Outcomes of Patients Treated in the UK Proton Overseas Programme: Non-central Nervous System Group.

AIMS: The UK Proton Overseas Programme (POP) was launched in 2008. The Proton Clinical Outcomes Unit (PCOU) warehouses a centralised registry for collection, curation and analysis of all outcomes data for all National Health Service-funded UK patients referred and treated abroad with proton beam therapy (PBT) via the POP. Outcomes are reported and analysed here for patients diagnosed with non-central nervous system tumours treated from 2008 to September 2020 via the POP. MATERIALS AND METHODS: All non-central nervous system tumour files for treatments as of 30 September 2020 were interrogated for follow-up information, and type (following CTCAE v4) and time of onset of any late (>90 days post-PBT completion) grade 3-5 toxicities. RESULTS: Four hundred and ninety-five patients were analysed. The median follow-up was 2.1 years (0-9.3 years). The median age was 11 years (0-69 years). 70.3% of patients were paediatric (<16 years). Rhabdomyosarcoma (RMS) and Ewing sarcoma were the most common diagnoses (42.6% and 34.1%). 51.3% of treated patients were for head and neck (H&N) tumours. At last known follow-up, 86.1% of all patients were alive, with a 2-year survival rate of 88.3% and 2-year local control of 90.3%. Mortality and local control were worse for adults (≥25 years) than for the younger groups. The grade 3 toxicity rate was 12.6%, with a median onset of 2.3 years. Most were in the H&N region in paediatric patients with RMS. Cataracts (30.5%) were the most common, then musculoskeletal deformity (10.1%) and premature menopause (10.1%). Three paediatric patients (1-3 years at treatment) experienced secondary malignancy. Seven grade 4 toxicities occurred (1.6%), all in the H&N region and most in paediatric patients with RMS. Six related to eyes (cataracts, retinopathy, scleral disorder) or ears (hearing impairment). CONCLUSIONS: This study is the largest to date for RMS and Ewing sarcoma, undergoing multimodality therapy including PBT. It demonstrates good local control, survival and acceptable toxicity rates.

Deletion of Tbc1d4/As160 abrogates cardiac glucose uptake and increases myocardial damage after ischemia/reperfusion.

BACKGROUND: Type 2 Diabetes mellitus (T2DM) is a major risk factor for cardiovascular disease and associated with poor outcome after myocardial infarction (MI). In T2DM, cardiac metabolic flexibility, i.e. the switch between carbohydrates and lipids as energy source, is disturbed. The RabGTPase-activating protein TBC1D4 represents a crucial regulator of insulin-stimulated glucose uptake in skeletal muscle by controlling glucose transporter GLUT4 translocation. A human loss-of-function mutation in TBC1D4 is associated with impaired glycemic control and elevated T2DM risk. The study's aim was to investigate TBC1D4 function in cardiac substrate metabolism and adaptation to MI. METHODS: Cardiac glucose metabolism of male Tbc1d4-deficient (D4KO) and wild type (WT) mice was characterized using in vivo [18F]-FDG PET imaging after glucose injection and ex vivo basal/insulin-stimulated [3H]-2-deoxyglucose uptake in left ventricular (LV) papillary muscle. Mice were subjected to cardiac ischemia/reperfusion (I/R). Heart structure and function were analyzed until 3 weeks post-MI using echocardiography, morphometric and ultrastructural analysis of heart sections, complemented by whole heart transcriptome and protein measurements. RESULTS: Tbc1d4-knockout abolished insulin-stimulated glucose uptake in ex vivo LV papillary muscle and in vivo cardiac glucose uptake after glucose injection, accompanied by a marked reduction of GLUT4. Basal cardiac glucose uptake and GLUT1 abundance were not changed compared to WT controls. D4KO mice showed mild impairments in glycemia but normal cardiac function. However, after I/R D4KO mice showed progressively increased LV endsystolic volume and substantially increased infarction area compared to WT controls. Cardiac transcriptome analysis revealed upregulation of the unfolded protein response via ATF4/eIF2α in D4KO mice at baseline. Transmission electron microscopy revealed largely increased extracellular matrix (ECM) area, in line with decreased cardiac expression of matrix metalloproteinases of D4KO mice. CONCLUSIONS: TBC1D4 is essential for insulin-stimulated cardiac glucose uptake and metabolic flexibility. Tbc1d4-deficiency results in elevated cardiac endoplasmic reticulum (ER)-stress response, increased deposition of ECM and aggravated cardiac damage following MI. Hence, impaired TBC1D4 signaling contributes to poor outcome after MI.

