Subtyping of Group 3/4 medulloblastoma as a potential prognostic biomarker among patients treated with reduced dose of craniospinal irradiation: a Japanese Pediatric Molecular Neuro-Oncology Group study

BACKGROUND

One of the most significant challenges in patients with medulloblastoma is reducing the dose of craniospinal irradiation (CSI) to minimize neurological sequelae in survivors. Molecular characterization of patients receiving lower than standard dose of CSI therapy is important to facilitate further reduction of treatment burden.

METHODS

We conducted DNA methylation analysis using an Illumina Methylation EPIC array to investigate molecular prognostic markers in 38 patients with medulloblastoma who were registered in the Japan Pediatric Molecular Neuro-Oncology Group and treated with reduced-dose CSI.

RESULTS

Among the patients, 23 were classified as having a standard-risk and 15 as high-risk according to the classic classification based on tumor resection rate and presence of metastasis, respectively. The median follow-up period was 71.5 months (12.0-231.0). The median CSI dose was 18 Gy (15.0-24.0) in both groups, and 5 patients in the high-risk group received a CSI dose of 18.0 Gy. Molecular subgrouping revealed that the standard-risk cohort included 5 WNT, 2 SHH, and 16 Group 3/4 cases; all 15 patients in the high-risk cohort had Group 3/4 medulloblastoma. Among the patients with Group 3/4 medulloblastoma, 9 of the 31 Group 3/4 cases were subclassified as subclass II, III, and V, which were known to an association with poor prognosis according to the novel subtyping among the subgroups. Patients with poor prognostic subtype showed worse prognosis than that of others (5-year progression survival rate 90.4% vs. 22.2%; p < 0.0001). The result was replicated in the multivariate analysis (hazard ratio12.77, 95% confidence interval for hazard ratio 2.38-99.21, p value 0.0026 for progression-free survival, hazard ratio 5.02, 95% confidence interval for hazard ratio 1.03-29.11, p value 0.044 for overall survival).

CONCLUSION

Although these findings require validation in a larger cohort, the present findings suggest that novel subtyping of Group 3/4 medulloblastoma may be a promising prognostic biomarker even among patients treated with lower-dose CSI than standard treatment.

Feasibility and Toxicity of Interval-Compressed Chemotherapy in Asian Children and Young Adults with Sarcoma

Twelve Asian patients with sarcoma received interval-compressed (ic-) chemotherapy scheduled every 14 days with a regimen of vincristine (2 mg/m²), doxorubicin (75 mg/m²), and cyclophosphamide (1200-2200 mg/m²) (VDC) alternating with a regimen of ifosfamide (9000 mg/m²) and etoposide (500 mg/m²) (IE), with filgrastim (5-10 mcg/kg/day) between cycles. Carboplatin (800 mg/m²) was added for CIC-rearranged sarcoma. The patients were treated with 129 cycles of ic-VDC/IE with a median interval of 19 days (interquartile range [IQR], 15-24 days. Median nadirs (IQR) were neutrophil count, 134 (30-396) × 10⁶/L at day 11 (10-12), recovery by day 15 (14-17) and platelet count, 35 (23-83) × 10⁹/L at day 11 (10-13), recovery by day 17 (14-21). Fever and bacteremia were observed in 36% and 8% of cycles, respectively. The diagnoses were Ewing sarcoma (6), rhabdomyosarcoma (3), myoepithelial carcinoma (1), malignant peripheral nerve sheath tumor (1), and CIC-DUX4 Sarcoma (1). Seven of the nine patients with measurable tumors responded (one CR and six PR). Interval-compressed chemotherapy is feasible in the treatment of Asian children and young adults with sarcomas.

Prevalence of pathogenic variants in cancer-predisposing genes in second cancer after childhood solid cancers

BACKGROUND

Second malignant neoplasms (SMNs) are one of the most severe late complications after pediatric cancer treatment. However, the effect of genetic variation on SMNs remains unclear. In this study, we revealed germline genetic factors that contribute to the development of SMNs after treatment of pediatric solid tumors.

METHODS

We performed whole-exome sequencing in 14 pediatric patients with SMNs, including three brain tumors.

