A. Iribas1, K. Özkaya Toraman2, S. Büyükkapu Bay3, Y. Dizdar1, R. Kebudi3, E. Kaytan Saglam4, and F. Agaoglu5; 1Istanbul University, Faculty of Medicine, Department of Radiation Oncology, Istanbul, Turkey, istanbul, Turkey, 2Istanbul University, Institute of Oncology, Radiation Oncology Department, Istanbul, Turkey, 3Istanbul University, Oncology Institute, Division of Pediatric Hematology Oncology, Istanbul, Turkey, istanbul, Turkey, 4Istanbul University, Institute of Oncology ; Memorial Sisli Hospital, Department of Radiation Oncology, Istanbul, Turkey, 5Acibadem Mehmet Ali Aydinlar University Atakent Hospital, Istanbul, Turkey
Purpose/Objective(s): Survival is poor in relapsed medulloblastoma. Despite salvage treatments, retaining tumor control is difficult. While the role of re-irradiation in other recurrent brain tumors is growing, strong data/proof of its effectiveness on medulloblastoma is still lacking. Materials/
Methods: Eighteen years old or younger medulloblastoma patients, who were diagnosed between 1990 and 2020 and underwent re-irradiation for recurrent disease, were evaluated retrospectively. Patient and tumor characteristics, treatment details, progression-free survival (PFS) and overall survival (OS) after recurrence, and acute and late effects of treatment were evaluated. The retrospective study design has been approved by the institutional review board. Results: Twenty-seven recurrent medulloblastoma patients who received re-irradiation were included. Six patients were in the standard-risk group, and 21 patients were in the high-risk group at initial diagnosis. Recurrence was intracranial in seven (26%) patients, neuro-axial spread in six (22%) patients, and both intracranial and neuro-axial spread in 14 (52%) patients. Among these patients, 10 of them could be operated on for recurrence. At relapse 19 received craniospinal irradiation (CSI), and eight received focal radiotherapy (RT). One-year and two-year PFS were 57% and 33% and 1-year and 2-year OS were 67% and 44% respectively. In univariate analysis, the median survival after relapse was significantly higher in males (18 vs 78 months p:0.043), in those who had a relapse 24 months after diagnosis (16 vs 88 months p:0.007), and in those who received chemotherapy (ChT) after re-RT (66 vs 8 months p: 0.01). There was no difference in survival between focal irradiation and CSI (p:0.81). One patient has developed multiple basal-cell skin carcinomas in the radiation field. Conclusion: In recurrent medulloblastoma, re-irradiation is a treatment option that can increase disease control.
