Proton Radiotherapy for Pediatric Ewing's Sarcoma: Initial Clinical Outcomes

UK guidelines for the management of bone sarcomas

This document is an update of the British Sarcoma Group guidelines (2016) and provides a reference standard for the clinical care of UK patients with primary malignant bone tumours (PMBT) and giant cell tumours (GCTB) of bone. The guidelines recommend treatments that are effective and should be available in the UK, and support decisions about management and service delivery. The document represents a consensus amongst British Sarcoma Group members in 2024. Key recommendations are that bone pain, or a palpable mass should always lead to further investigation and that patients with clinical or radiological findings suggestive of a primary bone tumour at any anatomic site should be referred to a specialist centre and managed by an accredited bone sarcoma multidisciplinary team. Treatment recommendations are provided for the major tumour types and for localised, metastatic and recurrent disease. Follow-up schedules are suggested.

Proton Therapy for Spinal Tumors: A Consensus Statement From the Particle Therapy Cooperative Group

PURPOSE

Proton beam therapy (PBT) plays an important role in the management of primary spine tumors. The purpose of this consensus statement was to summarize safe and optimal delivery of PBT for spinal tumors.

METHODS AND MATERIALS

The Particle Therapy Cooperative Group Skull Base/Central nervous system/Sarcoma Subcommittee consisting of radiation oncologists and medical physicists with specific expertise in spinal irradiation developed expert recommendations discussing treatment planning considerations and current approaches in the treatment of primary spinal tumors.

RESULTS

Computed tomography simulation: factors that require significant consideration include (1) patient comfort, (2) setup reproducibility and stability, and (3) accessibility of appropriate beam angles.

SPINE STABILIZATION HARDWARE

If present, hardware should be placed with cross-links well above/below the level of the primary tumor to reduce the metal burden at the level of the tumor bed. New materials that can reduce uncertainties include polyether-ether-ketone and composite polyether-ether-ketone-carbon fiber implants.

FIELD ARRANGEMENT

Appropriate beam selection is required to ensure robust target coverage and organ at risk sparing. Commonly, 2 to 4 treatment fields, typically from posterior and/or posterior-oblique directions, are used.

TREATMENT PLANNING METHODOLOGY

Robust optimization is recommended for all pencil beam scanning plans (the preferred treatment modality) and should consider setup uncertainty (between 3 and 7 mm) and range uncertainty (3%-3.5%). In the presence of metal hardware, use of an increased range uncertainty up to 5% is recommended.

CONCLUSIONS

The Particle Therapy Cooperative Group Skull Base/Central nervous system/Sarcoma Subcommittee has developed recommendations to enable centers to deliver PBT safely and effectively for the management of primary spinal tumors.

Comprehensive radiotherapy for pediatric Ewing Sarcoma: Outcomes of a prospective proton study

BACKGROUND AND PURPOSE

Patients with Ewing Sarcoma (EWS) are treated with multimodality therapy which includes radiation therapy (RT) as an option for local control. We report on the efficacy after proton radiation therapy (PRT) to the primary site for localized and metastatic EWS.

MATERIALS AND METHODS

Forty-two children with EWS (33 localized, 9 metastatic) treated between 2007 and 2020 were enrolled on 2 prospective registry protocols for pediatric patients undergoing PRT. PRT was delivered by passive scatter (74 %), pencil-beam scanning (12 %) or mixed technique (14 %). Treated sites included the spine (45 %), pelvis/sacrum (26 %), skull/cranium (14 %), extraosseous (10 %), and chest wall (5 %). Median radiation dose was 54 Gy-RBE (range 39.6-55.8 Gy-RBE). Patients with metastatic disease received consolidative RT to metastatic sites (4 at the time of PRT to the primary site, 5 after completion of chemotherapy). Median follow-up time was 47 months after PRT.

RESULTS

The 4-year local control (LC), progression-free survival (PFS), and overall survival (OS) rates were 83 %, 71 %, and 86 %, respectively. All local failures (n = 6) were in-field failures. Tumor size ≥ 8 cm predicted for inferior 4-year LC (69 % vs 95 %, p = 0.04). 4-year PFS and OS rates were not statistically different in patients with localized versus metastatic disease (72 % vs 67 %, p = 0.70; 89 % vs 78 %, p = 0.38, respectively).

CONCLUSION

In conclusion, LC for pediatric patients with EWS treated with PRT was comparable to that of historical patients who received photon-RT. Tumor size ≥ 8 cm predicted increased risk of local failure. Patients with metastatic disease, including non-pulmonary only metastases, received radiation therapy to all metastatic sites and had favorable survival outcomes.

Current topics and management of head and neck sarcomas

Given the low incidence, variety of histological types, and heterogeneous biological features of head and neck sarcomas, there is limited high-quality evidence available to head and neck oncologists. For resectable sarcomas, surgical resection followed by radiotherapy is the principle of local treatment, and perioperative chemotherapy is considered for chemotherapy-sensitive sarcomas. They often originate in anatomical border areas such as the skull base and mediastinum, and they require a multidisciplinary treatment approach considering functional and cosmetic impairment. Moreover, head and neck sarcomas may exhibit different behaviour and characteristics than sarcomas of other areas. In recent years, the molecular biological features of sarcomas have been used for the pathological diagnosis and development of novel agents. This review describes the historical background and recent topics that head and neck oncologists should know about this rare tumour from the following five perspectives: (i) epidemiology and general characteristics of head and neck sarcomas; (ii) changes in histopathological diagnosis in the genomic era; (iii) current standard treatment by histological type and clinical questions specific to head and neck; (iv) new drugs for advanced and metastatic soft tissue sarcomas; and (v) proton and carbon ion radiotherapy for head and neck sarcomas.

Effect of Radiotherapy Dose on Outcome in Nonmetastatic Ewing Sarcoma

Purpose

Radiation therapy (RT) is an integral part of Ewing sarcoma (EwS) therapy. The Ewing 2008 protocol recommended RT doses ranging from 45 to 54 Gy. However, some patients received other doses of RT. We analyzed the effect of different RT doses on event-free survival (EFS) and overall survival (OS) in patients with EwS.

Methods and Materials

The Ewing 2008 database included 528 RT-admitted patients with nonmetastatic EwS. Recommended multimodal therapy consisted of multiagent chemotherapy and local treatment consisting of surgery (S&RT group) and/or RT (RT group). EFS and OS were analyzed with uni- and multivariable Cox regression models including known prognostic factors such as age, sex, tumor volume, surgical margins, and histologic response.

Results

S&RT was performed in 332 patients (62.9%), and 145 patients (27.5%) received definitive RT. Standard dose ≤ 53 Gy (d1) was admitted in 57.8%, high dose of 54 to 58 Gy (d2) in 35.5%, and very high dose ≥ 59 Gy (d3) in 6.6% of patients. In the RT group, RT dose was d1 in 11.7%, d2 in 44.1%, and d3 in 44.1% of patients. Three-year EFS in the S&RT group was 76.6% for d1, 73.7% for d2, and 68.2% for d3 (P = .42) and in the RT group 52.9%, 62.5%, and 70.3% (P = .63), respectively. Multivariable Cox regression revealed age ≥ 15 years (hazard ratio [HR], 2.68; 95% confidence interval [CI], 1.63-4.38) and nonradical margins (HR, 1.76; 95% CI, 1.05-2.93) for the S&RT group (sex, P = .96; histologic response, P = .07; tumor volume, P = .50; dose, P = .10) and large tumor volume (HR, 2.20; 95% CI, 1.21-4.0) for the RT group as independent factors (dose, P = .15; age, P = .08; sex, P = .40).