RESULTS

Our analysis revealed that five of 14 (35.7%) patients had pathogenic germline variants in cancer-predisposing genes (CPGs), which was significantly higher than in the control cohort (p < 0.01). The identified genes with variants were TP53 (n = 2), DICER1 (n = 1), PMS2 (n = 1), and PTCH1 (n = 1). In terms of the type of subsequent cancer, leukemia and multiple episodes of SMN had an exceptionally high rate of CPG pathogenic variants. None of the patients with germline variants had a family history of SMN development. Mutational signature analysis showed that platinum drugs contributed to the development of SMN in three cases, which suggests the role of platinum agents in SMN development.

CONCLUSIONS

We highlight that overlapping effects of genetic background and primary cancer treatment contribute to the development of second cancers after treatment of pediatric solid tumors. A comprehensive analysis of germline and tumor samples may be useful to predict the risk of secondary cancers.

MEDB-30. Subclassification of Group 3/4 medulloblastoma as a potential prognostic biomarker to reduce the dose of craniospinal irradiation in patients with metastatic tumors: A Japanese Pediatric Molecular Neuro-Oncology Group study

BACKGROUND: In patients with medulloblastoma, one of the most significant challenges is to reduce the dose of craniospinal irradiation (CSI) to minimize neurological sequelae in survivors. Molecular characterization of patients treated using lower-dose CSI rather than standard therapy is important for further reducing the treatment burden. METHODS: We conducted DNA methylation analysis using an Illumina Methylation EPIC array to investigate molecular prognostic markers in 38 patients with medulloblastoma who were registered in the Japan Pediatric Molecular Neuro-Oncology Group and were treated using lower-dose CSI rather than standard-dose radiation therapy. RESULTS: Among the patients, 23 were classified as having a “standard-risk” and 15 as having a “high-risk” according to the classic classification based on tumor resection rate and presence of metastasis, respectively. The median follow-up period was 71.5 months. The median CSI dose was 18 Gy in both groups, and 10 patients in the “high-risk” group received a CSI dose of 23.4 Gy or 24 Gy. Molecular subgrouping revealed the “standard-risk” cohort included 5 WNT, 2 SHH, and 16 Group 3/4 cases; all 15 patients in the “high-risk” cohort had Group 3/4 medulloblastoma. Among the patients with Group 3/4 medulloblastoma, 13 of the 16 “standard-risk” patients were subclassified as subtypes I, IV, VI, and VII, which were associated with a good prognosis according to the novel sub-subclassification among Group 3/4 medulloblastomas. However, only 6 of the 15 “high-risk” patients were included in the subtypes. The good prognostic subtype cases among “high-risk” cohort were all survived without recurrence, in contrast to a worse prognosis (5-year progression free survival=33.3%; p=0.01) of the other cases. CONCLUSION: Although these findings require validation in a larger cohort, the present findings suggest that the novel sub-subclassification of Group 3/4 medulloblastoma may be a promising prognostic biomarker for reducing the dose of CSI in patients with metastatic medulloblastoma.

Quantitative assessment of copy number alterations by liquid biopsy for neuroblastoma

Liquid biopsy, a method of detecting genomic alterations using blood specimens, has recently attracted attention as a non-invasive alternative to surgical tissue biopsy. We attempted quantitative analysis to detect amplification of MYCN (MYCNamp) and loss of heterozygosity at 11q (11qLOH), which are clinical requisites as prognostic factors of neuroblastoma. In this study, cell-free DNA (cfDNA) was extracted from plasma samples from 24 neuroblastoma patients at diagnosis. Copy numbers of MYCN and NAGK genes were quantitatively analyzed by droplet digital PCR (ddPCR). 11qLOH was also assessed by detecting allelic imbalances of heterozygous single nucleotide polymorphisms in the 11q region. The results obtained were compared to those of specimens from tumor tissues. The correlation coefficient of MYCN copy number of cfDNA and tumor DNA was 0.88 (P < 0.00001). 11qLOH was also accurately detected from cfDNA, except for one case with localized NB. Given the high accuracy of liquid biopsy, to investigate components of cfDNA, the proportion of tumor-derived DNA was estimated by examining the variant allele frequency of tumor-specific mutations in cfDNA. The proportion of tumor-derived DNA in cfDNA was 42.5% (range, 16.9%-55.9%), suggesting sufficient sensitivity of liquid biopsy for neuroblastoma. In conclusion, MYCN copy number and 11qLOH could be quantitatively analyzed in plasma cfDNA by ddPCR assay. These results suggest that plasma cfDNA can be substituted for tumor DNA and can also be applied for comprehensive genomic profiling analysis. This article is protected by copyright. All rights reserved.

