Implementation of contemporary radiation therapy planning concepts for pediatric Hodgkin lymphoma: Guidelines from the International Lymphoma Radiation Oncology Group

Involved-site Radiotherapy Delineation Dilemmas in the Treatment of Adult Hodgkin Lymphoma: Turkish Society for Radiation Oncology Hematological Oncology, Pediatric Oncology and TBI Study Group Case-based Questionnaire Review (TROD 03-005)

AIMS

The International Lymphoma Radiation Oncology Group (ILROG) defined involved-site radiotherapy (ISRT) guidelines. These rules offer a certain variability that allows for autonomous decision-making in diverse clinical settings. However, this flexibility also gives rise to conflicts about the selection of treatment fields in the daily decision-making process. The aim of this study was to show the extent of interobserver variability when ILROG-ISRT recommendations were used in different clinical scenarios.

MATERIALS AND METHODS

The 10-question survey used in our study consisted of two parts (part A and part B) and was prepared by four senior radiation oncologists experienced in the haemato-oncology field. The results were presented by stratifying according to clinical experience (<10 years, ≥10 years). Binomial tests (one-sided) were conducted to assess whether answers for each group and the whole group reached a consensus.

RESULTS

Twenty-six radiation oncologists, 13 of whom had less than 10 years of experience and 13 seniors, participated in the survey. Eighty per cent of respondents thought ILROG did not bring sufficient solutions for all clinical scenarios but offered solutions in some cases. In different case-based scenarios, the consensus among the respondents decreased down to 38%. Senior radiation oncologists were found to have more doubts about the adequacy of current guidelines.

CONCLUSIONS

ILROG guidelines allow for a high degree of variability in real-life clinical scenarios and different interpretation of the recommendations may lead to increased toxicity and recurrences. Therefore, there is a need for refinement in ISRT delineation strategies. On behalf of the Turkish Society for Radiation Oncology Hematological Oncology, Pediatric Oncology and TBI Study Group, we are planning to carry out further educational contouring sessions to detect the interobserver variability in real-life contouring cases.

Dose-Volume Constraints fOr oRganS At risk In Radiotherapy (CORSAIR): An "All-in-One" Multicenter-Multidisciplinary Practical Summary

BACKGROUND

The safe use of radiotherapy (RT) requires compliance with dose/volume constraints (DVCs) for organs at risk (OaRs). However, the available recommendations are sometimes conflicting and scattered across a number of different documents. Therefore, the aim of this work is to provide, in a single document, practical indications on DVCs for OaRs in external beam RT available in the literature.

MATERIAL AND METHODS

A multidisciplinary team collected bibliographic information on the anatomical definition of OaRs, on the imaging methods needed for their definition, and on DVCs in general and in specific settings (curative RT of Hodgkin's lymphomas, postoperative RT of breast tumors, curative RT of pediatric cancers, stereotactic ablative RT of ventricular arrythmia). The information provided in terms of DVCs was graded based on levels of evidence.

RESULTS

Over 650 papers/documents/websites were examined. The search results, together with the levels of evidence, are presented in tabular form.

CONCLUSIONS

A working tool, based on collected guidelines on DVCs in different settings, is provided to help in daily clinical practice of RT departments. This could be a first step for further optimizations.

"Per protocol" practice patterns for Children's Oncology Group trials within the radiation oncology community

Little is known about the prevalence of pediatric radiation oncologists treating patients off study according to Children's Oncology Group (COG) trials before data are available regarding toxicity and efficacy of novel radiotherapy regimens. We conducted a 12-question survey of 358 pediatric radiation oncologists to characterize practice patterns regarding ongoing and completed COG protocols off study. With 130 responses (40.3%), the prevalence of providing treatment per protocol, but off study, before data are available in abstract or peer-reviewed form varied from 9.1% (for ACNS1422) to 88.1% (for AHOD1331). Future studies are needed to understand the effects of these practice patterns on outcomes.