Conclusions

In the combined local therapy modality group, treatment with higher RT dose had an effect on EFS, whereas higher dose of radiation when treated with definitive RT was associated with an increased OS. Indications for selection biases for dosage were found. Upcoming trials will assess the value of different RT doses in a randomized manner to control for potential selection bias.

Spinal tumours: recommendations of the Polish Society of Spine Surgery, the Polish Society of Oncology, the Polish Society of Neurosurgeons, the Polish Society of Oncologic Surgery, the Polish Society of Oncologic Radiotherapy, and the Polish Society of Orthopaedics and Traumatology

PURPOSE

The purpose of these recommendations is to spread the available evidence for evaluating and managing spinal tumours among clinicians who encounter such entities.

METHODS

The recommendations were developed by members of the Development Recommendations Group representing seven stakeholder scientific societies and organizations of specialists involved in various forms of care for patients with spinal tumours in Poland. The recommendations are based on data yielded from systematic reviews of the literature identified through electronic database searches. The strength of the recommendations was graded according to the North American Spine Society's grades of recommendation for summaries or reviews of studies.

RESULTS

The recommendation group developed 89 level A-C recommendations and a supplementary list of institutions able to manage primary malignant spinal tumours, namely, spinal sarcomas, at the expert level. This list, further called an appendix, helps clinicians who encounter spinal tumours refer patients with suspected spinal sarcoma or chordoma for pathological diagnosis, surgery and radiosurgery. The list constitutes a basis of the network of expertise for the management of primary malignant spinal tumours and should be understood as a communication network of specialists involved in the care of primary spinal malignancies.

CONCLUSION

The developed recommendations together with the national network of expertise should optimize the management of patients with spinal tumours, especially rare malignancies, and optimize their referral and allocation within the Polish national health service system.

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.

IMPT of head and neck cancer: unsupervised machine learning treatment planning strategy for reducing radiation dermatitis

Radiation dermatitis is a major concern in intensity modulated proton therapy (IMPT) for head and neck cancer (HNC) despite its demonstrated superiority over contemporary photon radiotherapy. In this study, dose surface histogram data extracted from forty-four patients of HNC treated with IMPT was used to predict the normal tissue complication probability (NTCP) of skin. Grades of NTCP-skin were clustered using the K-means clustering unsupervised machine learning (ML) algorithm. A new skin-sparing IMPT (IMPT-SS) planning strategy was developed with three major changes and prospectively implemented in twenty HNC patients. Across skin surfaces exposed from 10 (S10) to 70 (S70) GyRBE, the skin's NTCP demonstrated the strongest associations with S50 and S40 GyRBE (0.95 and 0.94). The increase in the NTCP of skin per unit GyRBE is 0.568 for skin exposed to 50 GyRBE as compared to 0.418 for 40 GyRBE. Three distinct clusters were formed, with 41% of patients in G1, 32% in G2, and 27% in G3. The average (± SD) generalised equivalent uniform dose for G1, G2, and G3 clusters was 26.54 ± 6.75, 38.73 ± 1.80, and 45.67 ± 2.20 GyRBE. The corresponding NTCP (%) were 4.97 ± 5.12, 48.12 ± 12.72 and 87.28 ± 7.73 respectively. In comparison to IMPT, new IMPT-SS plans significantly (P < 0.01) reduced SX GyRBE, gEUD, and associated NTCP-skin while maintaining identical dose volume indices for target and other organs at risk. The mean NTCP-skin value for IMPT-SS was 34% lower than that of IMPT. The dose to skin in patients treated prospectively for HNC was reduced by including gEUD for an acceptable radiation dermatitis determined from the local patient population using an unsupervised MLA in the spot map optimization of a new IMPT planning technique. However, the clinical finding of acute skin toxicity must also be related to the observed reduction in skin dose.

Early Experience Using Proton Beam Therapy for Extremity Soft Tissue Sarcoma: A Multicenter Study

Purpose

Proton beam therapy (PBT) may provide an advantage when planning well-selected patients with extremity soft tissue sarcoma (eSTS), specifically for large, anatomically challenging cases. We analyzed our early experience with PBT on toxicity and outcomes.

Materials and Methods

A retrospective study was performed for eSTS treated between June 2016 and October 2020 with pencil beam scanning PBT at 2 institutions. Diagnostic, treatment, and toxicity characteristics were gathered from baseline to last follow-up or death. Wound complications were defined as secondary operations for wound repair (debridement, drainage, skin graft, and muscle flap) or nonoperative management requiring hospitalization. Statistical analysis was performed with R software.

Results

Twenty consecutive patients with a median age 51.5 years (range, 19–78 years) were included. Median follow-up was 13.7 months (range, 1.7–48.1 months). Tumor presentation was primary (n = 17) or recurrent after prior combined modality therapy (n = 3). Tumor location was either lower extremity (n = 16) or upper extremity (n = 4). Radiation was delivered preoperatively in most patients (n = 18). Median pretreatment tumor size was 7.9 cm (range, 1.3 –30.0 cm). The 1-year locoregional control was 100%. Four patients (20%) had developed metastatic disease by end of follow-up. Maximum toxicity for acute dermatitis was grade 2 in 8 patients (40%) and grade 3 in 3 patients (15%). After preoperative radiation and surgical resection, acute wound complications occurred in 6 patients (35%). Tumor size was larger in patients with acute wound complications compared with those without (medians 16 cm, range [12–30.0 cm] vs 6.3 cm, [1.3–14.4 cm], P = .003).

Conclusion

PBT for well selected eSTS cases demonstrated excellent local control and similar acute wound complication rate comparable to historic controls. Long-term follow-up and further dosimetric analyses will provide further insight into potential advantages of PBT in this patient population.

Current approaches to management of bone sarcoma in adolescent and young adult patients

Bone tumors are a group of histologically diverse diseases that occur across all ages. Two of the commonest, osteosarcoma (OS) and Ewing sarcoma (ES), are regarded as characteristic adolescent and young adult (AYA) cancers with an incidence peak in AYAs. They are curable for some but associated with unacceptably high rates of treatment failure and morbidity. The introduction of effective new therapeutics for bone sarcomas is slow, and to date, complex biology has been insufficiently characterized to allow more rapid therapeutic exploitation. This review focuses on current standards of care, recent advances that have or may soon change that standard of care and challenges to the expert clinical research community that we suggest must be met.

Evaluation of skin reactions during proton beam radiotherapy - Patient-reported versus clinician-reported

BACKGROUND

Skin reaction is a common side-effect of radiotherapy and often only assessed as clinician-reported outcome (CRO). The aim was to examine and compare patient-reported outcome (PRO) of skin reactions with CRO for signs of acute skin reactions for patients with primary brain tumour receiving proton beam radiotherapy (PBT). A further aim was to explore patients' experiences of the skin reactions.

