The significance of serial histopathology in a residual mass for outcome of intermediate risk stage 3 neuroblastoma

Modern surgical strategies in pediatric neuroblastoma: Evolving approaches and treatment principles

Neuroblastoma, the most common extracranial solid tumor in children under the age of 5, has been described as early as the 19th century, and its complexity has continued to intrigue researchers, as well as medical and surgical specialists. At one end of the phenotypic spectrum, neuroblastoma is self-limiting with minimal to no intervention required, while on the opposite end exists the challenge of refractory disease despite aggressive management and toxic systemic treatments. The goal of this review is to describe a comprehensive surgical perspective and contemporary approach to neuroblastoma.

The prognostic role of 18F-FDG PET/CT-based response evaluation in children with stage 4 neuroblastoma

OBJECTIVES

To evaluate the association between metabolic response on 18F-FDG PET/CT and long-term survival in children with neuroblastoma (NB).

METHODS

A total of 39 consecutive children with newly diagnosed stage 4 NB undergoing both 18F-FDG PET/CT imaging at baseline and after chemotherapy were retrospectively analyzed. The associations between metabolic parameters, including SUVmax of the lesion with the most intense 18F-FDG uptake at baseline (SUVb), after chemotherapy (SUVe), and the percentage change between SUVb and SUVe, and long-term survival were evaluated.

RESULTS

With a median follow-up of 56 months, 22 patients who had achieved complete resolution on PET (no residual 18F-FDG uptake higher than the surrounding backgrounds) after chemotherapy had superior 5-year overall survival (OS) (73.6% vs. 39.0%, p = 0.044). SUVb > 6.9 indicated significantly poorer 5-year event-free survival (EFS) (12.5% vs. 59.3%, p = 0.005), as did SUVe > 1.2 (18.8% vs. 41.7%, p = 0.041). Children with SUVe > 1.2 had shorter 5-year OS (33.9% vs. 75.0%, p = 0.018). Multivariate analysis identified SUVe > 1.2 as an independent predictor for both EFS [hazard ratio (HR), 3.479, 95% CI, 1.381-8.761, p = 0.008] and OS (HR, 6.948, 95% CI, 1.663-29.025, p = 0.008), while SUVb > 6.9 was a predictor for EFS (HR, 2.889, 95% CI, 1.064-7.842, p = 0.037). Among 11 children with both SUVb > 6.9 and SUVe > 1.2, all experienced disease progression or relapse within 2 years since diagnosis.

CONCLUSION

18F-FDG PET/CT could be of useful to evaluate treatment response in children with stage 4 NB.

CLINICAL RELEVANCE STATEMENT

18F-FDG PET/CT after chemotherapy exhibits prognostic significance in neuroblastoma and holds potential as an alternative imaging modality for response evaluation, especially in cases with metaiodobenzylguanidine-nonavid or persistent avid disease.

KEY POINTS

The prognostic value of chemotherapy response on 18F-FDG PET/CT in advanced neuroblastoma is unknown. Higher 18F-FDG uptake after chemotherapy was associated with worse long-term event-free survival and overall survival. 18F-FDG PET/CT after chemotherapy holds prognostic significance in children with stage 4 neuroblastoma.

Dynamic Changes in Microvascular Density Can Predict Viable and Non-Viable Areas in High-Risk Neuroblastoma

Despite aggressive treatments, the prognosis of high-risk NB remains poor. Surgical oncology needs innovative intraoperative devices to help surgeons discriminate malignant tissue from necrotic and surrounding healthy tissues. Changes within the tumor vasculature could be used intraoperatively as a diagnostic tool to guide surgical resection. Here, we retrospectively analyzed the mean vascular density (MVD) of different NB subtypes at diagnosis and after induction chemotherapy using scanned histological samples. One patient was prospectively enrolled, and an ex vivo photoacoustic imaging (PAI) scan was performed on two representative sections to assess its capacity to discriminate different tumor regions. We found that post-chemotherapy, viable areas of differentiating NBs and ganglioneuroblastomas are associated with higher MVD compared to poorly differentiated NBs. Early necrotic regions showed higher MVD than late necrotic and viable regions. Finally, calcified areas showed significantly lower MVD than any other histological component. The acquired PAI images showed a good high-resolution ex vivo 3D delineation of NB margins. Overall, these results suggest that a high-definition preclinical imaging device such as PAI could potentially be exploited to guide surgical resection by identifying different vasculature signatures.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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