Patterns of Initial Relapse from a Phase 3 Study of Response-Based Therapy for High-Risk Hodgkin Lymphoma (AHOD0831): A Report from the Children's Oncology Group

PURPOSE

The Children's Oncology Group protocol AHOD0831, for pediatric patients with high-risk classical Hodgkin lymphoma (cHL), used response-adapted radiation fields, rather than larger involved-field radiation therapy (IFRT) that were historically used. This retrospective analysis of patterns of relapse among patients enrolled in the study was conducted to study the potential effect of a reduction in RT exposure.

METHODS AND MATERIALS

From December 2009 to January 2012, 164 eligible patients under 22 years old with stage IIIB (43%) and stage IVB (57%) enrolled on AHOD0831. All patients received 4 cycles of doxorubicin, bleomycin, vincristine, etoposide, prednisone, and cyclophosphamide (ABVE-PC). Those patients with a slow early response (SER) after the first 2 ABVE-PC courses were nonrandomly assigned to 2 intensification cycles with ifosfamide/vinorelbine before the final 2 ABVE-PC cycles. Response-adapted RT (21 Gy) was prescribed to initial areas of bulky disease and SER sites. Rapid early response (RER) sites without bulk were not targeted. Imaging studies at the time of progression or relapse were reviewed centrally for this retrospective analysis. Relapses were characterized with respect to site (initial, new, or both; and initial bulk or initial nonbulk), initial chemotherapy response, and radiation field (in-field, out-of-field, or both).

RESULTS

Of the entire cohort, 140 patients were evaluable for the patterns of failure analyses. To investigate the pattern of failure, this analysis focuses on 23 patients who followed protocol treatment and suffered relapses at a median 1.05 years with 7.97-year median follow-up time. These 23 patients (11 RER and 12 SER) experienced a relapse in 105 total sites (median, 4; range, 1-11). Of the 105 relapsed sites, 67 sites (64%) occurred within an initial site of involvement, with 12 of these 67 sites (18%) at an initial site of bulky disease and 63 of these 67 relapses (94%) occurring in sites that were not fluorodeoxyglucose (FDG)-avid after 2 cycles of ABVE-PC (PET2-negative). Of the 105 relapsed sites, 34 sites (32%) occurred in a new site of disease (that would not have been covered by RT); and, overall, only 4 of 140 patients (2.8%) (occurring in 3 RER and 1 SER) experienced isolated out-of-field relapses that would have been covered by historical IFRT.

CONCLUSIONS

For a cohort of high-risk patients with cHL patients, most failures occurred in nonbulky, initially involved sites, largely due to response-based consolidation RT delivered to patients with bulky disease. In this analysis, we discovered low rates of failures outside of these modern risk-adapted radiation treatment volumes. Also, FDG uptake on PET2 did not identify most relapse sites.

Vital organ sparing with proton therapy for pediatric Hodgkin lymphoma: Toxicity and outcomes in 50 patients

BACKGROUND AND PURPOSE

With high survival rates for pediatric Hodgkin lymphoma (HL), attention has turned to minimizing treatment-related morbidity and mortality. Chemotherapy and dose of radiation to organs at risk (OARs) contribute to elevated risks of secondary malignancy and cardiopulmonary disease. We sought to characterize the radiation dose to OARs, toxicities, and outcomes for pediatric HL patients treated with proton therapy (PT).

MATERIALS AND METHODS

Fifty patients aged 11-21 with HL consecutively treated with PT were evaluated 1-2 months following completion of PT and every 6 months thereafter. Acute and late toxicities were captured retrospectively using CTCAE v5. Patterns of relapse were characterized, and survival was assessed using Kaplan-Meier method.

RESULTS

Most (47, 94%) patients received PT to the mediastinum. Median mean heart dose was 4.3 Gy (RBE) and median bilateral lung V20Gy was 5.8%. Median integral dose was 1.7 Gy. For the 27 female patients, a median mean dose of 0.4 and 0.3 Gy (RBE) was delivered to ipsilateral and contralateral breast tissue, respectively. No on-treatment grade 3-5 toxicities were seen. At a median follow-up of 5.3 years, no PT-related grade 3-5 toxicities or secondary malignancies developed. Five patients relapsed at a median time of 9.2 months after PT (range 2.5-24.9 months; 5-year recurrence free survival 90%). Recurrences were both in- and out-of-field in all 5 cases with no marginal failures. All relapsed patients were successfully salvaged (5-year overall survival 100%).

