underwent ART, and 151 (51.0%) underwent ALND. The median (IQR) number of removed positive lymph nodes without ALND was 3 (1-4) nodes compared with 4 (2-9) nodes with ALND. There was no association of ALND with the proportion of patients undergoing adjuvant chemotherapy (81 of 145 [55.9%] vs 91 of 151 [60.3%]; adjusted odds ratio [aOR], 0.72; 95% CI, 0.19-2.67) and type of systemic therapy. Of 151 patients with NACT, 74 (51.0%) underwent ART, and 77 (49.0%) underwent ALND. The ratio of removed to positive nodes was a median (IQR) of 4 (3-7) nodes to 2 (1-3) nodes and 15 (12-19) nodes to 2 (1-5) nodes in the ART and ALND groups, respectively. There was no observed association of ALND with the proportion of patients undergoing postneoadjuvant systemic therapy (57 of 74 [77.0%] vs 55 of 77 [71.4%]; aOR, 0.86; 95% CI, 0.43-1.70), type of postneoadjuvant chemotherapy (eg, capecitabine: 10 of 74 [13.5%] vs 10 of 77 [13.0%]; trastuzumab emtansine–DM1: 9 of 74 [12.2%] vs 11 of 77 [14.3%]), or endocrine therapy (eg, aromatase inhibitors: 41 of 74 [55.4%] vs 36 of 77 [46.8%]; tamoxifen: 8 of 74 [10.8%] vs 6 of 77 [7.8%]).ConclusionResults of this cohort study suggest that patients without ALND were significantly understaged. However, ALND did not inform systemic therapy recommendations.