METHODS

Acute skin reactions were assessed one week after start of treatment, mid-treatment and end of treatment among 253 patients with primary brain tumour who underwent PBT. PRO skin reactions were assessed with the RSAS and CRO according to the RTOG scale. Fleiss' kappa was performed to measure the inter-rater agreement of the assessments of skin reactions.

RESULTS

The results showed a discrepancy between PRO and CRO acute skin reactions. Radiation dose was associated with increased skin reactions, but no correlations were seen for age, gender, education, occupation, other treatment or smoking. There was a poor agreement between patients and clinicians (κ = -0.016) one week after the start of PBT, poor (κ = -0.045) to (κ = 0.396) moderate agreement at mid treatment and poor (κ = -0.010) to (κ = 0.296) moderate agreement at end of treatment. Generally, patients' symptom distress toward skin reactions was low at all time points.

CONCLUSION

The poor agreement between PRO and CRO shows that the patient needs to be involved in assessments of skin reactions for a more complete understanding of skin reactions due to PBT. This may also improve patient experience regarding involvement in their own care.

Proton Radiotherapy to Reduce Late Complications in Childhood Head and Neck Cancers

In most childhood head and neck cancers, radiotherapy is an essential component of treatment; however, it can be associated with problematic long-term complications. Proton beam therapy is accepted as a preferred radiation modality in pediatric cancers to minimize the late radiation side effects. Given that childhood cancers are a rare and heterogeneous disease, the support for proton therapy comes from risk modeling and a limited number of cohort series. Here, we discuss the role of proton radiotherapy in pediatric head and neck cancers with a focus on reducing radiation toxicities. First, we compare the efficacy and expected toxicities in proton and photon radiotherapy for childhood cancers. Second, we review the benefit of proton radiotherapy in reducing acute and late radiation toxicities, including risks for secondary cancers, craniofacial development, vision, and cognition. Finally, we review the cost effectiveness for proton radiotherapy in pediatric head and neck cancers. This review highlights the benefits of particle radiotherapy for pediatric head and neck cancers to improve the quality of life in cancer survivors, to reduce radiation morbidities, and to maximize efficient health care use.

Childhood Cancer: Occurrence, Treatment and Risk of Second Primary Malignancies

Cancer represents the leading cause of disease-related death and treatment-associated morbidity in children with an increasing trend in recent decades worldwide. Nevertheless, the 5-year survival of childhood cancer patients has been raised impressively to more than 80% during the past decades, primarily attributed to improved diagnostic technologies and multiagent cytotoxic regimens. This strong benefit of more efficient tumor control and prolonged survival is compromised by an increased risk of adverse and fatal late sequelae. Long-term survivors of pediatric tumors are at the utmost risk for non-carcinogenic late effects such as cardiomyopathies, neurotoxicity, or pneumopathies, as well as the development of secondary primary malignancies as the most detrimental consequence of genotoxic chemo- and radiotherapy. Promising approaches to reducing the risk of adverse late effects in childhood cancer survivors include high precision irradiation techniques like proton radiotherapy or non-genotoxic targeted therapies and immune-based treatments. However, to date, these therapies are rarely used to treat pediatric cancer patients and survival rates, as well as incidences of late effects, have changed little over the past two decades in this population. Here we provide an overview of the epidemiology and etiology of childhood cancers, current developments for their treatment, and therapy-related adverse late health consequences with a special focus on second primary malignancies.

Proton beam therapy for children and adolescents and young adults (AYAs): JASTRO and JSPHO Guidelines

Children and adolescents and young adults (AYAs) with cancer are often treated with a multidisciplinary approach. This includes use of radiotherapy, which is important for local control, but may also cause adverse events in the long term, including second cancer. The risks for limited growth and development, endocrine dysfunction, reduced fertility and second cancer in children and AYAs are reduced by proton beam therapy (PBT), which has a dose distribution that decreases irradiation of normal organs while still targeting the tumor. To define the outcomes and characteristics of PBT in cancer treatment in pediatric and AYA patients, this document was developed by the Japanese Society for Radiation Oncology (JASTRO) and the Japanese Society of Pediatric Hematology/Oncology (JSPHO).

Ewing Sarcoma-Diagnosis, Treatment, Clinical Challenges and Future Perspectives

Ewing sarcoma, a highly aggressive bone and soft-tissue cancer, is considered a prime example of the paradigms of a translocation-positive sarcoma: a genetically rather simple disease with a specific and neomorphic-potential therapeutic target, whose oncogenic role was irrefutably defined decades ago. This is a disease that by definition has micrometastatic disease at diagnosis and a dismal prognosis for patients with macrometastatic or recurrent disease. International collaborations have defined the current standard of care in prospective studies, delivering multiple cycles of systemic therapy combined with local treatment; both are associated with significant morbidity that may result in strong psychological and physical burden for survivors. Nevertheless, the combination of non-directed chemotherapeutics and ever-evolving local modalities nowadays achieve a realistic chance of cure for the majority of patients with Ewing sarcoma. In this review, we focus on the current standard of diagnosis and treatment while attempting to answer some of the most pressing questions in clinical practice. In addition, this review provides scientific answers to clinical phenomena and occasionally defines the resulting translational studies needed to overcome the hurdle of treatment-associated morbidities and, most importantly, non-survival.

Skin Toxicity Profile of Photon Radiotherapy versus Proton Beam Therapy in Paediatric and Young Adult Patients with Sarcomas

AIMS

Radiotherapy is key in the management of patients with both Ewing sarcoma and rhabdomyosarcoma. However, there is little evidence in the literature with regards to radiation-induced skin toxicities (RISTs) for patients treated with conventional radiotherapy with X-rays (XRT) or proton beam therapy (PBT) for these two conditions. In the present study we evaluated acute and late RIST in patients treated within European protocols with either PBT or XRT, taking both clinical and dosimetric variables into consideration.

MATERIALS AND METHODS

This was a retrospective analysis of 79 paediatric/young adult patients treated with radical radiotherapy (with XRT or PBT) and concurrent chemotherapy. In all cases, radiotherapy was given in conventional fractionation (1.8 Gy/fraction). Acute and late RISTs were registered according to the Radiation Therapy Oncology Group (RTOG) scoring system.

RESULTS

With regards to acute RIST, 47.9% (23/48) of XRT patients and 48.4% (15/31) of PBT patients had acute grade 2/3 toxicity. When it comes to late RIST, 17.5% (7/40 with known toxicity profile) of XRT patients and 29.0% (9/31) of PBT patients had grade 1/2 toxicity. This difference of -11.5% (95% confidence interval -31.2 to 7.9%) in grade 1/2 toxicity between XRT and PBT was not statistically significant (P = 0.25). Regardless of the radiotherapy technique, V30Gy seems a good predictor of acute RIST. Moreover, for the same value of V30Gy, patients who receive PBT may have a higher risk of moderate-severe acute RIST. Perhaps due to the small sample, definitive conclusions on the predictive factors of late RIST could not be drawn.

