Detection of MYCN amplification using blood plasma: noninvasive therapy evaluation and prediction of prognosis in neuroblastoma

Purpose

Amplification of neuroblastoma derived (avian) v-myc myelocytomatosis viral related oncogene (MYCN) is an important risk-stratified indicator in neuroblastoma. To evaluate the feasibility of noninvasive measurement of MYCN amplification, we analyzed MYCN amplification in stored blood plasma samples.

Methods

We used quantitative real-time PCR to determine MYCN copy numbers in plasma-derived DNA of 10 healthy volunteers and 50 neuroblastoma cases. The copy number was calculated as the ratio of copies of MYCN to those of a reference gene. Plasma samples obtained after surgery or neoadjuvant therapy were also analyzed in five cases and four cases, respectively.

Results

In 34 neuroblastoma cases, MYCN was non-amplified in both tumor tissue and blood plasma. In 16 neuroblastoma cases, MYCN was amplified in both tumor tissue and blood plasma; 13 of the 16 cases showed poor outcomes. MYCN amplification was undetectable in blood plasma shortly after surgery or neoadjuvant therapy. The correlation coefficient between MYCN copy numbers in tumor tissue and in blood plasma was approximately 0.9.

Conclusion

We can detect MYCN amplification of tumor tissue noninvasively and quantitatively by measuring the MYCN copy number in blood plasma. Determination of MYCN copy number in plasma may be useful when evaluating surgery and neoadjuvant chemotherapy.     

Low NDRG1 mRNA expression predicts a poor prognosis in neuroblastoma patients

Purpose

N-myc downstream regulated gene 1 (NDRG1) markedly reduces metastasis of numerous tumors. However, NDRG1’s function in malignant tumors has not been fully determined. Therefore, we investigated the association of NDRG1 expression with clinical outcomes in neuroblastoma (NB) patients.

Methods

We obtained total RNA from residual cancer cells using microdissection from NB patients. Furthermore, we examined the expression of NDRG1 in NB patients using immunohistochemical staining.

Results

Of the 48 patients observed, low NDRG1 expression was associated with poor prognostic factors such as primary tumor size and MYCN amplification. Low expression of NDRG1 was associated with a poor prognosis (p = 0.001) and multivariate analysis identified low expression of NDRG1 as an independent risk factor for predicting poor prognosis in NB patients. Furthermore, in the MYCN non-amplification group (n = 33), low expression of NDRG1 was associated with a poor prognosis (p = 0.001). Immunohistochemical analysis showed NDRG1 expression at the plasma membranes of NB cells. NDRG1 expression levels were also correlated with expression of NDRG1 mRNA.

Conclusion

We confirmed that low NDRG1 expression is a significant and independent prognostic indicator in NB by multivariate analysis. Furthermore, NDRG1 may be a novel prognostic marker in MYCN non-amplification NB patients.     

Invariant natural killer T infiltration in neuroblastoma with favorable outcome

Background

Tumor immunity has been suggested to play a key role in clinical and biological behavior of neuroblastomas. Given that CD1-restricted invariant natural killer T (iNKT) cells enhance both innate and acquired tumor immunity, we investigated the expression of the iNKT-cell-specific T-cell receptor Vα24-Jα18 in neuroblastoma tissues and its correlation with clinical and biological characteristics.

Methods

Using real- time quantitative PCR, we quantified the expression of Vα24-Jα18 in untreated tumor samples from 107 neuroblastoma cases followed in our institution and analyzed the correlation between the presence of infiltrated iNKT cells and clinical characteristics or patients’ outcome.

Results

Vα24-Jα18 receptor was detected in 62 untreated cases (57.9%). The expression was significantly higher in stages 1, 2, 3, or 4S (P?=?0.0099), in tumors with low or intermediate risk (P?=?0.0050), with high TrkA expression (P?=?0.0229), with favorable histology (P?=?0.0026), with aneuploidy (P?=?0.0348), and in younger patients (P?=?0.0036). The overall survival rate was significantly higher in patients with iNKT-cell infiltration (log-rank; P?=?0.0089).

