Outcomes of Medulloblastoma Treated with Volumetric Modulated Arc Therapy Craniospinal Irradiation: A Retrospective Study
Abstract
Introduction
Cranio-spinal irradiation (CSI) is essential in treating central nervous system malignancies such as medulloblastoma, but conventional 3D-conformal radiotherapy poses challenges in dose uniformity and toxicity. Advanced techniques like Volumetric Modulated Arc Therapy (VMAT) offer improved target coverage and organ sparing, yet data on its use in resource-limited settings remain scarce. This study aimed to evaluate the clinical feasibility, dosimetric performance, toxicity profile, and early outcomes of CSI delivered via VMAT in medulloblastoma patients treated at a tertiary care center in Pakistan.
Materials and Methods
This retrospective study included 113 patients (median age 12 years, range 4–37) diagnosed with medulloblastoma and treated between 2018 and 2024. Patients underwent surgical resection followed by VMAT-based CSI, with doses ranging from 23.4 to 36 Gy and tumor boosts of 54–55.4 Gy. Dosimetric parameters including planning target volume (PTV) coverage, conformity index (CI), homogeneity index (HI), and organ-at-risk (OAR) doses were analyzed. Acute toxicities were graded, and disease-free survival (DFS) was assessed over a median follow-up of 15 months.
Results
Gross total or near-total resection was achieved in 38.1% of patients. Mean PTV coverage was 94%, with median CI and HI values of 1.02 and 0.10, respectively, indicating excellent dose conformity and homogeneity. The majority of patients required multiple isocenters for complete cranio-spinal coverage. Acute toxicities were predominantly mild to moderate, with esophagitis (11%), bone marrow suppression (12%), and nausea/vomiting (10%) most commonly observed. Organ doses remained within acceptable limits. The two-year DFS rate was 76%.
Conclusion
VMAT-based CSI is a feasible and effective treatment modality for medulloblastoma in a resource-constrained setting, providing superior dosimetric outcomes with manageable toxicity. These findings support the broader adoption of advanced radio-therapy techniques like VMAT in similar clinical environments.
© 2026 Muhammad Anas Tahseen Asar, Tabinda Sadaf, Asma Rashid, Aqueel Shahid, Fajar Rafi Ranjha, Raheel Mukhtar, Haniya Rizwan, Ahmad Rashid, published by Shakuat Khanum Memorial Cancer Hospital and Research Centre
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