Locoregional tumor progression after radiation therapy influences overall survival in pediatric patients with neuroblastoma

A Four-dimensional Computed Tomography Generated Internal Target Volume Approach to Paediatric High Risk Neuroblastoma to Reduce Organ at Risk and Normal Tissue Irradiation

AIMS

The magnitude of upper abdominal organ motion in children may be overestimated by current planning target volumes (PTV). A four-dimensional computed tomography (4DCT) - derived internal target volume (ITV) is frequently used in adult radiotherapy to take respiratory-related organ motion into account. In this study, the dosimetric consequences for target coverage and organs at risk from the use of an ITV approach compared to standard PTV margins in children with high-risk neuroblastoma were investigated.

MATERIALS AND METHODS

14 patients, median age 4.1 years, range 1.5 - 18.9 years, (9 midline targets, 5 lateralised) each had two dual arc volumetric modulated arc therapy (VMAT) plans (14 ×1.5 Gy) generated. One used an ITV-approach; motion information derived from 4DCT (PTV_itv) with a 5mm ITV to PTV expansion, and the other a PTV margin of 10mm from CTV to PTV (PTV_standard). Differences in absolute PTV volume and organ at risk doses are described.

RESULTS

The ITV approach resulted in a highly significant reduction in PTV size of 38% (p<0.0001). For midline targets, an ITV approach resulted in a small but statistically significant reduction in combined mean kidney dose of 0.8Gy, p 0.01. Mean heart and lung dose were reduced by an average of 1 Gy with an ITV approach. Non-PTV integral dose from 30.4 Gy L to 27.8 Gy L using an ITV approach.

CONCLUSION

An ITV-approach to respiratory related organ motion management in children can significantly reduce absolute PTV volumes, maintain target coverage and reduce dose delivered to normal tissue in proximity to the target. This is an essential step to maximising the benefits of highly conformal radiotherapy techniques including VMAT for this patient group, and in the future with Proton Therapy.

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.

Radiotherapy management of paediatric cancers with synchronous metastasis

Cancer in childhood represent 1% of all the new diagnosed cancers. About 30% of children with cancer receive radiation therapy, representing about 600 to 700 patients per year in France. As a consequence, paediatric cancers with synchronous metastasis is a very rare situation in oncology, with usually poor standard of care. However, considerable efforts are made by paediatric oncology scientific societies to offer trials or treatment consensus despite these rare situations. The article proposes to synthesize the radiotherapy management of both primary tumour and synchronous metastasis in the most "common" childhood or adolescent cancers.

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.

Expression of lncRNA CCAT2 in children with neuroblastoma and its effect on cancer cell growth

The aim of this study was to determine the expression of long-chain non-coding RNA (lncRNA) colon cancer-associated transcript 2 (CCAT2) in children with neuroblastoma and its effect on cancer cell growth. A polymerase chain reaction assay was carried out to quantify lncRNA CCAT2 miRNA in neuroblastoma cells, corresponding paracancerous cells, SH-SY5Y and SK-N-SH cells, and human umbilical vein endothelial cells (HUVEC), and two groups of children with different lncRNA CCAT2 expression were compared in clinical pathological parameters and prognosis. CCAT2-NC and si-CCAT2 were transfected into SH-SY5Y cells, separately. Then a 3-(4,5-Dimethylthiazol-2-yl)-2,5-Diphenyltetrazolium Bromide (MTT) assay was carried out to analyze the cell proliferation, migration, and invasion ability, a flow cytometry to detect cell apoptosis, and a Western blotting (WB) assay to quantify p53 and Bcl-2 proteins. lncRNA CCAT2 expression in cancer tissues of children with neuroblastoma was notably higher than that in corresponding paracancerous tissues (P < 0.05), and children with different tissue differentiation, tumor staging, and lymph node metastasis (LNM) showed notably different lncRNA CCAT2 expression (P < 0.05). In addition, children with neuroblastoma in the high lncRNA CCAT2 expression group showed lower 3-year survival rate than those in the low expression group (P < 0.05). Multivariate analysis revealed that tissue differentiation, tumor-node-metastasis staging, LNM, and lncRNA CCAT2 expression were all independent risk factors affecting the prognosis of children with neuroblastoma (all P < 0.05). Compared with HUVEC cells, SH-SY5Y and SK-N-SH cells showed notably up-regulated lncRNA CCAT2, and the expression of it in SH-SY5Y was higher than that in SK-N-SH cells (P < 0.05). Compared with the CCAT2-NC group, the si-CCAT2 group presented notably down-regulated CCAT2 (P < 0.05). Moreover, according to the MTT assay, the si-CCAT2 group showed notably weakened cell viability and proliferation than the CCAT2-NC group (both P < 0.05), and SH-SY5Y cells in the former group were less active than those in the latter group in terms of migration and invasion. The cell apoptosis rate of SH-SY5Y cells in the si-CCAT2 was higher than that in the CCAT2-NC. The results suggested that knock down of lncRNA CCAT2 could improve the apoptosis activity of neuroblastoma cells in children. According to the WB assay, the si-CCAT2 group showed notably higher p53 expression and notably lower Bcl-2 protein expression than the CCAT2-NC group (both P < 0.05). LncRNA CCAT2 can inhibit the proliferation of neuroblastoma cells and promote their apoptosis, which provides a basis for the treatment of neuroblastoma.