CONCLUSIONS

No clinically meaningful differences in acute and late RIST were observed between PBT and XRT subgroups. Systematic differences in the modelling of the build-up region may exist between XRT and PBT algorithms, which could make the comparison of dose metrics between techniques potentially biased. A more comprehensive analysis of dosimetric data on larger patient cohorts is needed to elucidate the most relevant skin dose metrics. Dose-effect models of RIST for this unique patient population would be an invaluable tool in radiotherapy plan optimisation.

Managing axial bone sarcomas in childhood

Introduction: Axial osteosarcoma and Ewing sarcoma are rare, aggressive neoplasms with a worse prognosis than with tumors involving the extremities because they are more likely to be associated with larger tumor volumes, older age, primary metastases, and a poor histological response to chemotherapy. The 5-year OS rates are reportedly in the range of 18-41% for axial osteosarcoma, and 46-64% for Ewing sarcoma.Area covered: The treatment of axial bone tumors is the same as for extremity bone tumors, and includes chemotherapy, surgery and/or radiotherapy.Expert opinion: Local treatment of axial tumors is particularly difficult due to their proximity to neurological and vascular structures, which often makes extensive and en bloc resections impossible without causing significant morbidity. The incidence of local relapse is consequently high, and this is the main issue in the treatment of these tumors. Radiotherapy is an option in the case of surgical resections with close or positive margins, as well as for inoperable tumors. Delivering high doses of RT to the spinal cord can be dangerous. Given the complexity and rarity of these tumors, it is essential for this subset of patients to be treated at selected reference institutions with specific expertise and multidisciplinary skills.

Treatment Outcomes After Proton Therapy for Ewing Sarcoma of the Pelvis

PURPOSE

Ewing sarcoma of the pelvis is associated with inferior local control compared with those arising from other primary sites. Despite its increased use, outcome data for treatment with proton therapy remain limited. We report 3-year disease control and toxicity in pediatric patients treated with proton therapy.

METHODS AND MATERIALS

Thirty-five patients aged ≤21 years (median, 14 years) with nonmetastatic pelvic Ewing sarcoma received proton therapy and chemotherapy between 2010 and 2018. Overall survival and tumor control rates were calculated using the Kaplan-Meier method. A log-rank test assessed significance between strata of prognostic factors. Significant toxicity was reported per the Common Terminology Criteria for Adverse Events, version 4.0.

RESULTS

Most patients received definitive radiation (n = 26; median dose 55.8 Gy relative biological effectiveness [RBE]; range, 54.0-64.8), 7 received preoperative radiation (50.4 Gy RBE), and 2 received postoperative radiation (45 Gy RBE and 54 Gy RBE). The median primary tumor size was 10.5 cm. With a median follow-up of 3 years (range, 0.3-9.0 years), the 3-year overall survival, progression-free survival, and local control rates were 83% (95% confidence interval [CI], 65%-93%), 64% (95% CI, 45%-79%), and 92% (95% CI, 74%-98%), respectively. There was no association between local control, progression-free survival, or overall survival and tumor size, patient age, radiation dose, or definitive versus pre-/postoperative radiation therapy. Median time to progression was 1 year (range, 0.1-1.9 years). All patients with large tumors (≥8 cm) who underwent definitive proton therapy with a higher dose (≥59.4 Gy RBE) remained free from tumor recurrence (n = 5). Five patients experienced grade ≥2 subacute/late toxicity, all of whom were treated with combined surgery and radiation.

CONCLUSIONS

Definitive proton therapy offers local control comparable to photon therapy in pediatric patients with pelvic Ewing sarcoma. These data lend preliminary support to radiation dose escalation without significant toxicity, which may contribute to the favorable outcomes. Combined surgery and radiation therapy, particularly preoperative radiation, is associated with postoperative complications, but not survival, compared with radiation alone.

How Technology Is Improving the Multidisciplinary Care of Sarcoma

Sarcomas are rare tumors but comprise a wide histologic spectrum. Advances in technology have emerged to address the biologic complexity and challenging diagnosis and treatment of this disease. The diagnostic approach to sarcomas has historically been based on morphologic features, but technologic advances in immunohistochemistry and cytogenetic/molecular testing have transformed the interdisciplinary work-up of mesenchymal neoplasms in recent years. On the therapeutic side, technologic advances in the delivery of radiation have made it a linchpin in the treatment of localized and oligometastatic sarcoma. In this review, we discuss recent advances in the pathologic diagnosis of sarcomas and discuss select sarcoma types that illustrate how newly discovered diagnostic, prognostic, and predictive biomarkers have refined existing classification schemes and substantially shaped our diagnostic approach. Such examples include conventional and epithelioid malignant peripheral nerve sheath tumors (MPNSTs), emerging entities in the group of round cell sarcomas, and other mesenchymal neoplasms with distinct cytogenetic aberrations. Recent advances in radiation oncology, including intensity-modulated, stereotactic, MRI-guided, and proton radiotherapy (RT), will be reviewed in the context of neoadjuvant or adjuvant localized soft-tissue sarcoma and oligometastatic or oligoprogressive disease. Innovations in translational research are expected to be introduced into clinical practice over the next few years and will likely continue to affect the rapidly evolving field of sarcoma diagnostics and therapy.

Impact of different treatment techniques for pediatric Ewing sarcoma of the chest wall: IMRT, 3DCPT, and IMPT with/without beam aperture

Purpose

To evaluate the dosimetric differences between photon intensity‐modulated radiation therapy (IMRT) plans, 3D conformal proton therapy (3DCPT), and intensity‐modulated proton therapy (IMPT) plans and to investigate the dosimetric impact of different beam spot size and beam apertures in IMPT for pediatric Ewing sarcoma of the chest wall.

Methods and Materials

Six proton pediatric patients with Ewing sarcoma in the upper, middle, and lower thoracic spine regions as well as upper lumbar spine region were treated with 3DCPT and retrospectively planned with photon IMRT and IMPT nozzles of different beam spot sizes with/without beam apertures. The plan dose distributions were compared both on target conformity and homogeneity, and on organs‐at‐risk (OARs) sparing using QUANTEC metrics of the lung, heart, liver, and kidney. The total integral doses of healthy tissue of all plans were also evaluated.

Results

Target conformity and homogeneity indices are generally better for the IMPT plans with beam aperture. Doses to the lung, heart, and liver for all patients are substantially lower with the 3DPT and IMPT plans than those of IMRT plans. In the IMPT plans with large spot without beam aperture, some OAR doses are higher than those of 3DCPT plans. The integral dose of each photon IMRT plan ranged from 2 to 4.3 times of proton plans.

Conclusion

Compared to IMRT, proton therapy delivers significant lower dose to almost all OARs and much lower healthy tissue integral dose. Compared to 3DCPT, IMPT with small beam spot size or using beam aperture has better dose conformity to the target.

