Proton radiotherapy for pediatric tumors: review of first clinical results

Abstract

Radiation therapy is a part of multidisciplinary management of several childhood cancers. Proton therapy is a new method of irradiation, which uses protons instead of photons. Proton radiation has been used safely and effectively for medulloblastoma, primitive neuro-ectodermal tumors, craniopharyngioma, ependymoma, germ cell intracranial tumors, low-grade glioma, retinoblastoma, rhabdomyosarcoma and other soft tissue sarcomas, Ewing’s sarcoma and other bone sarcomas. Moreover, other possible applications are emerging, in particular for lymphoma and neuroblastoma. Although both photon and proton techniques allow similar target volume coverage, the main advantage of proton radiation therapy is to sparing of intermediate-to-low-dose to healthy tissues. This characteristic could translate into clinical reduction of side effects, including a lower risk for secondary cancers. The following review presents the state of the art of proton therapy in the treatment of pediatric malignancies.

Proton Irradiation Increases the Necessity for Homologous Recombination Repair Along with the Indispensability of Non-Homologous End Joining

“…It is expected that the favorable depth-dose curves and linear energy transfer (LET) characteristics of charged particles will allow a precise targeting of deep-seated tumors while reducing the ionizing dose and irradiated volume of normal tissue. It is expected that these attempts to achieve a precise and more target-specific irradiation will help to lower the toxicity rates and the risk of developing secondary tumors [5][6][7][8][9][10][11]. In fact, particles pass through normal tissues on their track without losing much energy but instead releasing the main carried energy at a specific tissue depth shortly before their complete stop.…”

Proton Beam Therapy for Pediatric Brain Tumor

“…For comparison with the results of standard radiotherapy, papers were mainly selected based on three recent reviews written on pediatric brain tumor. 17 – 19) The outcomes of standard radiotherapy and PBT in articles are shown in Tables 1 – 5 .…”

Proton Beam Therapy for Pediatric Malignancies

“…The use of proton beam therapy to treat pediatric malignancies is increasing, with the possible benefit that this modality may improve quality of life for long-term cancer survivors (Palm & Johansson, 2007;Rombi et al, 2014). Longitudinal, comparative clinical trials with long-term follow-up are needed to assess survival outcomes and evaluate for late effects and secondary malignancies of proton beam therapy, as compared to photon therapy.…”