Introduction The aim of this study is to compare radiotherapy plans using helical tomotherapy (HT) and active scanning proton technique (PT) for a group of pediatric-adolescent Hodgkin Lymphoma (HL) patients treated with HT.
AIMSThe number of Proton Therapy (PT) facilities is still limited worldwide, and the access to treatment could be characterized by patients' logistic and economic challenges. Aim of the present survey is to assess the support provided to patients undergoing PT across Europe.METHODSThrough a personnel contact, an online questionnaire (62 multiple-choice and open-ended questions) via Microsoft Forms was administered to 10 European PT centers. The questionnaire consisted of 62 questions divided into 6 sections: i) personal data; ii) general information on clinical activity; iii) fractionation, concurrent systemic treatments and technical aspects of PT facility; iv) indication to PT and reimbursement policies; v) economic and/ or logistic support to patients vi) participants agreement on statements related to the possible limitation of access to PT. A qualitative analysis was performed and reported.RESULTSFrom March to May 2022 all ten involved centers filled the survey. Nine centers treat from 100 to 500 patients per year. Paediatric patients accounted for 10-30%, 30-50% and 50-70% of the entire cohort for 7, 2 and 1 center, respectively. The most frequent tumours treated in adult population were brain tumours, sarcomas and head and neck carcinomas; in all centers, the mean duration of PT is longer than 3 weeks. In 80% of cases, the treatment reimbursement for PT is supplied by the respective country's Health National System (HNS). HNS also provides economic support to patients in 70% of centers, while logistic and meal support is provided in 20% and 40% of centers, respectively. PT facilities offer economic and/or logistic support in 90% of the cases. Logistic support for parents of pediatric patients is provided by HNS only in one-third of centers. Overall, 70% of respondents agree that geographic challenges could limit a patient's access to proton facilities and 60% believe that additional support should be given to patients referred for PT care.CONCLUSIONSRelevant differences exist among European countries in supporting patients referred to PT in their logistic and economic challenges. Further efforts should be made by HNSs and PT facilities to reduce the risk of inequities in access to cancer care with protons.
Conventional radiotherapy (ie x-ray therapy) plays an important role in the multidisciplinary treatment of most of the cancers arising from the gastrointestinal (GI) tract. In this context, a narrow therapeutic window exists, due to 1) the usually large treatment volumes which are required to cover regions at risk for tumor spread and to 2) the close vicinity of several radiosensitive healthy tissues to the irradiated volume. The use of charged particles such as protons, with their unique dosimetric characteristics (a finite range in tissue along with a near zero dose beyond the end of its path), could be promising. The aim of this critical review was 1) to describe the rationale of the use of PT for the major GI cancers and 2) to report the clinical experiences currently available in literature
To evaluate cystic dynamics in two pediatric low grade gliomas during proton beam therapy (PBT) by weekly MRI and in the follow up (FU) time. Early late toxicity was also reported. Both solid and cystic tumor’s components were drown in weekly MRI performed during proton radiation and in the FU phase. P1 case was a multiple partially resected 5 yo girl with hypothalamic pylocitic Astrocytoma no-responding after second line of chemotherapy, who acutely lost visual acuity due to cystic tumor’s progression. P2 case was a 13 yo boy with progressive mesencephalic pylocitic Astrocytoma previously treated with multi-agents chemotherapy and several surgeries. After cystic drainage both were treated with PBT at 54 Gy GCE. During proton therapy # 7 MRI for P1 and # 6 MRI for P2 patient were performed and didn’t shown cyst growth which required intervention; P1 developed two episodes of severe acute headache and both developed partial alopecia. In P1 patient both cystic and solid component progressively reduced (cyst/solid-1w +2/-15%, cyst/solid-2w -9/-22%, cyst/solid-3w -17/-28%, cyst/solid-4w -18/-38%, cyst/solid-5w -30/-43%, cyst/solid-6w -34/-44%, cyst/solid-1FU -43/-50%, cyst/solid-2FU -51/-63%). In P2 patient only cyst part progressively increased (cyst/solid-2w +7/-4%, cyst/solid-3w +36/-10%, cyst/solid-4w +58/-12%, cyst/solid-5w +73/-15%, cyst/solid-6w +90/-15%, cyst/solid-7w +94/-16%, cyst/solid-1FU +126/-37%, cyst/solid-2FU -18/-45%). P2 had transient cyst growth after PT with significant volume reduction on the second FU. After 10 months of median FU, no late side effects were noted however P1 improved visual acuity.
