Encouraging Experience with Image-Guided Pencil Beam Scanning Proton Therapy in Craniopharyngioma—First Case Series From India

Abstract

PurposeTo report our early clinical experience with image-guided, pencil beam scanning proton beam therapy(PBS-PBT) for residual or recurrent craniopharyngiomas. Material and MethodsBetween September 2019 and January 2023, nineteen consecutive patients with residual, or recurrent craniopharyngioma, suitable for radiation and treated with image-guided PBS-PBT were analyzed. We documented detailed dosimetric data, acute toxicities, early outcomes and imaging response on follow-up MRI scans. ResultsA total of nineteen patients (11-males, 8-females) with residual or recurrent craniopharyngioma were treated in the given period. Median age of cohort was 14 years(range:3-33), majority constituting adamantinomatous histology(95%). Most common clinical presentation(prior to PBT) and endocrine deficit was visual disturbance(79%) and hypocortisolism(74%), respectively. Among 19, thirteen had recurrent craniopharyngioma and five of them had received radiation previously. 26% of patients(5) underwent surgery at least thrice or more before proton therapy. Median dose delivered was 54GyE. Most common acute toxicity was grade-1 alopecia(63%). None had grade-3 or above acute toxicities. With a median follow-up of 18 months(3-40 months), twelve patients showed shrinkage of residual tumor/cyst, of which, four showed dramatic cyst reduction at 3-9 months on follow-up. Two-patients had reduction in both solid and cystic components, and the remaining had reduction in cystic component only. The remaining eight patients had stable disease on MRI, with 100% disease control rate and overall survival. Visual functions remained stable post treatment. ConclusionOur preliminary experience with modern PBS-PBT and image guidance for craniopharyngioma is encouraging. Proton therapy in our cohort is well tolerated resulting in limited toxicities and promising early outcomes.