Cardiac-sparing whole lung IMRT in children with lung metastasis

Predictive factors for lung metastasis in pediatric differentiated thyroid cancer: a clinical prediction study

OBJECTIVES

The objective of this study was to develop and evaluate the efficacy of a nomogram for predicting lung metastasis in pediatric differentiated thyroid cancer.

METHODS

The SEER database was utilized to collect a dataset consisting of 1,590 patients who were diagnosed between January 2000 and December 2019. This dataset was subsequently utilized for the purpose of constructing a predictive model. The model was constructed utilizing a multivariate logistic regression analysis, incorporating a combination of least absolute shrinkage feature selection and selection operator regression models. The differentiation and calibration of the model were assessed using the C-index, calibration plot, and ROC curve analysis, respectively. Internal validation was performed using a bootstrap validation technique.

RESULTS

The results of the study revealed that the nomogram incorporated several predictive variables, namely age, T staging, and positive nodes. The C-index had an excellent calibration value of 0.911 (95 % confidence interval: 0.876-0.946), and a notable C-index value of 0.884 was achieved during interval validation. The area under the ROC curve was determined to be 0.890, indicating its practicality and usefulness in this context.

CONCLUSIONS

This study has successfully developed a novel nomogram for predicting lung metastasis in children and adolescent patients diagnosed with thyroid cancer. Clinical decision-making can be enhanced by assessing clinicopathological variables that have a significant predictive value for the probability of lung metastasis in this particular population.

Dosimetric Comparison of 3D Conformal Radiotherapy (3D-CRT), Intensity-Modulated Radiotherapy (IMRT), and Volumetric-Modulated Arc Therapy (VMAT) in Cardiac-Sparing Whole Lung Irradiation

Introduction Whole lung irradiation (WLI) is used for the treatment of lung metastasis in Wilms tumor and Ewing sarcoma; however, cardiac complications are one of the concerns. We report the dosimetric advantages of WLI using volumetric-modulated arc therapy (VMAT) and present a dosimetric comparison of VMAT with anteroposterior-posteroanterior (AP-PA) and static-field intensity-modulated radiation therapy (IMRT). Additionally, we evaluated the dosimetric impact of respiratory motion and intra-fractional motion during VMAT treatment. Methods Seven patients were recruited in this study. AP-PA, IMRT, one-isocenter (1-IC) VMAT, and 2-IC VMAT were planned on the maximum inspiration and expiration CT, respectively. The prescribed dose was 15 Gy in 10 fractions. To determine the effects of respiratory motion, the CT series was replaced and the dose was evaluated while maintaining the beam information. To determine the effect of patient motion, perturbed dose calculations were performed using a two-IC VMAT. The perturbation doses were calculated by shifting only the IC of the one side beam by 3 mm or 5 mm in the right-to-left (RL) direction. Results The mean heart dose was 1467.0 cGy, 790.0 cGy, 764.2 cGy, and 738.4 cGy for AP-PA, IMRT, 1-IC VMAT, and 2-IC VMAT, respectively. When the expiration CT plan was recalculated with inspiration CT, Dmax increased approximately by 8%. In the 2-IC VMAT plan, the D50%, D98%, and D2% dose differences were within ±2%, even with a 5 mm IC shift. Conclusion We confirmed a significant dosimetric advantage of VMAT over other techniques. 2-IC VMAT should be considered an effective treatment option during irradiation for large target volumes.

Proton Whole-Lung Irradiation: Initial Report of Outcomes

PURPOSE

Whole-lung irradiation is typically used in pediatric patients to decrease the risk of future lung metastases, but radiation dose to normal tissue is associated with long-term risks. Proton whole-lung irradiation (PWLI) provides an opportunity to decrease radiation dose to normal tissue and potentially decrease late toxicity.

METHODS AND MATERIALS

This retrospective study included patients treated with spot-scanning PWLI at a single institution. Toxicity and oncologic outcomes were reviewed. Intensity modulated radiation therapy (IMRT) plans were created prospectively or retrospectively for dosimetric comparisons. Simple paired t tests were performed to assess differences between IMRT and PWLI dosimetric parameters.

