Excellent Local Control From Radiation Therapy for High-Risk Neuroblastoma

Intraoperative Radiation Therapy for Relapsed or Refractory High-Risk Neuroblastoma: A 27-Year Experience

PURPOSE

To evaluate outcomes after intraoperative radiation therapy (IORT) in high-risk neuroblastoma (NB), including local control, overall survival, and toxicity.

METHODS AND MATERIALS

This was a single institution retrospective study of 92 pediatric patients with NB treated with IORT from 1995 to 2022. Each IORT application was considered a separate event for a total of 110 sites treated. Local failure was calculated using the cumulative incidence function and survival by Kaplan-Meier method from the day of surgery.

RESULTS

All patients had high-risk relapsed or treatment refractory disease. Median age was 6 years (range, 2-34 years). Median follow-up for all patients and surviving patients was 16 months and 4 years, respectively. All patients previously received chemotherapy, 93% had prior external beam radiation therapy to the site of IORT (median dose, 21.6 Gy; range, 10-36 Gy), and 94% had a prior surgery for tumor resection. The median IORT dose was 12 Gy (range, 8-18 Gy) and median area treated was 18 cm2 (range, 2.5-60 cm2). The cumulative incidence of local failure was 23% at 2 years and 29% at 5 years. The overall survival (OS) was 44% at 2 years and 29% at 5 years. Local failure after IORT was associated with worse OS (hazard ratio, 1.74; 95% CI, 1.07-2.84; P = .0267). Toxicity from IORT was rare, with postoperative complications likely related to IORT seen in 7 (8%) patients.

CONCLUSIONS

Our study represents the largest, most recent analysis of the efficacy and safety of IORT in patients with relapsed or refractory NB. Less than one-third of patients failed locally at 5 years, and achieving local control affected overall survival. Minimal toxicities directly related to IORT were observed. Overall, IORT is an effective and safe technique to achieve local control in high-risk relapsed or refractory neuroblastoma.

Enhancing the sensitization of neuroblastoma to radiotherapy by the construction of a dual-channel parallel free radicals nanoamplifier

Radiation therapy (RT) has emerged as one of the most promising anti-tumor strategies for neuroblastoma. Nevertheless, the special tumor microenvironment (TME), including hypoxic and GSH-overexpressed TME, often greatly restricts the RT outcome. In this study, we demonstrated a dual-channel parallel radicals nanoamplifier (ATO@PAE-PEG-AS1411/Fe3+). The nanoamplifier was shaped into a bilayer shell-core structure, in which atovaquone-loaded poly (β-amino esters)-poly (ethylene glycol) (ATO@PAE-PEG) served as the core while Fe3+-absorbed AS1411 aptamer (AS1411/Fe3+) served as the shell. Taking advantage of the targeting ability of AS1411, ATO@PAE-PEG-AS1411/Fe3+ specifically accumulated in tumor cells, and then released ATO as well as Fe3+ in response to the acidic TME. The released ATO dramatically inhibited the mitochondrial respiration of tumor cells, thus sparing vast amounts of oxygen for the generation of free radicals during RT process, which was the first free radicals-amplifying pathway Meanwhile, the released Fe3+ could consume the tumor-overexpressed GSH through the redox reaction, thus effectively preserving the generated free radicals in RT process, which was the second free radicals-amplifying pathway. Taken together, our study demonstrates a dual-channel parallel free radicals-amplifying RT strategy, and it is expected this work will promote the clinical application prospects of RT treatment against neuroblastoma.

Postchemotherapy gross residual tumor in non-high-risk neuroblastoma: Clinical significance and the role of adjuvant therapy

BACKGROUND

Although survival rate among patients with non-high-risk neuroblastoma is excellent, a gross residual tumor (GRT) is often present at the end of treatment. However, reliable data do not exist on the relevance of a GRT for the risk of progression and the role of adjuvant therapy for patients with GRT.

METHODS

A retrospective review of 131 patients with non-high-risk neuroblastoma who underwent chemotherapy was performed. GRT was defined as >1 cm³ residual soft tissue density on end-of-chemotherapy scans. Progression-free survival (PFS) and overall survival (OS) rates were compared between patients with GRT and those without GRT. A proportional hazards model was also used to assess the effects of GRT and adjuvant therapies, including radiation and isotretinoin therapy on outcomes.

RESULTS

GRT was found in 52 (40%) patients in the study cohort. Correlation was not found between GRT and outcomes (PFS; p = .954, OS; p = .222). In multivariable analysis, GRT remained a nonsignificant predictor of outcome after adjusting for confounders. Local radiation and isotretinoin therapy did not affect outcome for patients with GRT. However, within GRT subgroups, the degree of volume reduction, as well as absolute residual volume in the primary tumor after induction treatment, were significantly associated with outcomes.

CONCLUSION

GRT in non-high-risk neuroblastoma may not indicate active disease that requires additional treatment. However, risk of progression is increased in patients with GRT whose response to treatment was less prominent, thus adjuvant therapy should be reserved only for those patients.

The application and value of radiotherapy at the primary site in patients with high-risk neuroblastoma

OBJECTIVE

To retrospectively analyze radiotherapy (RT) regimens for patients with high-risk neuroblastoma (HRNB) at the primary site after surgery, and to further analyze the characteristics of patients who would benefit more from RT.

METHODS

98 pediatric patients with HRNB were analyzed for local control (LC), RT dose, extent of excision and prognostic factors. Among them, 69 children received RT.

RESULTS

The 3 year LC rates were 96.9 and 62.1% (p < 0.001) in the RT and non-RT groups, respectively. In the non-RT group, LC was better in patients with complete macroscopic resection (CME) than in those with incomplete macroscopic resection (IME) (p = 0.026), while in the RT group, no significant difference in LC was found (p = 0.985). Among patients with IME, the LC was 100% in patients with RT doses >= 36 Gy and 66.7% in patients with doses <36 Gy.

CONCLUSION

RT is valuable, provides patients with excellent LC, and is safe in the short term. RT had a complementary therapeutic effect on incompletely resected tumors, thus bringing their LC to the level of patients with CME. For patients with IME, RT at a dose of not less than 36 Gy may improve LC.

ADVANCES IN KNOWLEDGE

This study analysed the role of radiotherapy in HRNB, investigated the dose of RT depending on the degree of resection, and explored the characteristics of patients who would benefit more from RT.

A Phase II Trial of a Personalized, Dose-Intense Administration Schedule of 177Lutetium-DOTATATE in Children With Primary Refractory or Relapsed High-Risk Neuroblastoma-LuDO-N

Background

Half the children with high-risk neuroblastoma die with widespread metastases. Molecular radiotherapy is an attractive systemic treatment for this relatively radiosensitive tumor. 131I-mIBG is the most widely used form in current use, but is not universally effective. Clinical trials of 177Lutetium DOTATATE have so far had disappointing results, possibly because the administered activity was too low, and the courses were spread over too long a period of time, for a rapidly proliferating tumor. We have devised an alternative administration schedule to overcome these limitations. This involves two high-activity administrations of single agent 177Lu-DOTATATE given 2 weeks apart, prescribed as a personalized whole body radiation absorbed dose, rather than a fixed administered activity. "A phase II trial of 177Lutetium-DOTATATE in children with primary refractory or relapsed high-risk neuroblastoma - LuDO-N" (EudraCT No: 2020-004445-36, ClinicalTrials.gov Identifier: NCT04903899) evaluates this new dosing schedule.