Residual meta-iodobenzyl guanidine (MIBG) positivity following therapy for metastatic neuroblastoma: Patient characteristics, imaging, and outcome

BACKGROUND

Meta-iodobenzylguanidine(MIBG) scans are used to detect neuroblastoma metastatic lesions at diagnosis and during posttreatment surveillance. MIBG positivity following induction chemotherapy correlates with poor outcome; however, there are reports of patients with progression-free survival despite MIBG positivity at the end of therapy. The factors distinguishing these survivors from patients who progress or relapse are unclear. FDG-positron-emission tomography (PET) scans can also detect metastatic lesions at diagnosis; however, their role in posttherapy surveillance is less well studied.

METHODS

We performed a retrospective analysis of International Neuroblastoma Staging System (INSS) stage 4 patients to identify those with residual MIBG-avid metastatic lesions on end-of-therapy scans without prior progression. Data collected included age, disease sites, histopathology, biomarkers, treatment, imaging studies, and response.

RESULTS

Eleven of 265 patients met inclusion criteria. At diagnosis three of 11 patients were classified as intermediate and eight of 11 high risk; nine of 11 had documented marrow involvement. Histologic classification was favorable for four of 10 and MYCN amplification was detected in zero of 11 cases. The median time with persistent MIBG positivity following treatment was 1.5 years. Seven patients had at least one PET scan with low or background activity. Biopsies of three of three MIBG-avid residual lesions showed differentiation. All patients remain alive with no disease progression at a median of 4.0 years since end of therapy.

CONCLUSION

Persistently MIBG-avid metastatic lesions in subsets of patients following completion of therapy may not represent active disease that will progress. Further studies are needed to determine whether MYCN status or other biomarkers, and/or PET scans, may help identify patients with residual inactive MIBG lesions who require no further therapy.

Clinical impact of primary tumour 123ImIBG response to induction chemotherapy in children with high-risk neuroblastoma

BACKGROUND

More than 50% children with high-risk neuroblastoma (HR-NBL) experience disease progression, which we hypothesise is due to non-response of primary tumour to treatment. Current imaging techniques are unable to characterise response in primary tumour (necrotic versus viable tissue) at diagnosis or follow-up.

OBJECTIVES

Compare clinico-histological characteristics between primary ¹²³ImIBG-avid tumours that became entirely ¹²³ImIBG-non-avid (responders) after induction chemotherapy (IC) versus primary ¹²³ImIBG-avid tumour that remained ¹²³ImIBG-avid (non-responders).

METHODS

Retrospective review of clinico-radiological data of children diagnosed with ¹²³ImIBG-avid HR-NBL at our centre (2005-2016). Patients received Rapid COJEC IC and two additional courses of TVD if metastatic response was inadequate. Primary tumour ¹²³ImIBG response was assessed qualitatively as positive, negative or intermediate at diagnosis and after IC. Post-surgical histopathology slices were marked considering percentage of viable tissue.

RESULTS

Sixteen of 61 patients showed complete primary tumour ¹²³ImIBG response, 20 partial response, while 25 no response. There was no statistically significant difference between clinical demographics of complete responders and group of non- or partial responders. Mean percentage of viable tumour cells was higher in non-responders than in complete responders (44.6% vs 20.6%; p = 0.05). Five-year EFS was significantly higher in complete responders than non-responders (43 ± 15% vs 7 ± 6%; p < 0.005).

CONCLUSIONS

¹²³ImIBG response in primary HR-NBL correlates with amount of necrotic tissue, skeletal metastatic ¹²³ImIBG response and outcome. An entirely ¹²³ImIBG non-avid tumour can still harbour viable tumour cells. Therefore, our findings do not support utility of primary tumour ¹²³ImIBG response in decision making regarding residual tumour surgery. Combining both, primary and metastatic ¹²³ImIBG response will improve interpretability of clinical trial results.