Medulloblastoma is the most common malignant brain tumor in children. Even if current treatment dramatically improves the prognosis, survivors often develop long-term treatment-related sequelae. The current radiotherapy standard for medulloblastoma is craniospinal irradiation with a boost to the primary tumor site and to any metastatic sites. Proton therapy (PT) has similar efficacy compared to traditional photon-based radiotherapy but might achieve lower toxicity rates. We report on our multi-centric experience with 43 children with medulloblastoma (median age at diagnosis 8.7 years, IQR 6.6, M/F 23/20; 26 high-risk, 14 standard-risk, 3 ex-infant), who received active scanning PT between 2015 and 2021, with a focus on PT-related acute-subacute toxicity, as well as some preliminary data on late toxicity. Most acute toxicities were mild and manageable with supportive therapy. Hematological toxicity was limited, even among HR patients who underwent hematopoietic stem-cell transplantation before PT. Preliminary data on late sequelae were also encouraging, although a longer follow-up is needed.
Abstract BACKGROUND The high risk medulloblastoma remains a leading cause of cancer-related death in children. METHODS A total of 18 patients have been enrolled from February 2018 to May 2022.The median age was 7,5 years (range; 12 males and 6 female). The protocol predicted the first phase of induction with 4 cycles of chemotherapy. After induction patients with favorable histology without evidence of disease were enrolled to proton therapy (with concomitant vinorelbine biweekly). The maintenance phase with Lomustine repeated every 9 weeks and vinorelbine every 3 weeks for overall 12-18 months (PR). Conversely LC/A MB, were subjected to consolidation phase with high dose of chemotherapy with tiothepa followed by autologous HSC transplant and successive maintenance phase of 6 months. RESULTS At October 2023, the median follow up was 24 months. After the induction phase 14 patients showed CR, 2 PR, 1PD, 1SD. At subsequent re-evaluations two with PR, showed disease control, one CR and the other SD and the patient with PD showed CR. Patient with SD showed an unchanged state of the disease. During the reporting period two patient died for progression of the underlying disease. At 24 months from the start of treatment the PFS was 75,4 % (95% CI: 34.1% - 87.6%) and at 15 months the OS was 86,1% (95% CI: 68.1% - 99.2%). The principal expected side effects of chemotherapy were hematology toxicity and 58% rate of GH deficiency. Among the unexpected side effect was CMV retinopathy with complete blindness and leukoencephalopathy after high dose of thiotepa and proton irradiation. We reported only one case of ototoxicity. CONCLUSIONS The use of proton therapy combined with intensive chemotherapy and myeloablative chemotherapy only in selected cases and always before irradiation has proven feasible and effective in the treatment of high-risk patients medulloblastomas and other embryonic tumors.
Clinically relevant intensity modulated proton therapy (IMPT) treatment plans were measured in a newly developed anthropomorphic phantom (i) to assess plan accuracy in the presence of high heterogeneity and (ii) to measure plan robustness in the case of treatment uncertainties (range and spatial). The new phantom consists of five different tissue substitute materials simulating different tissue types and was cut into sagittal planes so as to facilitate the verification of co-planar proton fields. GafChromic films were positioned in the different planes of the phantom, and 3D-IMPT and distal edge tracking (DET) plans were delivered to a volume simulating a skull base chordoma. In addition, treatments planned on CTs of the phantom with HU units modified were delivered to simulate systematic range uncertainties (range-error treatments). Finally, plans were delivered with the phantom rotated to simulate spatial errors. Results show excellent agreement between the calculated and the measured dose distribution: >99% and 98% of points with a gamma value <1 (3%/3 mm) for the 3D-IMPT and the DET plan, respectively. For both range and spatial errors, the 3D-IMPT plan was more robust than the DET plan. Both plans were more robust to range than to the spatial uncertainties. Finally, for range error treatments, measured distributions were compared to a model for predicting delivery errors in the treatment planning system. Good agreement has been found between the model and the measurements for both types of IMPT plan.
