Radiotherapy for Recurrent Medulloblastoma in Children and Adolescents: Survival after Re-Irradiation and First-Time Irradiation

Simple Summary The treatment options for children with recurrent medulloblastoma are often limited due to extensive previously received treatments after initial diagnosis. Especially, repeated radiotherapy is associated with significant side-effects. In this study, we study the impact on survival of repeated radiotherapy at recurrence for patients with previous irradiation, as well as first irradiation at recurrence when no previous radiotherapy was applied. We find that repeated radiotherapy provides a short-time benefit in terms of survival, but survival ten years after recurrence is not significantly improved. At the same time, we find that applying radiotherapy at recurrence when patients received no previous irradiation did significantly improve survival, both short and long term.Abstract Background: Radiotherapy (RT) involving craniospinal irradiation (CSI) is important in the initial treatment of medulloblastoma. At recurrence, the re-irradiation options are limited and associated with severe side-effects. Methods: For pre-irradiated patients, patients with re-irradiation (RT2) were matched by sex, histology, time to recurrence, disease status and treatment at recurrence to patients without RT2. Results: A total of 42 pre-irradiated patients with RT2 were matched to 42 pre-irradiated controls without RT2. RT2 improved the median PFS [21.0 (CI: 15.7-28.7) vs. 12.0 (CI: 8.1-21.0) months] and OS [31.5 (CI: 27.6-64.8) vs. 20.0 (CI: 14.0-36.7) months]. Concerning long-term survival after ten years, RT2 only lead to small improvements in OS [8% (CI: 1.4-45.3) vs. 0%]. RT2 improved survival most without (re)-resection [PFS: 17.5 (CI: 9.7-41.5) vs. 8.0 (CI: 6.6-12.2)/OS: 31.5 (CI: 27.6-NA) vs. 13.3 (CI: 8.1-20.1) months]. In the RT-na & iuml;ve patients, CSI at recurrence improved their median PFS [25.0 (CI: 16.8-60.6) vs. 6.6 (CI: 1.5-NA) months] and OS [40.2 (CI: 18.7-NA) vs. 12.4 (CI: 4.4-NA) months]. Conclusions: RT2 could improve the median survival in a matched cohort but offered little benefit regarding long-term survival. In RT-na & iuml;ve patients, CSI greatly improved their median and long-term survival.