Nuclear Medicine Imaging in Neuroblastoma: Current Status and New Developments

Neuroblastoma is the most common extracranial solid malignancy in children. At diagnosis, approximately 50% of patients present with metastatic disease. These patients are at high risk for refractory or recurrent disease, which conveys a very poor prognosis. During the past decades, nuclear medicine has been essential for the staging and response assessment of neuroblastoma. Currently, the standard nuclear imaging technique is meta-[¹²³I]iodobenzylguanidine ([¹²³I]mIBG) whole-body scintigraphy, usually combined with single-photon emission computed tomography with computed tomography (SPECT-CT). Nevertheless, 10% of neuroblastomas are mIBG non-avid and [¹²³I]mIBG imaging has relatively low spatial resolution, resulting in limited sensitivity for smaller lesions. More accurate methods to assess full disease extent are needed in order to optimize treatment strategies. Advances in nuclear medicine have led to the introduction of radiotracers compatible for positron emission tomography (PET) imaging in neuroblastoma, such as [¹²⁴I]mIBG, [¹⁸F]mFBG, [¹⁸F]FDG, [⁶⁸Ga]Ga-DOTA peptides, [¹⁸F]F-DOPA, and [¹¹C]mHED. PET has multiple advantages over SPECT, including a superior resolution and whole-body tomographic range. This article reviews the use, characteristics, diagnostic accuracy, advantages, and limitations of current and new tracers for nuclear medicine imaging in neuroblastoma.

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

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

The effect of preoperative chemotherapy on histological subtyping and staging of Wilms tumors: The United Kingdom Children's Cancer Study Group (UKCCSG) Wilms tumor trial 3 (UKW3) experience

BACKGROUND

Two principal approaches to Wilms tumor (WT) treatment are immediate surgery (IS) and preoperative chemotherapy (PCT), and both treatments use the risk-adapted approach that includes histological subclassification of the tumor, combined with additional prognostic factors. In the UKW3 trial, these two approaches were compared. The aim of the present study was to compare histological features between the two groups, to assess the impact of PCT on distribution of histological subtyping and staging and to evaluate whether PCT resulted in more staging discrepancies between local and central pathology review (CPR).

MATERIALS AND METHODS

The cases were identified from the UKW3 trial database. The criteria for inclusion in the study were unilateral, nonmetastatic, nonanaplastic WTs, and submitted for CPR with an adequate number of slides. They were subclassified according to the NWTS and later the SIOP 9301 criteria.

RESULTS

There were 244 WTs in the IS and 182 in the PCT group subclassified as follows: blastemal 86 (35%) vs 9 (5%), epithelial 34 (14%) vs 12 (7%), stromal 12 (5%) vs 25 (14%), mixed 112 (46%) vs 45 (25%), respectively, plus 40% regressive and 10% completely necrotic WTs in the PCT group. The differences between the two groups for blastemal and mixed types were statistically significant. In the PCT group, there was a significant decrease in stage III tumors. The discrepancies in staging between local and CPR were not significant.

CONCLUSION

PCT significantly altered histological features and typing of WTs. It resulted in fewer stage III tumors, and staging discrepancies were equally represented in both groups.

Assessment of renal function in Japanese children with malignancies using serum cystatin C

Several factors besides renal function influence serum cystatin C (CysC) levels. The present study evaluates the value of serum CysC and the equation for CysC based estimated glomerular filtration rate (CysC-eGFR) for Japanese children with malignancies. We collected information at 36 time points from 13 patients aged ≤ 17 years with malignancies. We assessed tumor activity, cell recovery phase after chemotherapy, neutropenia phase, inflammation response and medication with granulocyte-colony stimulating factor, steroid, and levothyroxine as risk factors associated with serum CysC levels. Although no 24-h creatinine clearance (CCr) data collected at 36 time points indicated renal dysfunction, serum CysC levels were above and below the reference values at four and five time points, respectively. The frequency of elevated serum CysC levels was higher in patients without therapy or with stable or progressive disease than among those with a complete or partial response (p = 0.0046). The correlation coefficient between CCr and CysC-eGFR was 0.355 (p = 0.054), but this improved to 0.663 (p = 0.0010) when restricted to patients with a complete or partial response. Levels of serum CysC might become elevated regardless of renal function, and CysC-eGFR might become unpredictable during the active phase of tumors. J. Med. Invest. 65:231-235, August, 2018.