Conclusions

Since tumor-infiltrating iNKT cells were predominantly observed in neuroblastomas undergoing spontaneous differentiation and/or regression, we suggest that iNKT cells might play a key role in these processes.

     

In vitro CO2-induced ROS production impairs cell cycle in SH-SY5Y neuroblastoma cells

Purpose

We evaluated in vitro the role of CO₂-induced oxidative stress on the expression of proteins involved in cell-cycle regulation of neuroblastoma cells.

Methods

SH-SY5Y cells were exposed to CO₂ at 15 mmHg pressure (100 %) for 4 h and then moved to normal condition for 24 h. Control cells were maintained in 5 % CO₂ for the same time. ROS production was determined by fluorescent staining with H2DCF-DA. DNA damage was measured by COMET assay. p53 protein expression was analyzed by western blot and confocal laser scanning microscopy was used to evaluate its sub-cellular localization. Cyclin expression was quantified by real-time PCR and western blot. Cell-cycle analysis was performed by FACS.

Results

CO₂ incubation was associated with an increase in ROS production (p < 0.01), cell DNA damage mainly after 24 h (12 % increase of tail DNA content and 4-fold increase of tail length) and a significant up-regulation in p53 expression at 24 h with an intense nuclear staining. In CO₂-treated cells, we observed an S-phase arrest in correlation with a reduction of cyclin B1 expression.

Conclusions

In vitro-simulated pneumoperitoneum environment with CO₂ induces oxidative stress and cell DNA damage, leading to p53 up-regulation involved in cell-cycle arrest of neuroblastoma cells.     

Histological features of primary tumors after induction or high-dose chemotherapy in high-risk neuroblastoma

Purpose

In the recent years in Japan, an increasing number of patients with neuroblastoma (NB) are being treated by the “delayed local treatment (DL)” policy, undergoing surgery after the completion of high-dose chemotherapy with hematopoietic stem cell rescue (HDC). We reviewed the histopathological findings of second-look operations, including those of patients treated with DL.

Patients

From 1998 to 2013, 26 patients with high-risk NB underwent radical operation following chemotherapy. Surgery was performed after induction chemotherapy in 17 cases (standard; STD), whereas 9 cases completed induction chemotherapy and HDC before undergoing tumor resection (DL). The amount of necrosis and the degree of differentiation within the post-treatment tumor were assessed.

Results

Eighty-eight percent of the tumors showed necrosis in more than 1/3 of the specimen. Two DL cases showed complete disappearance of viable tumor cells. Amount of necrosis did not affect the prognosis of the patient. Tumors with immature, poorly differentiated phenotypes showed an extremely aggressive thereafter. Though not statistically proven, ¹²³I-MIBG (metaiodobenzylguanidine) uptake may be correlated with the amount of viable cells remaining within the tumor, but not with the degree of differentiation.

Conclusions

Our results support the previous reports advocating that tumors that sustain unfavorable histology after chemotherapy behave aggressively thereafter.     

Influence of hypoxia-dependent factors on the progression of neuroblastoma

Purpose

Several oxygen-dependent factors, e.g., CAIX (carbonic anhydrase IX) or phosphoglycerate kinase 1 (PGK1) interacting with the CXCR4/SDF1 axis (chemokine receptor 4/stromal cell derived factor 1) have been shown to be involved in processes of tumour pathology including tumourigenicity, tumour cell dissemination and poor survival in several solid tumour entities. The aim of the current study was to evaluate the influence of the hypoxia-inducible factors CAIX and PGK1 on progression of neuroblastoma and to evaluate the clinical relevance of possible therapeutic approaches.

Methods

Expression of hypoxia-dependent factors PGK1 and CAIX was examined in neuroblastoma specimen, was correlated with clinical parameters, and was studied in neuroblastoma cells. The impact of these hypoxic factors was evaluated by proliferation assays under targeted therapy.