CONCLUSION

For pediatric HL patients, proton treatment resulted in marked dose sparing of OARs with low rates of toxicity, no marginal failures, and excellent 5-year survival.

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.

Pediatric classical Hodgkin lymphoma

Over the past century, classical Hodgkin lymphoma (HL) has been transformed from a uniformly fatal disease to one of the most curable cancers. Given the high cure rate, a major focus of classical HL management is reducing the use of radiation therapy (RT) and chemotherapy agents such as procarbazine and doxorubicin to minimize long-term toxicities. In both North America and Europe, an important philosophy in the management of classical HL is to guide the intensity of treatment according to the risk category of the disease. The main factors used for risk classification are tumor stage, bulk of disease, and the presence of B symptoms. Response to chemotherapy is an important factor guiding the utilization of RT in ongoing Children's Oncology Group (COG) and European Network Pediatric Hodgkin Lymphoma (EuroNet-PHL) trials. Both trial groups have transitioned to reduced RT volumes that target the highest risk sites using highly conformal techniques, along with standard or intensified chemotherapy regimens to improve outcomes in higher risk patients. However, given the potential acute toxicities of intensified chemotherapy, immunoregulatory drugs are being investigated in upcoming trials. The purpose of this review is to summarize current approaches to treating pediatric classical HL according to the COG and EuroNet-PHL.

The risk of late effects following pediatric and adult radiotherapy regimens in Hodgkin lymphoma

PURPOSE

Adolescent young adults (AYA) with Hodgkin lymphoma (HL) are treated according to either pediatric or adult protocols, however, the best strategy has yet to be established. We describe the AYA patients referred for radiotherapy and quantify the risk of radiation-induced late effects and the corresponding life years lost (LYL) following pediatric and adult regimens.

METHODS

Patients ≤24 years irradiated for HL were included. For each patient, organs at risk (OARs) were contoured and dosimetric parameters were extracted. Estimated excess hazard ratios of radiation-induced late effects were calculated from dose-response models and LYL attributable to various late effects were estimated.

RESULTS

In total, 77 patients were analyzed (pediatric regimen: 15; adult regimen: 62). Age, clinical stage, and the number of patients enrolled in protocols were significantly different between the groups. Pediatric patients had more advanced disease, which resulted in larger target volumes and higher doses to most OARs, despite a lower prescribed dose compared to adult regimens. LYL estimates were all higher with the pediatric regimens. Total LYL with pediatric and adult treatment regimens were 3.2 years and 2.3 years, respectively. Due to the clinical stage variation and heterogeneity in disease location, a direct comparison of the estimated risks of late effects was only exploratory.

CONCLUSION

Pediatric regimens selected patients with more advanced disease to radiotherapy resulting in larger target volumes and higher doses to the OARs. Target volume rather than prescribed dose impacted OAR exposure. Consequently, the estimated risk of radiation-induced late effects and corresponding LYL was increased when compared to adult regimens.

A rapid review of evidence and recommendations from the SIOPE radiation oncology working group to help mitigate for reduced paediatric radiotherapy capacity during the COVID-19 pandemic or other crises

OBJECTIVE

To derive evidence-based recommendations for the optimal utilisation of resources during unexpected shortage of radiotherapy capacity.

METHODS AND MATERIALS

We have undertaken a rapid review of published literature on the role of radiotherapy in the multimodality treatment of paediatric cancers governing the European practise of paediatric radiotherapy. The derived data has been discussed with expert paediatric radiation oncologists to derive a hierarchy of recommendations.

RESULTS

The general recommendations to mitigate the potential detriment of an unexpected shortage of radiotherapy facilities include: (1) maintain current standards of care as long as possible (2) refer to another specialist paediatric radiotherapy department with similar level of expertise (3) prioritise use of existing radiotherapy resources to treat patients with tumours where radiotherapy has the most effect on clinical outcome (4) use chemotherapy to defer the start of radiotherapy where timing of radiotherapy is not expected to be detrimental (5) active surveillance for low-grade tumours if appropriate and (6) consider iso-effective hypofractionated radiotherapy regimens only for selected patients with predicted poor prognosis. The effectiveness of radiotherapy and recommendations for prioritisation of its use for common and challenging paediatric tumours are discussed.

