Criteria for evaluation of disease extent by (123)I-metaiodobenzylguanidine scans in neuroblastoma: a report for the International Neuroblastoma Risk Group (INRG) Task Force

GPOH Guidelines for Diagnosis and First-line Treatment of Patients with Neuroblastic Tumors, update 2025

The clinical course of neuroblastoma is more heterogeneous than any other malignant disease. Many low-risk patients experience regression after limited or even no chemotherapy. However, more than half of high-risk patients die from disease despite intensive multimodal treatment. Precise disease characterization for each patient at diagnosis is key for risk-adapted treatment. The guidelines presented here incorporate results from national and international clinical trials to produce recommendations for diagnosing and treating neuroblastoma patients in German hospitals outside of clinical trials.

Emerging Trends in Neuroblastoma Diagnosis, Therapeutics, and Research

This review explores the current understanding and recent advancements in neuroblastoma, one of the most common extracranial solid pediatric cancers, accounting for ~ 15% of childhood cancer-related mortality. The hallmarks of NBL, including angiogenesis, metastasis, apoptosis resistance, cell cycle dysregulation, drug resistance, and responses to hypoxia and ROS, underscore its complex biology. The tumor microenvironment's significance in disease progression is acknowledged in this study, along with the pivotal role of cancer stem cells in sustaining tumor growth and heterogeneity. A number of molecular signatures are being studied in order to better understand the disease, with many of them serving as targets for the development of new therapeutics. This includes inhibitor therapies for NBL patients, which notably concentrate on ALK signaling, MDM2, PI3K/Akt/mTOR, Wnt, and RAS-MAPK pathways, along with regulators of epigenetic mechanisms. Additionally, this study offers an extensive understanding of the molecular therapies used, such as monoclonal antibodies and CAR-T therapy, focused on both preclinical and clinical studies. Radiation therapy's evolving role and the promise of stem cell transplantation-mediated interventions underscore the dynamic landscape of NBL treatment. This study has also emphasized the recent progress in the field of diagnosis, encompassing the adoption of artificial intelligence and liquid biopsy as a non-intrusive approach for early detection and ongoing monitoring of NBL. Furthermore, the integration of innovative treatment approaches such as CRISPR-Cas9, and cancer stem cell therapy has also been emphasized in this review.

Application of modified Curie and SIOPEN skeleton scoring systems in 18F-AlF-NOTA-octreotide PET/CT for neuroblastoma

OBJECTIVE

The study aimed to explore the role of fluorine-18-aluminum fluoride-1,4,7-triazacyclononane-1,4,7-triacetic acid-octreotide (18F-OC) positron emission tomography/computed tomography (PET/CT) in neuroblastoma (NB) and compared it with Iodine-123 labeled metaiodobenzylguanidine (123I-MIBG) scintigraphy with single photon emission computed tomography/computed tomography (SPECT/CT), as well as to investigate the feasibility of the modified Curie scoring system and International Society of Pediatric Oncology Europe Neuroblastoma (SIOPEN) skeleton scoring system applied in 18F-OC PET/CT.

METHODS

Patients with pathologically confirmed NB underwent 123I-MIBG scintigraphy with SPECT/CT and 18F-OC PET/CT according the standard imaging protocols. The interval between the two imaging techniques ranged from 0 to 22 days (median interval: 9 days). The number of lesions in modified Curie scoring system and SIOPEN skeleton scoring system applied on 123I-MIBG SPECT/CT and 18F-OC PET/CT was compared.

RESULTS

A total of 50 NB patients (male: female = 25:25) with a median age of 62-month-old were enrolled. 123I-MIBG and 18F-OC imaging were positive in 22 patients and negative in 27 patients. 1 patient had positive 18F-OC but negative 123I-MIBG results (p = 1.000). In lesion-based analysis, 18F-OC PET/CT revealed more positive lesions than 123I-MIBG scintigraphy with SPECT/CT (57 vs. 44, p < 0.001), regardless of bone/bone marrow lesions (43 vs. 37, p = 0.031) or soft tissue lesions (14 vs. 7, p = 0.016). The Curie scores of the two imaging techniques showed a significant difference (p = 0.047), whereas no statistic difference for SIOPEN scores (p = 0.688). The Curie and SIOPEN scores were significantly higher in patients with the presence of MYCN amplification or positive bone marrow puncture result (p < 0.05).

CONCLUSION

18F-OC could be used in the evaluation of NB, and the modified Curie scoring system could be used to semi-quantify the disease extent of NB in 18F-OC PET/CT.

The prognostic significance of semi-quantitative metabolic parameters and tumoral metabolic activity based on 123I-MIBG SPECT/CT in pretreatment neuroblastoma patients

PURPOSE

To assess the prognosis predictive value of semi-quantitative metabolic parameters and tumoral metabolic activity based on 123I-meta-iodobenzylguanidine (MIBG) SPECT/CT in pretreatment neuroblastoma (NB) patients.

METHODS

A total of 50 children (25 girls, 25 boys, median age 37 months, range 1-102 months) with newly diagnosed NB, consecutively examined with pretherapeutic 123I-MIBG SPECT/CT between 2018 and 2024, were included in this retrospective study. The semi-quantitative metabolic parameters and activity of primary tumor were measured, including Tmax/Lmax, Tmean/Lmean, Tmax/Lmean, Tmax/Mmax, Tmean/Mmean and asphericity (ASP). The ratio was maximum or mean count of primary tumor, liver and muscle. Clinical data and image-related factors was recorded as well. The outcome endpoint was event-free survival (EFS). Independent predictors were identified through univariate and multivariate logistic regression analyses. Receiver operating characteristic (ROC) and Kaplan Meier analysis with log-rank test for EFS were performed.

RESULTS

Median follow-up was 42 months (range 2.5-74 months; 4 patients showed disease progression/relapse, 7 patients died). The univariate and multivariate Cox regression analysis demonstrated that bone/bone marrow metastasis [95% confidence interval (CI): 1.051, 18.570, p = 0.043], Tmax/Lmax (95% CI: 1.074, 1.459, p = 0.004) and ASP (95% CI: 2.618, 273.477, p = 0.006) were independent predictors of EFS. The Kaplan Meier survival analyses demonstrated that Tmax/Lmax undefined[Formula: see text]]]>6 and ASP [Formula: see text]undefined]]>34% and with bone/bone marrow metastasis had worse outcomes.

CONCLUSION

In this exploratory study, pretherapeutic 123I-MIBG image-derived semi-quantitative metabolic parameters and tumor asphericity provided prognostic value for EFS in NB patients. Tmax/Lmax [Formula: see text]undefined]]>6 and ASP [Formula: see text]undefined]]>34%, along with the presence of bone/bone marrow metastasis, could be considered as supplementary factors alongside existing ones.

A multiparameter diagnostic model based on 2-[18F]FDG PET/CT metabolic parameters and clinical variables can differentiate high-risk and non-high-risk pediatric neuroblastoma under the revised Children's Oncology Group classification system

Background

It is crucial to assist neuroblastoma (NB) pediatric patients in accurate risk stratification based on the revised Children's Oncology Group (COG) classification system through non-invasive examinations. This study assessed the diagnostic efficacy of integrating multiparametric 2-[18F]fluoro-D-glucose positron emission tomography/computed tomography (2-[18F]FDG PET/CT) metabolic parameters with clinical variables to differentiate between high- and non-high-risk pediatric NB according to the revised COG classification system.

