Proton radiotherapy for parameningeal rhabdomyosarcoma: clinical outcomes and late effects

Risk factors for neurocognitive impairment, emotional distress, and poor quality of life in survivors of pediatric rhabdomyosarcoma: A report from the Childhood Cancer Survivor Study

BACKGROUND

Prevalence and risk of poor psychological outcomes following rhabdomyosarcoma (RMS) are not well-established.

METHODS

Participants in this cross-sectional, case-control study (n = 713 survivors, 42.5% female; mean [SD] age, 30.5 [6.6] years; n = 706 siblings, 57.2% female; mean age, 32.8,[7.9] years) completed measures of neurocognition, emotional distress, and health-related quality of life (HRQOL). Multivariable logistic regression models identified treatments, health behaviors, and chronic conditions associated with impairment.

RESULTS

Relative to siblings, more survivors reported neurocognitive impairment (task efficiency: 21.1% vs. 13.7%, emotional regulation: 16.7% vs. 11.0%, memory: 19.3% vs. 15.1%), elevated emotional distress (somatic distress: 12.9% vs. 4.7%, anxiety: 11.7% vs. 5.9%, depression: 22.8% vs. 16.9%) and poorer HRQOL (physical functioning: 11.1% vs. 2.8%, role functioning due to physical problems: 16.8% vs. 8.2%, pain: 17.5% vs. 10.0%, vitality: 22.3% vs. 13.8%, social functioning: 14.4% vs. 6.8%, emotional functioning: 17.1% vs. 10.6%). Cranial radiation increased risk for impaired task efficiency (odds ratio [OR], 2.30; 95% confidence interval [CI], 1.14-4.63), whereas chest and pelvic radiation predicted increased risk of physical functioning (OR, 2.68; 95% CI, 1.16-6.21 and OR, 3.44; 95% CI, 1.70-6.95, respectively). Smoking was associated with impaired task efficiency (OR, 2.06; 95% CI, 1.14-3.70), memory (OR, 2.23; 95% CI, 1.26-3.95), anxiety (OR, 2.71; 95% CI, 1.36-5.41) and depression (OR, 1.77; 95% CI, 1.01-3.11). Neurologic conditions increased risk of anxiety (OR, 2.30; 95% CI, 1.04-5.10), and hearing conditions increased risk of depression (OR, 1.79; 95% CI, 1.05-3.03). Neurologic and hearing conditions, respectively, were associated with impaired memory (OR, 2.44; 95% CI, 1.20-4.95 and OR, 1.87; 95% CI, 1.05-3.35) and poor health perception (OR, 2.62; 95% CI, 1.62-1.28 and OR, 2.33; 95% CI, 1.34-4.06).

CONCLUSIONS

RMS survivors are at significant risk for poor psychological outcomes. Advancing therapies for local control, smoking cessation, and managing chronic medical conditions may mitigate poor outcomes following RMS.

Salivary and Dental Complications in Childhood Cancer Survivors Treated With Radiation Therapy to the Head and Neck: A PENTEC Comprehensive Review

PURPOSE

Radiation therapy (RT) to the head and neck (H&N) region is critical in the management of various pediatric malignancies; however, it may result in late toxicity. This comprehensive review from the Pediatric Normal Tissue Effects in the Clinic (PENTEC) initiative focused on salivary dysfunction and dental abnormalities in survivors who received RT to the H&N region as children.

MATERIALS & METHODS

This systematic review was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) method.

RESULTS

Of the 2,164 articles identified through a literature search, 40 were included in a qualitative synthesis and 3 were included in a quantitative synthesis. The dose-toxicity data regarding salivary function demonstrate that a mean parotid dose of 35 to 40 Gy is associated with a risk of acute and chronic grade ≥2 xerostomia of approximately 32% and 13% to 32%, respectively, in patients treated with chemo-radiation therapy. This risk increases with parotid dose; however, rates of xerostomia after lower dose exposure have not been reported. Dental developmental abnormalities are common after RT to the oral cavity. Risk factors include higher radiation dose to the developing teeth and younger age at RT.

CONCLUSIONS

This PENTEC task force considers adoption of salivary gland dose constraints from the adult experience to be a reasonable strategy until more data specific to children become available; thus, we recommend limiting the parotid mean dose to ≤26 Gy. The minimum toxic dose for dental developmental abnormalities is unknown, suggesting that the dose to the teeth should be kept as low as possible particularly in younger patients, with special effort to keep doses <20 Gy in patients <4 years old.

Proton beam therapy and dentofacial development in paediatric cancer patients: A scoping review

Purpose

It is known that radiation to dentofacial structures during childhood can lead to developmental disturbances. However, this appears to be a relatively subordinated research subject. For this reason, this review aims to establish the current evidence base on the effect of PBT on dentofacial development in paediatric patients treated for cancer in the head and neck region.

Materials and methods

A comprehensive search was undertaken to identify both published and unpublished studies or reports. A single reviewer completed initial screening of abstracts; 2 independent reviewers completed secondary screening and data extraction. A narrative synthesis was then conducted.

Results

82 records were screened in total, resulting in 11 included articles. These articles varied in terms of study design and reporting quality. Owing to both poor study reporting and limited patient numbers, it is not possible to determine the effect of cancer diagnosis, chronological age at treatment, radiation dose or treatment modality on the incidence of facial deformation or dental development anomalies.

Conclusion

Disturbances in dentofacial development are an under-reported toxicity in paediatric cancer survivors treated with PBT to the head and neck. There is a need for more research on dentofacial toxicity reporting, focused on the impact of treatment age, radiation dose, concurrent therapies, and the subsequent impact on quality of life.

An analysis of muscle growth after proton beam therapy for pediatric cancer

Retardation of growth and development is a well-known late effect after radiotherapy for pediatric patients. The goal of the study was to examine the effect of proton beam therapy (PBT) on the growth of muscles included in the irradiated area. The subjects were 17 pediatric patients (age ≤ 5 years) who received PBT with a treatment field including a muscle on only one side out of a pair of symmetrical bilateral muscles and had imaging evaluations for at least 1 year after PBT. The thicknesses of the irradiated and non-irradiated (contralateral) muscles were measured retrospectively on CT or MRI axial images collected before and after PBT. The change of thickness divided by the period (years) for each muscle was compared between the irradiated and contralateral sides. Correlations of muscle growth with irradiation dose and age at the start of treatment were also evaluated. The median observation period was 39.2 months. The measurement sites included the erector spinae (n = 9), gluteus maximus (n = 5) and rhomboids + trapezius (n = 3) muscles. The average changes in muscle thickness were 0.24 mm/year on the irradiated side and 1.19 mm/year on the contralateral side, showing significantly reduced growth on the irradiated side (P = 0.001). Younger patients had greater muscle growth. Irradiation dose was not significant, but muscle growth tended to decrease as the dose increased, and muscles irradiated at >50 Gy (RBE) showed little growth. These results show that muscle growth is affected by PBT and that long-term follow-up is needed to evaluate muscle growth retardation.