RESULTS

Twelve patients treated with PWLI were included in this study. Median age was 15 years (range, 3-34). Most (75%) had Ewing sarcoma. Most (92%) received 15 Gy in 10 fractions PWLI, and 3 (25%) received a focal pulmonary boost. Median follow-up was 16.5 months (range, 0-40.4 months). At last follow-up, 1 patient died of disease, while 11 were still alive (7 without disease, 4 with ongoing disease). During and immediately after treatment, 5 patients developed fatigue, 2 patients developed cough, and 1 patient developed nausea. Each treatment-related adverse event was Common Terminology Criteria for Adverse Events (version 5.0) grade 1 and resolved within 3 weeks of treatment completion. No patients have experienced clinical or radiographic pneumonitis or evidence of clinically apparent cardiac toxicity. Compared with IMRT plans, PWLI decreased mean dose to the heart, coronary artery, cardiac valve, left ventricle, aorta, breast, esophagus, kidney, liver, pancreas, thyroid, stomach, and spleen (all P < .001), without sacrificing target coverage.

CONCLUSIONS

PWLI is feasible to deliver, decreases dose to normal tissue compared with IMRT, and appears to be well-tolerated. PWLI provides potential for decreased late toxicity and merits further investigation.

Pulmonary dose tolerance in hemithorax radiotherapy for Ewing sarcoma of the chest wall: Are we overestimating the risk of radiation pneumonitis?

BACKGROUND

Children with chest wall Ewing sarcoma with malignant pulmonary effusion or pleural stranding require hemithorax radiation, often with plans that exceed lung constraints. We investigated disease control and pneumonitis in children requiring hemithorax radiation.

PROCEDURE

Eleven children (median age 13 years) received hemithorax radiotherapy. Symptomatic radiation pneumonitis was considered National Cancer Institute Common Terminology Criteria for Adverse Events (CTCAE) grade 1+ with respiratory symptoms. Mean lung dose (MLD), volume of lung exposed to a dose ≥5 Gy (V5), ≥20 Gy (V20), and ≥35 Gy (V35) were recorded. Adult and pediatric lung constraints were obtained from Quantitative Analysis of Normal Tissue Effects in the Clinic (QUANTEC) guidelines and Children's Oncology Group (COG) protocols, respectively.

RESULTS

Median hemithorax dose was 15 Gy (1.5 Gy/fraction). Median total dose was 51 Gy (1.8 Gy/fraction). Most plans delivered both protons and photons. The ipsilateral MLD, V5, and V20 were 27.2 Gy, 100%, and 48.3%; the bilateral MLD, V20, and V35 were 14.1 Gy, 22.8%, and 14.3%, respectively. One hundred percent, 36%, and 91% of treatments exceeded recommended adult ipsilateral lung constraints of V5 <65%, V20 <52%, and MLD of 22 Gy; 64%, 45%, and 82% exceeded COG bilateral lung constraints of V20 <20%, MLD <15 Gy, and MLD <12 Gy, respectively; 82% of treatments exceeded the COG ipsilateral lung constraint of V20 <30%. At a median 36 months (range 12-129), the symptomatic radiation pneumonitis incidence was 0%. Two patients progressed with nonpulmonary metastatic disease and died at a median 12 months following radiotherapy.

CONCLUSIONS

Existing guidelines may overestimate pneumonitis risk, even among young children receiving multiagent chemotherapy. For children with chest wall Ewing sarcoma and other thoracic malignancies, more data are needed to refine pediatric dose-effect models for pulmonary toxicity.