Development and validation of the Childhood Cancer Survivor Study-Neurocognitive Questionnaire (CCSS-NCQ) Japanese version

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Background: The lives of childhood cancer survivors (CCS) may be impacted by symptoms of neurocognitive dysfunction. Decline in executive function, one component of the construct concept of neurocognitive function, may affect the ability to be independent in later life; thus,ssessment and intervention are important. In the United States, the Childhood Cancer Survivor Study-Neurocognitive Questionnaire (CCSS-NCQ) developed by St. Jude Children’s Research Hospital has been widely utilized in clinical practice. It is a self-administered scale for screening daily difficulties regarding organization, emotional regulation, memory, and task efficiency which all fall under the concept of the executive function. To expand the tools for executive function assessment in Japan, we developed the CCSS-NCQ Japanese version and performed a validation study among the adolescent and young adult (AYA)-CCS population. Methods: The Japanese version of the CCSS-NCQ was developed by conducting linguistic validation. Japanese AYA-CCS of all cancer types were recruited and asked to complete this 32-question self-administered questionnaire. Exploratory and confirmatory factor analysis (FA) with the Promax rotation were conducted. Results: In total, 106 participants responded. The mean age of participants was 20.6 ± 5.3 years, and 49.1% were male. The mean age at diagnosis was 8.7 ± 4.8 years; 46.2% of participants were diagnosed with brain tumors, 37.7% with hematological malignancy, and 12.3% with solid tumors. The FA identified the similar four-factor structure of organization, emotional regulation, memory, and task efficiency as the original CCSS-NCQ with factor loading set at 0.4. The Cronbach’s alpha was 0.84 - 0.92. Conclusions: Neurocognitive dysfunction could be a crucial late complication of childhood cancer, and maintaining executive function, in particular, is essential for sustaining the quality of life among CCS. The CCSS-NCQ Japanese version is the first internationally translated CCSS-NCQ. The successful validation in the Japanese population will expand opportunities for future international collaboration to identify race/ethnicity-based disparities, as well as scale enhancement for application to CCS worldwide.

Gemtuzumab Ozogamicin Followed by Unrelated Cord Blood Transplantation With Reduced-intensity Conditioning for a Child With Refractory Acute Promyelocytic Leukemia

There is no established treatment for patients with acute promyelocytic leukemia (APL) refractory to targeted therapies with all-trans retinoic acid (ATRA) and/or arsenic trioxide (ATO). We report here a case of an 8-month-old girl with APL who failed standard ATRA-combined chemotherapy. Although molecular remission was achieved after introducing ATRA/ATO combination therapy, molecular relapse occurred during the ATO consolidation courses. Subsequent molecular remission was rapidly achieved after administering 2 doses of gemtuzumab ozogamicin. She was successfully treated with unrelated cord blood transplantation using reduced-intensity conditioning. Gemtuzumab ozogamicin might be a preferable choice for patients with APL refractory to standard therapy.

Japan Society of Clinical Oncology Clinical Practice Guidelines 2017 for fertility preservation in childhood, adolescent, and young adult cancer patients: part 2

The Japan Society of Clinical Oncology (JSCO) published the "JSCO Clinical Practice Guidelines 2017 for Fertility Preservation in Childhood, Adolescent, and Young Adult Cancer Patients" in 2017. This was the first guideline in cancer reproductive medicine in Japan. In the field of cancer reproductive medicine, close cooperation between an oncologist and a physician for reproductive medicine is important from before treatment initiation until long after treatment. The guideline takes into consideration disease specificity and provides opinions from the perspective of oncologists and specialists in reproductive medicine that are in line with the current state of the Japanese medical system. It is intended to serve as a reference for medical staff in both fields regarding the availability of fertility preservation therapy before the start of cancer treatment. Appropriate use of this guideline makes it easier to determine whether fertility preservation therapy is feasible and, ultimately, to improve survivorship in childhood, adolescent, and young adult cancer patients. In this article (Part 2), we describe details by organ/system and also for pediatric cancer.

