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The introduction of proton radiotherapy in the Netherlands resulted in the centralization of proton craniospinal irradiation (pCSI) for patients with medulloblastoma (MB) to a single center. For optimal outcome of MB patients, timely start of pCSI and treatment without interruptions is important. However, the technical complexity of pCSI and national-scale referrals pose a risk for treatment delays. Therefore, to aid in high quality care, integration of pCSI within the national pediatric oncology center and collaboration within the Dutch neuro oncology society – rare cancer working group was established. In this study, we evaluated the care infrastructure for pCSI for a nationwide defined MB patient cohort.

All pediatric and adult MB patients referred for pCSI to our center between February 2018 and July 2021 were included in this analysis. International referrals were excluded. The interval between surgery and start of pCSI was calculated, excluding patients who received pre-pCSI (neo-adjuvant) chemotherapy. Conform the SIOP PNET5 protocol, a maximum of 40 days was used as the benchmark. Overall treatment time and number of photon fractions were evaluated. Data regarding multidisciplinary care during pCSI including: need for anesthesia, involvement of (para)medical disciplines and hospitalization details were extracted from the medical records.

Between February 2018 and July 2021, 55 MB patients, including 38 (69%) pediatric (<18 years) patients were treated with pCSI at our center. The clinical characteristics and treatment details are listed in Table 1. The time interval between surgery and start of pCSI for pediatric and adult patients was median of 32 days (IQR 30, 35) and 44 days (IQR 36, 61) respectively. The benchmark of 40 days was reached in 91.7% of pediatric patients and 42% of adult patients. Reason for a longer interval was the medical condition for 2/3 pediatric patients and 4/7 adults. The median overall treatment time for pediatric and adult patients combined was 42 days. There was only 1 patient with a treatment interruption >3 days. Five patients received a median of 4 photon fractions (IQR 1, 9) as part of their treatment; for 4 patients this was due to medical reasons, for 1 patient 1 fraction due to downtime of the proton facility. The delivered multidisciplinary care during pCSI treatment is listed in Table 2. Anesthesia was performed predominantly for patients aged 8 years and younger.

The pCSI infrastructure for pediatric MB patients, integrated within the national pediatric oncology center, facilitated a timely start of treatment in over 90% of patients. For adult patients, post-surgical condition is a common reason for delayed start of treatment. During pCSI treatment, a well-orchestrated interplay between several (para)medical disciplines is required to provide all potential necessary care. We were able to deliver pCSI treatment with less than 3 days interruption to in 98% of patients.