Methods

The LuDO-N trial is a phase II, open label, multi-center, single arm, two stage design clinical trial. Children aged 18 months to 18 years are eligible. The trial is conducted by the Nordic Society for Pediatric Hematology and Oncology (NOPHO) and it has been endorsed by SIOPEN (https://www.siopen.net). The Karolinska University Hospital, is the sponsor of the LuDO-N trial, which is conducted in collaboration with Advanced Accelerator Applications, a Novartis company. All Scandinavian countries, Lithuania and the Netherlands participate in the trial and the UK has voiced an interest in joining in 2022.

Results

The pediatric use of the Investigational Medicinal Product (IMP) 177Lu-DOTATATE, as well as non-IMPs SomaKit TOC® (68Ga-DOTATOC) and LysaKare® amino acid solution for renal protection, have been approved for pediatric use, within the LuDO-N Trial by the European Medicines Agency (EMA). The trial is currently recruiting. Recruitment is estimated to be finalized within 3-5 years.

Discussion

In this paper we present the protocol of the LuDO-N Trial. The rationale and design of the trial are discussed in relation to other ongoing, or planned trials with similar objectives. Further, we discuss the rapid development of targeted radiopharmaceutical therapy and the future perspectives for developing novel therapies for high-risk neuroblastoma and other pediatric solid tumors.

Neuroblastoma

The survival of patients with high-risk neuroblastoma has improved significantly with the use of intensive multimodality treatment regimens, including chemotherapy, surgery, radiation therapy, myeloablative chemotherapy followed by stem cell rescue, and immunotherapy. This report summarizes the current treatment strategies used in the COG and SIOP for children with neuroblastoma. The improved global collaboration and the adoption of a uniform International Neuroblastoma Risk Group Staging System will help facilitate comparison of homogeneous pretreatment cohorts across clinical trials. Future research strategies regarding the indications for and dosages of radiation therapy to the primary and metastatic sites, and the integration of meta-iodobenzyl guanidine therapy into the multimodal treatment program, are discussed.

Pencil Beam Scanning Proton Therapy Case Selection for Paediatric Abdominal Neuroblastoma: Effects of Tumour Location and Bowel Gas

AIMS

Pencil beam scanning (PBS) proton therapy is an increasingly used radiation modality for childhood malignancies due to its ability to minimise dose to surrounding organs. However, the dosimetry is extremely sensitive to anatomical and density changes. The aims of this study were to investigate if there is a dosimetric benefit or detriment with PBS for paediatric abdominal neuroblastoma, assess gastrointestinal air variability and its dosimetric consequences, plus identify if there are factors that could assist case selection for PBS referral.

MATERIALS AND METHODS

Twenty neuroblastoma cases were double-planned with PBS and intensity-modulated arc therapy (IMAT). Cases were divided into unilateral, midline unilateral and midline bilateral locations in relation to the kidneys. Plans were recalculated after the gastrointestinal volume was simulated as air (Hounsfield Units -700) and water (Hounsfield Units 0), then compared with nominal plans (recalculated - nominal, ΔD). Forty-three weekly cone beam computed tomography scans were analysed to quantify gastrointestinal air variability during treatment.

RESULTS

PBS reduced the mean dose to normal tissues at all tumour locations, particularly unilateral tumours. However, 15% had better dosimetry with IMAT, all of which were midline tumours. Increased gastrointestinal air caused significant compromises to PBS versus IMAT plans for midline tumours [median/maximum ΔD95% clinical target volume (CTV) -2.4%/-15.7% PBS versus 1.4%/0% IMAT, P = 0.003], whereas minimal impact was observed for unilateral tumours (ΔD95% CTV -0.5%/-1.9% PBS versus 0.5%/-0.5% IMAT, P = 0.008). D95% CTV was significantly decreased in PBS plans if planning target volume (PTV) ≥400 cm3 (median -4.1%, P = 0.001) or PTV extension ≥60% anterior to vertebral body (-2.1%, P = 0.002). A larger variation in gastrointestinal air was observed in patients treated under general anaesthesia (median 38.4%) versus awake (11.5%); P = 0.004.

CONCLUSION

In this planning study, tumours at the unilateral location consistently showed improved dose reductions to normal tissue with minimal dose degradation from increased gastrointestinal air with PBS plans. Tumour location, PTV volume and anterior extension of PTV are useful characteristics in facilitating patient selection for PBS.

Proton Beam Therapy for Children With Neuroblastoma: Experiences From the Prospective KiProReg Registry

Objective

Radiotherapy (RT) is an integral part of the interdisciplinary treatment of patients with high-risk neuroblastoma (NB). With the continuous improvements of outcome, the interest in local treatment strategies that reduce treatment-related side effects while achieving optimal oncological results is growing. Proton beam therapy (PBT) represents a promising alternative to conventional photon irradiation with regard to the reduction of treatment burden.

Method

Retrospective analysis of children with high or intermediate risk NB receiving PBT of the primary tumor site during first-line therapy between 2015 and 2020 was performed. Data from the prospective in-house registry Standard Protonentherapie WPE - Kinder- (KiProReg) with respect to tumor control and treatment toxicity were analyzed. Adverse events were classified according to CTCAE Version 4 (V4.0) before, during, and after PBT.

Results

In total, 44 patients (24 male, 20 female) with high (n = 39) or intermediate risk NB (n = 5) were included in the analysis. Median age was 3.4 years (range, 1.4-9.9 years). PBT doses ranged from 21.0 to 39.6 Gray (Gy) (median 36.0 Gy). Five patients received PBT to the MIBG-avid residual at the primary tumor site at time of PBT according to the NB-2004 protocol. In 39 patients radiation was given to the pre-operative tumor bed with or without an additional boost in case of residual tumor. After a median follow-up (FU) of 27.6 months, eight patients developed progression, either local recurrence (n = 1) or distant metastases (n = 7). Four patients died due to tumor progression. At three years, the estimated local control, distant metastatic free survival, progression free survival, and overall survival was 97.7, 84.1, 81.8, and 90.9%, respectively. During radiation, seven patients experienced higher-grade (CTCAE ≥ °3) hematologic toxicity. No other higher grade acute toxicity occurred. After PBT, one patient developed transient myelitis while receiving immunotherapy. No higher grade long-term toxicity was observed up to date.

Conclusion

PBT was a well tolerated and effective local treatment in children with high and intermediate risk NB. The role of RT in an intensive multidisciplinary treatment regimen remains to be studied in the future in order to better define timing, doses, target volumes, and general need for RT in a particularly sensitive cohort of patients.

The importance of local control management in high-risk neuroblastoma in South Africa

PURPOSE

To investigate the impact of local therapies on high-risk neuroblastoma (HR-NB) outcomes in South Africa.

METHODS

Data from 295 patients with HR-NB from nine pediatric oncology units between 2000 and 2014 were analysed. All patients received chemotherapy. Five-year overall (OS) and event free survival (EFS) were determined for patients who had received local therapy, either surgery or radiotherapy or both.