Japan Society of Clinical Oncology Clinical Practice Guidelines 2017 for fertility preservation in childhood, adolescent, and young adult cancer patients: part 1

In 2017, the Japan Society of Clinical Oncology (JSCO) published the JSCO Clinical Practice Guidelines 2017 for Fertility Preservation in Childhood, Adolescent, and Young Adult Cancer Patients. These were the first Japanese guidelines to address issues of oncofertility. In this field of medicine, sustained close cooperation between oncologists and reproductive specialists is essential from the diagnosis of cancer until many years after completion of cancer treatment. These JSCO guidelines were intended to guide multidisciplinary medical staff in considering the availability of fertility preservation options and to help them decide whether to provide fertility preservation to childhood, adolescent, and young adult cancer patients before treatment starts, with the ultimate goal of improving patient survivorship. The guidelines are presented as Parts 1 and 2. This article (Part 1) summarizes the goals of the guidelines and the methods used to develop them and provides an overview of fertility preservation across all oncology areas. It includes general remarks on the basic concepts surrounding fertility preservation and explanations of the impacts of cancer treatment on gonadal function by sex and treatment modality and of the options for protecting/preserving gonadal function and makes recommendations based on 4 clinical questions. Part 2 of these guidelines provides specific recommendations on fertility preservation in 8 types of cancer (gynecologic, breast, urologic, pediatric, hematologic, bone and soft tissue, brain, and digestive).

MPC-6 Clinical significance of whole chromosomal aberration signatures in non-metastatic medulloblastomas treated with 18Gy of craniospinal irradiation

Background: One of the most significant challenges is a reduction in the dose of craniospinal irradiation (CSI) in patients with medulloblastoma to minimize neurological sequelae. However, a North American clinical trial failed to show the prognostic non-inferiority of lower-dose irradiation compared to that associated with standard-dose radiation therapy for non-metastatic medulloblastomas. A European retrospective study revealed that whole chromosomal aberration signatures (WCASs) are a potential prognostic factor in Group 3/4 medulloblastoma without metastasis, but whether the molecular signature has the same clinical impact in patients treated with lower-dose CSI remains unknown. Methods: We conducted DNA methylation analysis using an Illumina Infinium Human Methylation EPIC BeadChip array to investigate molecular prognostic markers in 23 medulloblastoma patients who were registered in the Japan Pediatric Molecular Neuro-Oncology Group and treated with lower-dose CSI relative to standard treatment. A WCAS was defined as the presence of at least two of three chromosomal changes as follows: chromosome (chr) 7 gain, chr 8 loss, and chr 11 gain.Results: All patients presented with no residue or a residual tumor smaller than 1.5 cm2 after surgery without metastasis. The median age at onset was 6.9 years, and the median follow-up period was 80.6 months. CSI was delivered at a median dose of 18.0 Gy. Regarding molecular subgrouping, there were 5 WNT, 2 SHH, 1 Group 3, and 15 Group 4 medulloblastomas. Seven patients with Group 3/4 medulloblastomas showed WCASs and had significantly better prognosis than those without the alteration (5-year progression-free survival 100% vs. 63%, p = 0.046). Two late relapses occurred at 89 and 115 months after diagnosis, respectively, and one of these patients presented with a WCAS.Conclusion: WCAS may be a molecular prognostic marker not only in patients with medulloblastoma treated with standard-dose CSI but also in those treated with lower-dose irradiation.

Risk factors for post-nephrectomy hypotension in pediatric patients

BACKGROUND

Although hypotension is a life-threatening complication of nephrectomy in children, risk factors for its development remain unknown. We evaluated the incidence, clinical course, and associated risk factors of pediatric post-nephrectomy hypotension in an observational study.

METHODS

This retrospective observational study included the clinical data of children who underwent nephrectomy in our center between 2002 and 2020. Patients undergoing nephrectomy at kidney transplantation and those who developed hypotension before nephrectomy were excluded.