Wilms Tumor (Nephroblastoma), Version 2.2021, NCCN Clinical Practice Guidelines in Oncology

The NCCN Guidelines for Wilms Tumor focus on the screening, diagnosis, staging, treatment, and management of Wilms tumor (WT, also known as nephroblastoma). WT is the most common primary renal tumor in children. Five-year survival is more than 90% for children with all stages of favorable histology WT who receive appropriate treatment. All patients with WT should be managed by a multidisciplinary team with experience in managing renal tumors; consulting a pediatric oncologist is strongly encouraged. Treatment of WT includes surgery, neoadjuvant or adjuvant chemotherapy, and radiation therapy (RT) if needed. Careful use of available therapies is necessary to maximize cure and minimize long-term toxicities. This article discusses the NCCN Guidelines recommendations for favorable histology WT.

Advances in radiotherapy technology for pediatric cancer patients and roles of medical physicists: COG and SIOP Europe perspectives

Over the last two decades, rapid technological advances have dramatically changed radiation delivery to children with cancer, enabling improved normal-tissue sparing. This article describes recent advances in photon and proton therapy technologies, image-guided patient positioning, motion management, and adaptive therapy that are relevant to pediatric cancer patients. For medical physicists who are at the forefront of realizing the promise of technology, challenges remain with respect to ensuring patient safety as new technologies are implemented with increasing treatment complexity. The contributions of medical physicists to meeting these challenges in daily practice, in the conduct of clinical trials, and in pediatric oncology cooperative groups are highlighted. Representing the perspective of the physics committees of the Children's Oncology Group (COG) and the European Society for Paediatric Oncology (SIOP Europe), this paper provides recommendations regarding the safe delivery of pediatric radiotherapy. Emerging innovations are highlighted to encourage pediatric applications with a view to maximizing the therapeutic ratio.

Locoregional control using highly conformal flank target volumes and volumetric-modulated arc therapy in pediatric renal tumors: Results from the Dutch national cohort

BACKGROUND AND PURPOSE

In pediatric renal tumors, conventional two opposing photon beams have been used to cover the postoperative flank target volume for decades. This single center study describes the locoregional outcome using highly conformal flank target volumes adjusted for postoperative changes and intra-fraction motion combined with Volumetric-Modulated Arc Therapy (VMAT).

MATERIALS AND METHODS

Between 01-2015 and 12-2019, 36/161 newly diagnosed patients with renal tumors underwent flank only irradiation (n = 30) or flank + whole lung irradiation (n = 6) using highly conformal target volumes in line with the SIOP-RTSG consensus statement. VMAT consisted of full-arc 10MV photon beams optimized for constraints of the organs at risk. In case of locoregional relapses, image co-registration and dose reconstruction was performed. Each relapse was classified as either 'infield' (V95%_relapse: ≥99.0%), 'marginal' (V95%_relapse: 20.0-98.9%) or 'outfield' (V95%_relapse: 0-19.9%).

RESULTS

At a median follow-up from diagnosis of 3.1 years (range:0.4-5.7), the estimated 2-year Locoregional Control Rate, Disease-Free Interval and Overall Survival were 94%, 91% and 94%, respectively. Locoregional relapse was observed in two patients. One patient had a combined tumor bed and regional recurrence, classified as infield (V95%_relapse: 100%) and outfield (V95%_relapse: 1.2%). The second patient had a regional relapse in the inferior vena cava classified as marginal recurrence (V95%_relapse: 93%). Relapses would not have been adequately covered by conventional beams.

CONCLUSIONS

This single center analysis provides encouraging evidence that excellent locoregional control can be obtained by using highly conformal flank target volumes with VMAT in pediatric renal tumors. The safety of this approach will be validated in a prospective multicenter study.

A New Proton Therapy Solution Provides Superior Cardiac Sparing Compared With Photon Therapy in Whole Lung Irradiation for Pediatric Tumor Patients

Objective

Whole lung irradiation (WLI) plays a crucial role in local control in pediatric patients with lung metastases and improves patient survival. The intention of this research was to explore the advantage of cardiac sparing between photons and protons during WLI. We also propose a new solution for cardiac sparing with proton techniques.

