Prevalence of survivors of childhood cancer based on a population-based cancer registry in Osaka, Japan.

Although the survival rate of patients with childhood cancer has greatly improved, long-term survivors face specific problems such as the late effects of cancer treatment. In this study, we estimated the number of people who had experienced childhood cancer to predict their needs for medical care and social resources. Using data from the population-based Osaka Cancer Registry, we identified children aged 0-14 years who were diagnosed with cancer between 1975 and 2019. We estimated the prevalence on December 31, 2019, and the 5- and 10-year prevalence (i.e., the number of survivors living up to 5 or 10 years after the diagnosis of cancer) over time. The prevalence proportion was age-standardized using a direct standardization method. The prevalence estimates for Osaka were applied to the national population to determine the national prevalence in Japan. Among 8186 patients diagnosed with childhood cancer in Osaka, 5252 (987 per million) survived until December 31, 2019. The 5-year prevalence per million increased from 194 in 1979 to 417 in 2019 (+116%), while the 10-year prevalence increased from 391 in 1984 to 715 in 2019 (+83%). Based on the long-term registry data, an estimated 73,182 childhood cancer survivors were living in Japan by the end of 2019. The increasing 5-year and 10-year prevalence proportions indicate the continued need for cancer survivorship support for children, adolescents, and young adults. These estimates of the prevalence of childhood cancer survivors, including long-term survivors, may be useful for policymakers and clinicians to plan and evaluate survivorship care.

Prognostic and therapeutic factors influencing the clinical outcome of metastatic Ewing sarcoma family of tumors: A retrospective report from the Japan Ewing Sarcoma Study Group.

BACKGROUND: The prognosis of patients with metastatic Ewing sarcoma family of tumors (ESFT) remains poor. PROCEDURE: We retrospectively analyzed 57 patients diagnosed with metastatic ESFT between 2000 and 2018 to identify prognostic and therapeutic factors affecting the clinical outcome. RESULTS: The 3-year overall survival (OS) rate of the entire cohort was 46.8% (95% confidence interval [CI], 33.0-59.4%). Treatment-related death was not observed. Multivariate analysis identified stem cell transplantation (SCT), response to first-line chemotherapy, and bone metastasis as independent risk factors for OS. Objective response rate to first-line chemotherapy was 65.1% in the 43 evaluable patients. There was no significant difference in the response to different types of first-line chemotherapy. Among patients with lung metastasis alone, the 3-year OS rate was higher in 13 patients who received local treatment than in four who did not, although the difference was not significant. CONCLUSIONS: One possible reason for the high OS rates was the absence of treatment-related mortality even in patients receiving SCT, which could be attributed to advances in the management of post-SCT complications. Novel first-line chemotherapy strategies need to be established to improve the disease status prior to SCT in a higher proportion of patients.

Phase III study of palonosetron for prevention of chemotherapy-induced nausea and vomiting in pediatric patients.

BACKGROUND: Palonosetron has demonstrated non-inferiority to ondansetron for prevention of chemotherapy-induced nausea and vomiting in pediatric patients in the United States and Europe. We conducted a single-arm registration study to evaluate the efficacy, safety and pharmacokinetics of palonosetron in pediatric patients in Japan. METHODS: Key inclusion criteria were age of 28 days to 18 years and malignant disease for which initial highly emetogenic chemotherapy or moderately emetogenic chemotherapy was planned. Patients received palonosetron at 20 µg/kg over at least 30 s intravenously before the start of highly emetogenic chemotherapy or moderately emetogenic chemotherapy and received dexamethasone on Days 1-3. The primary endpoint was the proportion of patients achieving a complete response in the overall phase (0-120 h) in Course 1, and its threshold was set at 30%. RESULTS: From December 2016 to June 2019, 60 patients were enrolled, and 58 received at least one dose of palonosetron. The proportion of patients achieving a complete response during the overall phase was 58.6% (95% confidence interval, 44.9%-71.4%), showing the primary endpoint was met (P < 0.0001). Treatment-related adverse events occurred in two patients (3.4%). Regarding the pharmacokinetics of palonosetron, neither the plasma concentration immediately after administration nor the area under the plasma concentration-time curve from time 0 to infinity differed significantly among the age groups. CONCLUSION: We demonstrated the efficacy of palonosetron in pediatric patients receiving highly emetogenic chemotherapy or moderately emetogenic chemotherapy and confirmed the appropriateness of the 20 µg/kg dose, regardless of age, considering the safety and pharmacokinetic profiles. TRIAL REGISTRATION: JapicCTI-163305, registered 6 June 2016.