RESULTS

The study included 55 nephrectomies in 51 patients, including 42 unilateral, 4 two-stage bilateral, and 5 simultaneous bilateral nephrectomies. The diagnoses were isolated Wilms tumor, neuroblastoma, congenital nephrotic syndrome, Denys-Drash syndrome, WAGR (Wilms tumor, aniridia, genitourinary malformations, and mental retardation) syndrome, and autosomal recessive polycystic kidney disease in 24, 10, 9, 6, 1, and 1 patient, respectively. Post-nephrectomy hypotension developed in 11 (20%) patients. Two patients (3.6%) had persistent hypotension; both had their kidneys resected, and one patient (1.8%) died. Male sex, kidney disease, resection of both kidneys, low estimated glomerular filtration rate, increased left ventricular posterior wall thickness in diastole, hypertension before nephrectomy, antihypertensive use, hyperreninemia, and hyperaldosteronism were significantly associated with post-nephrectomy hypotension. Multivariate logistic regression analysis revealed that hypertension before nephrectomy was the only significant risk factor for post-nephrectomy hypotension (P = 0.04).

CONCLUSIONS

Hypertension before nephrectomy is a significant risk factor for pediatric post-nephrectomy hypotension. Life-threatening hypotension, which might occur after bilateral nephrectomy in infants, should be considered, especially in children with higher risks.

Perspectives on follow-up care and research for childhood cancer survivors: results from an international SIOP meet-the-expert questionnaire in Kyoto, 2018

INTRODUCTION

Survival of childhood cancer has increased over the past decades. This has led to the development of strategies aiming to enhance follow-up care and research, for which priorities may vary globally. We explored perspectives of an international healthcare workers panel.

METHODS

Attendants of a meet-the-expert session on childhood cancer survivorship at the 2018 SIOP conference completed a survey about their view on important follow-up care and research aspects for survivors below and over 18 years. We analysed overarching categories and subtopics, and compared Asian versus European and North American healthcare workers.

RESULTS

A total of 58 participants from different medical specialties (67.2% paediatric oncologists) and continents (48.3% Asia, 39.7% Europe/North America) responded. Follow-up care priorities for survivors below and over 18 years included physical care (39.3% ≤18 years, 35.9% >18 years) and healthcare structure (29.4%, 26.0%). Physical care was also the most important research aspect for both age groups (52.5%, 50.7%). Psychological support was the most frequently reported subtopic. Asian clinicians (n = 22) primarily prioritized physical care aspects of follow-up care, whereas European/North American (n = 19) clinicians underscored the importance of healthcare structure.

CONCLUSION

Physical care is the most important aspect of survivorship care and research according to clinicians from several continents. Asian and European/North American respondents shared most priorities, however, healthcare structure was a more important category for European/North American clinicians. The most common subtopic was psychological support, underlining also the need to involve psychologists in follow-up.

Effect of high-dose chemotherapy plus stem cell rescue on the survival of patients with neuroblastoma modified by MYCN gene gain/amplification and remission status: a nationwide registration study in Japan

In high-risk neuroblastoma, the presence of an MYCN gain/amplification (MYCN-GA) is not always a risk factor of cancer-specific death. We herein examined the effect modification of high-dose chemotherapy with autologous hematopoietic stem cell rescue (HDC-autoSCR) in terms of the interaction between MYCN status and remission status (complete remission or very good partial remission [CR/VGPR] vs. partial remission or less [≤PR]). The present study recruited patient data from 1992 to 2017 in the Japan Society of Hematopoietic Cell Transplantation's national registry. The MYCN status was known in 586 of 950 patients with a single course of HDC-autoSCR. Cumulative hazard curves for neuroblastoma-specific death showed that a subgroup with MYCN-GA and ≤PR had a significantly poorer prognosis than three other subgroups, namely, the MYCN-NGA/ ≤ PR, MYCN-NGA/CR/VGPR, and MYCN-GA/CR/VGPR subgroups even after adjusting for non-infants and stage IV disease (hazard ratio: 2.79; 95% confidence interval: 1.91-4.09; P < 0.001). The interaction between MYCN-GA and ≤PR was significant (p_interaction = 0.006). Hence, the patients with MYCN-GA with non-remission status at HDC-autoSCR had a significantly poorer prognosis than the other subgroups, suggesting that HDC-autoSCR may be effective in patients with CR/VGPR regardless of MYCN gene status and in patients with MYCN-NGA regardless of remission status.