Methods

Eleven patients with pediatric tumors and pulmonary metastasis treated with 12 Gy WLI (all received volumetric-modulated arc therapy (VMAT)) in our institute between 2010 and 2019 were retrospectively selected. Each patient was replanned with intensity-modulated radiation therapy (IMRT), helical tomotherapy (HT), and two intensity-modulated proton radiotherapy (IMPT) plans (IMPT-1 and IMPT-2). IMPT-1 considered the whole lung as the planning target volume (PTV), utilizing the anteroposterior technique (0/180°). IMPT-2 was a new proton solution that we proposed in this research. This approach considered the unilateral lung as the PTV, and 3 ipsilateral fields were designed for each lung. Then, IMPT-2 was generated by summing two unilateral lung plans. The primary objective was to obtain adequate coverage (95% of the prescription dose to the PTV) while maximally sparing the dose to the heart. The PTV coverage, conformity index (CI), homogeneity index (HI), and dose–volume statistics of the heart and substructures were assessed by means of the averages of each comparison parameter.

Results

All treatment techniques achieved the target volume coverage required by clinical practice. HT yielded the best coverage and homogeneity for the target structure compared with other techniques. The CI from IMRT was excellent. For photon radiation therapy, the HT plan afforded superior dose sparing for the V₅, V₆, V₇, V₈, and D_mean of the heart and D_mean of the right ventricle (RV). IMRT displayed the most notable dose reductions in the V₉, V₁₀, V₁₁, and V₁₂ of the heart and D_mean of the right atrium (RA). The VMAT plan was the least effective on the heart and substructures. However, compared with photon radiation therapy, IMPT-1 did not show an advantage for heart protection. Interestingly, IMPT-2 provided significant superiority in cardiac sparing, including maximum dose sparing for the V₅, V₆, V₇, V₈, V₉ and D_mean of the heart and D_mean of the RA, RV, left atrium (LA) and left ventricle (LV) compared to all other techniques.

Conclusions

Considering the complex anatomical relation between target volumes and organs at risk (OARs), IMPT can provide a dose advantage for organs located outside of the target area rather than within or surrounding the area. It is hoped that advances in proton therapy (PT) plan design will lead to further improvements in radiotherapy approaches and provide the best treatment choice for individual patients.

The contribution of surgical clips for optimizing highly-conformal image-guided flank irradiation in pediatric renal tumors: A single center experience

BACKGROUND AND AIMS

Two-opposing photon beams are considered standard of care for flank irradiation in pediatric patients with renal tumors. Nowadays, Image-Guided Radiotherapy (IGRT) techniques allow high-precision dose delivery to complex flank target volumes taking into account postoperative organ shifts and tumor bed motion. This study examines the contribution of a lateral and superior surgical clip on flank target volume delineation intended for IGRT.

METHODS

Between 01-2015 and 09-2019, 30/162 newly-diagnosed pediatric patients with renal tumors, lateral/superior surgical clips (n = 30/30) and available 4D-CT-scans (n = 27/30), underwent postoperative flank irradiation. The lateral and superior clip, as respective markers for the lateral tumor extension and intrafraction motion, were analyzed. The positive and negative values depict the lateral/dorsal/cranial or the medial/ventral/caudal direction, respectively. Planning target volumes (PTV) were generated based on lateral clips (PTV_latclip), superior clips with 4D-CT technology (PTV_supclip), and both clips combined (PTV_combined), and compared to an approach without clips (PTV_noclip).

RESULTS

Indicated by clips, the mean lateral tumor bed extension along the posterior wall was 74° (range: 50°-93°), while mean intrafraction motion was +1.2 mm (range: -1.8/+4.8 mm), +0.6 mm (range: +0.6/+4.9 mm), -0.3 mm (range: -3.8/+0.7 mm) in craniocaudal, ventrodorsal, mediolateral direction, respectively. The median PTV_noclip (556 mL) was statistically different from the median PTV_latclip (454 mL, p = <0.01), median PTV_supclip (373 mL, p = <0.01) and median PTV_combined (348 mL p = <0.01).