Rhabdoid tumor predisposition syndrome with renal tumor 10 years after brain tumor.

We report a case of rhabdoid tumor predisposition syndrome with a renal tumor developing 10 years after a brain tumor, which demonstrated an unexpectedly favorable outcome. A 2-year-old boy underwent gross total resection of a brain tumor located in the fourth ventricle, and received adjuvant chemotherapy and radiotherapy. At the age of 11 years, a renal tumor was found and nephrectomy was performed. He is currently alive without evidence of disease over 2 years without postoperative therapy. Histologically, rhabdoid cells were observed in both brain and renal tumors. Loss of SMARCB1 (also known as INI1) expression was found in the nucleus of both tumor cells. Genetic testing revealed pathogenic variants of SMARCB1 exon 5 in the renal tumor and SMARCB1 exon 9 in the brain tumor. In addition, heterozygous deletion of 22q11.21-q11.23 containing the SMARCB1 locus was shared by both tumors and this deletion was identified in normal peripheral blood. Considering the histopathological and genetic findings, our case was considered to be rhabdoid tumor predisposition syndrome with atypical teratoid/rhabdoid tumor and late-onset rhabdoid tumor of the kidney.

[Gemcitabine and Docetaxel for the Treatment of Relapsed and Refractory Malignant Rhabdoid Tumor of Kidney and Atypical Teratoid Rhabdoid Tumor].

Gemcitabine and Docetaxel(GEM/DTX)are well known chemotherapeutic drugs for the treatment of soft tissue sarcomas. However, the efficacy of these drugs in the treatment of malignant rhabdoid tumors(MRTs)has not been well described. We used GEM/DTX as salvage chemotherapy for relapsed and refractory MRTs, including 2 patients with malignant rhabdoid tumor of the kidney(MRTK)and 2 with atypical teratoid rhabdoid tumor(ATRT). At the best, partial response was observed in 3 patients(2 MRTK and 1 ATRT). The remaining patient with ATRT had stable disease. Localized edema in the field of recent radiation therapy was discovered in 2 patients. In addition, one had pleural effusion without any evidence of tumor progression. GEM/DTX can be used as a potential chemotherapeutic drug for relapsed or refractory MRTs, although attention should be paid to its unique adverse events.

Double-conditioning regimen consisting of high-dose thiotepa and melphalan with autologous stem cell rescue for high-risk pediatric solid tumors: A second report.

BACKGROUND: Pediatric patients with high-risk, relapsed, or refractory solid tumors have a poor prognosis. We have previously reported a dose-finding experience of high-dose chemotherapy consisting of thiotepa and melphalan ("double-conditioning regimen"). Using doses derived from that study, we have treated patients since 2005. We now report a retrospective review of patients treated by this fixed dose. PROCEDURE: We reviewed 50 patients (median 4 years; range 0-15 years) with high-risk or relapsed/refractory solid tumors treated by this dose-fixed, double-conditioning regimen from April 2005 to May 2014. Doses were thiotepa 800 mg/m2 and melphalan 280 mg/m2 for children ≥2 years of age, and 32 mg/kg and 6 mg/kg, respectively, for children <2 years of age. Further, doses were reduced according to creatinine clearance with poor renal function. RESULTS: Nonhematological toxicity was mainly gastrointestinal-grade 3 mucositis (n = 41) and grade 3-4 diarrhea (n = 10). Neurological, renal, and endothelial cell toxicity and sinusoidal obstruction syndrome were not observed. There were two toxic deaths (interstitial viral pneumonia). This regimen demonstrated antitumor activity against several types of tumors. Although the frequency of gastrointestinal toxicity was high, other severe toxicity was not observed. CONCLUSIONS: Our double-conditioning regimen was very well tolerated and demonstrated antitumor activity. We are moving forward with multi-institutional trials now.

