Clinical Insight on Proton Therapy for Paediatric Rhabdomyosarcoma

Sabina Vennarini,1 Francesca Colombo,1,2 Alfredo Mirandola,3 Stefano Chiaravalli,4 Ester Orlandi,5 Maura Massimino,4 Michela Casanova,4 Andrea Ferrari4 1Pediatric Radiotherapy Unit, Fondazione IRCCS Istituto Nazionale Tumori, Milan, Italy; 2Department of Oncology and Hemato-Oncology (DIPO), University of Milan, Milan, Italy; 3Medical Physics Unit, Clinical Department, National Center for Oncological Hadrontherapy (CNAO), Pavia, Italy; 4Pediatric Oncology Unit, Fondazione IRCCS Istituto Nazionale Tumori, Milano, Italy; 5Radiation Oncology Unit, Clinical Department, National Center for Oncological Hadrontherapy (CNAO), Pavia, ItalyCorrespondence: Andrea Ferrari, Pediatric Oncology Unit, Fondazione IRCCS Istituto Nazionale Tumori, Via G. Venezian, Milano, MI, 1 20133, Italy, Tel +39 02 23902588, Fax +39 02 23902648, Email andrea.ferrari@istitutotumori.mi.itAbstract: This paper offers an insight into the use of Proton Beam Therapy (PBT) in paediatric patients with rhabdomyosarcoma (RMS). This paper provides a comprehensive analysis of the literature, investigating comparative photon-proton dosimetry, outcome, and toxicity. In the complex and multimodal scenario of the treatment of RMS, clear evidence of the therapeutic superiority of PBT compared to other modern photon techniques has not yet been demonstrated; however, PBT can be considered an excellent treatment option, in particular for young children and patients with specific primary sites, such as the head and neck area (and especially the parameningeal regions), genito-urinary, pelvic, and paravertebral regions. The unique depth-dose characteristics of protons can be exploited to achieve significant reductions in normal tissue doses and may allow an escalation of tumour doses and greater sparing of normal tissues, thus potentially improving local control while at the same time reducing toxicity and improving quality of life. However, access of children with RMS (and more in general with solid tumors) to PBT remains a challenge, due to the limited number of available proton therapy installations.Keywords: rhabdomyosarcoma, pediatric, proton beam therapy, local treatment, radiotherapy