Results

Expression of hypoxia-dependent factors was found in 50 % of neuroblastoma specimen. In neuroblastoma cells, CAIX and PGK1 expression is up regulated under hypoxia and correlates with response to targeted anti-proliferative treatment. The negative impact on survival, although significant for both CAIX and PGk1, appears to be stronger for CAIX.

Conclusions

Our results show that the hypoxic factors in the tumour`s microenvironment further the progression of tumour disease. This strengthens the perspectives for additive novel therapeutic approaches targeting hypoxia-dependent factors in this childhood disease.

     

Assessment of fine needle aspiration cytology samples for molecular genetic analysis in neuroblastoma

Purpose

To assess the utility of fine needle aspiration cytology (FNAC) samples for molecular genetic analysis of neuroblastoma.

Methods

The case files from the pediatric solid tumor clinic were reviewed to identify 20 neuroblastoma patients whose pre-treatment FNAC slides were preserved in the cytology laboratory. The FNAC slides were destained, air dried and hybridisation with fluorescence in situ hybridisation (FISH) probes was performed as per protocol. All slides were screened and analyzed carefully under the fluorescent microscope. Over four-fold increase of the N-myc signal numbers was defined as N-myc amplification. Focal occurrence of cells (at least 50) showing N-myc amplification surrounded by non-amplified tumor cells was defined as focal N-myc amplification. Presence of three or more signals for the long arm of chromosome 17 was defined as 17q gain.

Results

FISH analysis gave informative results for all the FNAC smears in our study. FISH analysis of FNAC smears showed N-myc amplification in 5 (25 %) out of 20 patients and 15 (75 %) showed normal N-myc copy number. Three out of these five patients had homogenous amplification and two patients had focal N-myc amplification, indicating tumor heterogeneity. On investigation of chromosome 17q status, 5 (25 %) out of 20 patients demonstrated gain of 17q and 15 (75 %) patients showed normal 17q status. Four out of the five patients with 17q gain also showed N-myc amplification.

Conclusions

The current study indicates that FNAC is a rapid and atraumatic diagnostic method for neuroblastoma which provides sufficient material for molecular genetic analyses by means of FISH.     

Thalidomide potentiates etoposide-induced apoptosis in murine neuroblastoma through suppression of NF-κB activation

Purpose

Treatment for high-risk neuroblastoma is still challenging. The purpose of the present study was to determine whether thalidomide suppresses etoposide-induced NF-κB activation and thus potentiates apoptosis in murine neuroblastoma.

Methods

A murine neuroblastoma cell line, C1300, and A/J mice were used in this study. We evaluated NF-κB activation after using etoposide with or without thalidomide by quantitative analysis of NF-κB by ELISA and by Western blot analysis of IκB phosphorylation in vitro and in vivo. Induction of apoptosis was evaluated by Western blot analysis of the apoptotic signals caspase-3, 8, and 9 in vitro and by TUNEL assays in vivo. We also evaluated the efficacy of the combination of etoposide and thalidomide by assessing tumor growth and mouse survival in vivo.

Results

Etoposide activated NF-κB in C1300 cells. This activation was suppressed by thalidomide and IκB was re-upregulated. The apoptotic signals were enhanced by the combination of thalidomide and etoposide compared with etoposide alone in vitro, which was consistent with TUNEL assays. The combination of etoposide and thalidomide also slowed tumor growth and mouse survival.

Conclusion

Thalidomide potentiates etoposide-induced apoptosis in murine neuroblastoma by suppressing NF-κB.