Retrospective analysis of children with high-risk acute myeloid leukemia who underwent allogeneic hematopoietic stem cell transplantation following complete remission with initial induction chemotherapy in the AML-05 clinical trial.

In the AML-05 clinical trial conducted by the Japanese Pediatric Leukemia/Lymphoma Group from 2006 to 2010, children with high-risk acute myeloid leukemia (HR AML) received allogeneic hematopoietic stem cell transplantation (allo-HSCT) at first complete remission (CR1). The aim of this study was to investigate the impact of allo-HSCT on the outcome of HR AML. Patients with either monosomy 7, 5q-, t(16;21), Ph1, FLT3-ITD, or induction failure after the first course of chemotherapy were eligible for transplant. Of 53 children with HR AML, 51 received allo-HSCT-45 in CR1, five in CR2, and one with non-CR. t(8;21), t(9;11), and t(16;21) abnormalities were identified in eight, five, and four patients, respectively. The stem cell sources varied-bone marrow in 30 patients, peripheral blood in three, and cord blood in 18. The median follow-up was 62 months. The overall survival (OS) rates at 3 years were 73% and 25% for patients who received transplant at CR1 and ≥CR2, respectively. Multivariable analysis showed that patients with chronic graft-versus-host disease (cGVHD) had better OS. This study supports that allo-HSCT is a suitable treatment for HR AML in CR1. The favorable outcome associated with cGVHD indicates that a graft-versus-leukemia effect might be occurring.

Successful treatment of metastatic cerebral recurrence of pleuropulmonary blastoma.

Pleuropulmonary blastoma (PPB) is a rare pediatric tumor. The central nervous system (CNS) is the most common site of extrathoracic metastasis. The prognosis of PPB patients with CNS metastases is dismal: most patients die within one year after recurrence. Here, we describe two patients diagnosed with PPB who developed intracranial recurrences shortly after the end of their initial treatment and were successfully treated by gross total resection, radiotherapy, and chemotherapy. Both patients are in complete remission four and three years after recurrence. Although an optimal regimen remains to be determined, these cases demonstrate that PPB with CNS metastases is potentially curable.

Histological and genetic analysis of anaplastic pleomorphic xanthoastrocytoma suspected of malignant progression over a 12-year clinical course.

We report a case of anaplastic PXA for which histological study and molecular analysis were performed at the time of the first resection and two recurrences. A 15-year-old girl had a temporal lobe tumor that had been followed as a cystic lesion from three years of age without histopathological examination. The first and second surgical specimens exhibited typical histological features of PXA such as nuclear and cytoplasmic pleomorphism. In addition, microvascular proliferation was observed in the second surgical specimen. On the other hand, nuclear pleomorphism was unclear in the third surgical specimen and it was mainly composed of spindle cells. Palisading necrosis was observed. Mitotic figures and the Ki-67 proliferation index gradually increased. BRAF V600E and TERT promoter mutation were detected in the first, second, and third surgical specimens. In addition, PTEN mutation and CDNK2A deletion were detected in the third surgical specimen. Considering the histopathological and genetic changes over time, we concluded that our case of anaplastic PXA underwent malignant progression.

[Single institution experience of HLA-haploidentical hematopoietic stem cell transplantation for children: current problems and perspective].