The radiosensitizing effect of platinum nanoparticles in proton irradiations is not caused by an enhanced proton energy deposition at the macroscopic scale.

Objective.Due to the radiosensitizing effect of biocompatible noble metal nanoparticles (NPs), their administration is considered to potentially increase tumor control in radiotherapy. The underlying physical, chemical and biological mechanisms of the NPs' radiosensitivity especially when interacting with proton radiation is not conclusive. In the following work, the energy deposition of protons in matter containing platinum nanoparticles (PtNPs) is experimentally investigated.Approach.Surfactant-free monomodal PtNPs with a mean diameter of (40 ± 10) nm and a concentration of 300 µg ml-1, demonstrably leading to a substantial production of reactive oxygen species (ROS), were homogeneously dispersed into cubic gelatin samples serving as tissue-like phantoms. Gelatin samples without PtNPs were used as control. The samples' dimensions and contrast of the PtNPs were verified in a clinical computed tomography scanner. Fields from a clinical proton machine were used for depth dose and stopping power measurements downstream of both samples types. These experiments were performed with a variety of detectors at a pencil beam scanning beam line as well as a passive beam line with proton energies from about 56-200 MeV.Main results.The samples' water equivalent ratios in terms of proton stopping as well as the mean proton energy deposition downstream of the samples with ROS-producing PtNPs compared to the samples without PtNPs showed no differences within the experimental uncertainties of about 2%.Significance.This study serves as experimental proof that the radiosensitizing effect of biocompatible PtNPs is not due to a macroscopically increased proton energy deposition, but is more likely caused by a catalytic effect of the PtNPs. Thus, these experiments provide a contribution to the highly discussed radiobiological question of the proton therapy efficiency with noble metal NPs and facilitate initial evidence that the dose calculation in treatment planning is straightforward and not affected by the presence of sensitizing PtNPs.

Pre-activated antiviral innate immunity in the upper airways controls early SARS-CoV-2 infection in children.

Children have reduced severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection rates and a substantially lower risk for developing severe coronavirus disease 2019 compared with adults. However, the molecular mechanisms underlying protection in younger age groups remain unknown. Here we characterize the single-cell transcriptional landscape in the upper airways of SARS-CoV-2-negative (n = 18) and age-matched SARS-CoV-2-positive (n = 24) children and corresponding samples from adults (n = 44), covering an age range of 4 weeks to 77 years. Children displayed higher basal expression of relevant pattern recognition receptors such as MDA5 (IFIH1) and RIG-I (DDX58) in upper airway epithelial cells, macrophages and dendritic cells, resulting in stronger innate antiviral responses upon SARS-CoV-2 infection than in adults. We further detected distinct immune cell subpopulations including KLRC1 (NKG2A)+ cytotoxic T cells and a CD8+ T cell population with a memory phenotype occurring predominantly in children. Our study provides evidence that the airway immune cells of children are primed for virus sensing, resulting in a stronger early innate antiviral response to SARS-CoV-2 infection than in adults.

Can a ToF-PET photon attenuation reconstruction test stopping-power estimations in proton therapy? A phantom study.

Objective. The aim of the phantom study was to validate and to improve the computed tomography (CT) images used for the dose computation in proton therapy. It was tested, if the joint reconstruction of activity and attenuation images of time-of-flight PET (ToF-PET) scans could improve the estimation of the proton stopping-power.Approach. The attenuation images, i.e. CT images with 511 keV gamma-rays (γCTs), were jointly reconstructed with activity maps from ToF-PET scans. Theß+activity was produced with FDG and in a separate experiment with proton-induced radioactivation. The phantoms contained slabs of tissue substitutes. The use of theγCTs for the prediction of the beam stopping in proton therapy was based on a linear relationship between theγ-ray attenuation, the electron density, and the stopping-power of fast protons.Main results. The FDG based experiment showed sufficient linearity to detect a bias of bony tissue in the heuristic look-up table, which maps between x-ray CT images and proton stopping-power.γCTs can be used for dose computation, if the electron density of one type of tissue is provided as a scaling factor. A possible limitation is imposed by the spatial resolution, which is inferior by a factor of 2.5 compared to the one of the x-ray CT.γCTs can also be derived from off-line, ToF-PET scans subsequent to the application of a proton field with a hypofractionated dose level.Significance. γCTs are a viable tool to support the estimation of proton stopping with radiotracer-based ToF-PET data from diagnosis or staging. This could be of higher potential relevance in MRI-guided proton therapy.γCTs could form an alternative approach to make use of in-beam or off-line PET scans of proton-inducedß+activity with possible clinical limitations due to the low number of coincidence counts.