     

Farnesyltransferaseinhibitoren

Methods and results

Molecular genetic alterations in neuroblastomas are interesting targets for the development of new therapeutic strategies (gene targeting). In neuroblastoma cell lines, autocrine growth stimulation by the brain-derived neurotrophic factor (BDNF) and the insulin-like growth factor (IGF-II) was observed. It was recently shown that signal transduction of the receptors of these growth factors was disrupted by inactivation of Ras proteins. By inhibition of farnesyltransferase for 4 days Ras proteins were inactivated in neuroblastoma cells by about 40%. In the treated cells, activation of MAP kinase, induction of N-myc expression, and proliferation were clearly reduced.

Discussion

Farnesyltransferase inhibitors are active against neuroblastoma cells. Phase I and phase II trials with other tumors showed low overall toxicity of farnesyltransferase inhibitors. Clinical tests of farnesyltransferase inhibitors with neuroblastoma patients may lead to an improvement of their survival.     

Dynamic pathology for circulating free DNA in a dextran sodium sulfate colitis mouse model

Purpose

In sepsis, circulating free DNA (cf-DNA) is increased, and is a marker of severity and prognosis of septic patients. This study aimed to evaluate cf-DNA in a dextran sodium sulfate-induced colitis mouse model, and its clinical implications.

Methods

Dynamic pathology of the cecum wall in the DSS-induced colitis mouse model was analyzed using multiphoton microscopy (MPM). Plasma cf-DNA concentrations in colitis mouse were quantified using PicoGreen dsDNA Assay Kit. Plasma cf-DNA was also measured in 123 human ulcerative colitis (UC) patients [mean age: 35.9 years (3–75 years) with 20 pediatric patients] to assess its relationships with clinical severity and Matt’s grade.

Results

Real-time images of cf-DNA were detected in the colitis model. The amount of labeled cf-DNA in the circulation of the colitis mice group was significantly higher compared with that in the control group (P < 0.05). In human UC blood samples, plasma cf-DNA concentrations in UC patients were significantly positively correlated with the clinical severity of UC and Matt’s grade (P < 0.05, P < 0.05, respectively).

Conclusions

Using MPM, we observed and analyzed real-time images of cf-DNA in a colitis mouse model. Plasma cf-DNA is a potential non-invasive blood marker for reflecting clinical severity and mucosal damage in UC patients.     

Comparison of long-term prognosis of laparoscopic and open adrenalectomy for local adrenal neuroblastoma in children

Objective

To investigate and compare long-term outcomes in children undergoing laparoscopic or open adrenalectomy for local adrenal neuroblastoma.

Methods

A retrospective review was conducted of 37 children with local adrenal neuroblastoma treated between January 2005 and December 2013 in our hospital. These patients met inclusion criteria for having adrenal neuroblastoma and undergoing operative resection. All patients were successfully followed up until December 2017.

Results

The local adrenal neuroblastoma cases included 25 males and 12 females with an average age of 37.24?±?37.55 months (range from 5 days to 158 months). Left adrenal lesions were present in 13 cases, the right in 24 cases. According to the INSS staging system, 27 patients were classified as stage I and 10 as stage II. Open adrenalectomy was performed in 24 patients. Laparoscopic adrenalectomy was performed in the other 13 patients, 2 of whom were converted to open surgery because of adhesions to renal vessels and diaphragmatic rupture. Significant differences were observed between the laparoscopic surgery and open surgery groups regarding tumor size (P?=?0.005). There were two recurrence cases in open surgery, but there was no recurrence in laparoscopic surgery. The average follow-up time was 86.78?±?24.52 months. The overall 5-year survival rate of open and laparoscopic surgery were 86.2 and 100% (P?=?0.316).

Conclusions

Laparoscopic adrenalectomy for neuroblastoma is feasible and can be performed with equivalent recurrence and mortality rates with open resection. For small tumor size and absence of vascular encasement, the adrenal neuroblastoma may be preferred laparoscopic surgery.