HLA-haploidentical 2 or 3-loci mismatched families are alternative donors for high-risk patients without HLA-matched donors. We retrospectively reviewed our case series of HLA-halpoidentical hematopoietic stem cell transplantations (haplo-HSCTs). Between Jul 2005 and Dec 2012, 25 patients (median age, 8 y; 13 ALL, 8 AML, 4 others) received haplo-HSCTs because of a worsening prognosis (i.e. induction failure, non-CR, or relapse after prior HSCT). Disease status was CR in 8 and non-CR in 17 patients. The 17 patients received myeloablative conditioning, while the 8 were given reduced-intensity conditioning because of their conditions (e.g. early relapse after prior HSCT). ATG was not administered in all but 3 patients. Tacrolimus and sMTX were used for prophylaxis GVHD and steroids were immediately given to prevent the onset of aGVHD. The 3-year OS and EFS were 35.6±10.0% and 31.3±10.1%, respectively (median follow-up, 49 mo); 14 patients died of their primary disease. Grade 3-4 aGVHD occurred in 7 patients, 2 of whom died of grade 4 aGVHD. Eleven patients had extensive cGVHD. While 4 of the 8 CR patients remained in CR, only 4 of the 17 non-CR patients achieved long-term CR (survival time, 6-89 mo). Haplo-HSCT was tolerable with strict control of infections and GVHD. However, further strategies for non-CR patients appear to be required.

Characteristics of malignant brain tumor-associated epileptic spasms.

Although epilepsy is the most common comorbidity of brain tumors, epileptic spasms rarely occur. Brain tumors associated with epileptic spasms are mostly low-grade gliomas. To date, few studies in the literature have reported on malignant (Grades 3-4) brain tumors associated with epileptic spasms. Thus, we aimed to investigate the characteristics of malignant brain tumor-associated epileptic spasms. We retrospectively reviewed patients with malignant brain tumors and epileptic spasms in our institution. Data on demographics, tumor histology, magnetic resonance imaging, epileptic spasm characteristics, electroencephalography, and treatment responsiveness were also collected. Six patients were included. In all cases, the brain tumors occurred in infancy in the supratentorial region and epileptic spasm onset occurred after the completion of brain tumor treatment. Anti-seizure medication did not control epileptic spasms; two patients were seizure-free after epileptic surgery. Although all patients had developmental delays caused by malignant brain tumors and their treatment, developmental regression proceeded after epileptic spasm onset. Two patients who achieved seizure-free status showed improved developmental outcomes after cessation of epileptic spasms. This is the first report of the characteristics of malignant brain tumor-associated epileptic spasms. Our report highlights a difficulties of seizure control and possibillity of efficacy of epileptic surgery in this condition. In malignant brain tumor-associated epileptic spasms, it is important to proceed with presurgical evaluation from an early stage, bearing in mind that epileptic spasms may become drug-resistant.

Retinoid Therapy for Neuroblastoma: Historical Overview, Regulatory Challenges, and Prospects.

Retinoids are vitamin A derivatives and include trans-retinoic acid, isotretinoin, tamibarotene, and bexarotene, all of which are currently available for clinical use. The clinical development of retinoid therapy for neuroblastoma has a history spanning more than four decades. The most promising agent is isotretinoin, which can contribute to improving event-free survival in patients with high-risk neuroblastoma by approximately 10% when administered over six months as maintenance therapy. Although isotretinoin is regarded as an essential component in the standard clinical management of high-risk neuroblastoma, its use for this purpose in the US and EU is off-label. To promote isotretinoin use in Japan as a treatment for neuroblastoma, our clinical research team is planning to launch an investigator-initiated, registration-directed clinical trial. The present review article discusses the basic science behind retinoid therapy, pre-clinical/clinical evidence on neuroblastoma, the concept of the proposed clinical trial, and prospects for this therapy.

Phase I study of bevacizumab plus irinotecan in pediatric patients with recurrent/refractory solid tumors.

