Temozolomide Versus Radiotherapy as First-Line Therapy for Low-Grade Glioma: Mature Results of a Randomized Phase III Trial (EORTC 22033-26033/NCIC-CTG/TROG/MRC-CTU)

B Brigitta G. Baumert (Department of Radiotherapy, Haaglanden Medisch Centrum, The Hague, the Netherlands) M Monika E. Hegi (Department of Radiation-Oncology (MAASTRO), Maastricht University Medical Center (MUMC) and GROW (School for Oncology), Maastricht, the Netherlands) M Martin J. van den Bent (Erasmus MC University MC Cancer Center, Rotterdam, the Netherlands) A Andreas von Deimling T Thierry Gorlia (European Organisation for Research and Treatment of Cancer, Brussels, Belgium) K Khe Hoang-Xuan (1Hôpital Pitié-Salpêtrière, Paris, France) A Alba A. Brandes (Department of Medical Oncology, AUSL-IRCCS Scienze Neurologiche, Bologna, Italy) P Paul Sargos (Department of Radiotherapy, Institut Bergonié, Bordeaux, France) M Martin J.B. Taphoorn (Department of Neurology, Medical Center Haaglanden, The Hague, the Netherlands) E Elodie Vauleon (Department of Medical Oncology and Radiotherapy, Centre Eugène Marquis, Rennes, France) C Claire Philips (Department of Radiation Oncology and Sir Peter MacCallum Department of Oncology, Peter MacCallum Cancer Centre, University of Melbourne, Melbourne, VIC, Australia) J Johan M. Kros (Department of Pathology, Erasmus Medical Center, Rotterdam, the Netherlands) P Pierre Bady (Neuroscience Research Center and Service of Neurosurgery, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland) W Wolfgang Wick R Roelien Enting (24Department of Neurology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands) M Michele Reni B Brian Thiessen (BC Cancer Agency, Vancouver, BC, Canada) F Frédéric Dhermain J Jacoline E. Bromberg (Erasmus MC University MC Cancer Center, Rotterdam, the Netherlands) J Julian Jacob (Department of Radiation-Oncology, Pitié-Salpêtrière Hospital, AP-HP, Sorbonne University, Paris, France) J Jaap C. Reijneveld (Department of Neurology & Brain Tumor Center Amsterdam, Amsterdam University Medical Center, Amsterdam, the Netherlands) O Olivier Chinot (Hôpital La Timone, Marseille, France) J Johanna M.M. Gijtenbeek (Department of Neurology, Radboud University Medical Centre, Nijmegen, the Netherlands) J John P. Rossiter (Department of Pathology and Molecular Medicine, Queen's University, Kingston, ON, Canada) C Carmen Balana A Ana Luisa Silva Azevedo (Instituto Portugues de Oncologia de Lisboa (IPO), Lissabon, Portugal) P Paul M. Clement (Department of Oncology, KU Leuven, Leuven, Belgium) A Anna Berghoff (3Division of Oncology Medical University of Vienna, Department of Medicine I, Vienna, Austria) T Tzahala Tzuk-Shina (Rambam, Haifa, Israel) M Michael Weller R Robert A. Nordal (Department of Oncology, Arthur Child Comprehensive Cancer Centre, University of Calgary, Calgary, Canada) J Jeremy Rees (National Hospital for Neurology and Neurosurgery, London, United Kingdom) D Denis A. Lacombe (European Organisation for Research and Treatment of Cancer, Brussels, Belgium) W Warren P. Mason (Princess Margaret Cancer Centre, University of Toronto, Toronto, ON, Canada) R Roger Stupp

Abstract

PURPOSE Prognosis in low-grade gliomas (LGGs) remains highly variable, and treatment-related late toxicity is a concern. This trial was comparing single-modality therapies in patients who often survive for years or decades and investigating differential responses according to molecular markers. METHODS Four hundred seventy-eight patients with clinical high-risk LGG (WHO grade 2) were randomly assigned to standard radiotherapy (RT; 28 × 1.8 Gy) or dose-dense temozolomide (TMZ; 75 mg/m 2 once daily × 21/28 days, up to 12 cycles). RESULTS There was no significant difference in progression-free survival or overall survival (OS) between study arms. Analyzable tumor tissue in 73% (351/478) of patients allowed for post hoc reclassification according to the 2021 WHO pathologic criteria. In astrocytoma, IDHmt/1p/19q noncodeleted (n = 178), median OS was similar, 6.6-6.7 years irrespective of arm (0.67-1.44, P = .93). In oligodendroglioma, IDHmt/1p/19q codeleted (n = 109), median OS was 12.9 years (9.4-not reached) with RT and 14.9 years (10.1-number of events not reached) with TMZ (hazard ratio [HR], 0.88 [0.52-1.49], P = .63). In 64 tumors without isocitrate dehydrogenase (IDH) mutations, survival favored the TMZ arm: OS 2.5 (1.8-3.3) versus 4.7 (2.2-7.2) years (HR, 0.47 [0.27-0.82], P = .0068). Patients age 40 years and older fared better than patients younger than 40 years, challenging the current notion of age alone as a negative prognostic factor. CONCLUSION The assigned initial treatment modality did not affect progression-free survival or OS, regardless of the molecular subtype. Combined-modality therapy was not tested in this trial but has since become a standard of care for IDH-mutant astrocytoma. With emerging novel therapeutic options, rational treatment strategies tailored at the individual clinical and pathologic recurrence risk profiles will be needed. The validity of an age cutoff as prognostic factor is challenged when tumors are molecularly classified.

