National multicentered retrospective review of salvage therapy for pediatric medulloblastoma: a Canadian experience

BackgroundAn effective strategy for salvage therapy in refractory or relapsed childhood brain tumours is yet to be established.MethodsA national retrospective review of 135 children diagnosed with treatment refractory or recurrent MB from 2000 to 2021 at 5 academic Canadian pediatric neurosurgical centers was performed.ResultsThe mean age at diagnosis was 7.09 years (SD 4.37) with a male predominance (64.4%) and 17.8% under the age of 3 years. Most of the tumour histology was classic MB. Just over a third of children experienced disease progression during or after adjuvant therapy with an average disease-free interval of 17.55 months (SD 4.04). The majority of children experienced local disease progression (55.3%). Just over thirty percent of children succumbed to disease progression (n = 47, 34.8%). The mean age of first srelapse was 10.85 years (SD 7.10) and was identified on average 17.55 months (SD 9.76) from diagnosis. Most children with progressive disease (82.9%) were deceased at the time of writing. The mean time from first and second relapse to death was 27.19 months (SD 36.17) and 9.93 months (11.92) respectively. The cause of death was most commonly disease progression followed by a medical complication. Initial response to salvage therapy with recurrence and biopsy at index surgery were independently associated with mortality. The children were followed up for a mean interval of 83.17 months (SD 54.15).ConclusionRecurrent disease in childhood medulloblastoma after provision of upfront therapy confers a very poor prognosis despite salvage therapy and is an unmet need for further study and therapeutic development.