OBJECTIVE: Studies have suggested that bevacizumab has shown activity against various pediatric solid tumors. We, therefore, conducted a Phase I study of bevacizumab plus irinotecan in Japanese children with recurrent, progressive or refractory solid tumors. METHODS: The starting dose was bevacizumab 10 mg/kg over 60-90 min and irinotecan 125 mg/m(2) over 90 min intravenously on Days 1, 15 and 29. The dose of irinotecan was 340 mg/m(2) for patients receiving enzyme-inducing antiepileptic drugs. Treatment was repeated every 6 weeks for up to three courses in the absence of disease progression or unacceptable toxicity. RESULTS: Of 11 patients, 9 (median age, 9 years) were fully assessable for toxicity and received 24 courses. Dose-limiting toxicities were Grade 2 diarrhea and Grade 4 neutropenia/thrombocytopenia in two of the five patients at dose level 1. No dose-limiting toxicities were observed in four patients at dose level -1 at bevacizumab 10 mg/kg and irinotecan 100 mg/m(2) (270 mg/m(2) for patients taking enzyme-inducing antiepileptic drugs). The maximum-tolerated dose was bevacizumab 10 mg/kg and irinotecan 100 mg/m(2). The most frequent non-dose-limiting toxicities were Grade 1 or 2 hypertension, bleeding and hematologic toxicity. One patient with optic nerve glioma had a partial response. Three patients with medulloblastoma, optic nerve glioma and diffuse intrinsic pontine glioma had stable disease. CONCLUSIONS: Combination chemotherapy of bevacizumab plus irinotecan was well tolerated in children. We plan Phase II pediatric studies at doses of bevacizumab 10 mg/kg and irinotecan 100 mg/m(2) every 2 weeks (270 mg/m(2) for patients taking enzyme-inducing antiepileptic drugs).

Minimal Residual Disease Detected by the 7NB-mRNAs ddPCR Assay Is Associated with Disease Progression in High-Risk Neuroblastoma Patients: A Prospective Multicenter Observational Study in Japan.

High-risk neuroblastoma (HR-NB) patients remain far from obtaining optimal outcomes, with more than 50% relapse/regrowth rate despite current intensive multimodal therapy. This originated from the activation/proliferation of chemoresistant minimal residual disease (MRD). MRD with a significant prognostic was reported by several quantitative PCR (qPCR) or droplet digital PCR (ddPCR) assays quantitating different sets of NB-associated mRNAs (NB-mRNAs). The 7NB-mRNAs ddPCR assay quantitating CRMP1, DBH, DDC, GAP43, ISL1, PHOX2B, and TH mRNAs was reported to outperform other qPCR assays by a retrospective in-house observational study. In the present study, the Japan Children's Cancer Group (JCCG) Neuroblastoma Committee conducted a prospective multicenter observational study aimed at evaluating a prognostic value of MRD in bone marrow (BM-MRD) and peripheral blood (PB-MRD) detected by 7NB-mRNAs ddPCR assay. Between August 2018 and August 2022, 7 HR-NB patients who registered for JCCG clinical trials (JN-H-11 and JN-H-15) were enrolled. A total of 19 BM and 19 PB samples were collected, and 4/15 BM and 4/15 PB samples were classified as progressive disease (PD)/non-PD samples. BM-MRD and PB-MRD estimated area under curve (AUC) of 0.767 and 0.800 with a significant accuracy (AUC > 0.7). The present study validated a prognostic value of BM-MRD obtained by a previous study (AUC 0.723) and revealed the significant accuracy of PB-MRD as well as BM-MRD.

Myeloid/natural killer (NK) cell precursor acute leukemia as a distinct leukemia type.

Myeloid/natural killer (NK) cell precursor acute leukemia (MNKPL) has been described on the basis of its unique immunophenotype and clinical phenotype. However, there is no consensus on the characteristics for identifying this disease type because of its rarity and lack of defined distinctive molecular characteristics. In this study, multiomics analysis revealed that MNKPL is distinct from acute myeloid leukemia, T cell acute lymphoblastic leukemia, and mixed-phenotype acute leukemia (MPAL), and NOTCH1 and RUNX3 activation and BCL11B down-regulation are hallmarks of MNKPL. Although NK cells have been classically considered to be lymphoid lineage-derived, the results of our single-cell analysis using MNKPL cells suggest that NK cells and myeloid cells share common progenitor cells. Treatment outcomes for MNKPL are unsatisfactory, even when hematopoietic cell transplantation is performed. Multiomics analysis and in vitro drug sensitivity assays revealed increased sensitivity to l-asparaginase and reduced levels of asparagine synthetase (ASNS), supporting the clinically observed effectiveness of l-asparaginase.