CONCLUSION

In pediatric patients with renal tumors, surgical clips at the lateral and superior border of the tumor bed can optimize flank target volume delineation and, consequently, reduce the normal tissue volume receiving high-dose irradiation when IGRT techniques are applied.

The SIOP-Renal Tumour Study Group consensus statement on flank target volume delineation for highly conformal radiotherapy

For decades, radiotherapy with two opposing photon beams has been the standard technique used to cover the flank target volume in paediatric patients with renal tumours. Nowadays, many institutes are implementing advanced radiotherapy techniques that spare healthy tissue. To decrease the radiotherapy dose to healthy structures while preserving oncological efficacy, the conventional approach of flank irradiation has been adapted into a guideline for highly conformal flank target-volume delineation by paediatric radiation oncologists and representatives of the International Society of Paediatric Oncology's Renal Tumour Study Group (SIOP-RTSG) board during four live international consensus meetings. The consensus was refined by delineation exercises and videoconferences by ten collaborating paediatric radiation oncologists. The final guideline includes eight chronological steps to generate the tumour bed and clinical, internal, and planning target volumes, and it describes the optional use of surgical clips to optimise treatment planning. This guideline will be added into the radiotherapy guideline of the UMBRELLA SIOP-RTSG protocol for paediatric renal tumours to improve international consistency of highly conformal flank target-volume delineation.

Effective heart-sparing whole lung irradiation using volumetric modulated arc therapy: a case report

Background

Late cardiovascular disease-related adverse events are one of the most common causes of premature mortality among long-term survivors of childhood cancer. As it is difficult to reduce the heart dose with traditional anteroposterior–posteroanterior field whole lung irradiation for pulmonary metastasis, improved radiation techniques are highly desirable. We report a case treated with whole lung irradiation using volumetric modulated arc therapy.

Case presentation

A 3-year-old Japanese girl with pulmonary metastases of Wilms’ tumor received 12 Gy in 8 fractions of whole lung irradiation using volumetric modulated arc therapy. The treatment was well tolerated, and the course was completed as planned without any toxicity. We found statistically significant reduced volumetric modulated arc therapy irradiation doses to organs at risk relative to those of the standard anteroposterior–posteroanterior field technique. The mean heart dose was 8.5 Gy for volumetric modulated arc therapy and 12.3 Gy for the anteroposterior–posteroanterior field. The doses to liver and thyroid were also more favorable with volumetric modulated arc therapy than with the anteroposterior–posteroanterior field technique. We confirmed the dosimetric advantages of volumetric modulated arc therapy over anteroposterior–posteroanterior field in whole lung irradiation in terms of superior normal organ protection.

Conclusions

Effective heart sparing is possible for whole lung irradiation using volumetric modulated arc therapy. Large-scale studies using standardized procedures should be conducted to validate our results.

Therapy-Related Cardiac Risk in Childhood Cancer Survivors: An Analysis of the Childhood Cancer Survivor Study

PURPOSE

The impacts of radiotherapy dose and exposed cardiac volume, select chemotherapeutic agents, and age at exposure on risk for late-onset cardiac disease in survivors of childhood cancer remain unresolved.

PATIENTS AND METHODS

We determined the rates of severe to fatal cardiac disease in 24,214 5-year survivors in the Childhood Cancer Survivor Study diagnosed between 1970 and 1999 at a median age of 7.0 years (range, 0 to 20.9 years), with a median attained age of 27.5 years (range, 5.6 to 58.9 years). Using piecewise exponential models, we evaluated the association between cardiac disease rates and demographic and treatment characteristics.

RESULTS

The cumulative incidence of cardiac disease 30 years from diagnosis was 4.8% (95% CI, 4.3 to 5.2). Low to moderate radiotherapy doses (5.0 to 19.9 Gy) to large cardiac volumes (≥ 50% of heart) were associated with an increased rate of cardiac disease (relative rate, 1.6; 95% CI, 1.1 to 2.3) compared with survivors without cardiac radiotherapy exposure. Similarly, high doses (≥ 20 Gy) to small cardiac volumes (0.1% to 29.9%) were associated with an elevated rate (relative rate, 2.4; 95% CI, 1.4 to 4.2). A dose-response relationship was observed between anthracycline chemotherapy and heart failure with younger children (age ≤ 13 years) at the greatest risk for heart failure after comparable dosing.