Methods

A retrospective study was conducted involving a total of 89 pediatric NB patients, including 71 high-risk and 18 non-high-risk patients, who underwent pre-treatment 2-[18F]FDG PET/CT imaging. All patients were confirmed by pathology, and clinical variables were collected. The metabolic parameters of 2-[18F]FDG PET/CT were evaluated, including maximum standard uptake value (SUVmax), mean standard uptake value (SUVmean), metabolic tumor volume (MTV) and total lesion glycolysis (TLG). The differences in diagnostic efficacy were evaluated by comparing the differences between receiver operating characteristic (ROC) curves. The DeLong test, integrated discrimination improvement (IDI), and net reclassification improvement (NRI) were utilized to assess the enhancement in diagnostic performance. The clinical utility of the diagnostic model was evaluated through decision curve analysis (DCA).

Results

The ROC curve analysis of TLG showed the highest differentiating diagnostic value [sensitivity =0.620, 95% confidence interval (CI): 0.496-0.730; specificity =0.833, 95% CI: 0.577-0.956; area under the curve (AUC) 0.764, 95% CI: 0.648-0.881; cut-off =234.70] among metabolic parameters of 2-[18F]FDG PET/CT. After multivariate forward stepwise logistic regression (LR) analysis, the combined diagnostics model of age, gender, the International Neuroblastoma Risk Group Staging System (INRGSS) stage (L1/L2 vs. M/MS) and TLG resulted in the highest AUC of 0.932 (95% CI: 0.867-0.998; sensitivity =0.901, 95% CI: 0.802-0.956; specificity =0.889, 95% CI: 0.604-0.978). Compared to TLG, the diagnostic efficiency of the model demonstrated a significant improvement [Z=3.089, P<0.001; IDI =0.388, P<0.001; NRI (categorical) =0.736, P<0.001]. The DCA further validated the clinical efficacy of the model.

Conclusions

The multiparameter diagnosis model based on 2-[18F]FDG PET/CT metabolic parameters and clinical parameters had excellent value in the differential diagnosis of high- and non-high-risk pediatric NB under the revised COG classification system.

The value of 123I-MIBG xSPECT/CT quantitative parameters in the diagnosis of bone metastasis in pediatric neuroblastoma patients

Background

The diagnostic value of quantitative single-photon emission computed tomography/computed tomography (xSPECT/CT) in the screening of bone metastases of various malignant tumors varies. This study investigated the differential diagnostic value of quantitative parameters of 123I-metaiodobenzylguanidine (123MIBG) xSPECT/CT imaging in the diagnosis of bone metastasis in pediatric neuroblastoma (NB) patients.

Methods

In this retrospective cohort study, the 123I-MIBG xSPECT/CT images of 125 children with NB confirmed by pathology at Beijing Friendship Hospital from March 2022 to December 2023 were assessed. A Spearman correlation analysis was conducted to assess the factors influencing normal bone quantitative parameters, and differences in the standardized uptake values (SUVs), including the maximum standardized uptake value (SUVmax), average standardized uptake value (SUVavg), minimum standardized uptake value (SUVmin), and peak standardized uptake value (SUVpeak), between metastatic bone lesions and normal bone were compared using the Mann-Whitney U test. Receiver operating characteristic (ROC) curves were used to determine the optimal cut-off values of the SUVs in the diagnosis of metastatic bone lesions. The above indexes were compared via a visual analysis, and using the chi-square test. The clinical parameters and semi-quantitative indexes of xSPECT/CT were also analyzed using univariate and multivariate methods.

Results

The study cohort comprised 75 girls and 50 boys with an average age of 5.94 years (0.6-9 years). The SUVs of metastatic bone lesions were significantly higher than those of normal bone (P<0.0001), but there was no statistically significant difference in the SUV values of metastatic bone lesions among the different Curie score subzones (P>0.05). The area under the curve (AUC) values for the SUVmax, SUVavg, SUVmin, and SUVpeak were 0.946 [95% confidence interval (CI): 0.921-0.971], 0.962 (95% CI: 0.939-0.984), 0.953 (95% CI: 0.928-0.978), and 0.959 (95% CI: 0.936-0.982), respectively (P<0.0001). The optimal diagnostic thresholds identified for the SUVmax, SUVavg, SUVmin, and SUVpeak were 0.39, 0.36, 0.19 and 0.35, respectively. The SUVavg was the best index among the different Curie score subzones, and the specificity of the quantitative analysis in diagnosing bone metastasis in NB patients was better than that of the visual analysis. We also showed that tumor stage and neuron specific enolase (NSE) levels are important factors influencing the diagnosis of bone metastasis. There was no statistically significant difference in the SUV values for normal bone among different physical parameters (P>0.05).

Conclusions

A SUVavg above 0.36 g/mL in NB patients had the best efficacy in the diagnosis of bone metastasis in NB patients. Quantitative indexes of xSPECT/CT had better specificity in the diagnosis of bone metastasis in NB patients than the visual analysis. 123I-MIBG xSPECT/CT imaging can increase the diagnostic confidence of bone metastasis in NB.

Recommendations for the use of nuclear medicine imaging in patients with neuroblastoma

Neuroblastoma (NB) is the most common extracranial solid cancer in children. Despite intensive multimodality treatment, long-term survival of patients with high-risk NB, which comprises more than half of all cases, remains poor. Nuclear medicine is key in diagnosis, staging, response assessment and long-term follow-up of NB. The emergence of novel tracers and the increasing complexity of studies require updated guidelines for nuclear medicine imaging in NB. Standardising diagnostic techniques are essential for improving study comparability and ensuring test quality. This article aims to provide a comprehensive review of NB radionuclide diagnostic imaging, including its characteristics, accuracy, advantages, and limitations. It offers practical recommendations to multidisciplinary teams responsible for treating patients with NB. This review summarises the opinions of leading experts from the Neuroblastoma Spanish Group within the Spanish Society of Paediatric Haematology and Oncology (SEHOP) and the Spanish Society of Nuclear Medicine and Molecular Imaging (SEMNIM).

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.

Radiolabeled Somatostatin Analogs for Cancer Imaging

Somatostatin receptors (SSTR) are expressed by many tumours especially those related to neuro-endocrine origin and molecular functional imaging of SSTR expression using radiolabelled somatostatin analogs have revolutionized imaging of patients with these group of malignancies. Coming a long way from the first radiolabelled somatostatin analog 123I-Tyr-3-octreotide, there has been significant developments in terms of radionuclides used, the ligands and somatostatin derivatives. 111In-Pentetreotide extensively employed for imaging NETs at the beginning has now been replaced by 68Ga-SSA based PET-CT. SSA-PET/CT performs superior to conventional imaging modalities and has evolved in the mainframe for NET imaging. The advantages were multiple: (i) superior spatial resolution of PET versus SPECT, (ii) quantitative capabilities of PET aiding in disease activity and treatment response monitoring with better precision, (iii) shorter scan time and (iv) less patient exposure to radiation. The modality is indicated for staging, detecting the primary in CUP-NETs, restaging, treatment planning (along with FDG: the concept of dual-tracer PET-CT) as well as treatment response evaluation and follow-up of NETs. SSA PET/CT has also been incorporated in the guidelines for imaging of Pheochromocytoma-Paraganglioma, Medullary carcinoma thyroid, Meningioma and Tumor induced osteomalacia. At present, there is rising interest on (a) 18F-labelled SSA, (b) 64Cu-labelled SSA, and (c) somatostatin antagonists. 18F offers excellent imaging properties, 64Cu makes delayed imaging feasible which has implications in dosimetry and SSTR antagonists bind with the SST receptors with high affinity and specificity, providing high contrast images with less background, which can be translated to theranostics effectively. SSTR have been demonstrated in non-neuroendocrine tumours as well in the peer-reviewed literature, with studies demonstrating the potential of SSA PET/CT in Neuroblastoma, Nasopharyngeal carcinoma, carcinoma prostate (neuroendocrine differentiation) and lymphoma. This review will focus on the currently available SSAs and their history, different SPECT/PET agents, SSTR antagonists, comparison between the various imaging tracers, and their utility in both neuroendocrine and non-neuroendocrine tumors.