RESULTS

Surgery was performed in only 35.9% (n = 106/295) patients. Surgical excision was done for 34.8% (n = 85/244) of abdominal primaries, 50.0% (n = 11/22) of thoracic primaries; 22.2% (n = 2/9) neck primaries and 66.7% (n = 8/12) of the paraspinal primaries. Only 15.9% (n = 47/295) of all patients received radiotherapy. Children, who had surgery, had an improved five-year OS of 32.1% versus 5.9% without surgery (p < 0.001). Completely resected disease had a five-year OS of 30.5%, incomplete resections 31.4% versus no surgery 6.0% (p < 0.001). Radiated patients had a five-year OS of 21.3% versus 14.2% without radiotherapy (p < 0.001). Patients who received radiotherapy without surgical interventions, had a marginally better five-year OS of 12.5% as opposed to 5.4% (p < 0.001). Patients who underwent surgery had a longer mean overall survival of 60.9 months, while patients, who were irradiated, had a longer mean overall survival of 7.9 months (p < 0.001). On multivariate analysis, complete metastatic remission (p < 0.001), surgical status (p = 0.027), and radiotherapy status (p = 0.040) were significant predictive factors in abdominal primaries.

CONCLUSION

Surgery and radiotherapy significantly improve outcomes regardless of the primary tumor site, emphasizing the importance of local control in neuroblastoma.

Role and toxicity of radiation therapy in neuroblastoma patients: A literature review

Neuroblastoma is the most common extracranial solid tumor, arising from primitive sympathetic ganglion cells, in pediatric patients. The unique features of neuroblastoma include variable clinical behaviors, such as rapid progression to death and maturation to benign ganglioneuroma, followed by regression. Radiation therapy (RT) is usually administered to both the primary tumor bed and persistent metastatic sites after induction chemotherapy for high-risk neuroblastoma. RT to the tumor bed after surgical resection contributes significantly to local disease control and prevention of local relapse, confirming the role of RT. Palliative radiotherapy for metastatic neuroblastoma is also effective and safe and mainly provides symptomatic relief. The late side effects of RT in neuroblastoma patients include growth and developmental failure, hypothyroidism, gastrointestinal dysfunction, neurocognitive defects, pulmonary and cardiac abnormalities, infertility, and secondary cancers. In this article, we reviewed the role and toxicity of RT in neuroblastoma patients.

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.

Pencil Beam Scanning Proton Therapy for Paediatric Neuroblastoma with Motion Mitigation Strategy for Moving Target Volumes

AIMS

More efforts are required to minimise late radiation side-effects for paediatric patients. Pencil beam scanning proton beam therapy (PBS-PT) allows increased sparing of normal tissues while maintaining conformality, but is prone to dose degradation from interplay effects due to respiratory motion. We report our clinical experience of motion mitigation with volumetric rescanning (vRSC) and outcomes of children with neuroblastoma.

MATERIALS AND METHODS

Nineteen patients with high-risk (n = 16) and intermediate-risk (n = 3) neuroblastoma received PBS-PT. The median age at PBS-PT was 3.5 years (range 1.2-8.6) and the median PBS-PT dose was 21 Gy (relative biological effectiveness). Most children (89%) were treated under general anaesthesia. Seven patients (37%) underwent four-dimensional computed tomography for motion assessment and were treated with vRSC for motion mitigation.

RESULTS

The mean result of maximum organ motion was 2.7 mm (cranial-caudal), 1.2 mm (left-right), 1.0 mm (anterior-posterior). Four anaesthetised children (21%) showing <5 mm motion had four-dimensional dose calculations (4DDC) to guide the number of vRSC. The mean deterioration or improvement to the planning target volume covered by 95% of the prescribed dose compared with static three-dimensional plans were: 4DDC no vRSC, -0.6%; 2 vRSC, +0.3%; 4 vRSC, +0.3%; and 8 vRSC, +0.1%. With a median follow-up of 14.9 months (range 2.7-49.0) there were no local recurrences. The 2-year overall survival was 94% and distant progression-free survival was 76%. Acute grade 2-4 toxicity was 11%. During the limited follow-up time, no late toxicities were observed.

CONCLUSIONS

The early outcomes of mainly high-risk patients with neuroblastoma treated with PBS-PT were excellent. With a subset of our cohort undergoing PBS-PT with vRSC we have shown that it is logistically feasible and safe. The clinical relevance of vRSC is debatable in anaesthetised children with small pre-PBS-PT motion of <5 mm.

Pediatric Patients with Adrenal Neuroblastoma: A SEER Analysis, 2004–2013

Adrenal neuroblastoma (NB) is a relatively common malignancy in children. The Surveillance, Epidemiology, and End Results database was used to present demographic data and a survival analysis with the aim of making tumor management better. The Surveillance, Epidemiology, and End Results database was used to search pediatric patients (age £16 years) with NB from 2004 to 2013. The Kaplan-Meier method was used to calculate the overall survival. And, we used Cox regression analysis to determine hazard ratios for prognostic variables. Independent prognostic factors were selected into the nomogram to predict individual's three-, five-, and seven-year overall survival. The study included a total of 1870 pediatric patients with NB in our cohort. Overall, three-, five-, and seven-year survival rates for adrenal NB were 0.777, 0.701, and 0.665, respectively, whereas the rates for nonadrenal NB were 0.891, 0.859, and 0.832, respectively. The multivariate analysis identified age >1 year, no complete resection (CR)/CR, radiation, and regional/distant metastasis as independent predictors of mortality for adrenal NB. Concordance index of the nomogram was 0.665 (95% confidence interval, 0.627–0.703). Pediatric patients with adrenal NB have significantly worse survival than those with nonadrenal NB. Adrenal NB with age <1 year, treated with surgery, no radiation, and localized tumor leads to a better survival. There was no survival difference for patients to receive CR and no CR.

Patient Transfer to Receive Proton Beam Therapy During Intensive Multimodal Therapy is Safe and Feasible for Patients With Newly Diagnosed High-risk Neuroblastoma

Neuroblastoma (NB) predominantly presents as high-risk disease, requiring intensive multimodal therapy. Proton beam therpy (PBT) is a promising option for many childhood cancers, but is not widely available. Patients with NB hoping to receive PBT may therefore need to be transferred between institutions during intensive multimodal therapy, risking undesirable effects. We evaluated patients with high-risk NB who received PBT at our institute as part of first-line therapy, mainly focusing on the safety and feasibility of mid-treatment patient transfer. Eighteen patients with newly diagnosed high-risk NB who received PBT between April 2010 and June 2016 were retrospectively analyzed for local control, outcomes, and toxicity. Survival (3-y overall survival 71%±11%; 3-y event-free survival 44%±12%) and local control rate (100%) were comparable with previous studies. Few acute adverse events were recorded, and all patients completed PBT without treatment delay. PBT for high-risk NB was safe and feasible for patients requiring mid-treatment interinstitutional transfer.

Patterns of recurrence after radiation therapy for high-risk neuroblastoma

Purpose

To investigate the patterns of recurrence in patients with neuroblastoma treated with radiation therapy to the primary tumor site.