Local Treatment of Children Suffering From Parameningeal Rhabdomyosarcoma: A Retrospective Single-Center Study From China

BACKGROUND

Treatment for parameningeal rhabdomyosarcoma (PM-RMS) has been a challenge since local control is difficult. The goal of this study was to analyse the impact of different local treatment approaches on childhood PM-RMS patients and help dispel the doubt that whether secondary radical surgery (SRS) should be encouraged in the management of PM-RMS.

METHODS

A total of 17 children with PM-RMS who received unified systemic chemotherapy and individualized local therapy such as radiotherapy (RT) and/or SRS were included in this retrospective study. The overall survival (OS) and event free survival (EFS) were compared between groups adopting different local strategies.

RESULTS

The 3-year OS and EFS of our PM-RMS patients was 75.5% and 56.5% respectively. The OS and EFS of patients who received SRS were both significantly lower than that of the non-SRS group (3-year OS: 50.0% vs 90.0%, P = .031; 3-year EFS: 33.3% vs 60.6%, P = .020). The OS and EFS of the patients who received RT was higher than that of the patients of the non-RT group (3-year OS: 85.6% vs 0%, P = .001; 3-year EFS: 64.0% vs 0%, P = .011).

CONCLUSION

This study illustrates that SRS was associated with poor prognosis of PM-RMS and should not be routinely performed. Optimized RT strategies along with more intensive chemotherapy may be alternative options to improve the survival of patients with PM-RMS. Multi-center, large sample and prospective studies are needed to further validate these findings.

The need for consensus on delineation and dose constraints of dentofacial structures in paediatric radiotherapy: Outcomes of a SIOP Europe survey

Background and purpose

Children receiving radiotherapy for head-and-neck tumours often experience severe dentofacial side effects. Despite this, recommendations for contouring and dose constraints to dentofacial structures are lacking in clinical practice. We report on a survey aiming to understand current practice in contouring and dose assessment to dentofacial structures.

Methods

A digital survey was distributed to European Society for Paediatric Oncology members of the Radiation Oncology Working Group, and member-affiliated centres in Europe, Australia, and New Zealand. The questions focused on clinical practice and aimed to establish areas for future development.

Results

Results from 52 paediatric radiotherapy centres across 27 countries are reported. Only 29/52 centres routinely delineated some dentofacial structures, with the most common being the mandible (25 centres), temporo-mandibular joint (22), dentition (13), orbit (10) and maxillary bone (eight). For most bones contoured, an 'As Low As Reasonably Achievable' dose objective was implemented. Only four centres reported age-adapted dose constraints.The largest barrier to clinical implementation of dose constraints was firstly, the lack of contouring guidance (49/52, 94%) and secondly, that delineation is time-consuming (33/52, 63%). Most respondents who routinely contour dentofacial structures (25/27, 90%) agreed a contouring atlas would aid delineation.

Conclusion

Routine delineation of dentofacial structures is infrequent in paediatric radiotherapy. Based on survey findings, we aim to 1) define a consensus-contouring atlas for dentofacial structures, 2) develop auto-contouring solutions for dentofacial structures to aid clinical implementation, and 3) carry out treatment planning studies to investigate the importance of delineation of these structures for planning optimisation.

Clinical Insight on Proton Therapy for Paediatric Rhabdomyosarcoma

This paper offers an insight into the use of Proton Beam Therapy (PBT) in paediatric patients with rhabdomyosarcoma (RMS). This paper provides a comprehensive analysis of the literature, investigating comparative photon-proton dosimetry, outcome, and toxicity. In the complex and multimodal scenario of the treatment of RMS, clear evidence of the therapeutic superiority of PBT compared to other modern photon techniques has not yet been demonstrated; however, PBT can be considered an excellent treatment option, in particular for young children and patients with specific primary sites, such as the head and neck area (and especially the parameningeal regions), genito-urinary, pelvic, and paravertebral regions. The unique depth-dose characteristics of protons can be exploited to achieve significant reductions in normal tissue doses and may allow an escalation of tumour doses and greater sparing of normal tissues, thus potentially improving local control while at the same time reducing toxicity and improving quality of life. However, access of children with RMS (and more in general with solid tumors) to PBT remains a challenge, due to the limited number of available proton therapy installations.

The significance of margins in pediatric Non-Rhabdomyosarcoma soft tissue sarcomas: Consensus on surgical margin definition harmonization from the INternational Soft Tissue SaRcoma ConsorTium (INSTRuCT)

BACKGROUND

Margin status following surgery in children, adolescents, and young adults with soft tissue sarcomas is controversial and has been defined differently by various specialties, with definitions changing over time and by cooperative group. The International Soft Tissue Sarcoma Consortium (INSTRuCT) is a collaboration of the Children's Oncology Group (COG) Soft Tissue Sarcoma Committee, European pediatric Soft Tissue sarcoma Study Group (EpSSG), and the European Cooperative Weichteilsarkom Studiengruppe (CWS) devoted to improving patient outcomes by pooling and mining cooperative group clinical trial data.

METHODS

The INSTRuCT non-rhabdomyosarcoma soft tissue sarcoma (NRSTS) working group aimed to develop international harmonized recommendations regarding surgical margin assessment and definitions in children and adolescents with soft tissue tumors.

RESULTS AND CONCLUSION

This review addresses accepted principles and areas of controversy, including the perspectives of surgeons, pathologists, radiation oncologists, and pediatric oncologists, to develop a framework for building common guidelines for future research.

Patient-reported outcomes in childhood head and neck rhabdomyosarcoma survivors and their relation to physician-graded adverse events-A multicenter study using the FACE-Q Craniofacial module

INTRODUCTION

Adverse events (AE) of treatment are prevalent and diverse in head and neck rhabdomyosarcoma (HNRMS) survivors. These AEs are often reported by physicians; however, patients' perceptions of specific AE are not well known. In this study, we explored patient-reported outcomes measuring appearance, health-related quality of life (HRQOL), and facial function in HNRMS survivors. Second, we assess the relationship between physician grading of AE and patient reporting.

MATERIALS AND METHODS

Survivors of pediatric HNRMS, diagnosed between 1993 and 2017, who were at least 2 years after completing treatment were invited to an outpatient clinic as part of a multicenter cross-sectional cohort study. At the outpatient clinics, survivors aged ≥8 years filled out the FACE-Q Craniofacial module; a patient-reported outcome instrument measuring issues specific to patients with facial differences. AE were systematically assessed by a multidisciplinary team based on the Common Terminology Criteria of Adverse Events system.

RESULTS

Seventy-seven survivors with a median age of 16 years (range 8-43) and median follow-up of 10 years (range 2-42) completed the questionnaire and were screened for AEs. Patient-reported outcomes varied widely between survivors. Many survivors reported negative consequences: 82% on appearance items, 81% on HRQOL items, and 38% on facial function items. There was a weak correlation between physician-scored AEs and the majority of patient-reported outcomes specific for those AEs.

CONCLUSIONS

Physician-graded AEs are not sufficient to provide tailored care for HNMRS survivors. Findings from this study highlight the importance of incorporating patient-reported outcome measures in survivorship follow-up.