Delineation atlas of the Circle of Willis and the large intracranial arteries for evaluation of doses to neurovascular structures in pediatric brain tumor patients treated with radiation therapy.

BACKGROUND: Survivors of pediatric brain tumors are susceptible to neurovascular disease after radiotherapy, with dose to the chiasm or Circle of Willis (CW) as risk factors. The aims of this study were to develop a delineation atlas of neurovascular structures, to investigate the doses to these structures in relation to tumor location and to investigate potential dose surrogates for the CW dose. MATERIAL AND METHODS: An atlas of the CW, the large intracranial arteries and the suprasellar cistern (SC) was developed and validated. Thirty proton plans from previously treated pediatric brain tumor patients were retrieved and grouped according to tumor site: 10 central, 10 lateralized, and 10 posterior fossa tumors. Based on the atlas, neurovascular structures were delineated and dose metrics (mean dose (Dmean) and maximal dose (Dmax)) to these structures and the already delineated chiasm were evaluated. The agreement between dose metrics to the CW vs. chiasm/SC was investigated. The minimal Hausdorff distance (HDmin) between the target and SC was correlated with the SC Dmean. RESULTS: The median Dmean/Dmax to the CW were 53 Gy(RBE)/55 Gy(RBE) in the central tumors, 18 Gy(RBE)/25 Gy(RBE) in the lateralized tumors and 30 Gy(RBE)/49 Gy(RBE) in the posterior fossa tumors. There was a good agreement between the Dmax/Dmean to the CW and the SC for all cases (R2=0.99), while in the posterior fossa group, the CW Dmax was underestimated when using the chiasm as surrogate (R2=0.76). Across all patients, cases with HDmin < 10 mm between the target and the SC received the highest SC Dmean. CONCLUSION: The pattern of dose to neurovascular structures varied with the tumor location. For all locations, SC doses could be used as a surrogate for CW doses. A minimal distance larger than 10 mm between the target and the SC indicated a potential for neurovascular dose sparing.

Feasibility of Proton Beam Therapy for Infants with Brain Tumours: Experiences from the Prospective KiProReg Registry Study.

AIMS: Proton beam therapy (PBT) has increasingly been applied for the treatment of young children when radiotherapy is needed. The treatment requires intensive multimodality care and is logistically demanding. In this analysis, we evaluated our experiences in treating infants with tumours of the central nervous system with PBT. MATERIALS AND METHODS: Children younger than 2 years of age treated with PBT for central nervous system tumours enrolled in the prospective registry study KiProReg were retrospectively analysed. Information on patient characteristics, treatment, toxicities and outcome were evaluated. Adverse events were classified according to the National Cancer Institute Common Terminology Criteria for Adverse Events (CTCAE V4.0) before, during and after PBT. RESULTS: Between September 2013 and June 2018, 51 infants were eligible. The median age was 19 months (range 11-23 months) at the time of PBT. Tumour entities were ependymoma (51.0%), atypical teratoid rhabdoid tumour (39.0%), high-grade glioma (6.0%), pineoblastoma (2.0%) and medulloblastoma (2.0%). The prescribed median total dose was 54.0 Gy (range 45.0-59.4 Gy). Most received local radiotherapy. In four patients, craniospinal irradiation followed by a boost to the local tumour bed was applied. The median follow-up time was 42.0 months (range 7.3-86.2 months). The estimated 3-year local control, progression-free survival and overall survival rates for all patients were 62.7, 47.1 and 76.5%, respectively. During radiotherapy, 24 events of higher-grade (CTCAE ≥ °III) toxicities were reported. Interruption of radiotherapy for more than 2 days was due to infection (n = 3) or shunt complication (n = 2). Unexpected hospitalisation during radiotherapy affected 12 patients. Late adverse events attributable to radiotherapy included endocrinopathy (CTCAE °II; 7.8%), new onset of hearing loss (CTCAE °III; 5.8%) and visual impairment (CTCAE °IV; 1.9%). Transient radiation-induced imaging changes occurred in five patients (9.8%). CONCLUSIONS: Our study indicates that PBT is feasible for very young children with central nervous system tumours, at least in the short term. However, it requires challenging interdisciplinary medical care and high logistical effort. For evaluation of late effects, longer follow-up and evaluation of neurocognitive outcome are desirable. More data have to be gathered to further define the role of radiotherapy in infants over time.

