Re-irradiation in Children With Recurrent Medulloblastoma

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.

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.

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.

In recurrent medulloblastoma, re-irradiation is a treatment option that may prolong survival.