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

Time to resolution of iodine-123 metaiodobenzylguanidine (123 I-MIBG) avidity and local control outcomes for high-risk neuroblastoma following radiation therapy

INTRODUCTION

¹²³ I-MIBG scan is used in neuroblastoma (NB) to monitor treatment response. Time to resolution of ¹²³ I-MIBG avidity after radiation therapy (RT) is unknown. We sought to determine time to resolution of ¹²³ I-MIBG avidity after RT and local failure (LF) rate.

METHODS

We performed a retrospective review of children with high-risk NB who underwent ¹²³ I-MIBG scans pre- and post-RT from 2003 to 2019. Time from RT to resolution of ¹²³ I-MIBG activity was analysed. LF and cumulative incidence of local progression (CILP) after RT stratified by site, presence of residual disease and use of boost RT were determined.

RESULTS

Forty-two patients with median age 3.9 years (1.9-4.7 years) were included, with median follow-up time 3.9 years (1.4-6.9). Eighty-six lesions were treated with RT to median dose of 21.6 Gy. Eighteen of 86 lesions were evaluable for time to resolution of MIBG avidity after RT, with median resolution time of 78 days (36-208). No LF occurred among 26 patients who received RT to primary sites after GTR, versus 4/12 (25%) patients treated with residual primary disease. 2-year CILP was 19% (12% primary disease 25% metastatic disease (P = 0.18)). 2-year CILP for non-residual primary, residual primary, non-residual metastatic and residual metastatic lesions was 0%, 42%, 11% and 30% respectively (P = 0.01) and for boosted and non-boosted residual lesions was 29% and 35% (P = 0.44).

CONCLUSION

Median time to MIBG resolution after RT was 78 days. Primary lesions without residual disease had excellent local control. LF rate was higher after RT for residual disease, with no benefit for boost RT.

MYCN Impact on High-Risk Neuroblastoma: From Diagnosis and Prognosis to Targeted Treatment

Simple Summary

Neuroblastoma is one of the most diffuse and the deadliest cancer in children. While many advances have been made in the last few decades to improve patients’ outcome, high-risk neuroblastoma (HR-NB) still shows a very aggressive pattern of development and poor prognosis, with only a 50% chance of 5-year survival. Moreover, while many factors contribute to defining the high-risk condition, MYCN status is well established as the major element in pathology disclosure. The aim of this review is to describe the current knowledge in the diagnosis, prognosis and therapeutic approaches of HR-NB, particularly in relation to MYCN. The review highlights how MYCN influences the HR-NB scenario and the new therapeutic approaches that are currently proposed to target it, in consideration of MYCN as a highly relevant target for HR-NB patient management.

Abstract

Among childhood cancers, neuroblastoma is the most diffuse solid tumor and the deadliest in children. While to date, the pathology has become progressively manageable with a significant increase in 5-year survival for its less aggressive form, high-risk neuroblastoma (HR-NB) remains a major issue with poor outcome and little survivability of patients. The staging system has also been improved to better fit patient needs and to administer therapies in a more focused manner in consideration of pathology features. New and improved therapies have been developed; nevertheless, low efficacy and high toxicity remain a staple feature of current high-risk neuroblastoma treatment. For this reason, more specific procedures are required, and new therapeutic targets are also needed for a precise medicine approach. In this scenario, MYCN is certainly one of the most interesting targets. Indeed, MYCN is one of the most relevant hallmarks of HR-NB, and many studies has been carried out in recent years to discover potent and specific inhibitors to block its activities and any related oncogenic function. N-Myc protein has been considered an undruggable target for a long time. Thus, many new indirect and direct approaches have been discovered and preclinically evaluated for the interaction with MYCN and its pathways; a few of the most promising approaches are nearing clinical application for the investigation in HR-NB.

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.

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

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

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.

Prospective Evaluation of Radiation Dose Escalation in Patients With High-Risk Neuroblastoma and Gross Residual Disease After Surgery: A Report From the Children's Oncology Group ANBL0532 Study

PURPOSE

A primary objective of the Children's Oncology Group (COG) ANBL0532 phase III study was to assess the effect of increasing local dose of radiation to a residual primary tumor on the cumulative incidence of local progression (CILP) in patients with high-risk neuroblastoma.

PATIENTS AND METHODS

Newly diagnosed patients with high-risk neuroblastoma were randomly assigned or assigned to receive single or tandem autologous stem-cell transplantation (SCT) after induction chemotherapy. Local control consisted of surgical resection during induction chemotherapy and radiotherapy after last SCT. Patients received 21.6 Gy to the preoperative primary tumor volume. For patients with incomplete surgical resection, an additional boost of 14.4 Gy was delivered to the gross residual tumor, for a total dose of 36 Gy. CILP (primary end point) and event-free (EFS) and overall survival (OS; secondary end points) were compared with the COG A3973 historical cohort, in which all patients received single SCT and 21.6 Gy without a boost.