Materials and Methods

We retrospectively analyzed patients with high-risk neuroblastoma managed with definitive treatment with radiation therapy to the primary tumor site between January 2003 and June 2017. These patients underwent three-dimensional conformal radiation therapy or intensity-modulated radiation therapy. A total of 14–36 Gy was delivered to the planning target volume, which included the primary tumor bed and the selected metastatic site. The disease stage was determined according to the International Neuroblastoma Staging System (INSS). We evaluated the recurrence pattern (i.e., local or systemic), progression-free survival, and overall survival.

Results

A total of 40 patients with high-risk neuroblastoma were included in this study. The median patient age was 4 years (range, 1 to 11 years). Thirty patients (75%) had INSS stage 4 neuroblastoma. At the median follow-up of 58 months, there were 6 cases of local recurrence and 10 cases of systemic recurrence. Among the 6 local failure cases, 4 relapsed adjacent to the radiation field. The other 2 relapsed in the radiation field (i.e., para-aortic and retroperitoneal areas). The main sites of distant metastasis were the bone, lymph nodes, and bone marrow. The 5-year progression-free survival was 70.9% and the 5-year overall survival was 74.3%.

Conclusion

Radiation therapy directed at the primary tumor site provides good local control. It seems to be adequate for disease control in patients with high-risk neuroblastoma after chemotherapy and surgical resection.

Neuroblastoma image-defined risk factors in adrenal neuroblastoma: role of radiologist

Neuroblastoma, one of the most common extracranial solid malignancies in children, is often localized in the adrenal glands (49%). The staging system for prognostic purpose was one of the first points of disagreement, which led to the International Neuroblastoma Staging System (INSS) of 1986, revised in 1989, which relies on surgical staging. The limit of this classification was the different surgical resection, also done at interval times from diagnosis. To overcome this difficulty, a new staging system was made based on preoperative imaging by the International Neuroblastoma Risk Group (INRG) in 2009. This new staging system uses 20 Image-Defined Risk Factors (IDRFs) across multiple organ systems. The scope of this IDRFs is to predict surgical outcomes and, in addition with clinical data, to provide risk stratification. The INRG Staging System (INRGSS) relies on Imaging-Defined Risk Factors (IDRFs) that are determined before surgery or other therapy. With the application of the INRGSS the radiologist's role in staging children with neuroblastoma increased. The review provides an overview of the INRGSS and the IDRFs in adrenal neuroblastoma.

Long term outcomes after concurrent ipsilateral nephrectomy versus kidney-sparing surgery for high-risk, intraabdominal neuroblastoma

PURPOSE

The impact of the extent of surgical resection including nephrectomy for high-risk neuroblastoma patients is controversial. In this study, we compared the renal late effects and long-term survival for patients who underwent kidney-sparing surgery (KSS) versus concurrent ipsilateral nephrectomy (CIN) for high-risk, intraabdominal neuroblastoma (HRIN).

METHODS

A retrospective analysis of patients diagnosed with HRIN between Jan 1998 and Dec 2008 in a tertiary referral center was performed. Demographics, preoperative features, surgical resection extent and outcomes were analyzed.

RESULTS

Of 58 patients who underwent surgical management of HRIN, 6 underwent CIN and 52 underwent KSS. Renal image-defined risk factors (IDRFs) were more common in patients who underwent CIN. Operating time was longer and EBL higher in CIN patients. There was no difference in recurrence or overall survival between the groups. Estimated GFR (eGFR) was comparable between the groups preoperatively, but was reduced postoperatively and at long-term follow-up in patients who underwent CIN.

CONCLUSION

Compared to KSS, CIN is not associated with an increase in local recurrence or inferior survival but does lead to reduced kidney function (eGFR of 90 ml/min/1.73 m² for CIN versus 127 ml/min/1.73 m² for KSS, p = 0.03) but without significant impact on clinical outcome.

LEVELS OF EVIDENCE

III (Retrospective comparative study).

Reduced-Dose Radiation Therapy to the Primary Site is Effective for High-Risk Neuroblastoma: Results From a Prospective Trial

PURPOSE

For patients with high-risk neuroblastoma (HR-NB), a dose of 21 Gy to the primary tumor site after gross total resection (GTR) provides excellent local control. However, no clinical trial has specifically evaluated the optimal dose of radiation therapy (RT), and RT-related long-term toxicities are of increasing concern. We sought to assess local control, survival outcomes, and toxicity after a reduction in dose to the primary site from 21 Gy to 18 Gy.

METHODS AND MATERIALS

After induction chemotherapy and GTR, patients with HR-NB were enrolled and treated on an RT dose-reduction prospective trial with 18 Gy hyperfractionated RT given in twice-daily fractions of 1.5 Gy each.

RESULTS

The 25 study subjects were 1.6 to 9.5 (median, 4.3) years old at enrollment and included 23 (92%) with stage IV and II (8%) with MYCN-amplified stage III disease. Eleven (44%) were in complete remission (CR), and 14 (56%) had persistence of osteomedullary disease postinduction. Three patients (12%) received proton therapy, and the rest received intensity modulated photon therapy. After a follow-up of 1.8 to 4.2 (median, 3.5) years from initiation of RT, no failures occurred within the RT field; 3 patients had marginal recurrences. The respective 3-year progression-free and overall survival rates were 54.5% and 90.9% for patients in first CR and 42.9% and 76.2% for patients not in metastatic CR. Acute toxicity was negligible.

CONCLUSIONS

Reduced-dose RT with 18 Gy did not compromise local control or survival outcomes in our cohort of patients with HR-NB after GTR. These findings support assessing further RT dose reduction and validation on a larger, multi-institutional trial.

Proton beam therapy in pediatric oncology

PURPOSE OF REVIEW

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

RECENT FINDINGS

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

SUMMARY

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

The Evidence for External Beam Radiotherapy in High-Risk Neuroblastoma of Childhood: A Systematic Review

AIMS

External beam radiotherapy is widely used in various ways in the management of neuroblastoma. Despite extensive clinical experience, the precise role of radiotherapy in neuroblastoma remains unclear. The purpose of this systematic review was to survey the published literature to identify, without bias, the evidence for the clinical effectiveness of external beam radiotherapy as part of the initial multimodality treatment of high-risk neuroblastoma. We considered four areas: treatment of the tumour bed and residual primary tumour, identification of any dose-response relationship, treatment of metastatic sites, identification of any technical advances that may be beneficial. We also aimed to define uncertainties, which may be clarified in future clinical trials.

MATERIALS AND METHODS

Bibliographic databases were searched for neuroblastoma and radiotherapy. Reviewers assessed 1283 papers for inclusion by title and abstract, with consensus achieved through discussion. Data extraction on 57 included papers was carried out by one reviewer and checked by another. Studies were assessed for their level of evidence and risk of bias, and a descriptive analysis of data was carried out.

RESULTS

Fifteen papers provided some evidence that radiotherapy to the tumour bed and residual tumour may possibly be of value. However, there is a significant risk of bias and no evidence that all subgroups will benefit. There is some suggestion from six papers that dose may be important, but no hard evidence. It remains unclear whether irradiation of metastatic sites is helpful. Technical advances may be of value in radiotherapy of high-risk neuroblastoma.