Comparison of 18 F-MFBG PET/CT and 18 F-FDG PET/CT Images of Metastatic Neuroblastoma

ABSTRACT

Two children with neuroblastoma underwent tumor resection and postoperative chemotherapy. After treatment, they participated in a clinical trial and received 18 F-MFBG and 18 F-FDG PET/CT examinations. Although similar lesions were found in the 2 examinations, the uptake pattern was different. The lymph nodes and bone lesions had intense 18 F-MFBG activity, whereas 18 F-FDG uptake was not very impressive. The uptake of bone marrow by 18 F-MFBG was significantly stronger than that by 18 F-FDG. This case emphasizes that 18 F-MFBG PET/CT is superior to 18 F-FDG PET/CT in detecting the metastases of neuroblastoma.

A nationwide phase II study of delayed local treatment for children with high-risk neuroblastoma: The Japan Children's Cancer Group Neuroblastoma Committee Trial JN-H-11

PURPOSE

Survival rates of patients with high-risk neuroblastoma are unacceptable. A time-intensified treatment strategy with delayed local treatment to control systemic diseases has been developed in Japan. We conducted a nationwide, prospective, single-arm clinical trial with delayed local treatment. This study evaluated the safety and efficacy of delayed surgery to increase treatment intensity.

PATIENTS AND METHODS

Seventy-five patients with high-risk neuroblastoma were enrolled in this study between May 2011 and September 2015. Delayed local treatment consisted of five courses of induction chemotherapy (cisplatin, pirarubicin, vincristine, and cyclophosphamide) and myeloablative high-dose chemotherapy (melphalan, etoposide, and carboplatin), followed by local tumor extirpation with surgery and irradiation. The primary endpoint was progression-free survival (PFS). The secondary endpoints were overall survival (OS), response rate, adverse events, and surgical complications.

RESULTS

Seventy-five patients were enrolled, and 64 were evaluable (stage 3, n = 8; stage 4, n = 56). The estimated 3-year PFS and OS rates (95% confidence interval [CI]) were 44.4% [31.8%-56.3%] and 80.7% [68.5%-88.5%], resspectively. The response rate of INRC after completion of the treatment protocol was 66% (42/64; 95% CI: 53%-77%; 23 CR [complete response], 10 VGPR [very good partial response], and nine PR [partial response]). None of the patients died during the protocol treatment or within 30 days of completion. Grade 4 adverse effects, excluding hematological adverse effects, occurred in 48% of patients [31/64; 95% CI: 36%-61%]. Major Surgical complications were observed in 25% of patients [13/51; 95% CI: 14%-40%].

CONCLUSION

This study indicates that delayed local treatment is feasible and shows promising efficacy, suggesting that this treatment should be considered further in a comparative study of high-risk neuroblastoma.

Comparison between whole-body magnetic resonance imaging and whole-body metaiodobenzylguanidine scintigraphy in the evaluation of primary tumor and metastases in neuroblastoma

BACKGROUND

Whole-body metaiodobenzylguanidine (131 I-MIBG) scintigraphy is the gold standard method to detect neuroblastoma; however, it depends on radioactive material and is expensive. In contrast, whole-body magnetic resonance imaging (WB-MRI) is affordable in developing countries and has been shown to be effective in the evaluation of solid tumors. This study aimed to compare the sensitivity and specificity of WB-MRI with MIBG in the detection of primary tumors and neuroblastoma metastases.

PROCEDURE

This retrospective study enrolled patients with neuroblastoma between 2013 and 2020. All patients underwent WB-MRI and MIBG at intervals of up to 15 days. The results were marked in a table that discriminated anatomical regions for each patient. Two experts evaluated, independently and in anonymity, the WB-MRI images, and two others evaluated MIBG. The results were compared in terms of sensitivity and specificity, for each patient, considering MIBG as the gold standard. This study was approved by the UNIFESP Ethics Committee.

RESULTS

Thirty patients with neuroblastoma were enrolled in this study. The age ranged from 1 to 15 years, with a mean of 5.7 years. The interval between exams (WB-MRI and MIBG) ranged from 1 to 13 days, with an average of 6.67 days. Compared to MIBG, WB-MRI presented a sensitivity and specificity greater than or equal to 90% for the detection of primary neuroblastoma in bones and lymph nodes. When we consider the patient without individualizing the anatomical regions, WB-MRI presented sensitivity of 90% and specificity of 73.33%.

CONCLUSION

In conclusion, WB-MRI is a sensitive and specific method to detect neuroblastoma in bone and lymph nodes and highly sensible to primary tumor diagnosis, suggesting that this test is a viable alternative in places where MIBG is difficult to access. Studies with a larger number of cases are necessary for definitive conclusions.

A Pictorial Review of I-123 MIBG Imaging of Neuroblastoma Utilizing a State-of-the-Art CZT SPECT/CT System

The field of nuclear medicine is entering a new era of gamma-camera technology. Solid-state SPECT/CT systems will gradually replace the thallium-activated sodium-iodide NaI(Tl) systems. This digital technology allows drastic improvements in image quality, radiotracer dose reduction, and procedure efficiency. This pictorial review presents our initial experience on an NM/CT 870 CZT system (GE Healthcare), equipped with dual-head cadmium zinc telluride (CZT) detectors, for I-123 metaiodobenzylguanidine (MIBG) imaging in pediatric neuroblastoma. On planar imaging, CZT shows greater image quality than at conventional gamma-camera using the Infinia Hawkeye (GE Healthcare). Physiologic structures such as salivary glands and myocardium show sharper borders with a more notable signal-to-noise ratio at CZT than conventional gamma camera. On SPECT imaging, the CZT scanner, combined with resolution recovery, demonstrates either comparable or greater image quality at 80% of the conventional gamma camera’s acquisition time. Due to the 2.46-mm detector pixel with fully registered collimator holes matching each pixel and direct conversion of photons into electrical signals, the CZT gamma camera system provides significant advantages in photon localization and energy resolution.

Nuclear medicine imaging for bone metastases assessment: what else besides bone scintigraphy in the era of personalized medicine?

Accurate detection and reliable assessment of therapeutic responses in bone metastases are imperative for guiding treatment decisions, preserving quality of life, and ultimately enhancing overall survival. Nuclear imaging has historically played a pivotal role in this realm, offering a diverse range of radiotracers and imaging modalities. While the conventional bone scan using 99mTc marked bisphosphonates has remained widely utilized, its diagnostic performance is hindered by certain limitations. Positron emission tomography, particularly when coupled with computed tomography, provides improved spatial resolution and diagnostic performance with various pathology-specific radiotracers. This review aims to evaluate the performance of different nuclear imaging modalities in clinical practice for detecting and monitoring the therapeutic responses in bone metastases of diverse origins, addressing their limitations and implications for image interpretation.