RESULTS

For all patients in ANBL0532 receiving radiotherapy (n = 323), 5-year CILP, EFS, and OS rates were 11.2% ± 1.8%, 56.2% ± 3.4%, and 68.4% ± 3.2% compared with 7.1% ± 1.4% (P = .0590), 47.0% ± 3.5% (P = .0090), and 57.4% ± 3.5% (P = .0088) for all patients in A3973 receiving radiotherapy (n = 328), respectively. Five-year CILP, EFS, and OS rates for patients in A3973 with incomplete resection and radiotherapy (n = 47) were 10.6% ± 4.6%, 48.9% ± 10.1%, and 56.9% ± 10.0%, respectively. In comparison, 5-year CILP, EFS, and OS rates for patients in ANBL0532 who were randomly assigned or assigned to single SCT and received boost radiotherapy (n = 74) were 16.3% ± 4.3% (P = .4126), 50.9% ± 7.0% (P = .5084), and 68.1% ± 6.7% (P = .2835), respectively.

CONCLUSION

Boost radiotherapy to gross residual tumor present at the end of induction did not significantly improve 5-year CILP. These results highlight the need for new strategies to decrease the risk of locoregional failure.

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.

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.

Pediatric minimally invasive surgery for malignant abdominal tumor: Single center experience

This study examined the safety and usefulness of minimally invasive surgery (MIS) for malignant abdominal tumors in pediatric patients and analyzed the factors affecting the resection margin, operative time, and hospital stay of neuroblastoma (NBL) patients.We retrospectively reviewed data of pediatric patients who underwent MIS for malignant abdominal tumors from January 2011 to June 2017 at the Seoul National University Children's Hospital. Sex; age at operation; diagnosis; tumor location; operation-related data, such as operation time and transfusion; and follow-up data were reviewed. We divided patients into an excision group and a biopsy group. Detailed pathologic data were reviewed to analyze factors affecting the resection margin of NBL. Median value and range were calculated for all continuous variables. Mann-Whitney test and χ test were used as appropriate. P values of <.05 were considered significant.Thirty-four pediatric patients were included; 21 were boys. The median age was 4 (0.2-18) years. The most common diagnosis was NBL (17 patients; 50.0%). Three patients each were diagnosed with lymphoma, solid pseudopapillary tumor of the pancreas, and teratoma. The median tumor size was 3.4 (0.5-10.2) cm. The median operation time was 108 (55-290) minutes, and the median hospital stay was 5 (2-11) days. The number of conversions to open surgery was 4. There were no postoperative complications or mortality. There were 18 patients in the excision group and 16 in the biopsy group. Diagnosis and the number of patients receiving preoperative chemotherapy differed between the 2 groups. R0 resection of NBL was significantly higher in patients with stage 1 disease and those aged >2 years. There were no clinical factors influencing operative time or hospital stay.MIS was feasible and safe in pediatric patients with malignant abdominal tumors. R0 resection of NBL was related to age and stage.

Efficacy of proton therapy in children with high-risk and locally recurrent neuroblastoma

PURPOSE

Proton therapy is currently used in the management of pediatric tumors to decrease late toxicities. However, one of the criticisms of proton therapy is the limited data regarding efficacy on disease control. The purpose of this study was to examine local and distant control rates after proton therapy for neuroblastoma.

METHODS AND MATERIALS

Eighteen patients with high-risk (n = 16) and locally recurrent neuroblastoma (n = 2) were treated with curative intent and received proton therapy to the primary site and up to three post-induction MIBG-avid metastatic sites. Primary sites (n = 18) were treated to 21-36 Gy (relative biological effectiveness [RBE]), and metastatic sites (n = 16) were treated to 21-24 Gy (RBE). Local control and survival rates were calculated using the Kaplan-Meier method.

RESULTS

With a median follow-up of 60.2 months, two- and five-year local control rates at the irradiated primary site were 94% and 87%, respectively. No failures at irradiated distant metastatic sites were observed. The five-year progression-free survival (PFS) was 64%, and the five-year overall survival (OS) was 94%. The extent of surgical resection was not associated with local control, PFS, or OS. No radiation-related nephropathy or hepatopathy was reported.

CONCLUSIONS

Excellent local control was achieved using proton therapy to the primary and post-induction MIBG-positive distant sites. The predominant site of failure is progression in post-induction non-MIBG-avid distant sites. Although proton therapy provides high rates of local control with acceptable toxicity for neuroblastoma, further advances in systemic therapy are needed for the improved control of systemic disease.

Outcomes After Proton Therapy for Treatment of Pediatric High-Risk Neuroblastoma

PURPOSE

Patients with high-risk neuroblastoma (HR-NBL) require radiation to the primary tumor site and sites of persistent metastatic disease. Proton radiation therapy (PRT) may promote organ sparing, but long-term outcomes have not been studied.

METHODS AND MATERIALS

Sequential patients with HR-NBL received PRT: 2160 cGy (relative biological effectiveness) to primary tumor bed and persistent metastatic sites, with 3600 cGy (relative biological effectiveness) to gross residual disease.