Auto-segmentation of important centers of growth in the pediatric skeleton to consider during radiation therapy based on deep learning

BACKGROUND

Routinely delineating of important skeletal growth centers is imperative to mitigate radiation-induced growth abnormalities for pediatric cancer patients treated with radiotherapy. However, it is hindered by several practical problems, including difficult identification, time consumption, and inter-practitioner variability.

PURPOSE

The goal of this study was to construct and evaluate a novel Triplet-Attention U-Net (TAU-Net)-based auto-segmentation model for important skeletal growth centers in childhood cancer radiotherapy, concentrating on the accuracy and time efficiency.

METHODS

A total of 107 childhood cancer patients fulfilled the eligibility criteria were enrolled in the training cohort (N = 80) and test cohort (N = 27). The craniofacial growth plates, shoulder growth centers, and pelvic ossification centers, with a total of 19 structures in the three groups, were manually delineated by two experienced radiation oncologists on axial, coronal, and sagittal computed tomography images. Modified from U-Net, the proposed TAU-Net has one main branch and two bypass branches, receiving semantic information of three adjacent slices to predict the target structure. With supervised deep learning, the skeletal growth centers contouring of each group was generated by three different auto-segmentation models: U-Net, V-Net, and the proposed TAU-Net. Dice similarity coefficient (DSC) and Hausdorff distance 95% (HD95) were used to evaluate the accuracy of three auto-segmentation models. The time spent on performing manual tasks and manually correcting auto-contouring generated by TAU-Net was recorded. The paired t-test was used to compare the statistical differences in delineation quality and time efficiency.

RESULTS

Among the three groups, including craniofacial growth plates, shoulder growth centers, and pelvic ossification centers groups, TAU-Net had demonstrated highly acceptable performance (the average DSC = 0.77, 0.87, and 0.83 for each group; the average HD95 = 2.28, 2.07, and 2.86 mm for each group). In the overall evaluation of 19 regions of interest (ROIs) in the test cohort, TAU-Net had an overwhelming advantage over U-Net (63.2% ROIs in DSC and 31.6% ROIs in HD95, p = 0.001-0.042) and V-Net (94.7% ROIs in DSC and 36.8% ROIs in HD95, p = 0.001-0.040). With an average time of 52.2 min for manual delineation, the average time saved to adjust TAU-Net-generated contours was 37.6 min (p < 0.001), a 72% reduction.

CONCLUSIONS

Deep learning-based models have presented enormous potential for the auto-segmentation of important growth centers in pediatric skeleton, where the proposed TAU-Net outperformed the U-Net and V-Net in geometrical precision for the majority status.

Late Dental Toxicities After Proton Chemoradiation for Rhabdomyosarcoma: A Pediatric Case Report

Purpose

Radiation therapy is an independent risk factor for adverse sequelae to the oral cavity and dentition in childhood cancer survivors. However, dental toxicities after radiation therapy often are underreported and there are minimal published data on disturbances in tooth development after proton beam therapy (PBT). We present the long-term clinical and radiographic dental findings 8 years after treatment completion for a patient treated with PBT and chemotherapy for rhabdomyosarcoma.

Materials and Methods

Clinical follow-up data of patients treated with PBT within the Proton Overseas Programme (POP) is stored in a National Database and curated by a dedicated outcomes unit at the Christie NHS PBT center. This case report was identified from the extraction and analysis of data for pediatric head and neck cancer patients in this database for a service evaluation project.

Results

The permanent dentition in this patient aged 3.5 years at the time of treatment was severely affected with abnormal dental development first observed 3.5 years after treatment completion. PBT delivered mean doses of 30 Gy(RBE = 1.1) to the maxilla and 25.9 Gy(RBE = 1.1) to the mandible.

Conclusion

Significant dental development abnormalities occurred in this pediatric patient, despite doses in areas being lower than the proposed thresholds in the literature. Improved descriptions of dental toxicities and routine contouring of the maxilla and mandible are needed to correlate dosimetric data. The dose to teeth should be kept as low as reasonably possible in younger patients until the dose thresholds for dental toxicities are known.

Local control of parameningeal rhabdomyosarcoma: An expert consensus guideline from the International Soft Tissue Sarcoma Consortium (INSTRuCT)

The International Soft Tissue Sarcoma Database Consortium (INSTRuCT) consists of a collaboration between the Children's Oncology Group (COG) Soft Tissue Sarcoma Committee, the European pediatric Soft Tissue Sarcoma Study Group (EpSSG), and the Cooperative Weichteilsarkom Studiengruppe (CWS). As part of the larger initiative of INSTRuCT to provide consensus expert opinions for clinical treatment of pediatric soft tissue sarcoma, we sought to provide updated, evidenced-based consensus guidelines for local treatment of parameningeal rhabdomyosarcoma using both existing literature as well as recommendations from the relevant cooperative group clinical trials. Overall, parameningeal rhabdomyosarcoma represents a distinctly challenging disease to treat, given its location near many critical structures in the head and neck, frequently advanced local presentation, and predilection for local failure. Definitive chemoradiation remains the standard treatment approach for parameningeal rhabdomyosarcoma, with surgery often limited to biopsy or salvage therapy for recurrent disease. In this consensus paper, we specifically discuss consensus guidelines and evidence for definitive local management with radiotherapy, with a focus on imaging for radiotherapy planning, dose and timing of radiation, approach for nodal irradiation, various radiation techniques, including proton therapy, and the limited role of surgical resection.

The Current State of Radiotherapy for Pediatric Brain Tumors: An Overview of Post-Radiotherapy Neurocognitive Decline and Outcomes

Tumors of the central nervous system are the most common solid malignancies diagnosed in children. While common, they are also found to have some of the lowest survival rates of all malignancies. Treatment of childhood brain tumors often consists of operative gross total resection with adjuvant chemotherapy or radiotherapy. The current body of literature is largely inconclusive regarding the overall benefit of adjuvant chemo- or radiotherapy. However, it is known that both are associated with conditions that lower the quality of life in children who undergo those treatments. Chemotherapy is often associated with nausea, emesis, significant fatigue, immunosuppression, and alopecia. While radiotherapy can be effective for achieving local control, it is associated with late effects such as endocrine dysfunction, secondary malignancy, and neurocognitive decline. Advancements in radiotherapy grant both an increase in lifetime survival and an increased lifetime for survivors to contend with these late effects. In this review, the authors examined all the published literature, analyzing the results of clinical trials, case series, and technical notes on patients undergoing radiotherapy for the treatment of tumors of the central nervous system with a focus on neurocognitive decline and survival outcomes.

New aspects and innovations in the local treatment of renal and urogenital pediatric tumors

Local treatment plays a key role for patients' outcome in tumors of the urogenital tract in children. Despite a great variety of different etiologies, the specific localization of pediatric urogenital tumors renders several characteristic demands to the treating personnel. Surgery and radiotherapy are the main elements of local treatment in this group of neoplasms. Numerous new guidelines and innovative technical developments of surgery and radiotherapy have recently been integrated into treatment concepts for pediatric urogenital tumors. Due to the broadness of the field it is not possible to give a full overview over all aspects. Therefore, this article highlights the most important innovations and new guidelines of surgery and radiotherapy of pediatric urogenital tumors.