The role of proton therapy in pediatric malignancies: Recent advances and future directions

Proton radiotherapy has promised an advantage in safely treating pediatric malignancies with an increased capability to spare normal tissues, reducing the risk of both acute and late toxicity. The past decade has seen the proliferation of more than 30 proton facilities in the United States, with increased capacity to provide access to approximately 3,000 children per year who will require radiotherapy for their disease. We provide a review of the initial efforts to describe outcomes after proton therapy across the common pediatric disease sites. We discuss the main attempts to assess comparative efficacy between proton and photon radiotherapy concerning toxicity. We also discuss recent efforts of multi-institutional registries aimed at accelerating research to better define the optimal treatment paradigm for children requiring radiotherapy for cure.

Outcomes following proton therapy for Ewing sarcoma of the cranium and skull base

PURPOSE

Despite the dosimetric advantages of proton therapy, little data exist on patients who receive proton therapy for Ewing sarcoma of the cranium and skull base. This study reports local disease control and toxicity in such patients.

MATERIALS/METHODS

We reviewed 25 patients (≤21 years old) with nonmetastatic Ewing sarcoma of the cranium and skull base treated between 2008 and 2018. Treatment toxicity was graded per the Common Terminology Criteria for Adverse Events v4.0. The Kaplan-Meier product limit method provided estimates of disease control and survival.

RESULTS

Median patient age was 5.9 years (range, 1-21.7). Tumor subsites included the skull base (48%), non-skull-base calvarial bones (28%), paranasal sinuses (20%), and nasal cavity (4%). All patients underwent multiagent alkylator- and anthracycline-based chemotherapy; 16% underwent gross total resection (GTR) before radiation. Clinical target volume (CTV) 1 received 45 GyRBE and CTV2 received 50.4 GyRBE following GTR or 54-55.8 GyRBE following biopsy or subtotal resection. Median follow-up was 3.7 years (range, 0.26-8.3); no patients were lost. The 4-year local control, disease-free survival, and overall survival rates were 96%, 86%, and 92%, respectively. Two patients experienced in-field recurrences. One patient experienced bilateral conductive hearing loss requiring aids, two patients developed intracranial vasculopathy, and 6 patients required hormone replacement therapy for neuroendocrine deficits. None developed a secondary malignancy.

CONCLUSION

Proton therapy is associated with a favorable therapeutic ratio in children with large Ewing tumors of the cranium and skull base. Despite its high conformality, we observed excellent local control and no marginal recurrences. Treatment dosimetry predicts limited long-term neurocognitive and neuroendocrine side effects.

Proton therapy in the most common pediatric non-central nervous system malignancies: an overview of clinical and dosimetric outcomes

Radiation therapy represents an important approach in the therapeutic management of children and adolescents with malignant tumors and its application with modern techniques – including Proton Beam Therapy (PBT) – is of great interest. In particular, potential radiation-induced injuries and secondary malignancies – also associated to the prolonged life expectancy of patients – are still questions of concern that increase the debate on the usefulness of PBT in pediatric treatments. This paper presents a literary review of current applications of PBT in non-Central Nervous System pediatric tumors (such as retinoblastoma, Hodgkin Lymphoma, Wilms tumor, bone and soft tissues sarcomas). We specifically reported clinical results achieved with PBT and dosimetric comparisons between PBT and the most common photon-therapy techniques. The analysis emphasizes that PBT minimizes radiation doses to healthy growing organs, suggesting for reduced risks of late side-effects and radiation-induced secondary malignancies. Extended follow up and confirms by prospective clinical trials should support the effectiveness and long-term tolerance of PBT in the considered setting.

Paediatric proton therapy

Proton beam therapy is a highly conformal form of radiation therapy, which currently represents an important therapeutic component in multidisciplinary management in paediatric oncology. The precise adjustability of protons results in a reduction of radiation-related long-term side-effects and secondary malignancy induction, which is of particular importance for the quality of life. Proton irradiation has been shown to offer significant advantages over conventional photon-based radiotherapy, although the biological effectiveness of both irradiation modalities is comparable. This review evaluates current data from clinical and dosimetric studies on the treatment of tumours of the central nervous system, soft tissue and bone sarcomas of the head and neck region, paraspinal or pelvic region, and retinoblastoma. To date, the clinical results of irradiating childhood tumours with high-precision proton therapy are promising both with regard to tumour cure and the reduction of adverse events. Modern proton therapy techniques such as pencil beam scanning and intensity modulation are increasingly established modern facilities. However, further investigations with larger patient cohorts and longer follow-up periods are required, in order to be able to have clear evidence on clinical benefits.

Spinal sarcomas and immunity: An undervalued relationship

Sarcomas, especially spine sarcomas, are rare yet debilitating and are underestimated types of cancer. Treatment options for spine sarcomas are limited to chemotherapy, radiotherapy and surgical intervention. Accumulating evidence suggests a complex course associated with the treatment of spine sarcomas as compared to other soft tissue sarcomas in the extremities since adjuvant therapy adds limited success to the oncological outcome. Likewise, the limitations of surgical interventions imposed by the proximity and high sensitivity of the spinal cord, leads to an increased recurrence and mortality rates associated with spine sarcomas. Finding novel treatment options to spine sarcomas as such is inevitable, necessitating a more thorough understanding of the different mechanisms of the underlying etiologies of these tumors. In this review, we discuss the most recent studies tackling the involvement of the immune system; a key player in the emergence of the different types of spine sarcomas and the promising immune-mediated targeted therapy that can be applied in these kind of rare cancers.

Current questions in bone sarcomas

PURPOSE OF REVIEW

Osteosarcoma and Ewing sarcoma, the most common primary bone tumours in young people, are curable in most patients. However, these tumours remain a significant challenge due to the complexity and intensity of treatment and its long-term morbidity and the significant proportion of patients in whom treatment is unsuccessful. This review addresses questions about current management and emerging therapeutic targets for patients with osteosarcoma, Ewing sarcoma and chondrosarcoma, the commonest bone sarcoma but more common in older patients.

RECENT FINDINGS

The largest collaborative international study in osteosarcoma, EURAMOS-1 determined that treatment of patients with resectable disease should not be altered on basis of pathological response to neoadjuvant chemotherapy. In view of little improvement in outcome being evident in recent years, novel therapeutic approaches are required. Putative targets and clinical trials of novel agents are discussed, including emerging targets such as poly (ADP-ribose) polymerase inhibition and isocitrate dehydrogenase inhibition in Ewing sarcoma and chondrosarcoma, respectively. Newer radiotherapy techniques including proton beam and particle ion therapy may be important for local tumour control in selected patients.

SUMMARY

Collaborative studies are essential to answer current questions and investigate novel therapies in these malignancies to improve outcome and quality of life for patients.

The Role of Particle Therapy for the Treatment of Skull Base Tumors and Tumors of the Central Nervous System (CNS)

Radiation therapy (RT) is a mainstay in the interdisciplinary treatment of brain tumors of the skull base and brain. Technical innovations during the past 2 decades have allowed for increasingly precise treatment with better sparing of adjacent healthy tissues to prevent treatment-related side effects that influence patients' quality of life. Particle therapy with protons and charged ions offer favorable kinetics with sharp dose deposition in a well-defined depth (Bragg-Peak) and a steep radiation fall-off beyond that maximum. This review highlights the role of particle therapy in the management of primary brain tumors and tumors of the skull base.