CONCLUSIONS

There are data that show that radiotherapy is of some efficacy in the management of high-risk neuroblastoma, but there is no level one evidence that shows that it is being used in the best possible way. Prospective randomised trials are necessary to provide more evidence to guide development of optimal radiotherapy treatment schedules.

Dose-escalation is needed for gross disease in high-risk neuroblastoma

BACKGROUND

Locoregional failure is common after subtotal resection in high-risk neuroblastoma. Although a dose of 21 Gy radiation therapy (RT) is standard for treatment of high-risk neuroblastoma after gross total resection, the dose needed for local control of patients with gross residual disease at the time of RT is unknown. We sought to evaluate local control after 21-36 Gy RT in patients with high-risk neuroblastoma undergoing subtotal resection.

METHODS

All patients with high-risk neuroblastoma who received RT to their primary site from 2000 to 2016 were reviewed. Of the 331 patients who received consolidative RT to their primary site, 19 (5.7%) underwent subtotal resection and were included in our analysis. Local failure (LF) was correlated with biologic prognostic factors and dose of RT.

RESULTS

Median follow-up among surviving patients was 6.0 years. Median RT dose was 25 Gy (range, 21 Gy-36 Gy). The 5-year cumulative incidence of LF among all patients was 17.2%. LF at 5 years was 30% in those who received <30 Gy versus 0% in those who received 30-36 Gy (P = 0.12). There was a trend towards improved local control in patients with tumor size ≤10 cm at diagnosis (P = 0.12). The 5-year event-free and overall survival were 44.9% and 68.7%, respectively.

CONCLUSION

After subtotal resection, patients who received less than 30 Gy had poor local control. Doses of 30-36 Gy are likely needed for optimal control of gross residual disease at the time of consolidative RT in high-risk neuroblastoma.

Musculoskeletal outcomes and the effect of radiation to the vertebral bodies on growth trajectories for long-term survivors of high-risk neuroblastoma

OBJECTIVE

Here, we report musculoskeletal outcomes and the impact of radiotherapy dose on vertebral body growth for an institutional series of long-term survivors of high-risk neuroblastoma.

METHODS

We conducted a retrospective study of 23 patients who were disease-free and at least 36 months from the end of treatment. The patients were initially treated from July 2003 to May 2012. Patient records were reviewed for growth percentiles (obtained at approximately 6-month intervals from onset of treatment to the last follow-up) and musculoskeletal comorbidities. RT plans and most recent surveillance CT scans were reviewed for locations of in-field vertebral bodies and corresponding vertebral growth patterns.

RESULTS

The median follow-up was 7.93 years. The median prescribed radiation dose was 21.6 Gy. Musculoskeletal abnormalities included scoliosis (5 patients), muscular hypoplasia (3), and hypodontia (1). The median growth percentile at treatment onset was 35.5 (range, 4.7-100) versus 10 (0-94.1) at the last follow-up. The median numbers of vertebral bodies encompassed (by at least half of their volume) by the 5-, 10-, 15-, and 20-Gy isodose lines were 7 (mean, 6.78), 7 (6.56), 6 (6.17), and 6 (5.52), respectively. Sixteen patients (70.0%) had in-field abnormalities in vertebral body growth, manifesting as stretches of successive vertebral bodies at the same height, while normally there is a gradual vertebral body height increase progressing caudally down the spinal column.

CONCLUSIONS

Musculoskeletal abnormalities, below average height, and stunted in-field vertebral body growth are routine in long-term survivors of high-risk neuroblastoma. Sparing vertebral bodies when feasible may lead to improvement in patient growth trajectories.

Neuroblastoma

Neuroblastoma is one of the most common solid tumors in children and has a diverse clinical behavior that largely depends on the tumor biology. Neuroblastoma exhibits unique features, such as early age of onset, high frequency of metastatic disease at diagnosis in patients over 1 year of age and the tendency for spontaneous regression of tumors in infants. The high-risk tumors frequently have amplification of the MYCN oncogene as well as segmental chromosome alterations with poor survival. Recent advanced genomic sequencing technology has revealed that mutation of ALK, which is present in ~10% of primary tumors, often causes familial neuroblastoma with germline mutation. However, the frequency of gene mutations is relatively small and other aberrations, such as epigenetic abnormalities, have also been proposed. The risk-stratified therapy was introduced by the Japan Neuroblastoma Study Group (JNBSG), which is now moving to the Neuroblastoma Committee of Japan Children's Cancer Group (JCCG). Several clinical studies have facilitated the reduction of therapy for children with low-risk neuroblastoma disease and the significant improvement of cure rates for patients with intermediate-risk as well as high-risk disease. Therapy for patients with high-risk disease includes intensive induction chemotherapy and myeloablative chemotherapy, followed by the treatment of minimal residual disease using differentiation therapy and immunotherapy. The JCCG aims for better cures and long-term quality of life for children with cancer by facilitating new approaches targeting novel driver proteins, genetic pathways and the tumor microenvironment.

Radiation Therapy to Sites of Metastatic Disease as Part of Consolidation in High-Risk Neuroblastoma: Can Long-term Control Be Achieved?

PURPOSE

As part of consolidative therapy in high-risk neuroblastoma, modern protocols recommend radiation therapy (RT) both to the primary site and to sites of metastatic disease that persist after induction chemotherapy. Although there are abundant data showing excellent local control (LC) with 21 Gy directed at the primary site, there are few data describing the feasibility and efficacy of RT directed at metastatic sites of disease as part of consolidation.

METHODS AND MATERIALS

All patients with neuroblastoma who received RT to metastatic sites of disease as a part of consolidative therapy at a single institution between 2000 and 2015 were reviewed. Among 159 patients, 244 metastases were irradiated.

RESULTS

The median follow-up period among surviving patients was 7.4 years. Over 85% of the irradiated metastases were treated with 21 Gy (range, 10.5-36 Gy). Tumor recurrence occurred in 43 of 244 irradiated metastases (18%). The 5-year LC rate of treated metastatic sites was 81%. Metastatic sites that cleared with induction chemotherapy had improved LC compared with sites with persistent uptake on metaiodobenzylguanidine scans (LC rate, 92% vs 67%; P < .0001). LC at irradiated metastatic sites did not differ based on total number of sites irradiated or site of disease irradiated (bone vs soft tissue). Patients with bulky, resistant disease who were treated with 30 to 36 Gy had worse LC (P = .02). However, on multivariate analysis, only persistence after induction chemotherapy remained a significant prognostic factor for LC (hazard ratio, 3.7; P < .0001). Patients who had LC at irradiated metastatic sites had improved overall survival compared with those who did not (overall survival rate, 71% vs 50%; P < .0001).

CONCLUSIONS

Response to chemotherapy is an important prognostic factor for LC at irradiated metastatic sites in neuroblastoma. Overall, consolidative RT appears to be an effective modality of LC. Long-term disease control can be achieved with such an approach.