Excellent prognosis of patients with intermediate-risk neuroblastoma and residual tumor postchemotherapy

BACKGROUND/PURPOSE

The prognosis of patients with intermediate-risk neuroblastoma is favorable; therefore, a reduction therapy is desired. However, the long-term prognosis of those with residual tumor is unclear. The aim of this study was to clarify the necessity of residual tumor resection.

METHODS

We retrospectively reviewed the records of patients diagnosed with intermediate-risk neuroblastoma who either were treated by chemotherapy only (nonresection group; n=16), or received postchemotherapy tumor resection (resection group; n=9).

RESULTS

In the nonresection group, tumor size decreased in 14 patients; 5 had no detectable local tumor at the end of the follow-up period. Tumor size increased in 2 patients 1.5-2.5years postchemotherapy. Both patients received additional treatment and survived. All patients survived during the median follow-up time of 127months. In the resection group, 5 patients received complete resections and 4 patients received nearly complete resections. All patients survived during the median follow-up time of 84months. In 8 out of 9 resected tumors, regression or maturation was pathologically induced by chemotherapy-only treatment.

CONCLUSION

Patients with intermediate-risk neuroblastoma with or without postchemotherapy residual tumor resection had an excellent long-term outcome. The tumor pathology with intermediate-risk neuroblastoma might be susceptible to change to regression or maturation by chemotherapy.

LEVEL OF EVIDENCE

IV.

Role of surgery in localized initially unresectable neuroblastoma

PURPOSE

Evaluating the role of surgery and the extent of tumor resection on the outcome of patients with localized initially unresectable neuroblastoma (NB).

PATIENTS AND METHODS

This was a retrospective case review study including patients with localized initially unresectable NB. The primary tumor was considered unresectable according to imaging defined risk factors (IDRFs). Surgical resection was attempted after four to six courses of chemotherapy. The extent of resection was classified as follows: ≥90% resection, incomplete resection (50-90%) and cases with <50% resection or just a biopsy. Survival analysis was performed using an intention-to-treat approach.

RESULTS

A total of 202 patients with NB were included. Surgical resection was done in 106 patients. It was ≥90% in 89 patients (83.9%). Surgical resection was not performed in 96 patients (47.5%). Fifty-five (57.2%) were in good response after primary chemotherapy and 41 patients (42.7%) had persisting IDRFs, nine of them had biopsy only, and a follow-up strategy was considered in the other 32 patients. The overall 5-year event-free survival (EFS) and overall survival (OS) were 89.1 ± 2.4% and 94.9 ± 1.7%, respectively, with significantly better OS and EFS for patients who had resection versus no resection (p = 0.003 and 0.04, respectively). There was no impact of extent of resection on EFS and OS in the whole group (p = 0.91, p = 0.9) and in subgroup analysis stratified by site, histology, and age of the patients.

CONCLUSION

In children with localized initially unresectable NB, surgical resection was the only significant risk factor associated with better survival. The extent of tumor resection had no impact on EFS and OS. The concept of accepting incomplete resection to avoid serious complications was successful.

Usefulness of fluorodeoxyglucose positron emission tomography/computed tomography for detection of a neuroblastic nodule in a ganglioneuroblastoma: a case report

Background

Ganglioneuroblastoma, nodular is defined as a composite tumor of biologically distinct clones. The peripheral neuroblastic tumors in this category are characterized by the presence of grossly visible neuroblastoma nodules coexisting with ganglioneuroblastoma, intermixed, or with ganglioneuroma. Making a correct diagnosis of ganglioneuroblastoma, nodular is often difficult by biopsy or partial tumor resection, because the neuroblastic nodule could be hidden and not sampled for pathological examination.

Case presentation

We report a case of a Japanese boy aged 3 years, 8 months, with an unresectable abdominal tumor and elevated vanillylmandelic acid and homovanillic acid levels. The initial biopsy was ganglioneuroma. However, after the second biopsy from a hidden neuroblastoma nodule that was clearly highlighted by fluorodeoxyglucose positron emission tomography/computed tomography, we reached the diagnosis of ganglioneuroblastoma, nodular. Because the nodule demonstrated neuroblastoma, differentiating subtype, with a low mitosis-karyorrhexis index (favorable histology) and nonamplified MYCN, the boy was treated according to the intermediate-risk protocol and is now alive and well 4 years after the diagnosis.