Impact of air gap, range shifter, and delivery technique on skin dose in proton therapy.

OBJECTIVE: Side effects of radiation therapy may include skin damage. The surface dose is of great interest and contains the buildup effect. In particular, the proton therapy community requires further experimental data to quantify doses in the surface region. This specification includes the skin dose, which is defined according to ICRU Report No. 39 at 70 µm water equivalent depth. The aim of this study is to gather more knowledge of the skin dose by varying key parameters defined by the patient treatment plan. This consists of clinical aspects such as the influence of the air gap, the application of a range shifter (RS), or the proton delivery technique. MATERIAL/METHODS: Skin doses were determined with a PTW 23391 extrapolation chamber with three thin Kapton® entrance windows operated as a conventional ionization chamber. The impact on the skin dose for quasi-monoenergetic pencil beam scanning (PBS) proton beams was evaluated for clinical air gaps between 3.5 and 51.1 cm. The differences in skin dose were assessed by irradiating equivalent fields with an RS of 51 mm water equivalent thickness (RS51) and without. Furthermore, the delivery techniques PBS, uniform scanning (US), and double scattering (DS) were compared by defining a spread-out Bragg peak (SOBP). TOPAS (V.3.1.2) was used to model an IBA nozzle with PBS and to score dose to water at the surface of a water phantom. RESULTS: For the monoenergetic fields without the application of the RS the skin dose was constant down to an air gap of 6.2 cm. A lower air gap of 3.5 cm showed a variation in skin dose by up to 2.4% compared to the results obtained with larger air gaps. With the inserted RS51 an increase in the skin dose was found for air gaps smaller than 11.3 cm. Experimentally, a dose difference of 1.4% was recorded for an air gap of 6.2 cm by inserting an RS and none. With the Monte Carlo calculations the largest dose increase was observed at the air gap of 3.5 cm with 1.7% and 4.0% relative to the skin dose results without the RS and to the largest evaluated air gap of 51.1 cm, respectively. The SOBP comparison of the beam modalities at the measuring plane at the isocenter revealed higher skin doses without RS (including RS) by up to +1.9% (+1.5%) for DS and +1.3% (+1.1%) for US compared to PBS. For all three techniques an approx. 2% rise in skin dose was observed for the largest evaluated air gap of 37.7 cm to an air gap of 6.2 cm when using an RS51. CONCLUSION: The study investigated aspects of skin dose of a water equivalent phantom by varying key parameters of a proton treatment plan. Parameters like the RS, the air gap, and the delivery modality have an impact on the order of 4.0% for the skin dose at the depth of 70 µm. The increases in skin dose are the effects of the contribution of the increased electron fluence at small air gaps and the emitted hadronic particles produced by the RS.

Determination of surface dose in pencil beam scanning proton therapy.