Impact of diagnostic and end-of-induction Curie scores with tandem high-dose chemotherapy and autologous transplants for metastatic high-risk neuroblastoma: A report from the Children's Oncology Group

BACKGROUND

Diagnostic mIBG (meta-iodobenzylguanidine) scans are an integral component of response assessment in children with high-risk neuroblastoma. The role of end-of-induction (EOI) Curie scores (CS) was previously described in patients undergoing a single course of high-dose chemotherapy (HDC) and autologous hematopoietic cell transplant (AHCT) as consolidation therapy.

OBJECTIVE

We now examine the prognostic significance of CS in patients randomized to tandem HDC and AHCT on the Children's Oncology Group (COG) trial ANBL0532.

STUDY DESIGN

A retrospective analysis of mIBG scans obtained from patients enrolled in COG ANBL0532 was performed. Evaluable patients had mIBG-avid, International Neuroblastoma Staging System (INSS) stage 4 disease, did not progress during induction therapy, consented to consolidation randomization, and received either single or tandem HDC (n = 80). Optimal CS cut points maximized the outcome difference (≤CS vs. >CS cut-off) according to the Youden index.

RESULTS

For recipients of tandem HDC, the optimal cut point at diagnosis was CS = 12, with superior event-free survival (EFS) from study enrollment for patients with CS ≤ 12 (3-year EFS 74.2% ± 7.9%) versus CS > 12 (59.2% ± 7.1%) (p = .002). At EOI, the optimal cut point was CS = 0, with superior EOI EFS for patients with CS = 0 (72.9% ± 6.4%) versus CS > 0 (46.5% ± 9.1%) (p = .002).

CONCLUSION

In the setting of tandem transplantation for children with high-risk neuroblastoma, CS at diagnosis and EOI may identify a more favorable patient group. Patients treated with tandem HDC who exhibited a CS ≤ 12 at diagnosis or CS = 0 at EOI had superior EFS compared to those with CS above these cut points.

Update on the Role of Imaging in Staging of Common Pediatric Abdominal Tumors

Neuroblastoma, Wilms tumor, and hepatoblastoma are the most common pediatric abdominal malignancies. Management of these diseases is a multidisciplinary process that continues to evolve based on the results of international collaborative trials and advances in understanding of tumor biology. Each of these tumors has unique characteristics and behavior which are reflected in their respective staging systems. It is important for clinicians involved in the care of children with abdominal malignancies to be familiar with current staging guidelines and imaging recommendations. This article reviews the current role of imaging in the management of these common pediatric abdominal malignancies, with emphasis on initial staging.

Imaging of pediatric neuroblastoma: A COG Diagnostic Imaging Committee/SPR Oncology Committee White Paper

Neuroblastoma is the most common extracranial solid neoplasm in children. This manuscript provides consensus-based imaging recommendations for pediatric neuroblastoma patients at diagnosis and during follow-up.

Case Report: Long-term complete response to PSMA-targeted radioligand therapy and abiraterone in a metastatic prostate cancer patient

Despite decades of research and clinical trials, metastatic castration-resistant prostate cancer (mCRPC) remains incurable and typically fatal. Current treatments may provide modest increases in progression-free survival but can come with significant adverse effects and are disaggregated from the diagnostic imaging needed to fully assess the spread of metastatic disease. A theranostic approach, using radiolabeled ligands that target the cell surface protein PSMA, simplifies the visualization and disease treatment process by enabling both to use similar agents. Here, we describe an exemplary case wherein a gentleman in his 70s with mCRPC on diagnosis was treated with 177Lu-PSMA-617 and abiraterone, and remains disease-free to date, over five years later.

Role of surgery in neuroblastoma

Neuroblastoma is the most common malignant solid tumor handled by pediatric surgeons. It is well-known that neuroblastoma shows variable biological and clinical behaviors. In this review article, surgical strategy in neuroblastoma was described by risk stratification. Also, strategy of biopsy and clinical conditions that require special considerations such as neuroblastoma detected by mass screening, relapsed neuroblastoma, patients with stage MS and dumbbell type tumors was mentioned. As multimodal systemic treatments have been expanding, the role of surgery in neuroblastoma has become relatively less significant but requisite. We surgeons should decide therapeutic strategy based on the correct understanding of biology of neuroblastoma thinking of the better future of children.

P B, Ramadwar M, Singh S, Shukla A, Panwala H, Sahu A, Siddharth L, Kapadia T. Imaging Recommendations for Diagnosis, Staging, and Management of Pediatric Solid Tumors

Paediatric extra-cranial solid tumours are one of the common causes for paediatric malignancies. Lack of appropriate imaging at presentation, staging and for follow-up is a major challenge for paediatric solid tumours. We have reviewed the paediatric solid tumour imaging protocols suggested by the major oncological societies/groups around the world (mainly the SIOP – Society International Pediatric Oncology, and the COG – Children's Oncology Group). We have adapted some of those protocols to develop imaging recommendations for the diagnosis, staging and management of extra-cranial solid tumours based on the treatment protocols followed in India.

Current and upcoming radionuclide therapies in the direction of precision oncology: A narrative review

As new molecular tracers are identified to target specific receptors, tissue, and tumor types, opportunities arise for the development of both diagnostic tracers and their therapeutic counterparts, termed "theranostics." While diagnostic tracers utilize positron emitters or gamma-emitting radionuclides, their theranostic counterparts are typically bound to beta and alpha emitters, which can deliver specific and localized radiation to targets with minimal collateral damage to uninvolved surrounding structures. This is an exciting time in molecular imaging and therapy and a step towards personalized and precise medicine in which patients who were either without treatment options or not candidates for other therapies now have expanded options, with tangible data showing improved outcomes. This manuscript explores the current state of theranostics, providing background, treatment specifics, and toxicities, and discusses future potential trends.

Prognostic value of texture analysis of the primary tumour in high-risk neuroblastoma: An 18 F-DOPA PET study

PURPOSE

To evaluate the prognostic value of texture analysis of the primary tumour with ¹⁸ fluorine-dihydroxyphenylalanine positron emission tomography/X-ray computed tomography (¹⁸ F-DOPA PET/CT) in patients affected by high-risk neuroblastoma (HR-NBL).

METHODS

We retrospectively analysed 18 patients with HR-NBL, which had been prospectively enrolled in the course of a previous trial investigating the diagnostic role of ¹⁸ F-DOPA PET/CT at the time of the first onset. Texture analysis of the primary tumour was carried out on the PET images using LifeX. Conventional indices, histogram parameters, grey level co-occurrence (GLCM), run-length (GLRLM), neighbouring difference (NGLDM) and zone-length (GLZLM) matrices parameter were extracted; their values were compared with the overall metastatic load, expressed by means of whole-body metabolic burden (WBMB) score and the progression-free/overall survival (PFS and OS).

