Js01.4.a centralized craniospinal proton therapy for medulloblastoma patients; an evaluation of the care infrastructure in the netherlands

Abstract BACKGROUND 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, national-scale referrals and the complexity of delivering pCSI pose a risk for treatment delays in these patients. 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 in the Netherlands. MATERIAL AND METHODS All Dutch MB patients referred for pCSI to our center were included in this analysis. The interval between surgery and start of pCSI was calculated, excluding patients who received neo-adjuvant chemotherapy. Overall treatment time, use of (back-up) photon fractions and plan adaptations were evaluated. Data regarding planned and additional multidisciplinary care during pCSI were extracted from the medical records. RESULTS Between February 2018 and December 2022, 79 MB patients, including 25 (32%) adult (>18 years) patients, were treated with pCSI. The median interval between surgery and start of pCSI for pediatric and adult patients was 32 days (IQR 30, 35) and 41 days (IQR 35, 55) respectively, and 91% and 47% started within 40 days from surgery. The median overall treatment time for all patients was 41 days (range 11). The longest treatment interruption was 3 days in one adult patient. Eight patients received a median of 9 photon fractions (IQR 2, 11); most often because of the need to start treatment quickly. In 30% of all patients a plan adaptation was needed, mostly because of changes in patient weight during treatment. In our center, it is considered standard of care to involve the (pediatric) medical oncologist and neurologist during pCSI. Clinical care (hospitalization) was required in 42% of the patients for a median of 10 days. Anesthesia was necessary predominantly for patients aged 8 years and younger. Other (para)medical disciplines involved during pCSI were neurosurgery (6%), neuropsychology (22%), speech therapy (25%), rehabilitation therapy (46%) and nutritional specialist (73%). CONCLUSION The Dutch pCSI infrastructure for MB patients facilitated a timely start of treatment in over 90% of pediatric patients and in nearly half of the adult patients. During pCSI treatment, a well-orchestrated interplay between several (para)medical disciplines is required to provide all potential necessary care. More disciplines were involved and more clinical care was required for pediatric patients. We were able to deliver pCSI treatment with less than 3 days interruption in 98% of patients.