CONCLUSION

These observations support advances in radiation field design and delivery technology to reduce cardiac dose/volume and should guide future treatment protocols. They also inform clinical practice guidelines for post-therapy surveillance and risk-reducing strategies.

Heart-sparing volumetric modulated arc therapy for whole lung irradiation

PURPOSE

Whole lung irradiation (WLI) is indicated for subgroups of patients with lung metastases from Wilms' tumor (nephroblastoma). WLI has traditionally been performed with an anterior/posterior field arrangement with poor potential for heart sparing; thus, new techniques are desirable to achieve a lower dose to the heart.

MATERIALS AND METHODS

We utilized volumetric modulated arc therapy (VMAT) for WLI with 18 Gy in a patient with metastatic nephroblastoma. The planning results were compared against a three-dimensional (3D) conformal plan.

RESULTS

VMAT resulted in adequate target volume coverage with the prescribed dose. Mean heart dose was 10.2 Gy. The dose to organs at risk (OAR) was generally more favorable with VMAT when compared with a 3D-conformal radiotherapy plan.

DISCUSSION

WLI with VMAT provides superior sparing of OARs and especially a considerably lower dose to the heart.

Cardiac-Sparing Whole Lung IMRT in Patients With Pediatric Tumors and Lung Metastasis: Final Report of a Prospective Multicenter Clinical Trial

PURPOSE

A prospective clinical trial was conducted for patients undergoing cardiac sparing (CS) whole lung irradiation (WLI) using intensity modulated radiation therapy (IMRT). The 3 trial aims were (1) to demonstrate the feasibility of CS IMRT with real-time central quality control; (2) to determine the dosimetric advantages of WLI using IMRT compared with standard anteroposterior (AP) techniques; and (3) to determine acute tolerance and short-term efficacy after a protocol-mandated minimum 2-year follow-up for all patients.

METHODS AND MATERIALS

All patients underwent a 3-dimensional chest computed tomography scan and a contrast-enhanced 4-dimensional (4D) gated chest computed tomography scan using a standard gating device. The clinical target volume was the entire bilateral 3-dimensional lung volume, and the internal target volume was the 4D minimum intensity projection of both lungs. The internal target volume was expanded by 1 cm to get the planning target volume. All target volumes, cardiac contours, and treatment plans were centrally reviewed before treatment. The different cardiac volumes receiving percentages of prescribed radiation therapy (RT) doses on AP and IMRT WLI plans were estimated and compared.

RESULTS

The target 20 patients were accrued in 2 years. Median RT dose was 15 Gy. Real-time central quality assurance review and plan preapproval were obtained for all patients. WLI using IMRT was feasible in all patients. Compared with standard AP WLI, CS IMRT resulted in a statistically significant reduction in radiation doses to the whole heart, atria, ventricles, and coronaries. One child developed cardiac dysfunction and pulmonary restrictive disease 5.5 years after CS IMRT (15 Gy) and doxorubicin (375 mg/m²). The 2- and 3-year lung metastasis progression-free survival was 65% and 52%, respectively.

CONCLUSIONS

We have demonstrated the feasibility of WLI using CS IMRT and confirmed the previously reported advantages of IMRT, including superior cardiac protection and superior dose coverage of 4D lung volumes. Further studies are required to establish the efficacy and safety of this irradiation technique.

