Dosimetric Comparison and Potential for Improved Clinical Outcomes of Paediatric CNS Patients Treated with Protons or IMRT.

Nicola Thorp,Kris Armoogum

doi:10.3390/cancers7020706

Abstract

Background: We compare clinical outcomes of paediatric patients with CNS tumours treated with protons or IMRT. CNS tumours form the second most common group of cancers in children. Radiotherapy plays a major role in the treatment of many of these patients but also contributes to late side effects in long term survivors. Radiation dose inevitably deposited in healthy tissues outside the clinical target has been linked to detrimental late effects such as neurocognitive, behavioural and vascular effects in addition to endocrine abnormalities and second tumours. Methods: A literature search was performed using keywords: protons, IMRT, CNS and paediatric. Of 189 papers retrieved, 10 were deemed relevant based on title and abstract screening. All papers directly compared outcomes from protons with photons, five papers included medulloblastoma, four papers each included craniopharyngioma and low grade gliomas and three papers included ependymoma. Results: This review found that while proton beam therapy offered similar clinical target coverage, there was a demonstrable reduction in integral dose to normal structures. Conclusions: This in turn suggests the potential for superior long term outcomes for paediatric patients with CNS tumours both in terms of radiogenic second cancers and out-of-field adverse effects.

Highlights

Central Nervous System (CNS) tumours are the second most common cancers in children, accounting for approximately 25% of all childhood cancers
A literature search was performed for clinical studies reporting on the outcomes of paediatric patients with CNS tumours treated with protons or intensity modulated photon radiotherapy (IMRT)
This study evaluated the risk of second cancer incidence in the vicinity of the primary radiation field for paediatric patients and compared passive scattering and pencil beam scanning proton therapy with IMRT

Summary

Introduction

Central Nervous System (CNS) tumours are the second most common cancers in children, accounting for approximately 25% of all childhood cancers. Regardless of the delivery modality, radiation dose inevitably deposited in healthy tissues outside the clinical target has been linked to detrimental late effects such as neurocognitive, behavioural and vascular effects in addition to endocrine abnormalities and second tumours. These late effects are compounded by the increasing long-term survival rates, and survivors of childhood CNS cancers face the prospect of developing secondary cancers several decades after primary treatment. Radiation dose inevitably deposited in healthy tissues outside the clinical target has been linked to detrimental late effects such as neurocognitive, behavioural and vascular effects in addition to endocrine abnormalities and second tumours. Conclusions: This in turn suggests the potential for superior long term outcomes for paediatric patients with CNS tumours both in terms of radiogenic second cancers and out-of-field adverse effects

Methods

Results

Discussion

Conclusion