Abstract
BACKGROUND: Given the rarity of medulloblastoma in adults (fewer than 50 incident cases annually across Canada), the optimal chemotherapy strategy in this population is unknown. The management of adult medulloblastomas is thought to vary from institution to institution. Guidelines often omit suggestions for specific chemotherapy regimens, reflecting the lack of high quality evidence in this population. We sought to understand Canadian adult medulloblastoma practice patterns, hoping to inform future quality metrics and guidelines. METHODS: In March 2022 a 30-question survey was sent out to 71 adult neuro-oncology clinicians on the Canadian Adolescent and Young Adult national rounds mailing list. Snowball sampling was permitted. RESULTS: There were 25 responses (up to 35% response rate). Radiation oncologists (11), neuro-oncologists (8), medical oncologists (4), and neurosurgeons (2) responded from 6/10 Canadian provinces. They each treated on average 1.6 medulloblastoma patients per year. Most (61% of respondents) said that medulloblastoma molecular subgrouping was always done at their centre. Half (50%) indicated that cerebrospinal fluid testing was always done at diagnosis. The most common (64%) radiation regimen was 36 Gy (in 20 fractions) craniospinal irradiation + 18 Gy (in 10 fractions) boost. Concomitant chemotherapy was rarely given (75% of respondents included chemotherapy less than half of the time). Adjuvant chemotherapy was frequently administered (79% of respondents give it more than half of the time). The most common adjuvant chemotherapy was Cisplatin/Lomustine/Vincristine (57%), but other regimens included Cisplatin/Lomustine/Vincristine alternating with Cyclophosphamide/Vincristine (21%), Cisplatin/Cyclophosphamide/Vincristine (14%), and carboplatin-based regimens (14%). Respondents noted challenges prescribing chemotherapy in this population: drug toxicities, limited resources, and clinical uncertainty. There was support for standard of care adult medulloblastoma guidelines in 92% of respondents. CONCLUSIONS: There is significant practice variation among Canadian neuro-oncology centres treating adult medulloblastoma. This variation can serve as an opportunity for quality improvement and clinical research.