Re‐irradiation in Children With Recurrent Medulloblastoma

PURPOSE: Achieving better survival rates for patients with relapsed medulloblastoma remains a challenge. Despite various attempts at salvage treatment, achieving tumor control proves challenging. While re-irradiation is increasingly considered in the management of other recurrent brain tumors, conclusive evidence of its effectiveness in treating medulloblastoma is still lacking. MATERIALS AND METHODS: Pediatric and adolescent patients with medulloblastoma aged 18 years or younger, 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), overall survival (OS) after recurrence, and the acute and late effects of treatment were evaluated. RESULTS: Twenty-seven recurrent medulloblastoma patients who received re-irradiation were included. At initial diagnosis, six patients were in the standard-risk group and 21 in the high-risk group. Recurrence manifested as intracranial in seven (26%) patients, neuro-axial spread in six (22%) patients, and both intracranial and neuro-axial spread in 14 (52%) patients. Of these, 10 underwent surgery for recurrence. Nineteen patients received craniospinal irradiation (CSI) at relapse. The 2- and 5-year PFS were 33% ± 9.1% and 19% ± 8.1%, while the 2- and 5-year OS were 44% ± 9.7% and 24% ± 8.4%, respectively. In the univariable analysis, the median survival after relapse was significantly higher in males (13 vs. 24 months, p = 0.043), in those who relapsed later than 24 months after diagnosis (9 vs. 38 months, p = 0.007), and in those who received chemotherapy after re-RT (7 vs. 24 months, p = 0.010). There was no significant difference in survival between the focal irradiation and CSI groups (p = 0.817). One patient developed multiple basal cell skin carcinomas within the radiation field. CONCLUSION: In recurrent medulloblastoma, re-irradiation is a treatment option that may prolong survival.