Clinically relevant radioresistant cell line: a simple model to understand cancer radioresistance

Radiotherapy (RT) is one of the major modalities for the treatment of human cancers and has been established as an excellent local treatment for malignant tumors. Conventional fractionated RT consists of 2-Gy X-rays, fractionated once a day, 5 days a week for 5-7 weeks in total 60 Gy. The efficacy of RT depends on the existence of radioresistant cells, which remains one of the most critical obstacles in RT and radio-chemotherapy. To improve the efficacy of RT, understanding the characteristics of radioresistant cells is one of the important subjects in radiation biology. Several studies have been reported to find out molecules implicated in radioresistance. However, it is noteworthy that cellular radioresistance has been mainly studied among cells with different genetic backgrounds and different origins. Therefore, making a system to compare between radioresistant and sensitive cells with the isogenic background is required. In this review, some aspects of cellular radioresistance mainly focusing on clinically relevant radioresistant (CRR) cell lines that can continue to proliferate even under exposure to 2-Gy X-rays, once a day, for more than 30 days, which is consistent with the conventional fractionated RT are discussed.

Chronic radiation exposure of neuroblastoma cells reduces nMYC copy number

Neuroblastoma accounts for >15% of cancer-associated mortalities of children in the USA. Despite aggressive treatment regimens, the long-term survival for these children remains <40%. The identification of v-Myc avian myelocytomatosis viral oncogene neuroblastoma-derived homolog (nMYC) gene amplification during diagnosis is associated with poor prognosis in neuroblastoma. There are limited studies examining changes in nMYC copy numbers in response to therapy and its biological effect on cancer cells. The aim of the present study was to evaluate the effect of radiation on nMYC expression and amplification status in high-risk neuroblastoma. The effect of acute (5 Gy) and chronic (25 Gy) radiation on two nMYC-amplified cell lines, SK-N-BE (2) and NB-1691, was investigated. The results demonstrate that, following chronic but not acute radiation, the two cell lines regained their proliferation potential similar to the controls. This increased proliferation was characterized by loss of nMYC mRNA and protein expression. It was also revealed that nMYC loss was accompanied by nuclear localization of c-Myc. Using fluorescent in situ hybridization and quantitative polymerase chain reaction analysis, the results of the present study demonstrated that chronic radiation causes a severe loss of nMYC gene copy number. The present study is the first to provide experimental evidence that prolonged radiation therapy affects nMYC gene copy number in high-risk neuroblastoma but does not significantly improve the prognostic outlook.

Advances in emerging drugs for the treatment of neuroblastoma

INTRODUCTION

Neuroblastoma is the most common solid extracranial tumor of childhood. Outcome for children with high-risk neuroblastoma remains suboptimal. More than half of children diagnosed with high-risk neuroblastoma either do not respond to conventional therapies or relapse after treatment with dismal prognosis. Areas covered: This paper presents a short review of the state of the art in the current treatment of high-risk neuroblastoma. An updated review of new targeted therapies in this group of patients is also presented. Expert opinion: In order to improve prognosis for high-risk patients there is an urgent need to better understand spatial and temporal heterogeneity and obtain new predictive preclinical models in neuroblastoma. Combination strategies with conventional chemotherapy and/or other targeted therapies may overcome current ALK inhibitors resistance. Improvement of international and transatlantic cooperation to speed clinical trials accrual is needed.

Favorable Local Control From Consolidative Radiation Therapy in High-Risk Neuroblastoma Despite Gross Residual Disease, Positive Margins, or Nodal Involvement

PURPOSE

To report the influence of radiation therapy (RT) dose and surgical pathology variables on disease control and overall survival (OS) in patients treated for high-risk neuroblastoma at a single institution.

METHODS AND MATERIALS

We conducted a retrospective study of 67 high-risk neuroblastoma patients who received RT as part of definitive management from January 2003 until May 2014.

RESULTS

At a median follow-up of 4.5 years, 26 patients (38.8%) failed distantly; 4 of these patients also failed locally. One patient progressed locally without distant failure. Local control was 92.5%, and total disease control was 59.5%. No benefit was demonstrated for RT doses over 21.6 Gy with respect to local relapse-free survival (P=.55), disease-free survival (P=.22), or OS (P=.72). With respect to local relapse-free survival, disease-free survival, and OS, no disadvantage was seen for positive lymph nodes on surgical pathology, positive surgical margins, or gross residual disease. Of the patients with gross residual disease, 75% (6 of 8) went on to have no evidence of disease at time of last follow-up, and the 2 patients who failed did so distantly.

CONCLUSIONS

Patients with high-risk neuroblastoma in this series maintained excellent local control, with no benefit demonstrated for radiation doses over 21.6 Gy, and no disadvantage demonstrated for gross residual disease after surgery, positive surgical margins, or pathologic lymph node positivity. Though the limitations of a retrospective review for an uncommon disease must be kept in mind, with small numbers in some of the subgroups, it seems that dose escalation should be considered only in exceptional circumstances.

Neuroblastoma (Peripheral neuroblastic tumours)

Peripheral neuroblastic tumours (PNTs), a family of tumours arising in the embryonal remnants of the sympathetic nervous system, account for 7-10% of all tumours in children. In two-thirds of cases, PNTs originate in the adrenal glands or the retroperitoneal ganglia. At least one third present metastases at onset, with bone and bone marrow being the most frequent metastatic sites. Disease extension, MYCN oncogene status and age are the most relevant prognostic factors, and their influence on outcome have been considered in the design of the recent treatment protocols. Consequently, the probability of cure has increased significantly in the last two decades. In children with localised operable disease, surgical resection alone is usually a sufficient treatment, with 3-year event-free survival (EFS) being greater than 85%. For locally advanced disease, primary chemotherapy followed by surgery and/or radiotherapy yields an EFS of around 75%. The greatest problem is posed by children with metastatic disease or amplified MYCN gene, who continue to do badly despite intensive treatments. Ongoing trials are exploring the efficacy of new drugs and novel immunological approaches in order to save a greater number of these patients.

Local Control With 21-Gy Radiation Therapy for High-Risk Neuroblastoma

PURPOSE

To evaluate local control after 21-Gy radiation therapy (RT) to the primary site in patients with high-risk neuroblastoma.

METHODS AND MATERIALS

After receiving dose-intensive chemotherapy and gross total resection (GTR), 246 patients (aged 1.2-17.9 years, median 4.0 years) with high-risk neuroblastoma underwent RT to the primary site at Memorial Sloan Kettering from 2000 to 2014. Radiation therapy consisted of 21 Gy in twice-daily fractions of 1.5 Gy each. Local failure (LF) was correlated with biologic prognostic factors and clinical findings at the time of diagnosis and start of RT.

RESULTS

Median follow-up of surviving patients was 6.4 years. Cumulative incidence of LF was 7.1% at 2 years after RT and 9.8% at 5 years after RT. The isolated LF rate was 3.0%. Eighty-six percent of all local failures were within the RT field. Local control was worse in patients who required more than 1 surgical resection to achieve GTR (22.4% vs 8.3%, P=.01). There was also a trend toward inferior local control with MYCN-amplified tumors or serum lactate dehydrogenase ≥1500 U/L (P=.09 and P=.06, respectively).