PURPOSE/OBJECTIVE: Quantification of surface dose within the first few hundred water equivalent µm is challenging. Nevertheless, it is of large interest for the proton therapy community to study dose effects in the skin. The experimental determination is affected by the detector properties, such as the detector volume and material. The International Commission on Radiation Units and Measurements in its report 39 recommends assessing the skin dose at a depth of 0.07 mm. The aim of this study is the estimation of the absorbed dose at and around a depth of 70 µm. We used various dosimetric approaches in conjunction with proton pencil beam scanning delivery to determine the skin dose in a clinical setting. MATERIAL/METHODS: Five different detectors were tested for determining the surface dose in water: EBT3 and HD-V2 GAFCHROMIC™ radiochromic film, LiF:Mg,Ti thermoluminescent dosimeter, IBA PPC05 plane-parallel ionization chamber, and PTW 23391 extrapolation chamber. The irradiation setup consisted of quasi-monoenergetic scanned proton pencil beams with kinetic energies of 100, 150, and 226.7 MeV, respectively. Radiochromic films were placed within a vertical stack and in wedge geometry and were analyzed with FilmQA Pro™ adopting triple channel dosimetry. The extrapolation chamber PTW 23391, which served as a reference in the current work, was used in a conventional ionization chamber setup with a fixed electrode gap of 2 mm. Three Kapton® entrance windows with thicknesses of 25, 50, and 75 µm were employed. Thermoluminescent dosimeters were provided as powder and were pressed onto a sheet of aluminum. Furthermore, the Monte Carlo code TOol for PArticle Simulation (TOPAS) in version 3.1.p2 was used to model an IBA pencil beam scanning nozzle and score dose to water in a water phantom. RESULTS: The resulting depth dose curves were normalized to their 100% dose at the reference depth of 3 cm. We obtained the skin doses with the extrapolation chamber and with TOPAS. For the experimental approach this resulted in 79.7 ± 0.3%, 86.0 ± 0.6%, and 87.1 ± 0.1% for the proton energies 100, 150, and 226.7 MeV, respectively. The results for TOPAS were 80.1 ± 0.2% (100 MeV), 87.1 ± 0.5% (150 MeV), and 86.9 ± 0.4% (226.7 MeV), respectively. Based on the experimental results of the skin dose, we provided a clinically relevant surface extrapolation factor for the common measurement methods. This allows the result of the first measurement depth of a detector to be scaled to the dose at the skin depth. Most practical would be the use of the surface extrapolation factor for the PPC05 chamber, due to its direct reading, the wide availability in clinics and the low uncertainties. The calculated factors were 0.986 ± 0.004 for 100 MeV, 0.961 ± 0.008 for 150 MeV, and 0.963 ± 0.003 for 226.7 MeV. CONCLUSIONS: In this study, dissimilar experimental approaches were evaluated with respect to measurements at depths close to the surface. The experimental depth dose curves are in good agreement with the simulation with TOPAS Monte Carlo. To the author's knowledge this was the first experimental determination of the skin dose according to the International Commission on Radiation Units and Measurements 39 definition in proton pencil beam scanning.

Stereotactical fields applied in proton spot scanning mode with range shifter and collimating aperture.

Some clinical indications require small fields with sharp lateral dose gradients, which is technically challenging in proton beam therapy. This holds especially true for low-range fields applied with the spot scanning technique, where large beam profiles entering from the beam-line or the insertion of range shifting blocks lead to large lateral gradients. We regard the latter case and solve it by shifting the range shifting block far upstream in conjunction with a collimating aperture close to the patient. The experiments of the current work are based on a commercial proton therapy treatment head designed for several delivery modes. In a research environment of the spot-scanning delivery mode a range shifter is inserted downstream of the scanning magnets in a slot which is usually employed only in a scattering delivery mode. This configuration is motivated by equations assuming a simple model of proton transport. In the experiments lateral dose planes are acquired with a scintillation screen and radiochromic films. Dose distributions are calculated with the Monte Carlo dose engine of the RayStation treatment planning system. We demonstrate that proton fields with 80%-20% lateral dose fall-off values between 1.4 mm and 4.0 mm can be achieved for water equivalent depths between 0 cm and 10 cm. The simulated lateral dose profiles agree with the experimental dose profiles. The sharpening of the field edges is set off by a broadening of the proton spots towards the center of the fields. This limits the clinical application mainly to small fields for which the distal and proximal conformality is of minor importance.

DMSO induces drastic changes in human cellular processes and epigenetic landscape in vitro.

