Abstract
BACKGROUND: In EORTC study 22033−26033 primary treatment with radiotherapy was compared to temozolomide chemotherapy alone in patients with high-risk low-grade glioma. There was no difference in progression-free survival between treatment modalities [Baumert et al. Lancet Oncol. 2016;17:1521-1532]. Considering the potential long-term deleterious impact of radiotherapy on memory functioning, this study also focused on the question whether temozolomide chemotherapy would be associated with a more favorable neurotoxic profile regarding memory functioning. METHODS: Memory functioning using the Rey Auditory Verbal Learning Test (Free Recall and Delayed Recall) was evaluated at baseline and subsequently every 6 months. Minimal compliance for statistical analyses was set at 60%. Total score over 5 trials of 15 items for free recall and total score on delayed recall were used as memory outcome measures. Using a mixed linear model memory functioning was compared between treatment arms and over time. RESULTS: In dedicated centers, a total of 98 patients (radiotherapy 52 patients, temozolomide 46 patients) were assessed at baseline. At 12 months compliance had dropped to 66%, thus analyses were restricted to baseline, 6 months, and 12 months. At baseline, patients in either treatment arm did not differ in the memory functioning, gender, age, or educational level. When compared to healthy matched controls, patients in both treatment arms at baseline had significantly lower free recall (p <.001) but not delayed recall. Over the relatively short time course of 1 year there was no change in memory functioning in either treatment arm. CONCLUSION: In patients with high-risk low-grade glioma there is no indication that radiotherapy has a more deleterious effect on memory function when compared to temozolomide chemotherapy from baseline up to 12 months follow-up. Further data maturation is needed not only for overall survival analyses but also for the full appreciation of long-term effects of radiotherapy in these patients.