CONCLUSION

After intensive chemotherapy and maximal surgical debulking, hyperfractionated RT with 21 Gy in high-risk neuroblastoma results in excellent local control. Given the young patient age, concern for late effects, and local control >90%, dose reduction may be appropriate for patients without MYCN amplification who achieve GTR.

Reassessing dose constraints of organs at risk in children with abdominal neuroblastoma treated with definitive radiation therapy: a correlation with late toxicity

BACKGROUND

In children treated with definitive radiation therapy (RT) for abdominal neuroblastoma, normal tissue constraints for organs at risk (OARs) are not well-standardized or evidence-based. In this study, we analyze dosimetric data of principal abdominal OARs, reassess existing RT planning constraints, and examine corresponding acute and late toxicity to OARs.

PROCEDURE

The treatment plans of 30 consecutive children who underwent definitive RT for high-risk abdominal neuroblastoma were reviewed. Dose-volume histogram (DVH) statistics were recorded for the ipsilateral kidney (if unresected), contralateral kidney, and liver. DVH data were analyzed to determine if OAR constraints from recent protocols were met and correlated with the development of toxicity.

RESULTS

The median follow-up period was 53.0 months. Ten, thirteen, and ten percent of patients' RT plans did not meet OAR DVH constraints for the liver, ipsilateral kidney, and contralateral kidney, respectively. Of the three patients whose plans did not achieve ipsilateral kidney DVH constraint(s), two developed evidence of late ipsilateral kidney hypoplasia, but maintained normal laboratory kidney function. No patient experienced late toxicity of the contralateral kidney nor developed RT-related late hepatic complications.

CONCLUSIONS

In children treated for abdominal neuroblastoma, the risk of developing clinically significant RT-related late toxicity of the kidney and liver is not appreciable, even when current DVH parameters for OARs are not achieved in planning. Toxicity outcomes did not necessarily correlate with present-day OAR dose constraints. Currently utilized DVH constraints are highly variable, and must be further studied and supported by toxicity outcomes to more accurately characterize risk of complications.

Long-term side effects of radiotherapy for pediatric localized neuroblastoma : results from clinical trials NB90 and NB94

INTRODUCTION

Neuroblastoma (NB) is the most frequent indication for extracranial pediatric radiotherapy. As long-term survival of high-risk localized NB has greatly improved, we reviewed treatment-related late toxicities in pediatric patients who received postoperative radiotherapy (RT) for localized NB within two French prospective clinical trials: NB90 and NB94.

PATIENTS AND METHODS

From 1990-2000, 610 children were enrolled. Among these, 35 were treated with induction chemotherapy, surgery, and RT. The recommended RT dose was 24 Gy at ≤ 2 years, 34 Gy at > 2 years, ± a 5 Gy boost in both age groups.

RESULTS

The 22 patients still alive after 5 years were analyzed. The median follow-up time was 14 years (range 5-21 years). Late effects after therapy occurred in 73 % of patients (16/22), within the RT field for 50 % (11/22). The most frequent in-field effects were musculoskeletal abnormalities (n = 7) that occurred only with doses > 31 Gy/1.5 Gy fraction (p = 0.037). Other effects were endocrine in 3 patients and second malignancies in 2 patients. Four patients presented with multiple in-field late effects only with doses > 31 Gy.

CONCLUSION

After a median follow-up of 14 years, late effects with multimodality treatment were frequent. The most frequent effects were musculoskeletal abnormalities and the threshold for their occurrence was 31 Gy.

Outcomes After Radiation Therapy to Metastatic Sites in Patients With Stage 4 Neuroblastoma

In patients with high-risk metastatic neuroblastoma, the benefit of radiation therapy (RT) to metastatic sites as part of primary treatment has not been fully investigated. The purpose of this single-institution study was to evaluate local control of irradiated metastatic sites, and characterize metastatic disease burden and anatomic distribution in patients with high-risk metastatic neuroblastoma. The records of all patients diagnosed with stage 4 neuroblastoma between August 2000 and January 2010 were reviewed. Exclusion criteria included: bone-marrow only metastatic site, total body irradiation, or no imaging follow-up. A total of 37 patients met eligibility criteria. Median follow-up period for patients without relapse was 61 months. Five-year overall survival for all patients was 67%. Thirteen patients (35%) received RT to a metastatic site as part of their primary treatment. Among these patients, in-field recurrence occurred in three patients (23%), including two of three treated calvarial sites. In patients treated with or without RT to a metastatic site, respectively, there was no significant difference in 5-year overall survival (73% vs. 63%, P=0.84) or relapse-free survival (46% and 55%, P=0.48). Current metastatic site RT dose may be suboptimal, and certain locations may predict for a poor response. Further studies are necessary to elucidate the optimal role of RT to metastatic sites.

Radiation therapy to the primary and postinduction chemotherapy MIBG-avid sites in high-risk neuroblastoma

PURPOSE

Although it is generally accepted that consolidation therapy for neuroblastoma includes irradiation of the primary site and any remaining metaiodobenzylguanidine (MIBG)-avid metastatic sites, limited information has been published regarding the efficacy of this approach.

METHODS AND MATERIALS

Thirty patients with high-risk neuroblastoma were treated at 1 radiation therapy (RT) department after receiving 5 cycles of induction chemotherapy and resection. All patients had at least a partial response after induction therapy, based upon international neuroblastoma response criteria. The primary sites were treated with 24 to 30 Gy whereas the MIBG-avid metastatic sites were treated with 24 Gy. RT was followed by high-dose chemotherapy with autologous stem cell rescue and 6 months of cis-retinoic acid.

RESULTS

The 5-year progression-free survival (PFS) and overall survival (OS) rates were 48% and 59%, respectively. The 5-year locoregional control at the primary site was 84%. There were no differences in locoregional control according to degree of primary surgical resection. The 5-year local control rate for metastatic sites was 74%. The 5-year PFS rates for patients with 0, 1, 2, and >3 postinduction MIBG sites were 66%, 57%, 20%, and 0% (P<.0001), respectively, whereas 5-year OS rates were 80%, 57%, 50%, and 0%, respectively (P<.0001).

CONCLUSIONS

RT to the primary site and postinduction MIBG-positive metastatic sites was associated with 84% and 74% local control, respectively. The number of MIBG-avid sites present after induction chemotherapy and surgery was predictive of progression-free and overall survival.

Intensity-modulated arc therapy to improve radiation dose delivery in the treatment of abdominal neuroblastoma

The standard European radiotherapy technique for children with neuroblastoma is a conventional parallel opposed pair. This frequently results in compromise on planning target volume coverage to stay within normal tissue tolerances. This study investigates the use of an intensity-modulated arc therapy (IMAT) technique to improve dose distribution and allow better protocol compliance. Among 20 previously treated patients, ten had received the full prescribed dose with conventional planning (protocol compliant) and ten had a compromise on planning target volume coverage (protocol noncompliant). All patients were replanned with IMAT. Dosimetric parameters of the conventional radiotherapy and IMAT were compared. The dose received by 98% of the planning target volume, homogeneity and conformity indices were all improved with IMAT (p < 0.001). IMAT would have enabled delivery of the full protocol dose in eight out of ten protocol-noncompliant patients. IMAT may improve outcomes through improved protocol compliance and better dose distributions.