Article Details

Volume / Issue Vol. 1, Issue 1
Published July 02, 2026
ISSN 0732-183X
Publisher Lippincott Williams & Wilkins

Journal Info

Journal of Clinical Oncology

Lippincott Williams & Wilkins

ISSN: 0732-183X Health Sciences

Authors (35)

B

Brigitta G. Baumert

Department of Radiotherapy, Haaglanden Medisch Centrum, The Hague, the Netherlands

M

Monika E. Hegi

Department of Radiation-Oncology (MAASTRO), Maastricht University Medical Center (MUMC) and GROW (School for Oncology), Maastricht, the Netherlands

M

Martin J. van den Bent

Erasmus MC University MC Cancer Center, Rotterdam, the Netherlands

A

Andreas von Deimling

T

Thierry Gorlia

European Organisation for Research and Treatment of Cancer, Brussels, Belgium

K

Khe Hoang-Xuan

1Hôpital Pitié-Salpêtrière, Paris, France

A

Alba A. Brandes

Department of Medical Oncology, AUSL-IRCCS Scienze Neurologiche, Bologna, Italy

P

Paul Sargos

Department of Radiotherapy, Institut Bergonié, Bordeaux, France

M

Martin J.B. Taphoorn

Department of Neurology, Medical Center Haaglanden, The Hague, the Netherlands

E

Elodie Vauleon

Department of Medical Oncology and Radiotherapy, Centre Eugène Marquis, Rennes, France

C

Claire Philips

Department of Radiation Oncology and Sir Peter MacCallum Department of Oncology, Peter MacCallum Cancer Centre, University of Melbourne, Melbourne, VIC, Australia

J

Johan M. Kros

Department of Pathology, Erasmus Medical Center, Rotterdam, the Netherlands

P

Pierre Bady

Neuroscience Research Center and Service of Neurosurgery, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland

W

Wolfgang Wick

R

Roelien Enting

24Department of Neurology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands

M

Michele Reni

B

Brian Thiessen

BC Cancer Agency, Vancouver, BC, Canada

F

Frédéric Dhermain

J

Jacoline E. Bromberg

Erasmus MC University MC Cancer Center, Rotterdam, the Netherlands

J

Julian Jacob

Department of Radiation-Oncology, Pitié-Salpêtrière Hospital, AP-HP, Sorbonne University, Paris, France

J

Jaap C. Reijneveld

Department of Neurology & Brain Tumor Center Amsterdam, Amsterdam University Medical Center, Amsterdam, the Netherlands

O

Olivier Chinot

Hôpital La Timone, Marseille, France

J

Johanna M.M. Gijtenbeek

Department of Neurology, Radboud University Medical Centre, Nijmegen, the Netherlands

J

John P. Rossiter

Department of Pathology and Molecular Medicine, Queen's University, Kingston, ON, Canada

C

Carmen Balana

A

Ana Luisa Silva Azevedo

Instituto Portugues de Oncologia de Lisboa (IPO), Lissabon, Portugal

P

Paul M. Clement

Department of Oncology, KU Leuven, Leuven, Belgium

A

Anna Berghoff

3Division of Oncology Medical University of Vienna, Department of Medicine I, Vienna, Austria

T

Tzahala Tzuk-Shina

Rambam, Haifa, Israel

M

Michael Weller

R

Robert A. Nordal

Department of Oncology, Arthur Child Comprehensive Cancer Centre, University of Calgary, Calgary, Canada

J

Jeremy Rees

National Hospital for Neurology and Neurosurgery, London, United Kingdom

D

Denis A. Lacombe

European Organisation for Research and Treatment of Cancer, Brussels, Belgium

W

Warren P. Mason

Princess Margaret Cancer Centre, University of Toronto, Toronto, ON, Canada

R

Roger Stupp