CONCLUSION

This review provides evidence-based treatment recommendations during unexpected shortage of paediatric radiotherapy facilities. It has wider applications for the optimal utilisation of facilities, to improve clinical outcome in low- and middle-income countries, where limited resources continue to be a challenge.

Irradiating Residual Disease to 30 Gy with Proton Therapy in Pediatric Mediastinal Hodgkin Lymphoma

Background:

Local relapse is a predominant form of recurrence among pediatric patients with Hodgkin lymphoma (PHL). Although PHL radiotherapy doses have been approximately 20 Gy, adults with Hodgkin lymphoma receiving 30 to 36 Gy experience fewer in-field relapses. We investigated the dosimetric effect of such a dose escalation to the organs at risk (OARs).

Materials and Methods:

Ten patients with PHL treated with proton therapy to 21 Gy involved-site radiation therapy (ISRT_21Gy) were replanned to deliver 30 Gy by treating the ISRT to 30 Gy (ISRT_30Gy), delivering 21 Gy to the ISRT plus a 9-Gy boost to postchemotherapy residual volume (rISRT_boost), and delivering 30 Gy to the residual ISRT target only (rISRT_30Gy). Radiation doses to the OARs were compared.

Results:

The ISRT_30Gy escalated the dose to the target by 42% but also to the OARs. The rISRT_boost escalated the residual target dose by 42%, and the OAR dose by only 17% to 26%. The rISRT_30Gy escalated the residual target dose by 42% but reduced the OAR dose by 25% to 46%.

Conclusion:

Boosting the postchemotherapy residual target dose to 30Gy can allow for dose escalation with a slight OAR dose increase. Treating the residual disease for the full 30Gy, however, would reduce the OAR dose significantly compared with ISRT_21Gy. Studies should evaluate these strategies to improve outcomes and minimize the late effects.

Association of Combined Modality Therapy vs Chemotherapy Alone With Overall Survival in Early-Stage Pediatric Hodgkin Lymphoma

Importance

To date, there is no well-defined standard of care for early-stage pediatric Hodgkin lymphoma (HL), which may include chemotherapy alone or combined modality therapy (CMT) with chemotherapy followed by radiotherapy. Although the use of radiotherapy in pediatric HL is decreasing, this strategy remains controversial.

Objective

To examine the use of CMT in pediatric HL and its association with improved overall survival using data from a large cancer registry.

Design, Setting, and Participants

This observational cohort study used data from the National Cancer Database to evaluate clinical features and survival outcomes among 5657 pediatric patients (age, 0.1-21 years) who received a diagnosis of stage I or II HL in the United States from January 1, 2004, to December 31, 2015. Statistical analysis was conducted from May 1 to November 1, 2018.

Exposures

Patients received definitive treatment with chemotherapy or CMT, defined as chemotherapy followed by radiotherapy.

Main Outcomes and Measures

Kaplan-Meier survival curves were used to examine overall survival. The association between CMT use, covariables, and overall survival was assessed in multivariable Cox proportional hazards regression models. Use of radiotherapy was assessed over time.

Results

Among the 11 546 pediatric patients with HL in the National Cancer Database, 5657 patients (3004 females, 2596 males, and 57 missing information on sex; mean [SD] age, 17.1 [3.6] years) with stage I or II classic HL were analyzed. Of these patients, 2845 (50.3%) received CMT; use of CMT vs chemotherapy alone was associated with younger age (<16 years, 1102 of 2845 [38.7%] vs 856 of 2812 [30.4%]; P < .001), male sex (1369 of 2845 [48.1%] vs 1227 of 2812 [43.6%]; P < .001), stage II disease (2467 of 2845 [86.7%] vs 2376 of 2812 [84.5%]; P = .02), and private health insurance (2065 of 2845 [72.6%] vs 1949 of 2812 [69.3%]; P = .002). The 5-year overall survival was 94.5% (confidence limits, 93.8%, 95.8%) for patients who received chemotherapy alone and 97.3% (confidence limits, 96.4%, 97.9%) for those who received CMT, which remained significant in the intention-to-treat analysis and multivariate analysis (adjusted hazard ratio for CMT, 0.57; 95% CI, 0.42-0.78; P < .001). In the sensitivity analysis, the low-risk cohort (stage I-IIA) and adolescent and young adult patients had the greatest benefit from CMT (adjusted hazard ratio, 0.47; 95% CI, 0.40-0.56; P < .001). The use of CMT decreased by 24.8% from 2004 to 2015 (from 59.7% [271 of 454] to 34.9% [153 of 438]).