Ewing Sarcoma in Nepal Treated With Combined Chemotherapy and Definitive Radiotherapy

PURPOSE

To our knowledge, we conducted the first prospective oncologic clinical trial in Nepal aimed at providing state-of-the-art chemotherapy to patients with Ewing sarcoma. The efficacy of external-beam radiotherapy (RT) as the sole local treatment modality was explored and deemed justified as a result of the lack of available advanced tumor-orthopedic services in Nepal.

PATIENTS AND METHODS

Twenty patients, 11 female and 9 male patients between the ages of 6 and 37 years, with newly diagnosed Ewing sarcoma were enrolled. Neoadjuvant combination chemotherapy, comprising well-established drug combinations, was administered in five courses before external-beam RT, during which one course of etoposide and ifosfamide was given. After RT, six additional chemotherapy courses were scheduled.

RESULTS

RT was tolerated well, providing rapid symptom relief and local tumor control, with no pathologic fractures observed among the 15 patients who received such treatment. Eleven patients completed the entire treatment protocol; seven patients were under continued follow-up, with no evidence of disease in six patients at a median follow-up time of 2.3 years (range, 1.3 to 3.1 years) and one patient alive but with a regional recurrence. Four patients experienced metastatic relapse and died as a result of their disease. Three treatment-related deaths linked to toxicity from chemotherapy occurred. Four of the six patients who refused to complete the treatment protocol and were lost to follow-up experienced progressive disease and were assumed dead.

CONCLUSION

This study was feasible with RT as the sole local treatment modality in combination with chemotherapy. As a result of the high number of patients lost to follow-up, no firm conclusions can be drawn, but the majority of the patients who completed treatment obtained durable long-term remissions.

Proton beam therapy in pediatric oncology

PURPOSE OF REVIEW

The advent of proton beam therapy (PBT) has initiated a paradigm shift in the field of pediatric radiation oncology, with increasing promise to alleviate both short-term and long-term toxicities. Given the dramatic rise in proton therapy centers in the United States, a discussion of the quality of evidence supporting its use in pediatric cancers is warranted.

RECENT FINDINGS

Proton radiotherapy appears to decrease the incidence and severity of late effects with the strongest evidence in pediatric brain tumor cohorts that shows benefits in neurocognitive, hearing, and endocrine outcomes. However, emerging data has shown that more conservative brainstem dose limits with protons compared with photons are required to limit brainstem toxicity; these modified recommendations have been incorporated into national cooperative group studies. Decreased toxicity in tumors outside of the CNS for PBT have also been reported in sarcomas, Hodgkin disease and neuroblastoma. Similarly, QoL outcomes are improved in brain tumor and other cohorts of patients treated with PBT.

SUMMARY

The collective findings demonstrate improved understanding and refinement of PBT in pediatric cancers. Data on QOL, toxicity and disease outcomes with PBT should continue to be collected and reported in order to understand the full extent of the risks and benefits associated with PBT.

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.

Risk of second cancer after ion beam radiotherapy: insights from animal carcinogenesis studies

Purpose: To review recent studies to better understand the risk of second cancer after ion beam radiotherapy and to clarify the importance of animal radiobiology therein. Results: Risk of developing second cancer after radiotherapy is a concern, particularly for survivors of childhood tumors. Ion beam radiotherapy is expected to reduce the risk of second cancer by reducing exposure of normal tissues to radiation. Large uncertainty lies, however, in the choice of relative biological effectiveness (RBE) of high linear energy transfer (LET) radiation (e.g. carbon ions and neutrons) in cancer induction, especially for children. Studies have attempted to predict the risk of second cancer after ion beam radiotherapy based on an assessment of radiation dose, the risk of low LET radiation, and assumptions about RBE. Animal experiments have yielded RBE values for selected tissues, radiation types, and age at the time of irradiation; the results indicate potentially variable RBE which depends on tissues, ages, and dose levels. Animal studies have also attempted to identify genetic alterations in tumors induced by high LET radiation. Conclusions: Estimating the RBE value for cancer induction is important for understanding the risk of second cancer after ion beam radiotherapy. More comprehensive animal radiobiology studies are needed.

Timing of Local Therapy Affects Survival in Ewing Sarcoma

PURPOSE

We aimed to investigate the relationship between survival and time to local therapy after initiation of up-front chemotherapy in the treatment of patients with localized Ewing sarcoma.

METHODS AND MATERIALS

The National Cancer Database was queried for patients with localized Ewing sarcoma treated with primary chemotherapy and subsequent local therapy. Kaplan-Meier survival curves were generated for patients initiating local therapy 6 to 15 weeks and ≥16 weeks after chemotherapy initiation. Multivariable binomial logistic regression was used to identify factors associated with prolonged time to local therapy. A multivariable Cox proportional hazards model was used to identify factors associated with overall survival (OS).

RESULTS

The final cohort included 1318 patients. A higher proportion of patients initiating local therapy 6 to 15 weeks after chemotherapy initiation versus ≥16 weeks after chemotherapy initiation were ≤21 years old (79.5% vs 72.0%; P = .004). Age >21 years (P < .001; hazard ratio, 1.65; 95% confidence interval, 1.28-2.12), tumor size >8 cm (P = .016), and time to local therapy ≥16 weeks (P = .005; hazard ratio, 1.41; 95% confidence interval, 1.11-1.80) were associated with reduced OS; after review of margin status, negative margins were associated with improved OS compared with gross disease (P = .029). Patients initiating local therapy at 6 to 15 weeks versus ≥16 weeks had a 5-year OS of 78.7% versus 70.4% and a 10-year OS of 70.3% versus 57.1%, respectively (P < .001). The difference in OS according to time to local therapy was particularly more important in patients receiving radiation therapy alone. Age >21 years and treatment by radiation therapy alone were associated with delayed time (>16 weeks) to local therapy, whereas private insurance and income >$48,000 were less likely to be associated with delayed local therapy.

CONCLUSIONS

Delayed time to local therapy ≥16 weeks after chemotherapy initiation was independently associated with worse survival in patients with localized Ewing sarcoma.

Interinstitutional patient transfers between rapid chemotherapy cycles were feasible to utilize proton beam therapy for pediatric Ewing sarcoma family of tumors

Aim

To assess the feasibility of transferring to the University of Tsukuba Hospital for proton beam therapy (PBT) during intensive chemotherapy in children with Ewing sarcoma family of tumors (ESFT) who had been diagnosed and started their first-line treatment at prefectural or regional centers for pediatric oncology.

Background

The treatment of ESFT relies on a multidisciplinary approach using intensive neoadjuvant and adjuvant chemotherapies with surgery and radiotherapy. Multi-agent chemotherapy comprising vincristine, doxorubicin, cyclophosphamide, ifosfamide, and etoposide (VDC-IE) is widely used for ESFT, and the interval between each course is very important for maintaining the intensity and effect of chemotherapy.

Materials and methods

Clinical information of patients who received PBT and VDC-IE between April 2009 and May 2016 was collected retrospectively. The intervals between each course of VDC-IE and adverse events were assessed.