     

Carbon dioxide modifies the morphology and function of mesothelial cells and facilitates transepithelial neuroblastoma cell migration

Background

The response of mesothelial cells to surgical trauma and bacterial contamination is poorly defined. We have recently shown that CO₂ pneumoperitoneum increases systemic metastasis of neuroblastoma cells in a murine model. Thus, we hypothesized that CO₂ alters the morphology and function of mesothelial cells and facilitates transmesothelial tumor cell migration.

Materials and methods

Murine mesothelial cells were exposed to 100% CO₂ and 5% CO₂ as control. Scanning electron microscopy (SEM) investigations, as well as LPS-induced granulocyte-colony stimulating factor (G-CSF) production and mitochondrial activity (MTT assay) were measured. Transmesothelial migration of neuroblastoma cells (Neuro2a) was determined using a transwell chamber system.

Results

CO₂ incubation was associated with a significant destruction of the microvillar formation in SEM. Migration studies showed that the barrier function of the mesothelial monolayer decreased. A significantly increased migration of neuroblastoma cells was identified after 100% CO₂ exposure (P < 0.05). Although the conversion of MTT as an indicator of mitochondrial activity was only slightly and not significantly reduced after CO₂ incubation, the release of G-CSF induced by LPS was completely blocked during the incubation with 100% CO₂ (P < 0.05). The capacity of G-CSF release recovered after the incubation.

Conclusion

We observed that peritoneal mesothelial cells lose their typical cell morphology by CO₂ incubation, which is accompanied by facilitated migration of neuroblastoma cells. Moreover, the synthesis of immunological factors is blocked, but this effect is not long lasting. These mechanisms may explain an increased metastasis rate of neuroblastoma cells after CO₂ pneumoperitoneum, which was recently observed in a murine model.     

Outcome of Neuroblastoma in India

Objectives

To assess the outcome of childhood neuroblastoma in India over the last 2 decades, identify management lacunae and suggest remedial measures.

Methods

A comprehensive search to identify literature addressing outcome of childhood neuroblastoma from India was performed. International Society of Paediatric Oncology and American Society of Clinical Oncology Annual-Meeting abstracts were hand searched to identify unpublished data. Clinico-demographic and outcome data was extracted.

Results

Outcome of approximately 700 patients has been published over the last 2 decades with predominantly small to moderate single center series from 6 cities. Primarily non-myeloablative multiagent chemotherapy protocols alongwith surgery, have been used for treatment. A large majority of patients had stage III/IV neuroblastoma. Limited diagnostic facilities were available at most centers. Survival outcome of 8.7 to 80 % has been reported with high death and relapse rates alongwith high incomplete control/disease progression and treatment abandonment. Few series have identified prognostic parameters. Few patients with high-risk disease have been adequately treated and cured.

Conclusions

There is a clear need for replicating neuroblastoma outcomes at centers of excellence in other cancer centers, improving diagnostic and laboratory facilities, administering adequate and appropriate contemporary therapy, assessing disease response and improving supportive care. National data management infrastructure along with better financial and social support initiatives are key factors.     

Outcomes and complications of surgery in patients with intermediate-risk neuroblastoma: experience from an Indian tertiary Cancer Centre

Purpose

The treatment of intermediate risk (IR) neuroblastoma has evolved with the focus now on reducing the drugs, dosage, and duration of chemotherapy. The aim of this study is to present the outcomes of treatment and the complications of surgery in patients with IR neuroblastoma treated at a tertiary cancer center in India.

Methods

All eligible patients with IR neuroblastoma treated between April 2005 and August 2016 were identified. The presence and number of image-defined risk factors (IDRF) before and after neoadjuvant chemotherapy were retrospectively analyzed as were the extent of surgery, complications, and outcomes.

Results

Of 282 neuroblastoma patients treated during the study period, 54 had IR neuroblastoma. Complete excision was achieved in 25 patients. There were 26 surgical complications in 22 patients with a similar incidence in patients with complete (n?=?13) or incomplete (n?=?13) resection (p?=?0.78). After a median follow-up of 47 months, the 4-year overall and event-free survival was 91.5% and 75%, respectively. There was no difference in survival between patients who underwent complete resection versus those with incomplete resection (p?=?0.9).