Disease Control and Patterns of Failure After Proton Beam Therapy for Rhabdomyosarcoma

PURPOSE

Pediatric patients with rhabdomyosarcoma (RMS) are treated with multimodal therapy, often with radiation therapy (RT) as part of local therapy. We report on the efficacy and patterns of failure after proton beam therapy (PBT) for RMS.

METHODS AND MATERIALS

Between January 2006 and February 2017, patients with RMS were enrolled in a prospective institutional review board-approved registry protocol for pediatric patients undergoing PBT. Demographics, clinical characteristics, and treatment related outcomes were reviewed.

RESULTS

Ninety-four RMS patients were treated with a combination of chemotherapy (CT) and PBT. The majority of patients had head and neck (49%) and genitourinary (30%) primaries. Median tumor size was 4.1 cm (range, 1.0-16.5 cm); 33 patients (35%) had primary tumors >5 cm. Median cyclophosphamide equivalent dose was 14.4 g/m² (range, 0-30.8 g/m²). Median time from CT initiation to RT initiation was 13 weeks (range, 1-58 weeks). With median follow-up of 4 years, 4-year overall survival (OS) was 71%, and 4-year progression-free survival (PFS) was 63%. Thirty patients (32%) experienced relapse (13% with local failure [LF]). Four-year local control (LC) was 85% overall; 4-year LC rates were 100% for low-risk, 85% for intermediate-risk, and 55% for high-risk patients (P = .02). Tumor size predicted LC (P = .007), with 7% versus 33% LF rate by tumor size (≤5 cm vs >5 cm). Delayed RT delivery (≥13 weeks from initiation of CT) predicted worse LC (P = .01). Increased tumor size predicted both inferior PFS (P = .02) and OS (P = .01). Delayed RT delivery predicted both inferior PFS (P = .04) and OS (P = .03).

CONCLUSIONS

PBT provides LC comparable to prior studies using photon RT. Inferior LC, PFS, and OS rates were observed for patients with larger tumors and those treated with delayed RT. This finding supports ongoing prospective efforts to dose-escalate treatment of tumors >5 cm; however, these data call into question the optimal timing of local therapy, particularly for patients treated with reduced-dose cyclophosphamide.

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).

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.

Urgent Proton Beam Therapy With Interinstitutional Transfer for Patients With Intracranial Rhabdomyosarcoma: Report of 3 Cases

A number of cases have been reported in recent years regarding the use of proton beam therapy to mitigate adverse events affecting important cranial organs in cases of rhabdomyosarcoma at parameningeal sites. However, few reports have described the use of proton beam therapy as urgent radiotherapy for parameningeal rhabdomyosarcoma with intracranial extension. We treated 3 patients diagnosed with parameningeal rhabdomyosarcoma extending into the cranium who were assessed at other hospitals as suitable for urgent radiotherapy and transferred to our hospital for proton beam therapy. These patients comprised 2 boys and 1 girl 6 to 12 years of age at diagnosis, and proton beam therapy was started on days 5, 11, and 23 after diagnosis, respectively. Patients with parameningeal rhabdomyosarcoma extending into the cranium can be transferred to institutions equipped to perform proton beam therapy. To minimize the interval to starting therapy, medical information should be shared with institutions capable of providing such therapy as soon as the possibility of intracranial soft-tissue sarcoma is recognized. Proton beam therapy is 1 option for radiotherapy in cases of intracranial rhabdomyosarcoma.

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.

An overview of radiological manifestations of acquired dental developmental disturbances in paediatric head and neck cancer survivors

OBJECTIVES

In paediatric cancer survivors treated with chemotherapy and radiotherapy therapy, late effects on dental development are quite common. Oral radiologists are not familiar with the radiographic images of these specific dental consequences of chemotherapy and radiotherapy. With the goal of educating colleagues, to raise awareness of the needs of survivors, and to identify directions for future research, we present dental radiographs of survivors treated for head and neck rhabdomyosarcoma with chemotherapy and radiotherapy. Also, based on the survivors reviewed, a radiographic inventory of commonly found late dental developmental effects seen in conjunction with treatment is presented.

METHODS

Panoramic radiographic findings of five illustrative cases are presented, from a group of 42 survivors of head and neck rhabdomyosarcoma treated at the Academic Medical Center Amsterdam, The Netherlands over the past 25 years.

RESULTS

Five cases showing dental developmental disorders are presented. These cases show an association of the location of the radiation field and the developmental stage of the teeth with the severity of the effect on dental development. We also report an inventory of severe and moderate effects of chemotherapy and radiotherapy on the development of molars and anterior teeth.

CONCLUSIONS

This paper presents five cases and a radiographic inventory to illustrate disturbances of dental development associated with chemotherapy and radiotherapy in children. Medical and dental professionals involved in the treatment of cancer survivors are relatively unaware of the dental consequences of radiation therapy and the age dependency of specific regional effects. These effects can be severe, with great impact on quality of life. Further research in this area could help improve planning of radiation therapy for children, potentially preventing or limiting dental or maxillofacial sequelae.

Patterns of failure and toxicity profile following proton beam therapy for pediatric bladder and prostate rhabdomyosarcoma

PURPOSE/OBJECTIVE(S)

Bladder and prostate are unfavorable sites for rhabdomyosarcoma (B/P-RMS), and represent a challenging location for radiotherapy.

MATERIALS/METHODS

Nineteen patients with B/P-RMS were enrolled on a prospective registry protocol (2008-2017) and treated with chemotherapy, proton beam therapy (PBT), and surgical resection (n = 8; 42%). Emphasis was given to treatment technique, disease-related outcomes, and toxicity associated with PBT.

RESULTS

The majority of patients had bladder RMS (74%) of embryonal histology (95%), Group III (68%), and intermediate-risk disease by Children's Oncology Group (COG) risk stratification (89%). Seven patients (37%) had primary tumors >5 cm in size. All patients were treated according to COG protocols. With a median follow-up of 66.2 months, 5-year overall survival (OS) and progression-free survival (PFS) were 76%. Four patients (21%) experienced disease relapse, all presenting with local failure. The 5-year local control (LC) rate was 76%. Tumor size predicted LC, with 5-year LC for patients with >5 cm tumors being 43% versus 100% for those with ≤5 cm tumors (P = .006). Univariate analysis demonstrated an effect of tumor size on OS (tumor >5 cm, hazard ratio [HR] 17.7, P = .049) and PFS (HR 17.7, P = .049). Acute grade 2 toxicity was observed in two patients (11%, transient proctitis). Late grade 2+ toxicity was observed in three patients (16%; n = 1 grade 2 skeletal deformity; n = 3 transient grade 2 urinary incontinence; one patient experienced both).

CONCLUSIONS

PBT for B/P-RMS affords promising disease-related outcomes with an acceptable toxicity profile. Higher local failure rates were observed for larger tumors, supporting dose-escalation components of ongoing RMS clinical trials.