Conclusions and Relevance

In this study, pediatric patients with early-stage HL receiving CMT experienced improved overall survival 5 years after treatment. There is a nationwide decrease in the use of CMT, perhaps reflecting the bias of ongoing clinical trials designed to avoid consolidation radiotherapy. This study represents the largest data set to date examining the role of CMT in pediatric HL.

Risk and Response Adapted Treatment Guidelines for Managing First Relapsed and Refractory Classical Hodgkin Lymphoma in Children and Young People. Recommendations from the EuroNet Pediatric Hodgkin Lymphoma Group

The objective of this guideline is to aid clinicians in making individual salvage treatment plans for pediatric and adolescent patients with first relapse or refractory (R/R) classical Hodgkin lymphoma (cHL). While salvage with standard dose chemotherapy followed by high dose chemotherapy and autologous stem cell transplant is often considered the standard of care in adult practice, pediatric practice adopts a more individualized risk stratified and response adapted approach to salvage treatment with greater use of non-transplant salvage. Here, we present on behalf of the EuroNet Pediatric Hodgkin Lymphoma group, evidence and consensus-based guidelines for standardized diagnostic, prognostic and response procedures to allocate children and adolescents with R/R cHL to stratified salvage treatments.

Proton therapy for adults with mediastinal lymphomas: the International Lymphoma Radiation Oncology Group guidelines

Among adult lymphoma survivors, radiation treatment techniques that increase the excess radiation dose to organs at risk (OARs) put patients at risk for increased side effects, especially late toxicities. Minimizing radiation to OARs in adults patients with Hodgkin and non-Hodgkin lymphomas involving the mediastinum is the deciding factor for the choice of treatment modality. Proton therapy may help to reduce the radiation dose to the OARs and reduce toxicities, especially the risks for cardiac morbidity and second cancers. Because proton therapy may have some disadvantages, identifying the patients and the circumstances that may benefit the most from proton therapy is important. We present modern guidelines to identify adult lymphoma patients who may derive the greatest benefit from proton therapy, along with an analysis of the advantages and disadvantages of proton treatment.

TEDDI: radiotherapy delivery in deep inspiration for pediatric patients - a NOPHO feasibility study

Background

Radiotherapy (RT) delivered in deep inspiration breath-hold (DIBH) is a simple technique, in which changes in patient anatomy can significantly reduce the irradiation of the organs at risk (OARs) surrounding the treatment target. DIBH is routinely used in the treatment of some adult patients to diminish the risk of late effects; however, no formalized studies have addressed the potential benefit of DIBH in children.

Methods/Design

TEDDI is a multicenter, non-randomized, feasibility study. The study investigates the dosimetric benefit of RT delivered in DIBH compared to free breathing (FB) in pediatric patients. Also, the study aims to establish the compliance to DIBH and to determine the accuracy and reproducibility in a pediatric setting. Pediatric patients (aged 5–17 years) with a tumor in the mediastinum or upper abdomen with the possible need of RT will be included in the study. Written informed consent is obligatory. Prior to any treatment, patients will undergo a DIBH training session followed by a diagnostic PET/CT- or CT-staging scan in both DIBH and FB. If the patient proceeds to RT, a RT planning CT scan will be performed in both DIBH and FB and two separate treatment plans will be calculated. The superior treatment plan, i.e. equal target coverage and lowest overall dose to the OARs, will be chosen for treatment. Patient comfort will be assessed daily by questionnaires and by adherence to the respiratory management procedure.