Diagnostic Use of Post-therapy 131I-Meta-Iodobenzylguanidine Scintigraphy in Consolidation Therapy for Children with High-Risk Neuroblastoma

¹²³I-meta-iodobenzylguanidine (¹²³I-mIBG) scintigraphy is used for evaluating disease extent in children with neuroblastoma. ¹³¹I-mIBG therapy has been used for evaluation in children with high-risk neuroblastoma, and post-therapy ¹³¹I-mIBG scintigraphy may detect more lesions compared with diagnostic ¹²³I-mIBG scintigraphy. However, no studies have yet revealed the detection rate of hidden mIBG-avid lesions on post-therapy ¹³¹I-mIBG whole-body scan (WBS) and SPECT images in neuroblastoma children without mIBG-avid lesions as demonstrated by diagnostic ¹²³I-mIBG scintigraphy. We retrospectively examined the diagnostic utility of post-therapy ¹³¹I-mIBG scintigraphy in children who received ¹³¹I-mIBG as consolidation therapy. Nineteen children with complete response to primary therapy were examined. Post-therapy ¹³¹I-mIBG scintigraphy was performed four days after injection. The post-therapy ¹³¹I-mIBG scintigraphy, 4 children exhibited abnormal uptake on the WBS. Post-therapy ¹³¹I-mIBG SPECT/CT provided additional information in 2 cases. In total, 6 children exhibited abnormal uptake. The site of abnormal accumulation was on the recurrence site in one case, operation sites in five cases, and bone metastasis in one case. Post-therapy ¹³¹I-mIBG scintigraphy could detect residual disease that was not recognized using diagnostic ¹²³I-mIBG scintigraphy in 32% of children with high-risk neuroblastoma and ganglioneuroblastoma. The diagnostic use of post-therapy ¹³¹I-mIBG scintigraphy can provide valuable information for detecting residual disease.

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.

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.

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.

A single center clinical analysis of children with high-risk neuroblastoma

The current multidisciplinary treatment for patients with high-risk neuroblastoma (NB) is the common census. However, protocols and opinions are different in different regions and institutions. We aimed to assess the protocol formulated by Chinese Children's Cancer Group study in 2009, and the impact of surgery extent was highlightly evaluated.

METHODS

This study enrolled patients with high-risk neuroblastoma between 2009 and 2014 in Department of Pediatric Oncology of Tianjin Medical University Cancer Institute and Hospital. The clinical characteristics of patients were illustrated and surgery extent was evaluated by the impact on survival rate.

RESULTS

The 3-year overall survival (OS) and progression-free survival (PFS) were 56.2% and 50.5%, respectively. LDH (P<0.001), bone marrow metastasis at time of diagnosis (P=0.001), bone marrow negative after neoadjuvant chemotherapy (P<0.001), radiotherapy (P<0.001) were significant predictors of OS and PFS. And surgery extent had no impact on the enhancement of high-risk neuroblastoma patients in short time.

CONCLUSIONS

This study showed no substantial survival benefit in patients with high-risk NB undergoing gross total tumor resection. Multidisciplinary intensive treatment was essential, especially for patients received subtotal tumor resection. Longer term follow-up is needed to survey complications in surviving patients who received intensive chemotherapy and radiotherapy.

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.

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.

Clinical results of proton beam therapy for advanced neuroblastoma

PURPOSE

To evaluate the efficacy of proton beam therapy (PBT) for pediatric patients with advanced neuroblastoma.

METHODS

PBT was conducted at 21 sites in 14 patients with neuroblastoma from 1984 to 2010. Most patients were difficult to treat with photon radiotherapy. Two and 6 patients were classified into stages 3 and 4, respectively, and 6 patients had recurrent disease. Seven of the 8 patients who received PBT as the initial treatment were classified as the high risk group. Twelve patients had gross residual disease before PBT and 2 had undergone intraoperative radiotherapy before PBT. Five patients received PBT for multiple sites, including remote metastases. Photon radiotherapy was used in combination with PBT for 3 patients. The PBT doses ranged from 19.8 to 45.5 GyE (median: 30.6 GyE).

RESULTS

Seven patients are alive with no evidence of disease, 1 is alive with disease progression, and 6 died due to the tumor. Recurrence in the treatment field was not observed and the 3-year locoregional control rate was 82%. Severe acute radiotoxicity was not observed, but 1 patient had narrowing of the aorta and asymptomatic vertebral compression fracture at 28 years after PBT, and hair loss was prolonged in one patient.