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.

Outcome and Patterns of Relapse in Childhood Parameningeal Rhabdomyosarcoma Treated With Proton Beam Therapy

PURPOSE

The standard of care of childhood parameningeal rhabdomyosarcoma (pRMS) is chemotherapy and local radiation therapy. Protons are increasingly being used to decrease late effects. The aim of the present study is to analyze the pattern of relapse and the correlation with dosimetric factors in pRMS treated with proton therapy.

METHODS AND MATERIALS

This retrospective evaluation includes children treated in our institution for pRMS. Information on demographics, treatment, tumor characteristics, and toxicities and outcome was prospectively collected within the in-house registry. For patients presenting with local relapse, a fusion of the dosimetry with magnetic resonance imaging displaying site and geometry of recurrence was performed.

RESULTS

Median follow-up time was 2.9 years (0.5-4.7). Forty-six patients were identified in our institution between July 2013 and November 2017. Main characteristics of patients were as follows: 56.5% male, median age 5.1 years (1.3-17.5), 39.1% alveolar histology, 26.1%, 52.2%, 8.7%, and 13% patients with subgroup risk classification D, E/F/G, H, or metastatic, respectively, median total prescribed dose 55.8 Gy (50.4-56.4). Estimated 2-year local control, metastasis-free survival, event-free survival, and overall survival were 83.8%, 87.8%, 76.9%, and 88.9%, respectively. No acute or late local toxicity exceeding grade 3 was observed. Risk-group was identified as prognostic factor for metastasis-free survival in univariate analysis but not in multivariate analysis (trend: P = .09). In this cohort, dosimetric factors did not correlate with outcome. Isolated local failure happened in 5 of the 11 relapses. Local relapses were matched with dosimetry for 6 patients: 4 of them occurred in the high dose volume and 2 in the intermediate or low dose volume.

CONCLUSIONS

Proton therapy was effective and well feasible even in a critical cohort. Still, local relapse within the target volume of the radiation therapy remains an important issue in pRMS and new treatment strategies are needed.

Radiobiological Proton Effects

The article contains an analysis of literature data and the author’s own results on the radiobiological effects of protons at the cellular, systemic (intercellular) and organismic levels, as applied to the practical tasks of radiation therapy of oncological diseases and the protons effects on the astronauts’ organism. It is established that the proton RBE is a variable value, depending on the LET of the particles, the amount and dose rate, the presence or absence of oxygen. Proton RBE varies depending on the object of study, the type of tissue, proton energy and particle penetration depth, as well as the method for evaluating the biological efficiency of protons. which corresponds to general radiobiology. In particular, it has been shown that the RBE of protons adopted in radiation therapy at the level of 1.1 is conditional. A firmly established and repeatedly confirmed is an increase in RBE with a decrease in proton energy and, accordingly, an increase in LET. The use of elements of the physical protection of a spacecraft during exposure to protons with an energy of 170 MeV leads to an increase in LET and RBE of protons in terms of the cellularity of the bone marrow. Pharmacological agents effective in photon irradiation are also effective when exposed to a proton beam. It has been shown that natural melanin pigment and recombinant manganese superoxide dismutase helps to preserve and accelerate the resumption of blood formation in animals irradiated by protons. The Grippol vaccine increases radioresistance during proton irradiation. Neuropeptide Semax has a positive effect on the central nervous system and the strength of the forepaws of animals irradiated with protons at Bragg’s peak.

125 I interstitial brachytherapy in management of pediatric skull base tumors

BACKGROUND

The purpose of this study was to present our preliminary assessment of the safety and efficacy of ¹²⁵ I interstitial brachytherapy (IBT) in the management of pediatric skull base tumors.

METHODS

Thirty pediatric patients with skull base tumors treated with ¹²⁵ I IBT from April 2007 to May 2017 were included in this study. The probabilities of local control (LC) and overall survival (OS) were calculated by the Kaplan-Meier method.

RESULTS

The one- and two-year LC rates were 96.7% and 74.8%, respectively. The one- and two-year OS rates were 93.3% and 72.2%, respectively. No severe acute toxicity was observed. Severe late toxicities were observed in one (3.33%) of 30 patients.

CONCLUSION

¹²⁵ I IBT is effective and safe in the management of pediatric skull base tumors, with satisfactory cosmetic and functional outcomes.

Patterns of failure following proton beam therapy for head and neck rhabdomyosarcoma

PURPOSE

Pediatric patients with rhabdomyosarcoma (RMS) of the head and neck (H&N) are treated with multimodal therapy, often with radiotherapy (RT) as definitive local therapy. We report on the patterns of failure following proton beam therapy (PBT) for H&N RMS.

METHODS

Forty-six H&N RMS patients were enrolled on a prospective registry protocol between 2006 and 2015. All were treated with a combination of chemotherapy (ChT) and PBT. Most patients (25 patients, 54%) had parameningeal tumors, of which 11 (24%) had intracranial extension (ICE). Thirteen patients (28%) had primary tumors greater than 5 cm. Median total cyclophosphamide (CPM) equivalent dose was 13.2 g/m² (range 0-16.8 g/m²). Median RT dose was 50.4 Gy(RBE) (range 36 Gy[RBE]-50.8 Gy[RBE]).

RESULTS

With median follow-up of 3.9 years, five-year overall survival was 76%, and five-year progression-free survival was 57%. Seventeen patients (37%) experienced relapse, including 7 with local failure (LF). Five-year local control (LC) was 84%. Tumor size greater than 5 cm predicted increased risk of LF (hazard ratio [HR] 6.49, p = 0.03), as did the presence of ICE at diagnosis (HR 5.21, p = 0.03). Six relapses occurred in patients with ICE; all included a component of central nervous system relapse, with leptomeningeal disease and/or LF with an intracranial component. Delayed RT delivery after week 4 of ChT predicted increased risk of relapse for ICE patients (HR 10.49, p = 0.006).

CONCLUSIONS

PBT confers excellent LC, and a favorable late toxicity profile as compared with prior photon RT data. Our observations support ongoing trial efforts to dose-escalate RT for patients with larger tumors. However, these data raise concerns regarding excess failures among patients with ICE.

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.

A Road Map for Important Centers of Growth in the Pediatric Skeleton to Consider During Radiation Therapy and Associated Clinical Correlates of Radiation-Induced Growth Toxicity

With the increasing use of advanced radiation techniques such as intensity modulated radiation therapy, stereotactic radiation therapy, and proton therapy, radiation oncologists now have the tools to mitigate radiation-associated toxicities. This is of utmost importance in the treatment of a pediatric patient. To best use these advanced techniques to mitigate radiation-induced growth abnormalities, the radiation oncologist should be equipped with a nuanced understanding of the anatomy of centers of growth. This article aims to enable the radiation oncologist to better understand, predict, and minimize radiation-mediated toxicities on growth. We review the process of bone development and radiation-induced growth abnormalities and provide an atlas for contouring important growth plates to guide radiation treatment planning. A more detailed recognition of important centers of growth may improve future treatment outcomes in children receiving radiation therapy.