Conclusions

This case illustrates the critical role of fluorodeoxyglucose positron emission tomography/computed tomography for detecting a neuroblastoma nodule in a ganglioneuroblastoma.

Neuroblastoma: clinical and biological approach to risk stratification and treatment

Neuroblastoma is the most common extra-cranial solid tumor of childhood and the most common in the first year of life. It is a unique malignancy in that infants often present with either localized or metastatic disease that can spontaneously regress without intervention while older children can succumb to the disease after months to years of arduous therapy. Given this wide range of outcomes, the International Neuroblastoma Risk Group was created to stratify patients based on presenting characteristics and tumor biology in order to guide intensity of treatment strategies. The goal has been to decrease therapy for low-risk patients to avoid long-term complications while augmenting and targeting therapies for high-risk patients to improve overall survival. The international risk stratification depends on age, stage, histology, MYCN gene amplification status, tumor cell ploidy and segmental chromosomal abnormalities. Treatment for asymptomatic low-risk patients with an estimated survival of > 98% is often observation or surgical resection alone, whereas intermediate-risk patients with an estimated survival of > 90% require moderate doses of response-adjusted chemotherapy along with resection. High-risk patients undergo multiple cycles of combination chemotherapy before surgery, followed by consolidation with myeloablative autologous hematopoietic stem cell transplantation and local radiation and finally immunotherapy with differentiation therapy as maintenance phase. With this approach, outcome for patients with neuroblastoma has improved, as the field continues to expand efforts in more targeted therapies for high-risk patients.

Revisions to the International Neuroblastoma Response Criteria: A Consensus Statement From the National Cancer Institute Clinical Trials Planning Meeting

Purpose More than two decades ago, an international working group established the International Neuroblastoma Response Criteria (INRC) to assess treatment response in children with neuroblastoma. However, this system requires modification to incorporate modern imaging techniques and new methods for quantifying bone marrow disease that were not previously widely available. The National Cancer Institute sponsored a clinical trials planning meeting in 2012 to update and refine response criteria for patients with neuroblastoma. Methods Multidisciplinary investigators from 13 countries reviewed data from published trials performed through cooperative groups, consortia, and single institutions. Data from both prospective and retrospective trials were used to refine the INRC. Monthly international conference calls were held from 2011 to 2015, and consensus was reached through review by working group leadership and the National Cancer Institute Clinical Trials Planning Meeting leadership council. Results Overall response in the revised INRC will integrate tumor response in the primary tumor, soft tissue and bone metastases, and bone marrow. Primary and metastatic soft tissue sites will be assessed using Response Evaluation Criteria in Solid Tumors (RECIST) and iodine-123 (123I) -metaiodobenzylguanidine (MIBG) scans or [18F]fluorodeoxyglucose-positron emission tomography scans if the tumor is MIBG nonavid. 123I-MIBG scans, or [18F]fluorodeoxyglucose-positron emission tomography scans for MIBG-nonavid disease, replace technetium-99m diphosphonate bone scintigraphy for osteomedullary metastasis assessment. Bone marrow will be assessed by histology or immunohistochemistry and cytology or immunocytology. Bone marrow with ≤ 5% tumor involvement will be classified as minimal disease. Urinary catecholamine levels will not be included in response assessment. Overall response will be defined as complete response, partial response, minor response, stable disease, or progressive disease. Conclusion These revised criteria will provide a uniform assessment of disease response, improve the interpretability of clinical trial results, and facilitate collaborative trial designs.