Though clinical trials for medical applications of dimethyl sulfoxide (DMSO) reported toxicity in the 1960s, later, the FDA classified DMSO in the safest solvent category. DMSO became widely used in many biomedical fields and biological effects were overlooked. Meanwhile, biomedical science has evolved towards sensitive high-throughput techniques and new research areas, including epigenomics and microRNAs. Considering its wide use, especially for cryopreservation and in vitro assays, we evaluated biological effect of DMSO using these technological innovations. We exposed 3D cardiac and hepatic microtissues to medium with or without 0.1% DMSO and analyzed the transcriptome, proteome and DNA methylation profiles. In both tissue types, transcriptome analysis detected >2000 differentially expressed genes affecting similar biological processes, thereby indicating consistent cross-organ actions of DMSO. Furthermore, microRNA analysis revealed large-scale deregulations of cardiac microRNAs and smaller, though still massive, effects in hepatic microtissues. Genome-wide methylation patterns also revealed tissue-specificity. While hepatic microtissues demonstrated non-significant changes, findings from cardiac microtissues suggested disruption of DNA methylation mechanisms leading to genome-wide changes. The extreme changes in microRNAs and alterations in the epigenetic landscape indicate that DMSO is not inert. Its use should be reconsidered, especially for cryopreservation of embryos and oocytes, since it may impact embryonic development.

Evolving Radiotherapy Techniques in Paediatric Oncology.

AIMS: Childhood cancer is rare and survival of childhood cancer has increased up to 80% at 5 years after diagnosis. Radiotherapy is an important element of the multimodal treatment concept. However, due to growing tissue, children are particularly sensitive to radiation-related side-effects and the induction of secondary malignancies. However, radiotherapy techniques have continuously progressed. In addition, modern treatment concepts have been improved in order to minimise long-term effects. Today, radiotherapy is used for various tumour types in childhood, such as sarcomas and tumours of the central nervous system. MATERIALS AND METHODS: External beam therapy with either photons or protons and brachytherapy are predominantly used for the treatment of childhood tumours. Technical developments and features, as well as clinical outcomes, for several tumour entities are presented. RESULTS: The development of radiotherapy techniques, as well as risk-adapted therapy concepts, resulted in promising outcome regarding tumour control, survival and therapy-related side-effects. It is assumed that proton therapy will be increasingly used for treating children in the future. However, more data have to be collected through multi-institutional registries in order to strengthen the evidence. CONCLUSION: The development of radiotherapy techniques is beneficial for children in terms of reducing dose exposure. As compared with other modern and highly conformal techniques, particularly proton therapy may achieve high survival rates and tumour control rates while decreasing the risk for side-effects. However, clinical evidence for modern radiotherapy techniques is still limited today. An optimal patient triaging with the selection of the most appropriate radiation technique for each individual patient will be an important goal for the future.

Collimated proton pencil-beam scanning for superficial targets: impact of the order of range shifter and aperture.

To assess if apertures shall be mounted upstream or downstream of a range shifting block if these field-shaping devices are combined with the pencil-beam scanning delivery technique (PBS). The lateral dose fall-off served as a benchmark parameter. Both options realizing PBS-with-apertures were compared to the uniform scanning mode. We also evaluated the difference regarding the out-of-field dose caused by interactions of protons in beam-shaping devices. The potential benefit of the downstream configuration over the upstream configuration was estimated analytically. Guided by this theoretical evaluation a mechanical adapter was developed which transforms the upstream configuration provided by the proton machine vendor to a downstream configuration. Transversal dose profiles were calculated with the Monte-Carlo based dose engine of the commercial treatment planning system RayStation 6. Two-dimensional dose planes were measured with an ionization chamber array and a scintillation detector at different depths and compared to the calculation. Additionally, a clinical example for the irradiation of the orbit was compared for both PBS options and a uniform scanning treatment plan. Assuming the same air gap the lateral dose fall-off at the field edge at a few centimeter depth is 20% smaller for the aperture-downstream configuration than for the upstream one. For both options of PBS-with-apertures the dose fall-off is larger than in uniform scanning delivery mode if the minimum accelerator energy is 100 MeV. The RayStation treatment planning system calculated the width of the lateral dose fall-off with an accuracy of typically 0.1 mm-0.3 mm. Although experiments and calculations indicate a ranking of the three delivery options regarding lateral dose fall-off, there seems to be a limited impact on a multi-field treatment plan.

Proton Therapy for Craniopharyngioma - An Early Report from a Single European Centre.