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.

Proton therapy for pediatric head and neck malignancies

PURPOSE

Pediatric head and neck malignancies are managed with intensive multimodality therapy. Proton beam therapy (PBT) may reduce toxicity by limiting exposure of normal tissue to radiation. In this study, we report acute toxicities and early outcomes following PBT for pediatric head and neck malignancies.

MATERIALS AND METHODS

Between 2010 and 2016, pediatric patients with nonhematologic malignancies of the head and neck were treated with PBT. Clinical and dosimetric data were abstracted from the medical record and treatment planning system with institutional review board approval.

RESULTS

Sixty-nine consecutive pediatric patients were treated with proton-based radiotherapy for head and neck malignancies. Thirty-five were treated for rhabdomyosarcoma to a median dose of 50.4 Gy relative biological effectiveness [RBE]. Ten patients were treated for Ewing sarcoma to a median dose of 55.8 Gy[RBE]. Twenty-four patients were treated for other histologies to a median dose of 63.0 Gy[RBE]. Grade 3 oral mucositis, anorexia, and dysphagia were reported to be 4, 22, and 7%, respectively. Actuarial 1-year freedom from local recurrence was 92% (95% CI 80-97). Actuarial 1-year overall survival was 93% (95% CI 79-98) in the entire cohort. Oral cavity mucositis was significantly correlated with oral cavity dose (D80 and D50 [P < 0.05], where D80 and D50 are dose to 50% of the volume and dose to 80% of the volume, respectively).

CONCLUSIONS

In this study, we report low rates of acute toxicity in a cohort of pediatric patients with head and neck malignancies. PBT appears safe for this patient population, with local control rates similar to historical reports. Longer follow-up will be required to evaluate late toxicity and long-term disease control.

Facial asymmetry in head and neck rhabdomyosarcoma survivors

INTRODUCTION

Radiotherapy is essential for achieving and maintaining local control in head and neck rhabdomyosarcoma (HNRMS) patients. However, radiotherapy may cause outgrowth disturbances of facial bone and soft tissue, resulting in facial asymmetry. The aim of this study was to develop a method to visualize and measure facial asymmetry in HNRMS survivors using three-dimensional (3D) imaging techniques.

METHODS

Facial deformity was evaluated in a multidisciplinary clinical assessment of 75 HNRMS survivors, treated with external beam radiotherapy (EBRT, n = 26) or Ablative surgery, MOulage brachytherapy, and REconstruction (AMORE, n = 49). Individual facial asymmetry was measured using 3D photogrammetry and expressed in a raw asymmetry index and a normalized sex-age-ethnicity-matched asymmetry signature weight. Facial asymmetry was also compared between British and Dutch controls and between survivors and their matched controls.

RESULTS

Facial asymmetry was more pronounced with increasing age (P < 0.01) in British controls compared with Dutch controls (P = 0.04). Survivors developed more facial asymmetry than matched controls (P < 0.001). The clinical assessment of facial deformity correlated with the raw asymmetry index (r = 0.60, P < 0.001).

DISCUSSION

3D imaging can be used for objective measurement of facial asymmetry in HNRMS survivors. The raw asymmetry index correlated with a clinical assessment of facial deformity. Comparisons between treatment groups seemed inappropriate given the differences in facial asymmetry between British and Dutch controls. In future studies, pretreatment images could act as matched controls for posttreatment evaluation.

A Dosimetric Comparison of Intensity-Modulated Proton Therapy, Volumetric-Modulated Arc Therapy, and 4π Non-Coplanar Intensity-Modulated Radiation Therapy for a Patient with Parameningeal Rhabdomyosarcoma

Rhabdomyosarcoma (RMS) is the most common soft tissue sarcoma in children and manifests as two major histological subtypes: embryonal and alveolar. The five-year local failure rate for RMS at parameningeal sites (middle ear, mastoid region, nasal cavity, etc.) is around 17% despite multiple Intergroup Rhabdomyosarcoma Study Group (IRS) trials conducted to determine the optimal radiation treatment regimen. This case report explores the use of intensity-modulated proton therapy (IMPT) for a 10-year-old child who presented with left eye irritation, facial pain, and headaches and was found to have an alveolar parameningeal rhabdomyosarcoma. He received systemic therapy as well as radiation therapy to 5,640 cGy and 4,320 cGy over 24 fractions, prescribed for gross tumor extension and adjacent high-risk involved sites, respectively, via simultaneous integrated boost. Approximately two years following treatment, the patient has had no recurrence of his RMS with no distant metastases. In addition, his presenting symptom of left eye irritation has improved. His only side effect from radiation at this point is short stature, possibly due to growth hormone deficiency. The patient’s IMPT plan was compared with volumetric-modulated arc therapy (VMAT) and 4π non-coplanar intensity-modulated radiation therapy (IMRT) plans, and comparisons of isodose lines show decreased dose to the distal brain tissue with preserved target conformality by IMPT. IMPT also allowed for increased sparing of the patient's retina, lens, and lacrimal gland. All radiation plans achieved conformal dose coverage to the planning/scanning target volumes, while the IMPT plan is potentially better at sparing the patient from developing long-term optic apparatus side effects and neurocognitive defects. In this case, IMPT is comparable, if not favorable, when long-term side effects can be reduced while maintaining dose conformality and local control.

Long-term follow-up after proton beam therapy for pediatric tumors: a Japanese national survey

Proton beam therapy (PBT) is a potential new alternative to treatment with photon radiotherapy that may reduce the risk of late toxicity and secondary cancer, especially for pediatric tumors. The goal of this study was to evaluate the long‐term benefits of PBT in cancer survivors. A retrospective observational study of pediatric patients who received PBT was performed at four institutions in Japan. Of 343 patients, 62 were followed up for 5 or more years. These patients included 40 males and 22 females, and had a median age of 10 years (range: 0–19 years) at the time of treatment. The irradiation dose ranged from 10.8 to 81.2 GyE (median: 50.4 GyE). The median follow‐up period was 8.1 years (5.0–31.2 years). The 5‐, 10‐ and 20‐year rates for grade 2 or higher late toxicities were 18%, 35% and 45%, respectively, and those for grade 3 or higher late toxicities were 6%, 17% and 17% respectively. Univariate analysis showed that the irradiated site (head and neck, brain) was significantly associated with late toxicities. No malignant secondary tumors occurred within the irradiated field. The 10‐ and 20‐year cumulative rates for all secondary tumors, malignant secondary tumors, and malignant nonhematologic secondary tumors were 8% and 16%, 5% and 13%, and 3% and 11%, respectively. Our data indicate that PBT has the potential to reduce the risk of late mortality and secondary malignancy. Longer follow‐up is needed to confirm the benefits of PBT for pediatric tumors.