Results

Fifteen patients were evaluated. No delays in the intervals of chemotherapy due to transfer were observed. There were no adverse events caused during/just after transfer and no increases in adverse events. The estimated 4-year overall and event-free survival rates were 94.6% and 84.8%, respectively.

Discussion

Although the results of efficacy are preliminary, survival rates were comparable with past studies. More experience and follow-up are required to further assess the efficacy of PBT for patients with ESFT.

Conclusion

Multidisciplinary therapy for children with ESFT involving transfer to our hospital for PBT during VDC-IE was feasible without treatment delay or an increase in adverse events.

Proton therapy for pediatric malignancies: Fact, figures and costs. A joint consensus statement from the pediatric subcommittee of PTCOG, PROS and EPTN

Radiotherapy plays an important role in the management of childhood cancer, with the primary aim of achieving the highest likelihood of cure with the lowest risk of radiation-induced morbidity. Proton therapy (PT) provides an undisputable advantage by reducing the radiation 'bath' dose delivered to non-target structures/volume while optimally covering the tumor with tumoricidal dose. This treatment modality comes, however, with an additional costs compared to conventional radiotherapy that could put substantial financial pressure to the health care systems with societal implications. In this review we assess the data available to the oncology community of PT delivered to children with cancer, discuss on the urgency to develop high-quality data. Additionally, we look at the advantage of combining systemic agents with protons and look at the cost-effectiveness data published so far.

Ewing sarcoma of the head and neck: The Mayo Clinic experience

BACKGROUND

Treatment options of Ewing sarcoma of the head and neck include surgery, radiotherapy (RT), and chemoradiotherapy. However, local control can be challenging.

METHODS

We conducted a retrospective review of all patients with head and neck Ewing sarcoma treated from 1972 to 2015 at a single tertiary care hospital.

RESULTS

Seventeen patients met criteria (median 21 years, range 5-58 years; 5 women). Mean follow-up was 10.4 years (range 2.2-39 years). Tumors occurred commonly in the cervical spine (5/17), the skull (3/17), and the paranasal sinuses (3/17). A total of 14 of 17 patients underwent surgical resection, 9 with gross total resection. After multimodality therapy, the 5-year overall survival (OS) and recurrence-free survival (RFS) was 87% and 75%, respectively.

CONCLUSION

Combined multimodal treatment resulted in a 5-year OS and RFS of 87% and 75%, respectively. Aggressive surgical resection with adjuvant chemoradiotherapy should be considered. Although negative margin surgery is the goal, subtotal resection may be acceptable in the setting of adjuvant treatment.

Pencil beam scanned protons for the treatment of patients with Ewing sarcoma

BACKGROUND

Few data exist regarding the clinical outcome of patients with Ewing sarcoma (EWS) treated with pencil beam scanning proton therapy (PT). We report the outcome of children, adolescents and young adults (AYA) treated with PT at the Paul Scherrer Institute.

MATERIALS

Thirty-eight patients (median age, 9.9 years) received a median dose of 54.9 Gy(RBE) (where RBE is relative biologic effectiveness). Size of the tumor ranged from 1.7 to 24 cm. Most common primary site was axial/pelvic (n = 27; 71%). Four patients (11%) presented with metastases at diagnosis. Twenty (53%) patients had chemo-PT only. Median follow-up was 49.6 months (range, 9.2-131.7).

RESULTS

The 5-year actuarial rate of local control (LC), distant metastasis-free survival (DMFS), and overall survival (OS) were 81.5%, 76.4%, and 83.0%, respectively. All local recurrences occurred in field and in patients with nonextremity primaries. Six patients died, all of tumor progression. Age < 10 years was a favorable factor of borderline significance for LC (P = 0.05) and OS (P = 0.05), but was significant for DMFS (P = 0.003). Tumor volume <200 ml was a significant prognostic factors for DMFS (P = 0.03), but not for OS (P = 0.07). Metastasis at diagnosis was a strong predictor of local failure (P = 0.003). Only two grade 3 late toxicities were observed. The 5-year actuarial rate of grade 3 toxicity-free survival was 90.9%.

CONCLUSIONS

These preliminary data suggest that the outcomes of children and AYA with EWS are good and PT was well tolerated with few late adverse events. The local and distant tumor control for older patients with large pre-PT tumor volumes remains problematic.

Provider views on the management of Ewing sarcoma of the spine and pelvis

BACKGROUND

Curative therapy for ES requires both chemotherapy and local control of primary tumor. There is no universally accepted standard approach to local control modalities. This survey was conducted to determine practice patterns and factors influencing the choice to offer various local control modalities to patients with ES of the spine and pelvis.

METHODS

The survey consisted of four scenarios involving a 15-year-old girl who presented with Ewing sarcoma of thoracic vertebra, sacrum, iliac wing, and acetabulum with or without neurologic compromise. The questionnaire was sent to oncologists, orthopedic surgeons, and radiation oncologists, asking their recommendations for local control modality.

RESULTS

Among 94 respondents, radiotherapy was most frequently chosen for sacral tumors (68.1%) and T10 vertebral tumors (46.2%) whereas surgery was preferred for iliac wing pelvic tumors (45.7%) and acetabular tumors (43.6%). Orthopedic surgeons were significantly more likely to offer surgery than radiation oncologists (OR 3.07, 95%CI 1.37-6.88, P = 0.007). Providers outside North America were more likely to offer combined surgery plus radiotherapy (OR 10.58, 95%CI 5.41-20.70, P < 0.001).

CONCLUSION

Considerable heterogeneity exists in local control modalities for Ewing sarcoma of the spine and pelvis. Specialty and location of practice may influence treatment recommendations.

Identification of Patients With Localized Ewing Sarcoma at Higher Risk for Local Failure: A Report From the Children's Oncology Group

PURPOSE

To identify clinical and treatment variables associated with a higher risk of local failure in Ewing sarcoma patients treated on recent Children's Oncology Group protocols.

METHODS AND MATERIALS

Data for 956 patients treated with ifosfamide and etoposide-based chemotherapy on INT-0091, INT-0154, and AEWS0031 were analyzed. Local treatment modalities were defined as surgery, definitive radiation therapy (RT), or surgery plus radiation (S+RT). Five-year cumulative incidence of local failure was determined.

RESULTS

The local failure rate for the entire cohort was 7.3%, with a 3.9% rate for surgery, 15.3% for RT (P<.01), and 6.6% for S+RT (P=.12). The local failure incidence was 5.4% for extremity tumors, 13.2% for pelvis tumors (P<.01), 5.3% for axial non-spine tumors (P=.90), 9.1% for extraskeletal tumors (P=.08), and 3.6% for spine tumors (P=.49). The incidence of local failure was 14.8% for extremity tumors and 22.4% for pelvis tumors treated with RT, compared with 3.7% for extremity tumors and 3.9% for pelvis tumors treated with surgery (P≤.01). There was no difference in local failure incidence by local treatment modality for axial non-spine, spine, and extraskeletal tumors. The local failure incidence was 11.9% in patients aged ≥18 years versus 6.7% in patients aged <18 years (P=.02). Age ≥18 years (hazard ratio 1.9, P=.04) and treatment with RT (hazard ratio 2.40, P<.01) remained independent prognostic factors for higher local failure incidence on multivariate analysis. Tumor size (</≥ 8 cm) was available in 40% of patients and did not correlate with local failure incidence.