RESULTS

There was a direct correlation between WBMB and radiomics parameter describing uptake intensity (SUV_mean : p = .004) and voxel heterogeneity (entropy: p = .026; GLCM_Contrast: p = .001). Conversely, texture indices of homogeneity showed an inverse correlation with WBMB (energy: p = .026; GLCM_Homogeneity: p = .006). On the multivariate model, WBMB (p < .01) and the first standardised uptake value (SUV) quartile (p < .001) predicted PFS; OS was predicted by WBMB and the N-myc proto-oncogene protein (MYCN) amplification (p < .05) for both.

CONCLUSIONS

Textural parameters describing heterogeneity and metabolic intensity of the primary HR-NBL are closely associated with its overall metastatic burden. In turn, the whole-body tumour load appears to be one of the most relevant predictors of progression-free and overall survival.

Comparative Role of 18F-DOPA PET/CT and 131I-MIBG Scintigraphy in Neuroblastoma and Application of Curie and SIOPEN Scoring Systems in 18F-DOPA PET/CT

Purpose

Neuroblastoma (NB) is childhood's most common extracranial solid malignancy. We have compared two imaging modalities, 131I-MIBG and 18F-DOPA PET/CT, to evaluate NB. Also, feasibility of the application of standardised scoring systems, SIOPEN and Curie scoring systems, in 18F-DOPA PET/CT was explored.

Methods

Patients with histopathology-proven NB underwent 131I-MIBG (planar and SPECT/CT) and 18F-DOPA PET/CT scans, as per standard imaging protocols. Duration between scans ranged from 1 to 30 days (median = 8 days). Number of lesions in Curie and SIOPEN scoring systems applied on both modalities was compared.

Results

Forty-six patients were included (M:F = 29:17) with a median age of 36 months. Both 131I-MIBG and 18F-DOPA scans were positive in 39 patients and negative in four patients. 18F-DOPA PET/CT was positive in additional three patients, in which 131I-MIBG was negative (p = 0.25). Overall, 18F-DOPA identified significantly greater number of lesions than 131I-MIBG, especially metastatic skeletal lesions (p < 0.05). Significant difference was observed between Curie scores in the two modalities, unlike SIOPEN scores. However, when the cut-off age of 18 months was taken, no significant difference was seen in either of the scoring systems in both the scans (p > 0.05). CS and SIOPEN scores were significantly higher in bone marrow-positive patients.

Conclusion

18F-DOPA PET/CT detected more lesions than 131I-MIBG but had little impact on staging of the disease. For evaluation of NB, both scans can be used interchangeably as per the availability. Furthermore, both SIOPEN and Curie scoring systems, standardised for MIBG, can also be used to semi-quantify disease extent in 18F-DOPA PET/CT.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13139-022-00762-6.

Advancing therapy for neuroblastoma

Neuroblastomas are tumours of sympathetic origin, with a heterogeneous clinical course ranging from localized or spontaneously regressing to widely metastatic disease. Neuroblastomas recapitulate many of the features of sympathoadrenal development, which have been directly targeted to improve the survival outcomes in patients with high-risk disease. Over the past few decades, improvements in the 5-year survival of patients with metastatic neuroblastomas, from <20% to >50%, have resulted from clinical trials incorporating high-dose chemotherapy with autologous stem cell transplantation, differentiating agents and immunotherapy with anti-GD2 monoclonal antibodies. The next generation of trials are designed to improve the initial response rates in patients with high-risk neuroblastomas via the addition of immunotherapies, targeted therapies (such as ALK inhibitors) and radiopharmaceuticals to standard induction regimens. Other trials are focused on testing precision medicine strategies for patients with relapsed and/or refractory disease, enhancing the antitumour immune response and improving the effectiveness of maintenance regimens, in order to prolong disease remission. In this Review, we describe advances in delineating the pathogenesis of neuroblastoma and in identifying the drivers of high-risk disease. We then discuss how this knowledge has informed improvements in risk stratification, risk-adapted therapy and the development of novel therapies.

Global Neuroblastoma Network: An international multidisciplinary neuroblastoma tumor board for resource-limited countries

BACKGROUND

Tumor boards are part of standard care of patients with complex cancers, but appropriate multidisciplinary expertise and infrastructure are often not available in low- and middle-income countries (LMIC) for pediatric cancers, such as neuroblastoma. Our goal was to review results of a Global Neuroblastoma Network (GNN) tumor board accessible to LMIC.

METHODS

De-identified clinical cases presented via internet conference during a weekly GNN virtual tumor board from 2010 through 2020 were evaluated in a standardized format, including diagnostic imaging, pathology, therapy information, resource limitations, and questions for discussion. Information summarized included the presentations, a survey of the impact on care, and a resource questionnaire.

RESULTS

Registered GNN participants included 575 individuals from 77 countries, with a median of 39 participants per session. Total 412 cases were presented from 32 countries, including 351 unique neuroblastoma patients, 52 follow-up cases, and nine non-neuroblastoma diagnoses. Twenty-eight educational sessions were presented. Limited critical resources for diagnostics and staging of cases included MYCN analysis (54.7%), metaiodobenzylguanidine (MIBG) scans (38.7%), and International Neuroblastoma Pathology Classification (49%). Therapies were also limited, with markedly decreased use of radiation and autologous stem cell transplant for high-risk cases, and no availability of anti-GD2 antibody in LMIC. Limited sampling with a post-presentation survey showed that 100% found the GNN helpful, and 70% altered the care plan based on the discussion.

CONCLUSION

This report shows the utility of an international tumor board for LMIC focused on a challenging solid tumor where local expertise may be limited, with international multidisciplinary expert participation and educational sessions.

Tandem high-dose 131I-MIBG therapy supported by dosimetry in pediatric patients with relapsed-refractory high-risk neuroblastoma: the Bambino Gesu' Children's Hospital experience

OBJECTIVE

131I-meta-iodobenzylguanidine (131I-MIBG) combined with myeloablative chemotherapy represents an effective treatment in children affected by relapsed/refractory neuroblastoma (NBL) for disease palliation and in improving progression-free survival. The aim of our study is to evaluate the feasibility, safety and efficacy of tandem 131I-MIBG followed by high-dose chemotherapy with Melphalan.

METHODS

Thirteen patients (age range: 3-17 years) affected by relapsed/refractory NB, previously treated according to standard procedures, were included in the study. Each treatment cycle included two administrations of 131I-MIBG (with a dosimetric approach) followed by a single dose of Melphalan with peripheral blood stem cell rescue.

RESULTS

At the end of the treatment, ten patients experienced grade 4 neutropenia, two grade 3 and one patient grade 2, three patients presented febrile neutropenia and all needed RBC and platelets transfusions; one patient presented grade 4 mucositis, four grade 3 and one patient grade 2 mucositis. One patient showed progressive disease, eight patients showed stable disease and four patients showed partial response.

CONCLUSION

High-dose 131I-MIBG therapy combined with chemotherapy represent a well-tolerated and effective modality of treatment in heavily pretreated patients affected by relapsed/refractory NBL. However, further studies, including a wider cohort of patients, are needed.

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.