Adherence to Treatment, Response and Patterns of Failure in Pediatric Parameningeal Rhabdomyosarcoma: Experience From a Tertiary Cancer Care Center From India

The study was aimed at evaluating adherence to treatment protocol and outcome in pediatric parameningeal rhabdomyosarcoma (PM-RMS). We analyzed the characteristics, treatment administered, outcomes and patterns of failure of pediatric PM-RMS, who were treated with multimodality therapy between January 2005 and December 2013.Univariate and multivariate analysis (MVA) was completed to evaluate the impact of various prognostic factors. Thirty-seven patients were treated at our institution. Majority of them had the primary disease in paranasal sinuses (n=13). Majority of the patients belonged to group III (n=30) and stage III (n=24). The overall response rate to treatment was 52.5% (n=21). At a mean follow-up of 19.1 months, 23 patients developed disease progression. The actuarial rates of failure-free survival and overall survival (OS) at 2 years were 40% and 67.5%, respectively. Patients who received >20 weeks of intended chemotherapy schedule (P=0.02) and had complete response to first-line treatment (P=0.0004) were found to have superior failure-free survival on MVA. Complete response was the lone determinant of superior OS on MVA (P=0.006). Majority of patients with PM-RMS present with advanced stage disease. Response to first-line treatment is a significant predictor of superior progression-free survival and OS in these patients.

Pencil Beam Scanning Proton Therapy for Pediatric Parameningeal Rhabdomyosarcomas: Clinical Outcome of Patients Treated at the Paul Scherrer Institute

BACKGROUND

Parameningeal rhabdomyosarcomas (PM-RMSs) represent approximately 25% of all rhabdomyosarcoma (RMS) cases. These tumors are associated with early recurrence and poor prognosis. This study assessed the clinical outcome and late toxicity of pencil beam scanning (PBS) proton therapy (PT) in the treatment of children with PM-RMS.

PROCEDURES

Thirty-nine children with PM-RMS received neoadjuvant chemotherapy followed by PBS-PT at the Paul Scherrer Institute, with concomitant chemotherapy. The median age was 5.8 years (range, 1.2-16.1). Due to young age, 25 patients (64%) required general anesthesia during PT. The median time from the start of chemotherapy to PT was 13 weeks (range, 3-23 weeks). Median prescription dose was 54 Gy (relative biologic effectiveness, RBE).

RESULTS

With a mean follow-up of 41 months (range, 9-106 months), 10 patients failed. The actuarial 5-year progression-free survival (PFS) was 72% (95% CI, 67-94%) and the 5-year overall survival was 73% (95% CI, 69-96%). On univariate analysis, a delay in the initiation of PT (>13 weeks) was a significant detrimental factor for PFS. Three (8%) patients presented with grade 3 radiation-induced toxicity. The estimated actuarial 5-year toxicity ≥grade 3 free survival was 95% (95% CI, 94-96%).

CONCLUSIONS

Our data contribute to the growing body of evidence demonstrating the safety and effectiveness of PT for pediatric patients with PM-RMS. These preliminary results are encouraging and in line with other combined proton-photon and photons series; observed toxicity was acceptable.

The impact of radiotherapy on clinical outcomes in parameningeal rhabdomyosarcoma

PURPOSE

Radiotherapy (RT) is considered a mainstay of treatment in parameningeal rhabdomyosarcoma (PM-RMS). We aim to determine the treatment outcomes and prognostic factors for PM-RMS patients who treated with RT. In addition, we tried to evaluate the adequate dose and timing of RT.

MATERIALS AND METHODS

Twenty-two patients with PM-RMS from 1995 to 2013 were evaluated. Seven patients had intracranial extension (ICE) and 17 patients had skull base bony erosion (SBBE). Five patients showed distant metastases at the time of diagnosis. All patients underwent chemotherapy and RT. The median radiation dose was 50.4 Gy (range, 40.0 to 56.0 Gy).

RESULTS

The median follow-up was 28.7 months. Twelve patients (54.5%) experienced failure after treatment; 4 local, 2 regional, and 6 distant failures. The 5-year local control (LC) and overall survival (OS) were 77.7% and 38.5%, respectively. The 5-year OS rate was 50.8% for patients without distant metastases and 0% for patients with metastases (p < 0.001). Radiation dose (<50 Gy vs. ≥50 Gy) did not compromise the LC (p = 0.645). However, LC was affected by ICE (p = 0.031). Delayed administration (>22 weeks) of RT was related to a higher rate of local failure (40.0%).

CONCLUSION

RT resulted in a higher rate of local control in PM-RMS. However, it was not extended to survival outcome. A more effective treatment for PM-RMS is warranted.

Late Toxicities of Intensity-Modulated Radiation Therapy for Head and Neck Rhabdomyosarcoma

PURPOSE/OBJECTIVES

To examine the late effects of intensity-modulated radiation therapy (IMRT) in pediatric patients with rhabdomyosarcoma of the head and neck.

MATERIALS/METHODS

All 1-year survivors of pediatric head and neck rhabdomyosarcoma treated with IMRT at a single institution from 1999 to 2014 were assessed for long-term complications. Late toxicities were graded according to CTCAE version 4.03.

RESULTS

Among 30 patients, median age at IMRT was 7.4 (1.5-20.8) years, median follow-up was 7.7 (1.2-14.4) years, and median IMRT dose was 50.4 (36-50.4) Gy. Tumor subsites included parameningeal (80%), orbit (13%), and other (7%). Common late toxicities were facial disfigurement (n = 23, 77%), growth hormone deficiency (n = 11, 37%), cataract (n = 10, 34%), and dental problems (n = 10, 33%). Twenty-two patients (73%) had ≥2 late toxicities and 14 patients (47%) had ≥3 late toxicities. Seventeen patients (57%) experienced grade 2 toxicity and 10 patients (33%) had grade 3 toxicity. Grade 3 toxicities included visual disturbance, cataract, facial disfigurement, chronic sinusitis/otitis, and hearing loss. Severe facial deformity was noted in nine patients (30%), and three patients underwent cosmetic surgery. Patients with severe facial deformity were treated at younger ages (median 6.0 years vs. 8.1 years for patients with no/nonsevere facial deformity) and more likely to have infratemporal fossa tumors. There were no secondary solid malignancies.

CONCLUSIONS

Late radiation toxicities are common in survivors of pediatric head and neck rhabdomyosarcoma treated with IMRT. While the majority of late effects are mild-moderate, they can significantly impact quality of life, particularly facial disfigurement.

Patterns of Failure in Pediatric Rhabdomyosarcoma After Proton Therapy

PURPOSE

To report on the patterns of failure in children with rhabdomyosarcoma treated with proton therapy.

PATIENTS AND METHODS

Between February 2007 and November 2013, 66 children with a median age of 4.1 years (range, 0.6-15.3 years) diagnosed with nonmetastatic rhabdomyosarcoma were treated with proton therapy. Clinical target volume 1 was defined as the prechemotherapy tumor plus a 1-cm anatomically constrained margin. Clinical target volume 2 was defined as the postchemotherapy tumor (or tumor bed) plus a 0.5-cm anatomically constrained margin, further expanded to encompass potential pathways of spread, including soft tissue infiltrated with tumor at diagnosis.