Cardiac-Sparing Whole Lung Intensity Modulated Radiation Therapy in Children With Wilms Tumor: Final Report on Technique and Abdominal Field Matching to Maximize Normal Tissue Protection

PURPOSE

Cardiac-sparing whole lung intensity modulated radiation therapy (WL IMRT) has been shown to improve cardiac protection and lung volume dose coverage compared with standard anteroposterior techniques. This dosimetry study had 2 aims: To determine the dosimetric advantages of a modified WL IMRT (M-WL IMRT) technique, designed to reduce radiation exposure to the thyroid gland and breast tissues, compared with standard WL IMRT (S-WL IMRT) and to determine the dosimetric advantages of M-WL IMRT and dosimetrically matched abdomen and flank radiation therapy (RT) fields designed to reduce normal tissue exposure compared with standard field matching techniques.

METHODS AND MATERIALS

Computed tomography scans of the chest and abdomen that were obtained during computed tomography simulation of 10 female children were used. For Aim 1, for S-WL IMRT, the planning target volume (PTV) was obtained with a 1-cm expansion of the 4-dimensional lung volume (internal target volume). For M-WL IMRT, the PTV was reduced around the breast and thyroid gland to facilitate thyroid and breast sparing. For Aim 2, standard matching techniques for 3-dimensional anterior/posterior-posterior/anteriorwhole lung and abdominal RT fields were compared with a new dosimetric matching technique for WL IMRT and abdomen and flank fields. For both aims, the dose coverage of the lungs and radiation exposure to normal tissues (heart, thyroid, breasts) were statistically compared.

RESULTS

Compared with S-WL IMRT, the M-WL IMRT technique provided similar lung PTV dose coverage and a significantly superior reduction in mean breast and thyroid doses, without compromising cardiac protection. The M-WL IMRT technique combined with a dosimetrically matched abdomen and flank fields showed significantly superior normal tissue protection compared with standard matched anterior/posterior-posterior/anteriorlung and abdomen and flank RT fields.

CONCLUSIONS

This study has shown that the M-WL IMRT technique can reduce radiation exposure to the thyroid gland and breast tissue without compromising cardiac protection and 4-dimensional lung volume dose coverage. This report also describes a new dosimetric matching technique between WL IMRT and abdomen and flank fields that will improve normal tissue sparing compared with standard techniques.

The Children's Oncology Group Radiation Oncology Discipline: 15 Years of Contributions to the Treatment of Childhood Cancer

PURPOSE

Our aim was to review the advances in radiation therapy for the management of pediatric cancers made by the Children's Oncology Group (COG) radiation oncology discipline since its inception in 2000.

METHODS AND MATERIALS

The various radiation oncology disease site leaders reviewed the contributions and advances in pediatric oncology made through the work of the COG. They have presented outcomes of relevant studies and summarized current treatment policies developed by consensus from experts in the field.

RESULTS

The indications and techniques for pediatric radiation therapy have evolved considerably over the years for virtually all pediatric tumor types, resulting in improved cure rates together with the potential for decreased treatment-related morbidity and mortality.

CONCLUSIONS

The COG radiation oncology discipline has made significant contributions toward the treatment of childhood cancer. Our discipline is committed to continuing research to refine and modernize the use of radiation therapy in current and future protocols with the goal of further improving the cure rates and quality of life of children with cancer.

Respiratory-gated bilateral pulmonary radiotherapy for Ewing's sarcoma and nephroblastoma in children and young adults: Dosimetric and clinical feasibility studies

PURPOSE

Bilateral pulmonary radiotherapy in children and young adults aims to reduce the recurrence of lung metastases. The radiation field includes liver tissue, which is sensitive to even low radiation doses. We investigated the feasibility of respiratory gating radiotherapy using voluntary deep inspiration breath hold and its toxicity in these patients.

PATIENTS AND METHOD

A retrospective clinical review was conducted for all patients who had undergone bilateral pulmonary radiotherapy, with or without deep inspiration breath hold, treated in our institution between October 1999 and May 2012. A dosimetric study was conducted on seven consecutive children using 4D-scan data on free-breathing and a SpiroDyn'RX-system-scan on deep inspiration breath hold. A radiation treatment of 20Gy was simulated.