Conclusion

Outcomes of IR neuroblastoma are favorable. The extent of resection does not affect the survival and complications can occur even when the resection is incomplete.

     

Glypican-3 mRNA expression level in Wilms tumor: correlation with histological type,stage, and outcome

Purpose

To correlate expression of Glypican-3 in Wilms tumor with histopathology, stage, and outcome.

Methods

Glypican-3 mRNA expression by real-time PCR on tumor and normal germline samples from 75 fresh nephrectomies for Wilms tumor with fold change after normalization against GAPDH was compared. Survival analysis for event-free and overall survival (EFS, OS) with 2-year follow-up for Glypican-3 overexpression (>1.5 times) and clinicopathological parameters was performed.

Results

Glypican-3 was overexpressed in 37/75 (49.3%). It was overexpressed in 77% (10/13) cases with blastema predominance or anaplastic histology, as compared to 44% of other histologies (27/62) (p = 0.03). OS was 73 and 93%, respectively (p = 0.016), for those with and without GPC-3 overexpression. EFS was not significantly different with Glypican-3 overexpression (p = 0.11). All 5 deaths among blastema predominant tumors and 4/5 deaths among triphasic tumors had overexpressed Glypican-3. Most deaths in Stage IV, Stage III, and Stage I + II (5/7, 3/3, 1/1) had GPC-3 overexpression. On multivariate analysis, only histology and stage were found to have independent prognostic value.

Conclusion

Glypican-3 overexpression in Wilms tumor correlates with poor OS on univariate analysis. However, only histology and stage have independent prognostic value. Glypican-3 levels may help to stratify intermediate outcome histology (triphasic) and Stage III Wilms tumors.

     

The roles of microRNAs in neuroblastoma

Background

Neuroblastoma (NB) is the most common extracranial solid tumor in childhood and displays remarkable heterogeneity in clinical behaviors, ranging from spontaneous regression to rapid progression or resistance to multimodal treatment. Recent evidence has shown that microRNAs (miRNAs), a class of small non-coding RNAs, are involved in tumor development and progression. This article aimed to review recent advances in investigating the roles of miRNAs in NB.

Methods

We searched the PubMed/MEDLINE database for articles about the expression profile, functions and target genes of miRNAs in NB.

Results

We reviewed the most recent evidence regarding the functional roles of oncogenic and tumor suppressive miRNAs in NB and application of novel miRNA-based methods for diagnostic, prognostic and therapeutic purposes.

Conclusions

Deregulation of miRNAs is associated with the development and progression of NB, suggesting that miRNAs may serve as novel targets for the treatment of high-risk NB patients. However, their precise functions and underlying mechanisms still warrant further studies.     

What is the result: chylous leakage following extensive radical surgery of neuroblastoma

Background

Postoperative chylous leakage is a rare complication that results from disruption of either mediastinal or retroperitoneal lymphatic channels during dissection or from obstruction by original lesions such as a malignancy. There is lack of clinical experience in pediatric patients about how to manage the leakage and what the result will be.

Methods

We retrospectively analyzed the clinical outcomes of 5 children with neuroblastoma (NB) (stage 4 in 4 children and stage 1?C2 in 1 child) who had received non-surgical treatment of chylothorax and/or chylous ascites after retroperitoneal/posterior mediastinal extensive radical resection of NB for complete tumor removal. Conservative therapy with low-fat diet, mediumchain triglyceride and/or total parenteral nutrition was the mainstay treatment for chylous leakage.

Results

Four of the 5 children recovered after 6?C32 days of conservative treatment, and the last one who did not respond was cured by surgical management for chylous fistula 45 days after primary surgery. Postoperative imaging showed that more than 90% of tumors were resected and all of them showed very good partial remission (VGPR). Among the 4 patients in stage 4, 3 relapsed after radical resection of NB. The patient of stage 1?C2 was still in VGPR.