Development and validation of a LC-MS/MS method for in vivo quantification of meta-iodobenzylguanidine (mIBG)

meta-iodobenzylguanidine (mIBG) is a radiopharmaceutical used for the diagnosis and treatment of neuroendocrine cancers. Previous quantification of mIBG in biodistribution and pharmacokinetic studies mainly relied on the use of radiolabeled mIBG, which involves the handling of highly radioactive materials. The goal of this study was to develop a nonradioactive analytical method for quantifying mIBG in mouse plasma and tissue homogenates using high performance liquid chromatography-tandem mass spectrometry (LC-MS/MS). Samples were prepared for analysis using a protein precipitation method. Mass spectrometry analysis was performed using 4-hydroxyphenformin as the internal standard, and the mass-to-charge transitions were 276.1 → 217.0 for mIBG and 222.1 → 121.0 for 4-hydroxyphenformin. The quantification limit of mIBG was 0.98 ng/mL, and the method was linear up to 500 ng/mL. The accuracy, inter-day and intra-day precision were 96-112%, 5.5-14.4%, and 3.7-14.1%, respectively, suggesting that the method was accurate and precise in quantifying mIBG at multiple concentrations in mouse plasma and liver homogenates. The extraction recovery was 96-106% and the matrix effect was 95-110%, indicating that the method was reproducible in quantifying mIBG with minimal impact from the biological matrices. In summary, we have developed and validated a fast, high-throughput quantification method of non-radiolabeled mIBG using LC-MS/MS. This method is reproducible, accurate, and precise, and can be used to quantify mIBG in plasma and tissue matrices to determine the pharmacokinetics and biodistribution of mIBG in preclinical animal models.

68Ga-DOTATATE and 123I-mIBG as imaging biomarkers of disease localisation in metastatic neuroblastoma: implications for molecular radiotherapy

PURPOSE

Iodine-131-labelled meta-iodobenzylguanidine (I-mIBG) and lutetium-177-labelled DOTATATE (Lu-DOTATATE) are used for molecular radiotherapy of metastatic neuroblastoma. These are taken up by the noradrenaline transporter (NAT) and the somatostatin receptor subtype 2 (SSTR-2), respectively. Scintigraphy of iodine-123-labelled meta-iodobenzylguanidine (I-mIBG) and gallium-68 DOTATATE (Ga-DOTATATE) PET are used to select patients for therapy. These demonstrate the extent and location of tumour, and avidity of uptake by cells expressing NAT and SSTR-2, respectively. This study compared the similarities and differences in the anatomical distribution of these two imaging biomarkers in an unselected series of patients with metastatic neuroblastoma undergoing assessment for molecular radiotherapy.

METHODS

Paired whole-body planar I-mIBG views and Ga-DOTATATE maximum intensity projection PET scans of metastatic neuroblastoma patients were visually compared. The disease extent was assessed by a semiquantitative scoring method.

RESULTS

Paired scans from 42 patients were reviewed. Ga-DOTATATE scans were positive in all patients, I-mIBG scans were negative in two. In two patients, there was a mismatch, with some lesions identified only on the I-mIBG scan, and others visible only on the Ga-DOTATATE scan.

CONCLUSION

Ga-DOTATATE and I-mIBG scans yield complementary information. For a more comprehensive assessment, consideration could be given to the use of both I-mIBG and Ga-DOTATATE imaging scans. Because of the heterogeneity of distribution of molecular targets revealed by these techniques, a combination of both I-mIBG and Lu-DOTATATE molecular radiotherapy may possibly be more effective than either alone.

Theranostics in Neuroblastoma

Theranostics combines diagnosis and targeted therapy, achieved by the use of the same or similar molecules labeled with different radiopharmaceuticals or identical with different dosages. One of the best examples is the use of metaiodobenzylguanidine (MIBG). In the management of neuroblastoma-the most common extracranial solid tumor in children. MIBG has utility not only for diagnosis, risk-stratification, and response monitoring but also for cancer therapy, particularly in the setting of relapsed/refractory disease. Improved techniques and new emerging radiopharmaceuticals likely will strengthen the role of nuclear medicine in the management of neuroblastoma.

An Impressive Approach in Nuclear Medicine: Theranostics

Radiometal-based theranostics or theragnostics, first used in the early 2000s, is the combined application of diagnostic and therapeutic agents that target the same molecule, and represents a considerable advancement in nuclear medicine. One of the promising fields related to theranostics is radioligand therapy. For instance, the concepts of targeting the prostate-specific membrane antigen (PSMA) for imaging and therapy in prostate cancer, or somatostatin receptor targeted imaging and therapy in neuroendocrine tumors (NETs) are part of the field of theranostics. Combining targeted imaging and therapy can improve prognostication, therapeutic decision-making, and monitoring of the therapy.

A rare case of adrenal ganglioneuroblastoma-intermixed in an adult and a review of literature

Peripheral neuroblastic tumors are extremely rare in the adult with less just over 20 cases involving adrenal gland described in the literature. We reported herewith the case of a 22-year-old young male who presented with epigastric pain and diarrhea. Imaging studies documented a 3.5cm x 3cm x 4cm solid well-circumscribed right adrenal mass, of heterogeneous structure and with fine calcifications. The lesion turned negative at MIBG scintigraphy. A right robotic-assisted adrenalectomy was performed leading to complete excision of the lesion without complications. Histology was consistent with intermixed stroma-rich ganglioneuroblastoma. A wait-and-see strategy was considered adequate. Two years after diagnosis patient is alive disease-free. Although the definitive diagnosis of a peripheral neuroblastic tumor is obtained after histopathological analysis, CT, and MRI are helpful to further characterize masses and useful in pretreatment risk stratification. Clinicians should be aware of the possibility of GNB development in adult population and its malignant potential.

Mediastinal neuroblastoma, ganglioneuroblastoma, and ganglioneuroma: Pathology review and diagnostic approach

Neuroblastic tumors are a group of tumors of the sympathetic ganglia and adrenal medulla that derive from primordial neural crest cells. These tumors include neuroblastoma, intermixed ganglioneuroblastoma, nodular ganglioneuroblastoma, and ganglioneuroma. Neuroblastomas are the most common extracranial solid tumor arising in childhood and may occur in different anatomic sites. Neuroblastic tumors are common mesenchymal tumors of the mediastinum. Herein, we describe advances in our understanding of neuroblastic tumor biology. Pathologists should be aware of diagnostic challenges associated with these tumors to ensure correct histologic diagnosis and appropriate clinical management. We describe updated mediastinal neuroblastic tumor pathology, focusing on morphological, immunohistochemical, and molecular features and differential diagnoses.

123Iodine-metaiodobenzylguanidine scintigraphy versus whole-body magnetic resonance imaging with diffusion-weighted imaging in children with high-risk neuroblastoma - pilot study

BACKGROUND

The prognostic value of the International Society of Paediatric Oncology European Neuroblastoma Research Network (SIOPEN) skeletal score using ¹²³iodine-metaiodobenzylguanidine (MIBG) has been confirmed for people with high-risk neuroblastoma. Whole-body MRI with diffusion-weighted imaging is used increasingly.

OBJECTIVE

To compare the original SIOPEN score and its adaption by diffusion-weighted imaging in high-risk stage 4 neuroblastoma and to evaluate any consequences of score differences on overall survival.

MATERIALS AND METHODS

This retrospective observational study included pediatric patients who underwent MIBG scintigraphy and whole-body MRI, including diffusion-weighted imaging, between 2010 and 2015. Semi-quantitative skeletal scores for each exam were calculated independently. A difference of two or more points was defined as clinically relevant and counted as M+ (more in diffusion-weighted imaging) or S+ (more in MIBG). In cases of a negative result in one of the studies, residual disease of 1 point was also rated as relevant. We tested correlation and differences on an exam basis and also grouped by different therapeutic conditions. Overall survival was used to evaluate prognostic relevance.