CONCLUSION

PBT may be a better alternative to photon radiotherapy for children with advanced neuroblastoma, and may be conducted safely for patients with neuroblastoma that is difficult to manage using photon beams.

Intensity modulated radiation therapy provides excellent local control in high-risk abdominal neuroblastoma

BACKGROUND

Locoregional failure is a significant concern in patients with high-risk abdominal neuroblastoma (NB) receiving radiotherapy. Locoregional control outcomes were studied in children with NB receiving intensity modulated radiotherapy (IMRT).

PROCEDURE

Twenty children (11 females, 9 males) with NB (median age at diagnosis 3.4 years) receiving IMRT were analyzed for locoregional failure, outcomes, and toxicities. IMRT doses were 23.4 Gy (n = 12), 30 Gy (n = 1), 30.6 Gy (n = 5), and 36.0 Gy (n = 2) based on extent of resection. Five patients had tumors with MYCN amplification, and 19 had metastatic disease. All patients were treated consistently using reproducible immobilization techniques; physiological motion was assessed by 4D-CT, and target localization by cone-beam computed tomography. ICRU 62 volumetric conventions were employed based on institutional data for pediatric target volume and organ motion.

RESULTS

No patient developed primary site infield or locoregional failure at a median follow-up of 2.2 years. Distant failure (median time to distant failure 1.6 years) occurred in the brain, lungs, or skeletal sites in eight patients, five of whom died. The 2-year event-free survival was 58.5 ± 13.3% and cumulative incidence of local and distant failures was 0% and 41.5 ± 11.9%, respectively. Asymptomatic loose stool during RT occurred in nearly all patients, but required no intervention.

CONCLUSIONS

IMRT is feasible, safe in the short term, and yields excellent locoregional control. Despite subtotal resection in some cases, locoregional control appeared to be increased by conformal radiotherapy with ICRU 62-compliant volumes. Dose escalation beyond 30.6 Gy may be unnecessary with improved target volume coverage.

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.

Neuroblastoma management in Chinese children

BACKGROUND

This study assesses the clinical features of neuroblastoma and survival. Data for 98 patients between January 2000 and December 2006 at Children's Hospital of Fudan University, Shanghai, China, were retrospectively analyzed.

PATIENTS AND METHODS

Diagnostic methods included imaging, 24-hr urine catecholamines, bone marrow biopsies, and histopathology analyses. Treatment followed the modified Japanese Study Group Protocol. Clinical characteristics, treatment, and outcome were depicted, and difficulties encountered were analyzed.

RESULTS

The median age of patients was 48 months. There were 3, 13, 31, 49, and 2 patients in stages 1, 2, 3, 4, and 4s disease, respectively. Positive urinary vanillylmandelic acid (VMA) prevalence was low in localized disease (51.1%) and high in disseminated disease (70.6%, p = .03). Gross total resection rate was 60.8%. The five-year overall survival (OS) rate was 80% for stages 1 and 2, 48.3% for stage 3, and 20% for stage 4. The five-year OS rates significantly decreased in children older than 18 months (p < .01), and were higher after gross total resection was performed (p = .023). In stage 4 patients, gross total resection significantly improved the five-year OS rate (p = .029).

CONCLUSION

From these data, we suggest that positive urinary VMA, age greater than 18 months, incomplete tumor resection, and advanced stage predict poor prognosis. The results in children with advanced neuroblastoma were not satisfactory in our center. We speculated that lack of multidisciplinary teamwork, nonstandardized treatment, resource limitation, and indigence were the main causes for poorer outcome in late stages.

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.

Local control, survival, and operative morbidity and mortality after re-resection, and intraoperative radiation therapy for recurrent or persistent primary high-risk neuroblastoma

BACKGROUND/PURPOSE

Patients with locally recurrent or persistent high-risk neuroblastoma are difficult to treat. We describe our experience using intraoperative radiation therapy (IORT) after re-resection in this high-risk population.

METHODS

We retrospectively reviewed 44 consecutive patients who received IORT at our institution between April 2000 and September 2009 after gross total resection of recurrent/persistent tumor. Specifically, we evaluated local recurrence rates, complications, and overall survival.

RESULTS

The median age at diagnosis was 41.5 months. Median follow-up after IORT was 10.5 months. Each patient received prior chemotherapy and surgery, while 94.5% had previous external beam radiation therapy. MYCN was amplified in 34% of patients. There were no operative or postoperative deaths, and 18 patients (40.9%) had postoperative complications. There was a 50.4% probability of local control. MYCN amplification did not affect local control (local recurrence rate of 53.9% vs 52.4%, P = .89). Median overall survival was 18.7 months (95% confidence interval, 11.7-25.6 months). Mean survival for MYCN-amplified patients was 13.0 vs 39.2 months for those without MYCN amplification (P = .035).

CONCLUSIONS

Intraoperative radiation therapy after re-resection of locally recurrent/persistent neuroblastoma results in a reasonable rate of local control with acceptable morbidity and survival. This approach should be considered in this high-risk population.