Paediatric radiotherapy in the United Kingdom: an evolving subspecialty and a paradigm for integrated teamworking in oncology.

Many different malignancies occur in children, but overall, cancer in childhood is rare. Survival rates have improved appreciably and are higher compared with most adult tumour types. Treatment schedules evolve as a result of clinical trials and are typically complex and multi-modality, with radiotherapy an integral component of many. Risk stratification in paediatric oncology is increasingly refined, resulting in a more personalized use of radiation. Every available modality of radiation delivery: simple and advanced photon techniques, proton beam therapy, molecular radiotherapy, and brachytherapy, have their place in the treatment of children's cancers. Radiotherapy is rarely the sole treatment. As local therapy, it is often given before or after surgery, so the involvement of the surgeon is critically important, particularly when brachytherapy is used. Systemic treatment is the standard of care for most paediatric tumour types, concomitant administration of chemotherapy is typical, and immunotherapy has an increasing role. Delivery of radiotherapy is not done by clinical or radiation oncologists alone; play specialists and anaesthetists are required, together with mould room staff, to ensure compliance and immobilization. The support of clinical radiologists is needed to ensure the correct interpretation of imaging for target volume delineation. Physicists and dosimetrists ensure the optimal dose distribution, minimizing exposure of organs at risk. Paediatric oncology doctors, nurses, and a range of allied health professionals are needed for the holistic wrap-around care of the child and family. Radiographers are essential at every step of the way. With increasing complexity comes a need for greater centralization of services.

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.

Interleukin 2 with anti-GD2 antibody ch14.18/CHO (dinutuximab beta) in patients with high-risk neuroblastoma (HR-NBL1/SIOPEN): a multicentre, randomised, phase 3 trial.

BACKGROUND: Immunotherapy with the chimeric anti-GD2 monoclonal antibody dinutuximab, combined with alternating granulocyte-macrophage colony-stimulating factor and intravenous interleukin-2 (IL-2), improves survival in patients with high-risk neuroblastoma. We aimed to assess event-free survival after treatment with ch14.18/CHO (dinutuximab beta) and subcutaneous IL-2, compared with dinutuximab beta alone in children and young people with high-risk neuroblastoma. METHODS: We did an international, open-label, phase 3, randomised, controlled trial in patients with high-risk neuroblastoma at 104 institutions in 12 countries. Eligible patients were aged 1-20 years and had MYCN-amplified neuroblastoma with stages 2, 3, or 4S, or stage 4 neuroblastoma of any MYCN status, according to the International Neuroblastoma Staging System. Patients were eligible if they had been enrolled at diagnosis in the HR-NBL1/SIOPEN trial, had completed the multidrug induction regimen (cisplatin, carboplatin, cyclophosphamide, vincristine, and etoposide, with or without topotecan, vincristine, and doxorubicin), had achieved a disease response that fulfilled prespecified criteria, had received high-dose therapy (busulfan and melphalan or carboplatin, etoposide, and melphalan) and had received radiotherapy to the primary tumour site. In this component of the trial, patients were randomly assigned (1:1) to receive dinutuximab beta (20 mg/m2 per day as an 8 h infusion for 5 consecutive days) or dinutuximab beta plus subcutaneous IL-2 (6 × 106 IU/m2 per day on days 1-5 and days 8-12 of each cycle) with the minimisation method to balance randomisation for national groups and type of high-dose therapy. All participants received oral isotretinoin (160 mg/m2 per day for 2 weeks) before the first immunotherapy cycle and after each immunotherapy cycle, for six cycles. The primary endpoint was 3-year event-free survival, analysed by intention to treat. This trial was registered with ClinicalTrials.gov, number NCT01704716, and EudraCT, number 2006-001489-17, and recruitment to this randomisation is closed. FINDINGS: Between Oct 22, 2009, and Aug 12, 2013, 422 patients were eligible to participate in the immunotherapy randomisation, of whom 406 (96%) were randomly assigned to a treatment group (n=200 to dinutuximab beta and n=206 to dinutuximab beta with subcutaneous IL-2). Median follow-up was 4·7 years (IQR 3·9-5·3). Because of toxicity, 117 (62%) of 188 patients assigned to dinutuximab beta and subcutaneous IL-2 received their allocated treatment, by contrast with 160 (87%) of 183 patients who received dinutuximab beta alone (p<0·0001). 3-year event-free survival was 56% (95% CI 49-63) with dinutuximab beta (83 patients had an event) and 60% (53-66) with dinutuximab beta and subcutaneous IL-2 (80 patients had an event; p=0·76). Four patients died of toxicity (n=2 in each group); one patient in each group while receiving immunotherapy (n=1 congestive heart failure and pulmonary hypertension due to capillary leak syndrome; n=1 infection-related acute respiratory distress syndrome), and one patient in each group after five cycles of immunotherapy (n=1 fungal infection and multi-organ failure; n=1 pulmonary fibrosis). The most common grade 3-4 adverse events were hypersensitivity reactions (19 [10%] of 185 patients in the dinutuximab beta group vs 39 [20%] of 191 patients in the dinutuximab plus subcutaneous IL-2 group), capillary leak (five [4%] of 119 vs 19 [15%] of 125), fever (25 [14%] of 185 vs 76 [40%] of 190), infection (47 [25%] of 185 vs 64 [33%] of 191), immunotherapy-related pain (19 [16%] of 122 vs 32 [26%] of 124), and impaired general condition (30 [16%] of 185 vs 78 [41%] of 192). INTERPRETATION: There is no evidence that addition of subcutaneous IL-2 to immunotherapy with dinutuximab beta, given as an 8 h infusion, improved outcomes in patients with high-risk neuroblastoma who had responded to standard induction and consolidation treatment. Subcutaneous IL-2 with dinutuximab beta was associated with greater toxicity than dinutuximab beta alone. Dinutuximab beta and isotretinoin without subcutaneous IL-2 should thus be considered the standard of care until results of ongoing randomised trials using a modified schedule of dinutuximab beta and subcutaneous IL-2 are available. FUNDING: European Commission 5th Frame Work Grant, St. Anna Kinderkrebsforschung, Fondation ARC pour la recherche sur le Cancer.