RESULTS

From September 2010 through September 2015, 45 patients with HR-NBL received PRT after systemic therapy, primary tumor resection, and high-dose chemotherapy with stem cell rescue. Median age was 46 months at the time of PRT (range, 10 months to 12 years); 23 patients (51%) were male. Primary tumors were adrenal in 40 (89%); 11 (24%) received boost. Ten metastatic sites in 8 patients were radiated. Double scattered proton beams were used for 19 (42%) patients, in combination with x-rays for 2 (5%). The remaining 26 (58%) received pencil beam scanning, available since January 2013. We observed 97% freedom from primary site recurrence at 3, 4, and 5 years. Overall survival rates were 89%, 80%, and 80% and disease-free survival rates were 77%, 70%, and 70%, at 3, 4, and 5 years, respectively. With median follow-up of 48.7 months from diagnosis (range, 11-90 months) for all patients (57.4 months for those alive), 37 (82%) patients are alive, and 32 (71%) are without evidence of disease. One patient experienced locoregional recurrence; the remaining 12 (27%) experienced relapse at distant, nonradiated sites. Acute toxicities during treatment were mainly grade 1. No patient has experienced World Health Organization grade 3 or 4 long-term renal or hepatic toxicity. Pencil beam scanning plans required less planning time and resources than double scattered plans.

CONCLUSIONS

We observe excellent outcomes in patients treated with PRT for HR-NBL from 2010 through 2015, with 82% of patients alive and 97% free of primary site recurrence. No patient has experienced long-term renal or liver toxicity. This treatment maximizes normal tissue preservation and is appropriate for this patient population.

Advances in neuroblastoma therapy

PURPOSE OF REVIEW

Our understanding of the biologic basis of neuroblastoma, the genetic heterogeneity of this malignancy and the role of host factors has expanded significantly in recent years. In this review, we highlight current and future risk-based treatment approaches and discuss the opportunities and challenges of selecting optimal therapies for specific patient subsets.

RECENT FINDINGS

Significant progress has been made in understanding neuroblastoma predisposition and new approaches have been taken to treatment of this disease. Although survival remains poor for patients with high-risk neuroblastoma, current-era therapy has improved outcomes. Integration of new prognostic markers into neuroblastoma classification systems will allow more precise risk classification and refined treatment assignment. Promising treatments that include targeted therapies as well as immunotherapeutics are being evaluated in clinical trials, and new predictive biomarkers are being developed.

SUMMARY

As our understanding of neuroblastoma biology deepens, our approaches to therapy for this disease continue to evolve. Improved risk stratification and the use of predictive biomarkers will aid in treatment selection for patients with neuroblastoma, and it is expected that future treatments will be associated with greater efficacy and less toxicity.

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.

Analysis of the risk factor for the poor prognosis of localized neuroblastoma after the surgical

Neuroblastoma is a unique malignancy in infants often presenting with either localized or metastatic disease. The study was carried out to explore the risk stratification of the poor prognosis for patients underwent surgical treatment.60 patients diagnosed with neuroblastoma were primarily enrolled in the study from April 2008 to April 2016. All the patients underwent surgical treatment and received 5-year follow-up. Clinical variables, including age, International Neuroblastoma Staging System (INSS) stage, tumor size and site, histology, and MYCN status were retrospectively analyzed, and EFS was chosen as the endpoint.The median age of patients was 8.2 months and average follow-up period was 40.2 ± 8.6 months. Among 60 patients, complete remission was achieved in 35 patients and partial remission in 14 subjects. Poor prognosis including patient death and tumor progression were overserved in 11 patients. Cox multifactor regression analysis revealed that age, histology and MYCN status had significant prognostic effect on event-free survival (EFS) rate for neuroblastoma patients underwent surgical treatment.In our study, we identified a series of prognostic factors including age, histology, and MYCN status predicting the prognosis of neuroblastoma patients after surgical treatment.

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.

Acquired resistance to tyrosine kinase inhibitors may be linked with the decreased sensitivity to X-ray irradiation

Acquired resistance to chemotherapy and radiation therapy is one of the major obstacles decreasing efficiency of treatment of the oncologic diseases. In this study, on the two cell lines (ovarian carcinoma SKOV-3 and neuroblastoma NGP-127), we modeled acquired resistance to five target anticancer drugs. The cells were grown on gradually increasing concentrations of the clinically relevant tyrosine kinase inhibitors (TKIs) Sorafenib, Pazopanib and Sunitinib, and rapalogs Everolimus and Temsirolimus, for 20 weeks. After 20 weeks of culturing, the half-inhibitory concentrations (IC₅₀) increased by 25 – 186% for the particular combinations of the drugs and cell types. We next subjected cells to 10 Gy irradiation, a dose frequently used in clinical radiation therapy. For the SKOV-3, but not NGP-127 cells, for the TKIs Sorafenib, Pazopanib and Sunitinib, we noticed statistically significant increase in capacity to repair radiation-induced DNA double strand breaks compared to naïve control cells not previously treated with TKIs. These peculiarities were linked with the increased activation of ATM DNA repair pathway in the TKI-treated SKOV-3, but not NGP-127 cells. Our results provide a new cell culture model for studying anti-cancer therapy efficiency and evidence that there may be a tissue-specific radioresistance emerging as a side effect of treatment with TKIs.