AIMS: Proton beam therapy (PBT) is being increasingly used for craniopharyngioma. We describe our early outcome of patients treated with PBT. MATERIALS AND METHODS: Between August 2013 and July 2016, 18 patients with craniopharyngiomas were treated with 54 Cobalt Gray Equivalent (CGE) in 30 fractions over 6 weeks at our centre. The early outcome of 16 patients included in a registry study was analysed. Radiological response was assessed by RECIST criteria and the disease- and treatment-related toxicities were scored according to the CTCAE 4.0. RESULTS: All patients are alive at a median follow-up of 32.6 months (range 9.2-70.6 months) from initial diagnosis. The median age at PBT was 10.2 years (range 5.4-46.9 years). One patient progressed 8.7 months after PBT and subsequently had complete resection of the tumour. At a median follow-up of 18.4 months after PBT, five patients remained in complete remission, four in partial remission and seven with stable disease. The most common adverse effects during PBT were grade 1 (cutaneous in seven patients and fatigue in six patients). There were no treatment-related grade 3 toxicities. CONCLUSIONS: Our early results are encouraging and comparable with the limited literature on PBT for craniopharyngioma.

Comprehensive clinical commissioning and validation of the RayStation treatment planning system for proton therapy with active scanning and passive treatment techniques.

PURPOSE: To commission the treatment planning system (TPS) RayStation for proton therapy including beam models for spot scanning and for uniform scanning. METHODS: Tests consist of procedures from ESTRO booklet number 7, the German DIN for constancy checks of TPSs, and extra tests checking the dose perturbation function. The dose distributions within patients were verified in silico by a comparison of 65 clinical treatment plans with the TPS XiO. Dose-volume parameters, dose differences, and three-dimensional gamma-indices serve as measures of similarity. The monthly constancy checks of Raystation have been automatized with a script. RESULTS: The basic functionality of the software complies with ESTRO booklet number 7. For a few features minor enhancements are suggested. The dose distribution in RayStation agrees with the calculation in XiO. This is supported by a gamma-index (3mm/3%) pass rate of >98.9% (median over 59 plans) for the volume within the 20% isodose line and a difference of <0.3% of V95 of the PTV (median over 59 plans). If spot scanning is used together with a range shifter, the dose level calculated by RayStation can be off by a few percent. CONCLUSIONS: RayStation can be used for the creation of clinical proton treatment plans. Compared to XiO RayStation has an improved modelling of the lateral dose fall-off in passively delivered fields. For spot scanning fields with range shifter blocks an empirical adjustment of monitor units is required. The computation of perturbed doses also allows the evaluation of the robustness of a treatment plan.

The Evolving Role of Proton Beam Therapy for Sarcomas.

As an alternative to conventional photon-based radiotherapy, radiation with protons is recognised to offer considerable advantages. Today, central nervous system tumours, various sarcomatous tumours, childhood cancer and head and neck tumours are commonly treated with proton therapy. This review evaluates current data from clinical and dosimetric trials on the treatment of selected sarcomatous tumours like rhabdomyosarcoma, osteosarcoma, chordoma, chondrosarcoma and Ewing sarcoma. Special considerations for paediatric tumours and future prospects of proton therapy are outlined. Proton therapy is already an internal part in the multidisciplinary management of childhood sarcomas in contiguity to sensitive structures, especially at the base of skull, spine and pelvis. It offers special advantages for tumours requiring high-precision radiotherapy, particularly when total resection seems not feasible. Previous and ongoing research is generating evidence for the benefit of protons in sarcoma patients. Up to now, proton therapy has been safely applied with encouraging results. For future research, prospective, multi-institutional, large registries are required to answer open questions. Modern radiotherapy techniques, such as pencil beam scanning and intensity modulation are increasingly established in proton therapy. More research is needed to understand protons' limitations and potential.

Transcriptomic and proteomic insight into the effects of a defined European mistletoe extract in Ewing sarcoma cells reveals cellular stress responses.

