Omission of Axillary Dissection Following Nodal Downstaging With Neoadjuvant Chemotherapy
Authors: Montagna Giacomo , Mrdutt Mary M. , Sun Susie X. , Hlavin Callie , Diego Emilia J. , Wong Stephanie M. , Barrio Andrea V. , van den Bruele Astrid Botty , Cabioglu Neslihan , Sevilimedu Varadan , Rosenberger Laura H. , Hwang E. Shelley , Ingham Abigail , Papassotiropoulos Bärbel , Nguyen-Sträuli Bich Doan , Kurzeder Christian , Aybar Danilo Díaz , Vorburger Denise , Matlac Dieter Michael , Ostapenko Edvin , Riedel Fabian , Fitzal Florian , Meani Francesco , Fick Franziska , Sagasser Jacqueline , Heil Jörg , Karanlık Hasan , Dedes Konstantin J. , Romics Laszlo , Banys-Paluchowski Maggie , Muslumanoglu Mahmut , Perez Maria Del Rosario Cueva , Díaz Marcelo Chávez , Heidinger Martin , Fehr Mathias K. , Reinisch Mattea , Tukenmez Mustafa , Maggi Nadia , Rocco Nicola , Ditsch Nina , Gentilini Oreste Davide , Paulinelli Regis R. , Zarhi Sebastián Solé , Kuemmel Sherko , Bruzas Simona , di Lascio Simona , Parissenti Tamara K. , Hoskin Tanya L. , Güth Uwe , Ovalle Valentina , Tausch Christoph , Kuerer Henry M. , Caudle Abigail S. , Boileau Jean-Francois , Boughey Judy C. , Kühn Thorsten , Morrow Monica , Weber Walter P. 
Published: April 2024

ImportanceData on oncological outcomes after omission of axillary lymph node dissection (ALND) in patients with breast cancer that downstages from node positive to negative with neoadjuvant chemotherapy are sparse. Additionally, the best axillary surgical staging technique in this scenario is unknown.ObjectiveTo investigate oncological outcomes after sentinel lymph node biopsy (SLNB) with dual-tracer mapping or targeted axillary dissection (TAD), which combines SLNB with localization and retrieval of the clipped lymph node.Design, Setting, and ParticipantsIn this multicenter retrospective cohort study that was conducted at 25 centers in 11 countries, 1144 patients with consecutive stage II to III biopsy-proven node-positive breast cancer were included between April 2013 and December 2020. The cumulative incidence rates of axillary, locoregional, and any invasive (locoregional or distant) recurrence were determined by competing risk analysis.ExposureOmission of ALND after SLNB or TAD.Main Outcomes and MeasuresThe primary end points were the 3-year and 5-year rates of any axillary recurrence. Secondary end points included locoregional recurrence, any invasive (locoregional and distant) recurrence, and the number of lymph nodes removed.ResultsA total of 1144 patients (median [IQR] age, 50 [41-59] years; 78 [6.8%] Asian, 105 [9.2%] Black, 102 [8.9%] Hispanic, and 816 [71.0%] White individuals; 666 SLNB [58.2%] and 478 TAD [41.8%]) were included. A total of 1060 patients (93%) had N1 disease, 619 (54%) had ERBB2 (formerly HER2)–positive illness, and 758 (66%) had a breast pathologic complete response. TAD patients were more likely to receive nodal radiation therapy (85% vs 78%; P = .01). The clipped node was successfully retrieved in 97% of TAD cases and 86% of SLNB cases (without localization). The mean (SD) number of sentinel lymph nodes retrieved was 3 (2) vs 4 (2) (P &amp;lt; .001), and the mean (SD) number of total lymph nodes removed was 3.95 (1.97) vs 4.44 (2.04) (P &amp;lt; .001) in the TAD and SLNB groups, respectively. The 5-year rates of any axillary, locoregional, and any invasive recurrence in the entire cohort were 1.0% (95% CI, 0.49%-2.0%), 2.7% (95% CI, 1.6%-4.1%), and 10% (95% CI, 8.3%-13%), respectively. The 3-year cumulative incidence of axillary recurrence did not differ between TAD and SLNB (0.5% vs 0.8%; P = .55).Conclusions and RelevanceThe results of this cohort study showed that axillary recurrence was rare in this setting and was not significantly lower after TAD vs SLNB. These results support omission of ALND in this population.