Discussion

RT in DIBH is expected to diminish irradiation of the OARs surrounding the treatment target and thereby reduce the risk of late effects in childhood cancer survivors.

Trial registration

The Danish Ethical Committee (H-16035870, approved November 24th 2016, prospectively registered). The Danish Data Protection Agency (2012–58-0004, approved January 1st 2017, prospectively registered). Registered at clinicaltrials.gov (NCT03315546, October 20th  2017, retrospectively registered).

Minimal Treatment of Low-Risk, Pediatric Lymphocyte-Predominant Hodgkin Lymphoma: A Report From the Children's Oncology Group

PURPOSE

Children's Oncology Group study AHOD03P1 was designed to determine whether excellent outcomes can be maintained for patients with low-risk, pediatric lymphocyte-predominant Hodgkin lymphoma (LPHL) with a strategy of resection alone or minimal chemotherapy.

PATIENTS AND METHODS

Patients with stage IA LPHL in a single node that was completely resected were observed without further therapy; recurrences were treated with three cycles of doxorubicin/vincristine/prednisone/cyclophosphamide (AV-PC). Patients with unresected stage IA or stage IIA LPHL were treated with three cycles of AV-PC. Patients with less than a complete response (CR) to AV-PC received 21-Gy involved-field radiation therapy (IFRT).

RESULTS

A total of 183 eligible patients were enrolled; 178 were evaluable. Of these, 52 patients underwent complete resection of a single node. There were 13 relapses at a median of 11.5 months; 5-year event-free survival (EFS) was 77% (range, 62% to 87%). A total of 135 patients received AV-PC; 126 were treated at diagnosis and nine at relapse after surgery alone. Eleven patients receiving AV-PC had less than CR and received IFRT. Fourteen first events occurred among 135 patients (12 relapses and two second malignancies). Two relapses occurred in patients who had received IFRT. Five-year EFS was 88.8% (95% CI, 81.8% to 93.2%). Five-year EFS for the entire cohort was 85.5% (95% CI, 79.2% to 90.1%); overall survival was 100%.

CONCLUSION

Some 75% of highly selected pediatric patients with LPHL may be spared chemotherapy after surgical resection alone. Pediatric LPHL has excellent EFS with chemotherapy that is less intensive than standard regimens; > 90% of patients can avoid radiation therapy. The salvage rate for the few relapses is high, with 100% survival overall.

Treatment of Early-Stage Unfavorable Hodgkin Lymphoma: Efficacy and Toxicity of 4 Versus 6 Cycles of ABVD Chemotherapy With Radiation

PURPOSE

The German Hodgkin Study Group HD11 trial validated 4 cycles of doxorubicin, bleomycin, vinblastine, dacarbazine (ABVD) chemotherapy followed by involved field radiation therapy (IFRT) for early unfavorable Hodgkin lymphoma (HL) patients. However, practitioners often recommend 6 cycles followed by RT, especially for bulky disease. We compared patient outcomes after treatment with 4 or 6 cycles of ABVD followed by RT (IFRT and involved site RT [ISRT]).

METHODS AND MATERIALS

We identified 128 patients treated for early unfavorable HL (GHSG criteria) between 2000 and 2013. Clinical outcomes (overall survival [OS] and freedom from relapse [FFR]) were estimated using Kaplan-Meier analysis. Toxicities were evaluated.

RESULTS

The median follow-up time was 5.0 years. Patients received 4 (70 patients, 55%) or 6 (58 patients, 45%) cycles of chemotherapy. Bulky disease was present in 22 patients (31%; 0 stage IA, 3 stage IB, 19 stage IIA) of the 4-cycle group and 42 patients (72%; 5 stage IA, 3 stage IB, 34 stage IIA) of the 6-cycle group. For patients receiving 4 and 6 cycles, the 6-year OS was 100% and 97% (P=.35), respectively, and the 6 year FFR was 100% and 98% (P=.28), respectively. More patients received 6 cycles if they were treated before 2010 (HD11 report) (P=.01) and if they had bulky disease (P<.01). Sixty-eight percent of patients received ISRT. The 6-year FFR was 99% and 100% for patients receiving ISRT and IFRT, respectively (P=.58). More patients experienced bleomycin pulmonary toxicity in the 6-cycle group (20% vs 31%, P=.16). For patients with bulky disease, the 4-year FFR was similar with receipt of 4 (100%) or 6 (98%) cycles (P=.48) and IFRT (100%) or ISRT (98%) (P=.52). There were no deaths among patients with bulky disease.

