Current status of proton therapy outcome for paediatric cancers of the central nervous system – Analysis of the published literature

Abstract

IntroductionThe most common solid tumours that develop in children are cancers of the central nervous system. Due to the increased rate of survival over the past decades, greater focus has been placed on the minimisation of long term side effects. In childhood cancer survivors, over 60% report one or more radiation-related late toxicities while half of these adverse events are graded as life-threatening or severe. Proton therapy enables high conformity with the planning target volume and a reduction in dose to areas beyond the target. Owing to the unique nature of dose delivery with proton therapy a reduction of low doses to normal tissues is achievable, and is believed to allow for a decrease in long-term treatment-related side effects. This paper aims to review the published literature around the effectiveness of proton therapy for the treatment of paediatric cancers of the central nervous system, with a focus on treatment outcomes and treatment-related toxicities. MethodsA search strategy utilising the Medline database was created with the intent of including all articles reporting on proton therapy, paediatric cancers, CNS tumours and treatment outcomes. The final search strategy included the following limitations: limited to humans, English, published from 2000 onwards. The final article count total was 74. Results and conclusionsProton therapy for the treatment of paediatric cancers of the central nervous system was found to provide survival and tumour control outcomes comparable to photon therapy. Reduced incidence of severe acute and late toxicities was also reported with the use of proton therapy. This includes reduced severity of endocrine, neurological, IQ and QoL deficits. Currently, extensive follow-up of proton patient populations still needs to be made to determine incidences of late-onset toxicities and secondary malignancies. Current evidence surrounding proton therapy use in paediatric patients supports its effectiveness and potential benefits in reducing the incidence of severe toxicities in later life.