Conclusions

The majority of patients with chylous ascites/chylothorax after extensive radical surgery for posterior mediastinum/retroperitoneum NB could be cured by non-surgical treatment. But the final result of original disease has not been greatly changed by intensive surgery for stage 4 NB.     

How specific is the MRI appearance of supratentorial atypical teratoid rhabdoid tumors?

Background

Supratentorial atypical teratoid rhabdoid tumor (ATRT) in many cases has a distinctive appearance on post-gadolinium MRI.

Objective

We sought to determine whether this is a unique appearance allowing ATRT to be distinguished accurately from other types of pediatric supratentorial tumors.

Materials and methods

Retrospective review of all available preoperative MRI of pediatric supratentorial tumors at two tertiary children’s hospitals, and systematic literature review of case series and reports describing the MRI imaging appearances of supratentorial ATRT.

Results

We had 61 supratentorial tumors, including 32 gliomas, 6 ATRT, 8 ependymomas, 6 gangliogliomas, 2 pilomyxoid astrocytomas, 3 primitive neuro-ectodermal tumors, 2 choroid plexus papillomas, and 2 meningiomas. ATRT presented in significantly younger patients than astrocytomas (mean age 2.6 years vs. 9.9 years, P?<?0.05). The visual pattern of a thick, wavy (irregular) heterogeneously enhancing wall around a cystic center was seen in 5/6 (83%) ATRTs and only 3/55 (5.4%) other tumors (P?<?0.0001), for specificity of 95%, sensitivity of 83%, positive predictive value of 63% and a negative predictive value of 95%.

Conclusion

A supratentorial tumor with a thick, wavy (irregular) heterogeneously enhancing wall surrounding a central cystic region is suggestive of ATRT in the appropriate clinical setting, especially in a child of preschool age.     

Decreased aortic growth and middle aortic syndrome in patients with neuroblastoma after radiation therapy

Background

Long-term CT follow-up studies are required in pediatric patients who have received intraoperative radiation therapy (IORT) and external beam radiation therapy (EBRT) to assess vascular toxicities and to determine the exact complication rate.

Objective

To analyze with CT the effects of radiation therapy (RT) on the growth of the aorta in neuroblastoma patients.

Materials and methods

Abdominal CT scans of 31 patients with intraabdominal neuroblastoma (stage II–IV), treated with RT (20 IORT±EBRT, 11 EBRT alone), were analyzed retrospectively. The diameter of the abdominal aorta was measured before and after RT. These data were compared to normal and predicted normal aortic diameters of children, according to the model of Fitzgerald, Donaldson and Poznanski (aortic diameter in centimeters?=?0.844?+?0.0599?×?age in years), and to the diameters of a control group of children who had not undergone RT. Statistical analyses for the primary aims were performed using the chi-squared test, t-test, Mann-Whitney test, nonparametric Wilcoxon matched-pairs test and analysis of variance for repeated measures. Clinical files and imaging studies were evaluated for signs of late vascular complications of neuroblastoma patients who had received RT.

Results

The mean diameter before and after RT and the growth of the aorta were significantly lower than expected in patients with neuroblastoma (P<0.05 for each) and when compared to the growth in a control group with normal and nonirradiated aortas. Among the patients who had received RT, there was no difference due to the type of RT. Seven patients from the IORT±EBRT group developed vascular complications, which included hypertension (five), middle aortic syndrome (two), death due to mesenteric ischemia (one) and critical aortic stenosis, which required aortic bypass surgery (two).

Conclusion

Patients with neuroblastoma who had received RT showed impaired growth of the abdominal aorta. Significant long-term vascular complications occurred in seven patients who received IORT±EBRT. Thus, CT evaluation of patients with neuroblastoma who receive RT should include not only reports of changes in tumor extension, but also documentation of perfusion, and the size and growth of the aorta and its branches over time.