BACKGROUND: The hydrophobic triterpenes, oleanolic and betulinic acid as well as the hydrophilic mistletoe lectins and viscotoxins possess anticancer properties. They do all occur in combination in European mistletoe (Viscum album L.). Commercial Viscum album L. extracts are aqueous, excluding the insoluble triterpenes. We have previously shown that mistletoe lectins and triterpene acids are effective against Ewing sarcoma in vitro, ex vivo and in vivo. METHODS: We recreated a total mistletoe effect (viscumTT) by combining an aqueous extract (viscum) and a triterpene extract (TT) solubilised with cyclodextrins and analysed the effects of viscumTT and the single extracts on TC-71 Ewing sarcoma cells in vitro by transcriptomic and proteomic profiling. RESULTS: Treatment with the extracts strongly impacted Ewing sarcoma cell gene and protein expression. Apoptosis-associated and stress-activated genes were upregulated, proteasomal protein abundance enhanced and ribosomal and spliceosomal proteins downregulated. The mechanism of action of viscum, TT and viscumTT in TC-71 and MHH-ES-1 cells suggests the involvement of the unfolded protein response. While viscum and viscumTT extract treatment indicate response to oxidative stress and activation of stress-mediated MAPK signalling, TT extract treatment suggests the involvement of TLR signalling and autophagy. CONCLUSIONS: Since the combinatory extract viscumTT exerts highly effective pro-apoptotic effects on Ewing sarcoma cells in vitro, this phytopolychemotherapy could be a promising adjuvant therapeutic option for paediatric patients with Ewing sarcoma.

Proton therapy in paediatric oncology: an Irish perspective.

BACKGROUND: Proton therapy (PT) is a radiotherapy treatment modality that uses protons, rather than conventional photons. PT is often used in paediatric oncology due to its reported capability to reduce acute and late adverse treatment effects. As PT is unavailable in Ireland, patients are referred abroad for treatment. AIMS: To: (1) produce a descriptive study of Irish children referred abroad for PT, and (2) discuss the case for PT in general. METHODS: A retrospective review of all children referred for PT before October 2015 was performed. Information was gathered regarding demographics, diagnosis, referral timeline, adverse effects attributable to PT, current status and cost. A review of the relevant literature was performed. RESULTS: Seventeen children treated in Ireland have been referred abroad for PT. The largest number was in the 0-4 year old group. At initial diagnosis the median age was 4.8 years. The average cost per child was €37,312. Two patients suffered disease relapse. Four have encountered PT-related adverse effects. CONCLUSION: Despite the fact that >100,000 patients worldwide have been treated with PT, the level of published evidence to support superiority over conventional treatment remains low. It is debated that randomised control trials in this area would be inconsistent with the principle of clinical equipoise. In contrast, there is a call for level 1 evidence to justify drastic changes in patient care, particularly in light of recent reports of unexpected toxicities. In time, careful evaluation, follow-up and clinical trials will likely support the preferential use of PT in children.

Diagnosis and Treatment of Nasopharyngeal Carcinoma in Children and Adolescents - Recommendations of the GPOH-NPC Study Group.

Nasopharyngeal carcinoma (NPC) is a rare malignant tumor arising from epithelial cells of the nasopharynx. Its incidence is highest in Southeast Asia. Age distribution of NPC is bimodal, with one peak in young adolescents and another in patients 55-59 years of age. EBV appears to be the primary etiologic agent in the pathogenesis, environmental factors such as nitrosamines and genetic factors are contributory. NPC is most commonly diagnosed in locally advanced stages, with lymph node metastases occurring in up to 90% of patients. About 5-10% of patients present with distant metastases. Diagnosis of NPC is made histologically, supported by an abnormal anti-EBV-VCA IgA titer and elevated plasma EBV-DNA load. Superior results in children and adolescents with advanced locoregional NPC, with overall and event-free survival rates>90%, have been achieved by neoadjuvant chemotherapy with 5-fluoruracil and cisplatin, followed by synchronous radiochemotherapy and subsequent maintenance therapy with interferon-ß as demonstrated by the 2 prospective studies GPOH-NPC-91 and -2003. Response to therapy can be assessed by PET-imaging and in patients with complete remission after neoadjuvant chemotherapy, the radiation dose to the primary tumor can be safely reduced from 59.4 to 54.4 Gy. Since the majority of long term sequalae such as xerostomia, skin and tissue fibrosis are caused by high radiation dosages, radiotherapy modalities such as intensity-modulated radiotherapy should be used to efficiently spare non-tumorous tissue. For patients with metastatic disease and relapse, survival chances are low. New treatment strategies, such as the application of EBV-specific T-lymphocytes should be considered for these patients.