• Jean Raymond, Anass Benomar, Jean-Christophe Gentric, Elsa Magro, Lorena Nico, Emma Bacchus, Ruby Klink, Daniela Iancu, Alain Weill, Daniel Roy, Michel W Bojanowski, Chiraz Chaalala, Omer Eker, Isabelle Pelissou-Guyotat, Michel Piotin, Sorin Aldea, Charlotte Barbier, Thomas Gaberel, Chrysanthi Papagiannaki, Stéphane Derrey, Thanh N Nguyen, Mohamad Abdalkader, Christophe Cognard, Anne-Christine Januel, Jean-François Sabatier, Vincent Jecko, Xavier Barreau, Vincent Costalat, Marine Le Corre, Jean-Yves Gauvrit, Xavier Morandi, Alessandra Biondi, Laurent Thines, Hubert Desal, Romain Bourcier, Rémy Beaujeux, François Proust, Geraldine Viard, Guylaine Gevry, Tim E Darsaut, and TOBAS Collaborative Group.
• Department of Radiology, Service of Neuroradiology, Centre Hospitalier de l'Université de Montréal (CHUM), Montreal, Quebec, Canada. Electronic address: jean.raymond@umontreal.ca.
• World Neurosurg. 2023 Apr 1; 172: e611e624e611-e624.

BackgroundThe Treatment of Brain Arteriovenous Malformations Study (TOBAS) is an all-inclusive pragmatic study comprising 2 randomized clinical trials (RCTs). Patients excluded from the RCTs are followed in parallel treatment and observation registries, allowing a comparison between RCT and registry patients.MethodsThe first randomized clinical trial (RCT-1) offers 1:1 randomized allocation of intervention versus conservative management for patients with arteriovenous malformation (AVM). The second randomized clinical trial (RCT-2) allocates 1:1 pre-embolization or no pre-embolization to surgery or radiosurgery patients judged treatable with or without embolization. Characteristics of RCT patients are reported and compared to registry patients.ResultsFrom June 2014 to May 2021, 1010 patients with AVM were recruited; 498 patients were observed and 373 were included in the treatment registries. Randomized allocation in RCT-1 was applied to 139 (26%) of the 512 patients (including 127 of 222 [57%] with unruptured AVMs) considered for curative treatment. RCT-1 AVM patients differed (in rupture status, Spetzler-Martin grade and baseline modified Rankin Score) from those in the observation or treatment registries (P < 0.001). Most patients had small (<3 cm; 71%) low-grade (Spetzler-Martin I-II; 64%) unruptured (91%) AVMs. The allocated management was conservative (n = 71) or curative (n = 68), using surgery (n = 39), embolization (n = 16), or stereotactic radiosurgery (n = 13). Pre-embolization was considered for 179/309 (58%) patients allocated/assigned to surgery or stereotactic radiosurgery; 87/179 (49%) were included in RCT-2. RCT-2 patient AVMs differed in size, eloquence and grade from patients of the pre-embolization registry (P < 0.01). Most had small (<3 cm in 82%) low-grade (83%) AVMs in non-eloquent brain (64%).ConclusionsPatients included in the RCTs differ significantly from registry patients. Meaningful results can be obtained if multiple centers actively participate in the TOBAS RCTs.Copyright © 2023 Elsevier Inc. All rights reserved.

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