CONCLUSIONS

Patients with early unfavorable HL have excellent outcomes with 4 cycles of ABVD chemotherapy followed by ISRT. Six cycles of chemotherapy does not appear superior for disease control, even for bulky disease.

A Comparative Evaluation of Normal Tissue Doses for Patients Receiving Radiation Therapy for Hodgkin Lymphoma on the Childhood Cancer Survivor Study and Recent Children's Oncology Group Trials

PURPOSE

Survivors of pediatric Hodgkin lymphoma (HL) are recognized to have an increased risk of delayed adverse health outcomes related to radiation therapy (RT). However, the necessary latency required to observe these late effects means that the estimated risks apply to outdated treatments. We sought to compare the normal tissue dose received by children treated for HL and enrolled in the Childhood Cancer Survivor Study (CCSS) (diagnosed 1970-1986) with that of patients treated in recent Children's Oncology Group (COG) trials (enrolled 2002-2012).

METHODS AND MATERIALS

RT planning data were obtained for 50 HL survivors randomly sampled from the CCSS cohort and applied to computed tomography planning data sets to reconstruct the normal tissue dosimetry. For comparison, the normal tissue dosimetry data were obtained for all 191 patients with full computed tomography-based volumetric RT planning on COG protocols AHOD0031 and AHOD0831.

RESULTS

For early-stage patients, the mean female breast dose in the COG patients was on average 83.5% lower than that for CCSS patients, with an absolute reduction of 15.5 Gy. For advanced-stage patients, the mean breast dose was decreased on average by 70% (11.6 Gy average absolute dose reduction). The mean heart dose decreased on average by 22.9 Gy (68.6%) and 17.6 Gy (56.8%) for early- and advanced-stage patients, respectively. All dose comparisons for breast, heart, lung, and thyroid were significantly lower for patients in the COG trials than for the CCSS participants. Reductions in the prescribed dose were a major contributor to these dose reductions.

CONCLUSIONS

These are the first data quantifying the significant reduction in the normal tissue dose using actual, rather than hypothetical, treatment plans for children with HL. These findings provide useful information when counseling families regarding the risks of contemporary RT.

Involved site radiation therapy for the treatment of early-stage Hodgkin lymphoma in adolescents and young adults

Radiation therapy technology has permitted the development of new treatment planning techniques. Involved field, involved node, and involved site radiotherapy fields are discussed and compared. Indications for and implications of combined modality therapy are examined, particularly as pertinent to the adolescent and young adult population.

Pediatric Hodgkin Lymphoma

Hodgkin lymphoma (HL) is one of the most curable pediatric and adult cancers, with long-term survival rates now exceeding 90% after treatment with chemotherapy alone or combined with radiotherapy (RT). Of note, global collaboration in clinical trials within cooperative pediatric HL study groups has resulted in continued progress; however, survivors of pediatric HL are at high risk of potentially life-limiting second cancers and treatment-associated cardiovascular disease. Over the last three decades, all major pediatric and several adult HL study groups have followed the paradigm of response-based treatment adaptation and toxicity sparing through the reduction or elimination of RT and tailoring of chemotherapy. High treatment efficacy is achieved using dose-dense chemotherapy. Refinement and reduction of RT have been implemented on the basis of results from collaborative group studies, such that radiation has been completely eliminated for certain subgroups of patients. Because pediatric staging and response criteria are not uniform, comparing the results of trial series among different pediatric and adult study groups remains difficult; thus, initiatives to harmonize criteria are desperately needed. A dynamic harmonization process is of utmost importance to standardize therapeutic risk stratification and response definitions as well as improve the care of children with HL in resource-restricted environments.