Reduced-dose WBRT as consolidation treatment for patients with primary CNS lymphoma: an LOC network study
Paul Lesueur, Gandhi Damaj, Khê Hoang‐Xuan, Virginie Roland, Anna Schmitt, Olivier Chinot, Michel Fabbro, Philippe Agapé, Cécile Moluçon‐Chabrot, Safia Chebrek, Agustí Alentorn, L. Feuvret, Daniel Delgadillo, Dinu Stefan, Sylvain Choquet, Lucia Nichelli, Karima Mokhtari, Bertrand Mathon, Sylvain Dureau, Carole Soussain, Caroline Houillier
Abstract
The optimal consolidation strategy for primary central nervous system lymphoma (PCNSL) remains controversial. Preventing radio-induced neurotoxicity of consolidation treatment through reduced-dose whole-brain radiotherapy (rdWBRT) at a dose of 23.4 Gy is an interesting alternative to conventional WBRT in patients aged <60 years. From the LOC Network (Network for Oculo-cerebral Lymphomas) database, we retrospectively selected patients with PCNSL aged <60 years who showed complete (CR) or unconfirmed CR after high-dose methotrexate-based chemotherapy and had received consolidation rdWBRT as the first-line treatment. If available, prospective neuropsychological follow-ups were reported. Twenty-nine patients diagnosed between 2013 and 2018 met the study selection criteria. Nine (31%) patients experienced relapse during the follow-up, with a median time from radiotherapy to recurrence of 8.7 months (interquartile range, 4-11.5). Five of those patients received salvage treatment and consolidation with intensive chemotherapy and autologous stem cell transplantation. Progression-free survival rates were 89% (95% confidence interval [CI] 79%-100%), 72% (95% CI, 56%-88%), and 69% (95% CI, 52%-85%) at 1, 2, and 5 years, respectively. Overall survival rates were 100%, 89% (95% CI, 79%-100%), and 86% (95% CI, 74%-99%) at 1, 2, and 5 years, respectively, and were consistent with those observed for standard-dose WBRT (sdWBRT). No prognostic factor was identified. The results of the 36-month neuropsychological follow-up for a subset of patients appeared reassuring, with most patients exhibiting maintenance of or improvements in their baseline conditions. Our results, combined with phase 2 study results, support the use of rdWBRT instead of sdWBRT as a consolidation treatment in <60-year-old patients showing CR after induction treatment.