Ten challenges in the management of neuroblastoma

Neuroblastoma is a complex disease with many contradictions and challenges. It is, by and large, a cancer of babies and preschool children, but it does occur, albeit increasingly rarely, in older children, adolescents and young adults. The prognosis is very variable, with outcome related to age, stage and molecular pathology. Neuroblastoma may behave in an almost benign way, with spontaneous regression in some infants, but the majority of older patients have high-risk disease, which is usually fatal, despite best current treatments. As a rare disease, international collaboration is essential to run clinical trials of adequate statistical power to answer important questions in a reasonable time frame. High-risk disease requires multimodality therapy including chemotherapy, surgery and radiotherapy as well as biological and immunological treatments for optimal outcomes. Innovative treatment approaches, sometimes associated with appreciable toxicity, offer hope for the future but, despite parental wishes, cannot be generally implemented without adequate assessment in clinical trials.

Historical trends in the use of radiation therapy for pediatric cancers: 1973-2008

PURPOSE

This study was undertaken to assess historical trends in the use of radiation therapy (RT) for pediatric cancers over the past 4 decades.

METHODS

The National Cancer Institute's Surveillance, Epidemiology, and End Results database of the 9 original tumor registries (SEER-9) was queried to identify patients aged 0 to 19 years with acute lymphoblastic leukemia, acute myeloid leukemia, bone and joint cancer, cancer of the brain and nervous system, Hodgkin lymphoma, neuroblastoma, non-Hodgkin lymphoma, soft tissue cancer, Wilms tumor, or retinoblastoma from 1973 to 2008. Patients were grouped into 4-year time epochs. The number and percentage of patients who received RT as part of their initial treatment were calculated per epoch by each diagnosis group from 1973 to 2008.

RESULTS

RT use for acute lymphoblastic leukemia, non-Hodgkin lymphoma, and retinoblastoma declined sharply from 57%, 57%, and 30% in 1973 to 1976 to 11%, 15%, and 2%, respectively, in 2005 to 2008. Similarly, smaller declines in RT use were also seen in brain cancer (70%-39%), bone cancer (41%-21%), Wilms tumor (75%-53%), and neuroblastoma (60%-25%). RT use curves for Wilms tumor and neuroblastoma were nonlinear with nadirs in 1993 to 1996 at 39% and 19%, respectively. There were minimal changes in RT use for Hodgkin lymphoma, soft tissue cancer, or acute myeloid leukemia, roughly stable at 72%, 40%, and 11%, respectively. Almost all patients treated with RT were given external beam RT exclusively. However, from 1985 to 2008, treatments involving brachytherapy, radioisotopes, or combination therapy increased in frequency, comprising 1.8%, 4.6%, and 11.9% of RT treatments in brain cancer, soft tissue cancer, and retinoblastoma, respectively.

CONCLUSIONS

The use of RT is declining over time in 7 of 10 pediatric cancer categories. A limitation of this study is a potential under-ascertainment of RT use in the SEER-9 database including the delayed use of RT.

Basic principles of paediatric radiotherapy

This article gives an introduction to the fundamentals of paediatric radiotherapy, describing the historical development of the speciality and its organisation in the UK, the clinical pathway (including issues around immobilisation) and an overview of indications for radiotherapy in the paediatric population. Late effects of radiotherapy, their mitigation and the role of the late effects clinic are summarised.

Intracranial metastatic neuroblastoma treated with gamma knife stereotactic radiosurgery: report of two novel cases

Intracranial metastasis of neuroblastoma (IMN) is associated with poor survival. No curative therapy for the treatment of IMN currently exists. Unfractionated radiotherapy may be beneficial in the treatment of IMN given the known radiosensitivity of neuroblastoma as well as its proclivity to metastasize as discrete lesions. We present two patients with IMN treated with Gamma Knife stereotactic radiosurgery (SRS). Single-fraction radiotherapy yielded temporary reduction of tumor burden and stability of disease in both patients. SRS may be a useful palliative tool in the treatment of IMN and expands the overall treatment options for this disease.

Results of a quality assurance review of external beam radiation therapy in the International Society of Paediatric Oncology (Europe) Neuroblastoma Group's High-risk Neuroblastoma Trial: a SIOPEN study

PURPOSE

Radiation therapy is important for local control in neuroblastoma. This study reviewed the compliance of plans with the radiation therapy guidelines of the International Society of Paediatric Oncology (Europe) Neuroblastoma Group (SIOPEN) High-Risk Trial protocol.

METHODS AND MATERIALS

The SIOPEN trial central electronic database has sections to record diagnostic imaging and radiation therapy planning data. Individual centers may upload data remotely, but not all centers involved in the trial chose to use this system. A quality scoring system was devised based on how well the radiation therapy plan matched the protocol guidelines, to what extent deviations were justified, and whether adverse effects may result. Central review of radiation therapy planning was undertaken retrospectively in 100 patients for whom complete diagnostic and treatment sets were available. Data were reviewed and compared against protocol guidelines by an international team of radiation oncologists and radiologists. For each patient in the sample, the central review team assigned a quality assurance score.

RESULTS

It was found that in 48% of patients there was full compliance with protocol requirements. In 29%, there were deviations for justifiable reasons with no likely long-term adverse effects resulting. In 5%, deviations had occurred for justifiable reasons, but that might result in adverse effects. In 1%, there was a deviation with no discernible justification, which would not lead to long-term adverse events. In 17%, unjustified deviations were noted, with a risk of an adverse outcome resulting.

CONCLUSIONS

Owing to concern over the proportion of patients in whom unjustified deviations were observed, a protocol amendment has been issued. This offers the opportunity for central review of radiation therapy plans before the start of treatment and the treating clinician a chance to modify plans.

Guidelines for imaging and staging of neuroblastic tumors: consensus report from the International Neuroblastoma Risk Group Project

Neuroblastoma is an enigmatic disease entity; some tumors disappear spontaneously without any therapy, while others progress with a fatal outcome despite the implementation of maximal modern therapy. However, strong prognostic factors can accurately predict whether children have "good" or "bad" disease at diagnosis, and the clinical stage is currently the most significant and clinically relevant prognostic factor. Therefore, for an individual patient, proper staging is of paramount importance for risk assessment and selection of optimal treatment. In 2009, the International Neuroblastoma Risk Group (INRG) Project proposed a new staging system designed for tumor staging before any treatment, including surgery. Compared with the focus of the International Neuroblastoma Staging System, which is currently the most used, the focus has now shifted from surgicopathologic findings to imaging findings. The new INRG Staging System includes two stages of localized disease, which are dependent on whether image-defined risk factors (IDRFs) are or are not present. IDRFs are features detected with imaging at the time of diagnosis. The present consensus report was written by the INRG Imaging Committee to optimize imaging and staging and reduce interobserver variability. The rationales for using imaging methods (ultrasonography, magnetic resonance imaging, computed tomography, and scintigraphy), as well as technical guidelines, are described. Definitions of the terms recommended for assessing IDRFs are provided with examples. It is anticipated that the use of standardized nomenclature will contribute substantially to more uniform staging and thereby facilitate comparisons of clinical trials conducted in different parts of the world.