RESULTS

Seventeen children with 25 paired examinations were evaluated. Median MIBG scintigraphy score was 0 (interquartile range [IQR] 0-4, range 0-25) vs. a median whole-body MRI score of 1 (IQR 0-5.5, range 0-35) (P=0.018). A relevant difference between whole-body MRI and MIBG scintigraphy was noted in 14 of the 25 paired examinations (M+: n=9; S+: n=5). After treatment, the median survival of cases with M+ was 14 months (IQR 4-59, range 1-74 months), while S+ cases showed a median survival of 49 months (IQR 36-52, range 36-52 months) (P=0.413).

CONCLUSION

The SIOPEN scoring system is feasible for whole-body MRI but might result in slightly higher scores, probably because of MRI's superior spatial resolution. Further studies are necessary to validate any impact on prognosis.

123I metaiodobenzylguanidine (MIBG) uptake predicts early relapse of neuroblastoma using semi-quantitative SPECT/CT analysis

OBJECTIVE

123I metaiodobenzylguanidine (MIBG) scintigraphy is a useful tool for the diagnosis of neuroblastoma (NB). MIBG uptake is correlated with norepinephrine transporter expression; hence, it is expected that high-MIBG tumors would be more highly differentiated and have a better prognosis than those with lower expression. We have introduced a method of assessing MIBG accumulation semi-quantitatively using SPECT/CT fusion images. The purpose of this study was to evaluate the relationship of 123I MIBG uptake measured by semi-quantitative values of SPECT/CT and early relapse of NB.

METHODS

We studied the cases of 11 patients (5 males and 6 females, age 5-65 months, median age 20 months) with histopathologically proven NB between April 2010 and March 2015. The early-relapse group was defined as patients who had relapsed within 3 years after the first 123I MIBG SPECT/CT exam. Other patients were classified as the delay-relapse group. Uptake of MIBG was evaluated using the count ratio of tumor and muscles. T/Mmax and T/Mmean were defined as follows: T/Mmax = max count of tumor/max count of muscle, T/Mmean = mean count of tumor/mean count of muscle.

RESULTS

The average T/Mmean values of the early-relapse group and delay-relapse group were 2.65 ± 0.58 and 7.66 ± 2.68, respectively. The T/Mmean values of the early-relapse group were significantly lower than those of delay-relapse group (p < 0.05). The average T/Mmax of the early-relapse group and delay-relapse group were 8.86 ± 3.22 and 16.20 ± 1.97, respectively. There was no significant difference in T/Mmax values between the two groups.

CONCLUSIONS

Low 123I MIBG uptake using semi-quantitative SPECT/CT analysis was correlated with early relapse of NB.

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.

Development and Validation of a Prediction Model of Overall Survival in High-Risk Neuroblastoma Using Mechanistic Modeling of Metastasis

Prognosis of high-risk neuroblastoma (HRNB) remains poor despite multimodal therapies. Better prediction of survival could help to refine patient stratification and better tailor treatments. We established a mechanistic model of metastasis in HRNB relying on two processes: growth and dissemination relying on two patient-specific parameters: the dissemination rate μ and the minimal visible lesion size S_vis. This model was calibrated using diagnosis values of primary tumor size, lactate dehydrogenase circulating levels, and the meta-iodobenzylguanidine International Society for Paediatric Oncology European (SIOPEN) score from nuclear imaging, using data from 49 metastatic patients. It was able to describe the data of total tumor mass (lactate dehydrogenase, R² > 0.99) and number of visible metastases (SIOPEN, R² = 0.96). A prediction model of overall survival (OS) was then developed using Cox regression. Clinical variables alone were not able to generate a model with sufficient OS prognosis ability (P = .507). The parameter μ was found to be independent of the clinical variables and positively associated with OS (P = .0739 in multivariable analysis). Critically, addition of this computational biomarker significantly improved prediction of OS with a concordance index increasing from 0.675 (95% CI, 0.663 to 0.688) to 0.733 (95% CI, 0.722 to 0.744, P < .0001), resulting in significant OS prognosis ability (P = .0422).

Immunotherapeutic Strategies for Neuroblastoma: Present, Past and Future

Neuroblastoma is the most common extracranial pediatric solid tumor with a heterogeneous clinical course, ranging from spontaneous regression to metastatic disease and death, irrespective of intensive chemotherapeutic regimen. On the basis of several parameters, children affected by neuroblastoma are stratified into low, intermediate and high risk. At present, more than 50% of high-risk patients with metastatic spread display an overall poor long-term outcome also complicated by devastating long-term morbidities. Thus, novel and more effective therapies are desperately needed to improve lifespan of high-risk patients. In this regard, adoptive cell therapy holds great promise and several clinical trials are ongoing, demonstrating safety and tolerability, with no toxicities. Starting from the immunological and clinical features of neuroblastoma, we here discuss the immunotherapeutic approaches currently adopted for high-risk patients and different innovative therapeutic strategies currently under investigation. The latter are based on the infusion of natural killer (NK) cells, as support of consolidation therapy in addition to standard treatments, or chimeric antigen receptor (CAR) T cells directed against neuroblastoma associated antigens (e.g., disialoganglioside GD2). Finally, future perspectives of adoptive cell therapies represented by γδ T lymphocyes and CAR NK cells are envisaged.

The Current Status and Future Potential of Theranostics to Diagnose and Treat Childhood Cancer

In theranostics (i.e., therapy and diagnostics) radiopharmaceuticals are used for both therapeutic and diagnostic purposes by targeting one specific tumor receptor. Biologically relevant compounds, e.g., receptor ligands or drugs, are labeled with radionuclides to form radiopharmaceuticals. The possible applications are multifold: visualization of biological processes or tumor biology in vivo, diagnosis and tumor staging, therapy planning, and treatment of specific tumors. Theranostics research is multidisciplinary and allows for the rapid translation of potential tumor targets from preclinical research to “first-in-man” clinical studies. In the last decade, the use of theranostics has seen an unprecedented value for adult cancer patients. Several radiopharmaceuticals are routinely used in clinical practice (e.g., [⁶⁸Ga/¹⁷⁷Lu]DOTATATE), and dozens are under (pre)clinical development. In contrast to these successes in adult oncology, theranostics have scarcely been developed to diagnose and treat pediatric cancers. To date, [^123/131I]meta-iodobenzylguanidine ([^123/131I]mIBG) is the only available and approved theranostic in pediatric oncology. mIBG targets the norepinephrine transporter, expressed by neuroblastoma tumors. For most pediatric tumors, including neuroblastoma, there is a clear need for novel and improved radiopharmaceuticals for imaging and therapy. The strategy of theranostics for pediatric oncology can be divided in (1) the improvement of existing theranostics, (2) the translation of theranostics developed in adult oncology for pediatric purposes, and (3) the development of novel theranostics for pediatric tumor-specific targets. Here, we describe the recent advances in theranostics development in pediatric oncology and shed a light on how this methodology can affect diagnosis and provide additional treatment options for these patients.