The neuroendocrine sequelae of paediatric craniopharyngioma: a 40-year meta-data analysis of 185 cases from three UK centres.

OBJECTIVES: The management of paediatric craniopharyngiomas was traditionally complete resection (CR), with better reported tumour control compared to that by partial resection (PR) or limited surgery (LS). The subsequent shift towards hypothalamic sparing, conservative surgery with adjuvant radiotherapy (RT) to any residual tumour aimed at reducing neuroendocrine morbidity, has not been systematically studied. Hence, we reviewed the sequelae of differing management strategies in paediatric craniopharyngioma across three UK tertiary centres over four decades. METHODS: Meta-data was retrospectively reviewed over two periods before (1973-2000 (Group A: n = 100)) and after (1998-2011 (Group B: n = 85)) the introduction of the conservative strategy at each centre. RESULTS: Patients had CR (A: 34% and B: 19%), PR (A: 48% and B: 46%) or LS (A: 16% and B: 34%), with trends reflecting the change in surgical approach over time. Overall recurrence rates between the two periods did not change (A: 38% vs B: 32%). More patients received RT in B than A, but recurrence rates were similar: for A, 28% patients received RT with 9 recurrences (32%); for B, 62% received RT with 14 recurrences (26%). However, rates of diabetes insipidus (P = 0.04), gonadotrophin deficiency (P < 0.001) and panhypopituitarism (P = 0.001) were lower in B than those in A. In contrast, post-operative obesity (BMI SDS >+2.0) (P = 0.4) and hypothalamic (P = 0.1) and visual (P = 0.3) morbidity rates were unchanged. CONCLUSION: The shift towards more conservative surgery has reduced the prevalence of hormone deficiencies, including diabetes insipidus, which can be life threatening. However, it has not been associated with reduced hypothalamic and visual morbidities, which remain a significant challenge. More effective targeted therapies are necessary to improve outcomes.

[131I]meta-iodobenzylguanidine and topotecan combination treatment of tumors expressing the noradrenaline transporter.