A clinically adaptable method to enhance the cytotoxicity of natural killer cells against B-cell malignancies.

BACKGROUND AIMS: Retroviral transduction of anti-CD19 chimeric antigen receptors significantly enhances the cytotoxicity of natural killer (NK) cells against B-cell malignancies. We aimed to validate a more practical, affordable and safe method for this purpose. METHODS: We tested the expression of a receptor containing CD3ζ and 4-1BB signaling molecules (anti-CD19-BB-ζ) in human NK cells after electroporation with the corresponding mRNA using a clinical-grade electroporator. The cytotoxic capacity of the transfected NK cells was tested in vitro and in a mouse model of leukemia. RESULTS: Median anti-CD19-BB-ζ expression 24 h after electroporation was 40.3% in freshly purified (n =18) and 61.3% in expanded (n = 31) NK cells; median cell viability was 90%. NK cells expressing anti-CD19-BB-ζ secreted interferon (IFN)-γ in response to CD19-positive target cells and had increased cytotoxicity. Receptor expression was detectable 6 h after electroporation, reaching maximum levels at 24-48 h; specific anti-CD19 cytotoxicity was observed at 96 h. Levels of expression and cytotoxicities were comparable with those achieved by retroviral transduction. A large-scale protocol was developed and applied to expanded NK cells (median NK cell number 2.5 × 10(8), n = 12). Median receptor expression after 24 h was 82.0%; NK cells transfected under these conditions exerted considerable cytotoxicity in xenograft models of B-cell leukemia. CONCLUSIONS: The method described here represents a practical way to augment the cytotoxicity of NK cells against B-cell malignancies. It has the potential to be extended to other targets beyond CD19 and should facilitate the clinical use of redirected NK cells for cancer therapy.

Mutations profile of polycythemia vera and essential thrombocythemia among Japanese children.

BACKGROUND: Acquired somatic mutations of JAK2 have been reported to play a pivotal role in the pathogenesis of BCR-ABL1-negative myeloproliferative neoplasm (MPN). However, the molecular characteristics of childhood MPN remain to be elucidated. PATIENT AND METHODS: We investigated a group of pediatric patients diagnosed either with essential thrombocythemia (ET; N = 9) or polycythemia vera (PV; N = 4) according to WHO criteria (median age = 10 years; range 1.5-15 years) in whom direct sequencing was performed for the existence of genetic alterations in JAK2, MPL, TET2, ASXL1, CBL, IDH1, and IDH2. More sensitive allele specific polymerase chain reaction was used for JAK2(V617F) genotyping. RESULTS: We found three patients harbor JAK2(V617F) mutation (2/9 ET and 1/4 PV). Bone marrow examination showed small and large megakaryocytes with dysplastic features in JAK2(V617F)-positive ET patients compared to those without JAK2(V617F). We identified a previously unrecognized missense mutation at codon 1230 in exon 12 of ASXL1 gene in ET and PV patients (1/9 ET and 1/4 PV). Otherwise, no genetic alterations could be detected in JAK2 exon 12, MPL, TET2, CBL, IDH1, and IDH2 in all ET and PV patients. CONCLUSION: Although JAK2 mutations in childhood ET and PV are not as frequent as reported in adult patients, JAK2 is the most frequently mutated gene in childhood MPN known so far. Owing to the presence of childhood MPN without any genetic alterations in JAK2, MPL, TET2, ASXL1, CBL, IDH1, and IDH2, new biological markers have to be found.