Persistent positive metaiodobenzylguanidine scans after autologous peripheral blood stem cell transplantation may indicate maturation of stage 4 neuroblastoma

Metaiodobenzylguanidine (MIBG) scans are sensitive testing tools for neuroblastoma. Persistent positive MIBG scans in patients with stage 3 neuroblastoma have previously been found to indicate maturation rather than regression. We assessed the significance of this finding in stage 4 neuroblastoma in the present study. Fifteen consecutive pediatric patients with stage 4 neuroblastoma treated between 2004 and 2014 at the Kagoshima University Hospital were retrospectively examined. Treatment involved a combination of multiagent chemotherapy, resection, autologous peripheral blood stem cell transplantation (PBSCT), radiotherapy, and maintenance therapy with retinoic acid. The MIBG uptake in each patient during treatment was assessed using a Curie score. The 5-year event-free and overall survival rates in 15 patients were 38.9% and 58.7%, respectively. Four patients with persistent positive MIBG scans who underwent autologous PBSCT but experienced decreased ¹²³I-MIBG uptake during the clinical course survived without progression, and their event-free survival (EFS) was significantly superior to that of patients who showed negative MIBG scans after PBSCT (5-year EFS rate: 18.2%, p = 0.0176). Therefore, persistent positive MIBG scans with gradually decreased uptake after PBSCT do not always indicate neuroblastoma progression, and may instead indicate tumor maturation in some selected cases, if not all cases, of stage 4 neuroblastoma.

Neuroblastoma

Neuroblastoma is the most common extracranial solid tumour occurring in childhood and has a diverse clinical presentation and course depending on the tumour biology. Unique features of these neuroendocrine tumours are the early age of onset, the high frequency of metastatic disease at diagnosis and the tendency for spontaneous regression of tumours in infancy. The most malignant tumours have amplification of the MYCN oncogene (encoding a transcription factor), which is usually associated with poor survival, even in localized disease. Although transgenic mouse models have shown that MYCN overexpression can be a tumour-initiating factor, many other cooperating genes and tumour suppressor genes are still under investigation and might also have a role in tumour development. Segmental chromosome alterations are frequent in neuroblastoma and are associated with worse outcome. The rare familial neuroblastomas are usually associated with germline mutations in ALK, which is mutated in 10-15% of primary tumours, and provides a potential therapeutic target. Risk-stratified therapy has facilitated the reduction of therapy for children with low-risk and intermediate-risk disease. Advances in therapy for patients with high-risk disease include intensive induction chemotherapy and myeloablative chemotherapy, followed by the treatment of minimal residual disease using differentiation therapy and immunotherapy; these have improved 5-year overall survival to 50%. Currently, new approaches targeting the noradrenaline transporter, genetic pathways and the tumour microenvironment hold promise for further improvements in survival and long-term quality of life.

SIOP-PODC adapted risk stratification and treatment guidelines: Recommendations for neuroblastoma in low- and middle-income settings

Neuroblastoma is the most common extracranial solid tumor in childhood in high-income countries (HIC), where consistent treatment approaches based on clinical and tumor biological risk stratification have steadily improved outcomes. However, in low- and middle- income countries (LMIC), suboptimal diagnosis, risk stratification, and treatment may occur due to limited resources and unavailable infrastructure. The clinical practice guidelines outlined in this manuscript are based on current published evidence and expert opinions. Standard risk stratification and treatment explicitly adapted to graduated resource settings can improve outcomes for children with neuroblastoma by reducing preventable toxic death and relapse.

Long-term follow-up results of the observation program for neuroblastoma detected at 6-month mass screening

We conducted an observation program of neuroblastoma in infants, detected by mass screening at 6 months of age; we followed up with them for 15 years. No recurrence was observed after disappearance of tumors, and persistent tumors showed no malignant transformation or metastasis. Histology of the resected tumors showed age-related differentiation.

Progression-free survival of two cases of high-risk neuroblastoma with refractory/relapsed disease following surgery alone

Outcome for the vast majority of high-risk neuroblastoma patients with refractory or relapsed disease is dismal. We report two high-risk patients who remain progression-free for more than 113 and 18 months following the diagnosis of refractory/relapsed disease who were treated with surgery alone. Complete resolution of a refractory thoracic mass and relapsed liver nodules was observed in one patient. The refractory/relapsed disease in the second patient has remained stable. In both cases, the tumor showed histologic evidence of neuroblastoma maturation. These cases demonstrate that refractory/relapsed neuroblastoma is clinically heterogeneous and highlight the need for better biomarkers to optimize patient care.