PURPOSE: Both [(131)I]meta-iodobenzylguanidine ([(131)I]MIBG) and the topoisomerase I inhibitor topotecan are effective as single-agent treatments of neuroblastoma. The aim of this study was to investigate the efficacy of [(131)I]MIBG in combination with topotecan in vitro and in vivo. EXPERIMENTAL DESIGN: The cell lines used were SK-N-BE(2c) (human neuroblastoma) and UVW/NAT (glioma cell line transfected with the noradrenaline transporter gene). Three different treatment schedules were assessed: topotecan given before (schedule 1), after (schedule 2), or simultaneously (schedule 3) with [(131)I]MIBG. DNA strand breakage was evaluated by comet assay, and cytotoxicity was determined by clonogenic survival. Efficacy was also measured by growth delay of tumor xenografts in nude mice. RESULTS: Combination schedules 2 and 3 caused more cytotoxicity than schedule 1. Similarly, significant DNA damage was observed following treatment schedules 2 and 3 (P < 0.005) but not schedule 1. The mean number of days for a doubling in volume of SK-N-BE(2c) tumors and a 10-fold increase in volume of UVW/NAT tumors were 10.4 and 18.6 (untreated), 19.7 and 25.3 (topotecan alone), 22.8 and 31.9 ([(131)I]MIBG alone), 26.3 and 37.1 (combination schedule 1), 34.3 and 49.7 (combination schedule 2), and 53.2 and >71 (combination schedule 3), respectively. The highest rate of cure of both xenografts was observed following treatment with combination schedule 3. CONCLUSIONS: The combination of topotecan and [(131)I]MIBG compared with either treatment alone gave rise to greater than additive DNA damage, clonogenic cell kill, and tumor growth delay. These effects were dependent on the scheduling of the two agents.

Feasibility of dosimetry-based high-dose 131I-meta-iodobenzylguanidine with topotecan as a radiosensitizer in children with metastatic neuroblastoma.

INTRODUCTION: (131)I-meta iodobenzylguanidine ((131)I-mIBG) therapy is established palliation for relapsed neuroblastoma. The topoisomerase-1 inhibitor, topotecan, has direct activity against neuroblastoma and acts as a radiation sensitiser. These 2 treatments are synergistic in laboratory studies. Theoretically, the benefit of (131)I-mIBG treatment could be enhanced by dose escalation and combination with topotecan. Haematological support would be necessary to overcome the myelosuppression, which is the dose-limiting toxicity. AIMS: Firstly, one aim of this study was to establish whether in vivo dosimetry could be used to guide the delivery of a precise total whole-body radiation-absorbed dose of 4 Gy accurately from 2 (131)I-mIBG treatments. Secondly, the other aim of this study was to determine whether it is feasible to combine this treatment with the topotecan in children with metastatic neuroblastoma. MATERIAL AND METHODS: An activity of (131)I-mIBG (12 mCi/kg, 444 MBq/kg), estimated to give a whole-body absorbed-radiation dose of approximately 2 Gy, was administered on day 1, with topotecan 0.7 mg/m(2) administered daily from days 1-5. In vivo dosimetry was used to calculate a 2nd activity of (131)I-mIBG, to be given on day 15 which would give a total whole-body dose of 4 Gy. A further 5 doses of topotecan were given from days 15-19. The myeloablative effect of this regimen was circumvented by peripheral blood stem cell or bone marrow support. RESULTS: Eight children with relapsed stage IV neuroblastoma were treated. The treatment was delivered according to protocol in all patients. There were no unanticipated side-effects. Satisfactory haematological reconstitution occurred in all patients. The measured total whole-body radiation-absorbed dose ranged from 3.7 Gy to 4.7 Gy (mean, 4.2 Gy). CONCLUSIONS: In vivo dosimetry allows for a specified total whole-body radiation dose to be delivered accurately. This schedule of intensification of (131)I-mIBG therapy by dose escalation and radiosensitization with topotecan with a haemopoietic autograft is safe and practicable. This approach should now be tested for efficacy in a phase II clinical trial.