RESULTS

Of the 66 children, 11 developed locally progressive disease at a median of 16 months (range, 14-32 months), for an actuarial 2-year local control rate of 88%. Among the children who progressed, median age and tumor size at diagnosis were 6.7 years (range, 0.6-16 years) and 6 cm (range, 2-8 cm), respectively. Of the recurrences, 64% and 36% were embryonal and alveolar, respectively. Disease progression was observed in 7 (64%) parameningeal, 2 (18%) head and neck (other), and 2 (18%) bladder/prostate subsites. At diagnosis, 8 of 11 patients who developed a recurrence were Intergroup Rhabdomyosarcoma Study stage 3, and all 11 were group III. Of the relapses, 100% (11 of 11) were confirmed as in-field within the composite 95% isodose line. One of the 11 patients (9%) developed a new simultaneous regional nodal recurrence outside of the previously treated radiation field.

CONCLUSION

Early data suggest that the sharp dosimetric gradient associated with proton therapy is not associated with an increased risk of marginal failure. Routine use of a 0.5- to 1-cm clinical target volume 1/2 margin with highly conformal proton therapy does not compromise local control in children diagnosed with rhabdomyosarcoma with unfavorable risk features.

Tumour control and Quality of Life in children with rhabdomyosarcoma treated with pencil beam scanning proton therapy

PURPOSE

To assess clinical outcomes in children with rhabdomyosarcoma (RMS) treated with pencil beam scanning (PBS) proton therapy (PT).

METHODS AND MATERIALS

Eighty-three RMS (embryonal, n=74; 89%) patients treated between January 2000 and December 2014 were included. The median age was 4.5years (range, 0.8-15.5). All patients received systemic chemotherapy according to prospective protocols. Patients had low-, intermediate-, and high-risk disease in 24%, 63%, and 13% of cases, respectively. The median total dose delivered was 54Gy(RBE) (range, 41.4-64.8).

RESULTS

After a median follow-up time of 55.5 months (range, 0.9-126.3), local failure occurred in 16 patients. The 5-year local-control survival rate was 78.5% [95% confidence interval (CI), 69.5-88.5%]. Significant predictors for local failure were group/stage, tumour location, and size. Fourteen patients (16%) died, all from tumour progression. The 5-year overall survival was 80.6% (95%CI, 71.8-90.0%). The 5-year incidence of grade 3 non-ocular late toxicity was 3.6% (95%CI, 1-12%). No grade 4-5 late toxicities were observed. One radiation-induced malignancy was observed (1.2%). The Quality of Life (QoL) scores increased significantly after PT compared to baseline values.

CONCLUSIONS

PBS PT led to excellent outcome in children with RMS. Late non-ocular toxicity was minimal and QoL good.

Proton beam therapy for pediatric malignancies: a retrospective observational multicenter study in Japan

Recent progress in the treatment for pediatric malignancies using a combination of surgery, chemotherapy, and radiotherapy has improved survival. However, late toxicities of radiotherapy are a concern in long‐term survivors. A recent study suggested reduced secondary cancer and other late toxicities after proton beam therapy (PBT) due to dosimetric advantages. In this study, we evaluated the safety and efficacy of PBT for pediatric patients treated in Japan. A retrospective observational study in pediatric patients who received PBT was performed. All patients aged <20 years old who underwent PBT from January 1983 to August 2014 at four sites in Japan were enrolled in the study. There were 343 patients in the study. The median follow‐up periods were 22.6 months (0.4–374.3 months) for all patients and 30.6 months (0.6–374.3 months) for survivors. The estimated 1‐, 3‐, 5‐, and 10‐year survival rates were 82.7% (95% CI: 78.5–87.0%), 67.4% (61.7–73.2%), 61.4% (54.8–67.9%), and 58.7% (51.5–65.9%), respectively. Fifty‐two events of toxicity ≥ grade 2 occurred in 43 patients. Grade 4 toxicities of myelitis, visual loss (two cases), cerebral vascular disease, and tissue necrosis occurred in five patients. This study provides preliminary results for PBT in pediatric patients in Japan. More experience and follow‐up with this technique are required to establish the efficacy of PBT in this patient population.

Hearing loss in survivors of childhood head and neck rhabdomyosarcoma: a long-term follow-up study

OBJECTIVES

To determine the hearing status of survivors treated for head and neck rhabdomyosarcoma (HNRMS) at long-term follow-up.

DESIGN

Cross-sectional long-term follow-up study.

SETTING

Tertiary comprehensive cancer centre.

PARTICIPANTS

Survivors treated for HNRMS during childhood in two concurrent cohorts; survivors in London had been treated with external beam radiotherapy (EBRT-based local therapy); survivors in Amsterdam were treated with AMORE (Ablative surgery, MOuld technique afterloading brachytherapy and surgical REconstruction) if feasible, otherwise EBRT (AMORE-based local therapy).

MAIN OUTCOME MEASURES

We assessed hearing status of HNRMS survivors at long-term follow-up. Hearing thresholds were obtained by pure-tone audiometry.

METHODS

We assessed the hearing thresholds, the number of patients with clinically relevant hearing loss and hearing impairment graded according to the Common Terminology Criteria for Adverse Events version 4.0 (CTCAEv4) and Boston criteria. Furthermore, we compared hearing loss between survivors treated with EBRT-based local therapy (London) and AMORE-based local therapy (Amsterdam).

RESULTS

Seventy-three survivors were included (median follow-up 11 years). We found clinically relevant hearing loss at speech frequencies in 19% of survivors. Multivariable analysis showed that survivors treated with EBRT-based treatment and those with parameningeal tumours had significantly more hearing impairment, compared to survivors treated with AMORE-based treatment and non-parameningeal tumours.

CONCLUSIONS

One in five survivors of HNRMS developed clinically relevant hearing loss. AMORE-based treatment resulted in less hearing loss compared to EBRT-based treatment. As hearing loss was highly prevalent and also occurred in survivors with orbital primaries, we recommend systematic audiological follow-up in all HNRMS survivors.

A Patient-Derived Xenograft Model of Parameningeal Embryonal Rhabdomyosarcoma for Preclinical Studies

Embryonal rhabdomyosarcoma (eRMS) is one of the most common soft tissue sarcomas in children and adolescents. Parameningeal eRMS is a variant that is often more difficult to treat than eRMS occurring at other sites. A 14-year-old female with persistent headaches and rapid weight loss was diagnosed with parameningeal eRMS. She progressed and died despite chemotherapy with vincristine, actinomycin-D, and cyclophosphamide plus 50.4 Gy radiation therapy to the primary tumor site. Tumor specimens were acquired by rapid autopsy and tumor tissue was transplanted into immunodeficient mice to create a patient-derived xenograft (PDX) animal model. As autopsy specimens had an ALK R1181C mutation, PDX tumor bearing animals were treated with the pan-kinase inhibitor lestaurtinib but demonstrated no decrease in tumor growth, suggesting that single agent kinase inhibitor therapy may be insufficient in similar cases. This unique parameningeal eRMS PDX model is publicly available for preclinical study.