RESULTS

Concerning the clinical study, seven patients of mean age 11.9 years (range: 4.9-21.1 years) were treated with free-breathing and ten patients of mean age 15.6 years (range: 8.6-19.7 years) were treated with deep inspiration breath hold for mainly Ewing sarcoma and nephroblastoma. Within six months of radiotherapy, all patients experienced mild liver toxicity (grade 1 or 2 altered levels of alanine/aspartate aminotransferase [n=8 of 9] or cholestasis [n=1 of 9]), which resolved completely with no difference between deep inspiration breath hold and free-breathing technique. Over a median follow-up of 2.6 years (range: 0.1-9.3 years), four patients died from disease progression (mean 1.5 years post-radiotherapy [range: 1.1-1.6 years]) and three experienced grade III-V lung toxicity. Concerning the dosimetric study, the irradiated liver volume was significantly lower with deep inspiration breath hold than free-breathing, for each isodose (V5: 73.80% versus 86.74%, P<0.05; V20: 5.70% versus 26.44%, P<0.05).

CONCLUSIONS

The dosimetric data of respiratory-gated bilateral pulmonary radiotherapy showed a significantly spare of normal liver tissue. Clinical data showed that this technique is feasible even in young children. However, no liver toxicity difference between deep inspiration breath hold and free-breathing was shown.

Whole Lung Irradiation in Adults with Metastatic Ewing Sarcoma: Practice Patterns and Implications for Treatment

Background. Whole lung irradiation (WLI) is a standard treatment component for children with metastatic Ewing Sarcoma (ES), but data on WLI for adults are sparse. Design. An email survey was sent to expert sarcoma-dedicated oncologists worldwide: An adult with excellent performance status presents with primary ES in the leg and multiple pulmonary metastases. The patient achieves complete radiographic response after chemotherapy and resection of the primary. Would you give bilateral WLI to (1) this adult patient?, (2) this patient if 20 years old (yo)?, (3) this patient if 45 yo?, or (4) this patient if 60 yo? Results. 38 experts responded, including 24 adult, 1 adolescent young adult, and 13 pediatric oncologists. 63%, 63%, 62%, and 50% of respondents offered WLI to the adult, 20-year-old, 45-year-old, and 60-year-old, respectively. Pediatric oncologists more likely endorsed WLI across all ages including the adult (P = 0.01), 20-year-old (P = 0.005), 45-year-old (P = 0.01), and 60-year-old (P = 0.08). There were no significant differences between medical and radiation oncologists or between European/Australian and American providers. Conclusions. Almost two-thirds of experts surveyed supported WLI for adults with metastatic ES up to age 45 and half supported WLI for a 60-year-old. Continued collaboration across adult and pediatric oncology is needed to define evidence-based strategies across the age spectrum.

Whole-lung irradiation in the treatment of metastatic synovial sarcoma

Whole-lung irradiation (WLI) is standard of care in the treatment of patients with rhabdomyosarcoma, Ewing sarcoma, and Wilms tumor and pulmonary metastases. However, it is not routinely utilized in the treatment of pulmonary metastases arising from other soft tissue sarcoma histologies. A patient presented with synovial sarcoma of his groin and punctate pulmonary metastases. After completion of multimodality treatment to his primary lesion, he received WLI. The patient is without evidence of disease at 3.8 years. This case demonstrates the need for further study of WLI in synovial sarcoma as it may improve outcomes in patients with this disease.

Children's Oncology Group's 2013 blueprint for research: radiation oncology

Radiation therapy (RT) is used to treat children with CNS tumors, solid tumors or Hodgkin lymphoma. Pediatric radiation oncologists have provided critical input into the development and implementation of concepts for clinical trials to further define the modality's role and test newer methods to reduce side effects or intensify therapy. The quality of pediatric oncology clinical trials that include radiation therapy is linked to the quality of guidelines. Radiation oncology is an adult medical specialty; thus, pediatric radiation oncologists are uniquely positioned to work with adult cancer investigators in the reorganized US National Cancer Institute Clinic Trials Network.