CONCLUSIONS

Local tumor control is excellent and similar between surgery and RT for axial non-spine, spine, and extraskeletal tumors. Age ≥18 years and use of RT, primarily for pelvis and extremity tumors, are associated with the highest risk of local failure. Further efforts should focus on improving outcomes for these patients.

Does Proton Therapy Have a Future in CNS Tumors?

OPINION STATEMENT

Proton therapy is characterized by certain physical properties leading to a reduction in integral dose. As proton therapy becomes more widely available, the ongoing discussion on the real indications for proton therapy becomes more important. In the present article, data on proton therapy for tumors of the central nervous system (CNS) is summarized and discussed in view of modern photon treatments. Still today, no randomized controlled trials are available confirming any clinical benefit of protons in CNS tumors. For certain skull base lesions, such as chordomas and chondrosarcomas, dose escalation is possible with protons thus patients should be referred to a proton center if readily available. For vestibular schwannoma, at present, proton data are inferior to advanced photons. For glioma patients, early data is present for low-grade gliomas, presenting comparable results to photons; dose escalation studies for high-grade gliomas have led to significant side effects, thus strategies of dose-escalation need to rethought. For skull base meningiomas, data from stereotactic series and IMRT present excellent local control with minimal side effects, thus any improvement with protons might only be marginal. The largest benefit is considered in pediatric CNS tumors, due to the intricate radiation sensitivity of children's normal tissue, as well as the potential of long-term survivorship. Long-term data is still lacking, and even recent analyses do not all lead to a clear reduction in side effects with improvement of outcome; furthermore, clinical data seem to be comparable. However, based on the preclinical evidence, proton therapy should be evaluated in every pediatric patient. Protons most likely have a benefit in terms of reduction of long-term side effects, such as neurocognitive sequelae or secondary malignancies; moreover, dose escalation can be performed in radio-resistant histologies. Clinical data with long-term follow-up is still warranted to prove any superiority to advanced photons in CNS tumors. If available, protons should be evaluated for chordoma or chondrosarcoma of the skull base and pediatric tumors. However, many factors are important for excellent oncology care, and no time delay or inferior oncological care should be accepted for the sake of protons only.

Management of Bone Sarcoma

Treatment of bone sarcoma requires careful planning and involvement of an experienced multidisciplinary team. Significant advancements in systemic therapy, radiation, and surgery in recent years have contributed to improved functional and survival outcomes for patients with these difficult tumors, and emerging technologies hold promise for further advancement.

Primary Ewing's sarcoma of the sinonasal tract in adults: A challenging disease

BACKGROUND

Sinonasal localization of Ewing's sarcoma in adults is an exceedingly rare event.

METHODS

The clinical records of 5 patients with primary sinonasal Ewing's sarcoma treated from 1992 to 2012 were retrospectively analyzed. All pathologic slides were reviewed by 2 experienced pathologists. All patients underwent multimodality treatments.

RESULTS

Median age was 36 years (range, 25-52 years). At referral, 2 patients had the original diagnosis changed by review of the histologic slides. Tumors were classified as T4aN0M0 (4 patients) and T2N0M0 (1 patient). Median follow-up was 110 months (range, 70-139 months). Only 1 patient, who started treatment elsewhere based on an incorrect histologic diagnosis, experienced multiple recurrences and eventually died of widespread metastasis.

CONCLUSION

Correct pathologic diagnosis can have a crucial impact on treatment planning and outcome. Multimodality therapy is the key for long-term successful results. Because of the rarity of the tumor, referral to highly experienced care centers is strongly recommended. © 2016 Wiley Periodicals, Inc. Head Neck 39: E45-E50, 2017.

Limited Margin Radiation Therapy for Children and Young Adults With Ewing Sarcoma Achieves High Rates of Local Tumor Control

PURPOSE

To determine the rate of local failure using focal conformal, limited margin radiation therapy (RT) and dose escalation for tumors ≥8 cm (greatest dimension at diagnosis) in children and young adults with Ewing sarcoma (EWS).

METHODS AND MATERIALS

Eligible patients with EWS were treated on a phase 2 institutional trial of focal conformal, limited margin RT using conformal or intensity modulated techniques. The treatment volume incorporated a 1-cm constrained margin around the gross tumor. Unresected tumors, <8 cm at diagnosis, received a standard dose of 55.8 Gy and tumors ≥8 cm, an escalated dose to 64.8 Gy. Patients with microscopic residual disease after resection received adjuvant RT to 50.4 Gy. Adjuvant brachytherapy was permitted in selected patients.

RESULTS

Forty-five patients were enrolled: 26 with localized and 19 with metastatic disease. Median (range) age, tumor size, and follow-up were 13.0 years (2.9-24.7 years), 9.0 cm (2.4-17.0 cm), and 54.5 months (1.9-122.2 months), respectively. All patients received systemic chemotherapy. The median (range) RT dose for all patients was 56.1 Gy (45-65.5 Gy). Seventeen patients received adjuvant, 16 standard-dose, and 12 escalated-dose RT. Failures included 1 local, 10 distant, and 1 local/distant. The estimated 10-year cumulative incidence of local failure was 4.4% ± 3.1%, with no statistical difference seen between RT treatment groups and no local failures in the escalated-dose RT treatment group.

CONCLUSIONS

Treatment with focal conformal, limited margin RT, including dose escalation for larger tumors, provides favorable local tumor control in EWS.

Innovative radiotherapy of sarcoma: Proton beam radiation

This review on proton beam radiotherapy (PBT) focusses on an historical overview, cost-effectiveness, techniques, acute and late toxicities and clinical results of PBT for sarcoma patients. PBT has gained its place among the armamentarium of modern radiotherapy techniques. For selected patients, it can be cost-effective.

Secondary Malignancy Risk Following Proton Radiation Therapy

Radiation-induced secondary malignancies are a significant, yet uncommon cause of morbidity and mortality among cancer survivors. Secondary malignancy risk is dependent upon multiple factors including patient age, the biological and genetic predisposition of the individual, the volume and location of tissue irradiated, and the dose of radiation received. Proton therapy (PRT) is an advanced particle therapy with unique dosimetric properties resulting in reduced entrance dose and minimal to no exit dose when compared with standard photon radiation therapy. Multiple dosimetric studies in varying cancer subtypes have demonstrated that PRT enables the delivery of adequate target volume coverage with reduced integral dose delivered to surrounding tissues, and modeling studies taking into account dosimetry and radiation cell biology have estimated a significantly reduced risk of radiation-induced secondary malignancy with PRT. Clinical data are emerging supporting the lower incidence of secondary malignancies after PRT compared with historical photon data, though longer follow-up in proton treated cohorts is awaited. This article reviews the current dosimetric and clinical literature evaluating the incidence of and risk factors associated with radiation-induced secondary malignancy following PRT.