18F-meta-fluorobenzylguanidine (18F-mFBG) to monitor changes in norepinephrine transporter expression in response to therapeutic intervention in neuroblastoma models

Targeted radiotherapy with 131I-mIBG, a substrate of the human norepinephrine transporter (NET-1), shows promising responses in heavily pre-treated neuroblastoma (NB) patients. Combinatorial approaches that enhance 131I-mIBG tumour uptake are of substantial clinical interest but biomarkers of response are needed. Here, we investigate the potential of 18F-mFBG, a positron emission tomography (PET) analogue of the 123I-mIBG radiotracer, to quantify NET-1 expression levels in mouse models of NB following treatment with AZD2014, a dual mTOR inhibitor. The response to AZD2014 treatment was evaluated in MYCN amplified NB cell lines (Kelly and SK-N-BE(2)C) by Western blot (WB) and immunohistochemistry. PET quantification of 18F-mFBG uptake post-treatment in vivo was performed, and data correlated with NET-1 protein levels measured ex vivo. Following 72 h AZD2014 treatment, in vitro WB analysis indicated decreased mTOR signalling and enhanced NET-1 expression in both cell lines, and 18F-mFBG revealed a concentration-dependent increase in NET-1 function. AZD2014 treatment failed however to inhibit mTOR signalling in vivo and did not significantly modulate intratumoural NET-1 activity. Image analysis of 18F-mFBG PET data showed correlation to tumour NET-1 protein expression, while further studies are needed to elucidate whether NET-1 upregulation induced by blocking mTOR might be a useful adjunct to 131I-mIBG therapy.

Antitumor activity without on-target off-tumor toxicity of GD2-chimeric antigen receptor T cells in patients with neuroblastoma

The reprogramming of a patient's immune system through genetic modification of the T cell compartment with chimeric antigen receptors (CARs) has led to durable remissions in chemotherapy-refractory B cell cancers. Targeting of solid cancers by CAR-T cells is dependent on their infiltration and expansion within the tumor microenvironment, and thus far, fewer clinical responses have been reported. Here, we report a phase 1 study (NCT02761915) in which we treated 12 children with relapsed/refractory neuroblastoma with escalating doses of second-generation GD2-directed CAR-T cells and increasing intensity of preparative lymphodepletion. Overall, no patients had objective clinical response at the evaluation point +28 days after CAR-T cell infusion using standard radiological response criteria. However, of the six patients receiving ≥108/meter2 CAR-T cells after fludarabine/cyclophosphamide conditioning, two experienced grade 2 to 3 cytokine release syndrome, and three demonstrated regression of soft tissue and bone marrow disease. This clinical activity was achieved without on-target off-tumor toxicity. Targeting neuroblastoma with GD2 CAR-T cells appears to be a valid and safe strategy but requires further modification to promote CAR-T cell longevity.

Safety, tolerability and pharmacokinetics of crizotinib in combination with cytotoxic chemotherapy for pediatric patients with refractory solid tumors or anaplastic large cell lymphoma (ALCL): a Children's Oncology Group phase 1 consortium study (ADVL1212)

PURPOSE

This phase 1 study aimed to determine the safety, tolerability and recommended phase 2 dose (RP2D) of crizotinib in combination with cytotoxic chemotherapy for children with refractory solid tumors and ALCL.

METHODS

Pediatric patients with treatment refractory solid tumors or ALCL were eligible. Using a 3 + 3 design, crizotinib was escalated in three dose levels: 165, 215, or 280 mg/m²/dose BID. In Part A, patients received crizotinib oral solution (OS) in combination with topotecan and cyclophosphamide (topo/cyclo); in Part B, crizotinib OS was administered with vincristine and doxorubicin (vcr/dox). In Parts C and D, patients received topo/cyclo in combination with either crizotinib-formulated capsules (FC) or microspheres (cMS), respectively. Crizotinib pharmacokinetic evaluation was required.

RESULTS

Forty-four eligible patients were enrolled, 39 were evaluable for toxicity. Parts A and B were terminated due to concerns regarding palatability and tolerability of the OS. In Part C, crizotinib, FC 215 mg/m²/dose BID, in combination with topo/cyclo was tolerated. In Part D, the maximum tolerated dose (MTD) was exceeded at 165 mg/m²/dose of crizotinib cMS. Pharmacokinetics of crizotinib in combination with chemotherapy was similar to single-agent crizotinib and exposures were not formulation dependent.

CONCLUSIONS

The RP2D of crizotinib FCs in combination with cyclophosphamide and topotecan was 215 mg/m²/dose BID. The oral solution of crizotinib was not palatable in this patient population. Crizotinib cMS was palatable; however, patients experienced increased toxicity that was not explained by the relative bioavailability or exposure and warrants further investigation.

CLINICAL TRIAL REGISTRY

The trial is registered as NCT01606878 at Clinicaltrials.gov.

Personalisation of Molecular Radiotherapy through Optimisation of Theragnostics

Molecular radiotherapy, or targeted radionuclide therapy, uses systemically administered drugs bearing a suitable radioactive isotope, typically a beta emitter. These are delivered via metabolic or other physiological pathways to cancer cells in greater concentrations than to normal tissues. The absorbed radiation dose in tumour deposits causes chromosomal damage and cell death. A partner radiopharmaceutical, most commonly the same vector labelled with a different radioactive atom, with emissions suitable for gamma camera or positron emission tomography imaging, is used to select patients for treatment and to assess response. The use of these pairs of radio-labelled drugs, one optimised for therapy, the other for diagnostic purposes, is referred to as theragnostics. Theragnostics is increasingly moving away from a fixed number of defined activity administrations, to a much more individualised or personalised approach, with the aim of improving treatment outcomes, and minimising toxicity. There is, however, still significant scope for further progress in that direction. The main tools for personalisation are the following: imaging biomarkers for better patient selection; predictive and post-therapy dosimetry to maximise the radiation dose to the tumour while keeping organs at risk within tolerance limits; imaging for assessment of treatment response; individualised decision making and communication about radiation protection, adjustments for toxicity, inpatient and outpatient care.

Association between end-induction response according to the revised International Neuroblastoma Response Criteria (INRC) and outcome in high-risk neuroblastoma patients

BACKGROUND

The 1993 International Neuroblastoma Response Criteria (INRC) were revised in 2017 to include modern functional imaging studies and methods for quantifying disease in bone marrow. We hypothesized the 2017 INRC would enable more precise assessment of response to treatment and provide superior prognostic information compared with the 1993 criteria.

METHODS

High-risk (HR) neuroblastoma patients from two institutions in Chicago diagnosed between 2006 and 2016 were identified. Patients were assessed post induction chemotherapy via the 1993 and 2017 INRC and classified as responder (≥ mixed response [MXR] or ≥ minor response [MR], respectively) or nonresponder (< MXR or < MR). Event-free survival (EFS) and overall survival (OS) for responders versus nonresponders were determined from end induction and stratified by Cox regression. Patients with progressive disease at end induction were eliminated from the EFS analyses but included in the OS analysis.

RESULTS

The 1993 criteria classified 52 of the 60 HR patients as responders, whereas 54 responders were identified using the 2017 criteria (Spearman correlation r = 0.82, P < 0.001). No statistically significant difference in EFS was observed for responders versus nonresponders using either criteria (P = 0.48 and P = 0.08). However, superior OS was observed for responders (P = 0.01) using either criteria. Both criteria were sensitive in identifying responders among those with good outcomes. The specificity to identify nonresponders among those with poor outcomes was poor.

CONCLUSIONS

In HR neuroblastoma, end-induction response defined by the 1993 or 2017 INRC is associated with survival. Larger cohorts are needed to determine if the 2017 INRC provides more precise prognostication.