Identifying Issues in Fertility Preservation for Childhood and Adolescent Patients with Cancer at Pediatric Oncology Hospitals in Japan

Purpose: We conducted a questionnaire survey in 15 pediatric oncology hospitals in Japan to better understand the current status of fertility preservation in childhood and adolescents. Methods: The survey period was from September 2020 to December 2020. We mailed questionnaires to 64 departments involved in pediatric cancer treatments at the 15 hospitals. The primary outcomes were the timing of providing explanations on fertility preservation, presence of health care provider while providing explanations, cooperation between medical staff, and cooperation between hospitals. Results: The response rate was 100% (64/64). Regarding the time at which this information was provided, 79.6% of patients (43/54) received it before cancer treatment; 5.6% (3/54), after remission; and 14.8% (8/54), both time points. Nurses were mostly in attendance (70%) when oncologists provided information to patients. Nine (60%) hospitals did not have a reproductive department. Among these, 28.6% of the respondents referred patients to a reproductive facility that performed fertility preservation. Providing information about fertility preservation was challenging owing to the shortage of specific explanatory materials (35.1%) and the lack of cooperation between pediatric oncologists and reproductive endocrinologists (24.6%). Conclusion: Based on this survey, educational activities regarding fertility preservation centered on pediatric oncologists and nurses are needed. Furthermore, a system for providing explanatory materials for fertility preservation and encouraging cooperation at the physician and hospital levels is also needed (IRB No. H2020-111).

Thiotepa-melphalan myeloablative therapy for high-risk neuroblastoma

BACKGROUND

Appropriate high-dose chemotherapy (HDC) for high-risk neuroblastoma has not yet been established. In Japan, a unique HDC regimen that comprises two cycles of a total of 800 mg/m² of thiotepa and a total of 280 mg/m² of melphalan is widely utilized.

METHODS

To evaluate the safety and efficacy of this thiotepa-melphalan high-dose therapy for high-risk neuroblastoma, we reviewed the medical records of 41 patients with high-risk neuroblastoma who underwent this regimen followed by autologous peripheral blood stem cell rescue between 2002 and 2012. MYCN-amplified high-risk neuroblastomas were observed in 23 patients. All patients underwent intensive multidrug induction chemotherapy, but none underwent anti-GD2 antibody immunotherapy. The primary tumor was resected at the adequate time point.

RESULTS

The median follow-up duration for living patients was 9.2 years (range 5.5-14.0 years). The 5-year event-free survival (EFS) and overall survival from treatment initiation were 41.5 ± 7.7% and 56.1 ± 7.8%, respectively. The 5-year EFS of MYCN-amplified high-risk neuroblastoma patients was 60.9 ± 10.2%, which was significantly superior compared with those with MYCN-nonamplified high-risk neuroblastoma (16.7 ± 8.8%; p < .001). MYCN amplification was the most favorable prognostic factor for EFS (hazard ratio = 0.29; 95% confidence interval = 0.12-0.66). Of the 41 patients, three died because of regimen-related toxicity (infection, n = 2; microangiopathy, n = 1).

CONCLUSION

The thiotepa-melphalan high-dose therapy with thiotepa and melphalan may be effective for high-risk neuroblastoma. However, this regimen is toxic and warrants special attention in clinical practice.

Initial symptoms and diagnostic delay in children with brain tumors at a single institution in Japan

Background

A prolonged interval between onset of symptoms and diagnosis of childhood brain tumor is associated with worse neurological outcomes. The objectives of this study are to determine factors contributing to diagnostic delay and to find an interventional focus for further reduction in the interval between symptom onset and diagnosis in Japan.

Methods

We retrospectively analyzed 154 patients younger than 18 years with newly diagnosed brain tumors who visited our institution from January 2002 to March 2013.

Results

The median age at diagnosis was 6.2 years and the median total diagnostic interval (TDI) was 30 days. Patients with low-grade tumors and cerebral midline tumor location had significantly long TDI. Durations between the first medical consultation and diagnosis (diagnostic interval, DI) were exceedingly longer for patients with visual, hearing, or smelling abnormalities as the first symptom (median, 303 days). TDI and DI of patients who visited ophthalmologists or otolaryngologist for the first medical consultation were significantly longer. Among these patients, longer DI was associated with worse visual outcome.

Conclusion

Raising awareness of brain tumor diagnosis among ophthalmologists and otolaryngologists may reduce diagnostic delay and may improve the neurological impairment of children with brain tumors in Japan.

ATRT-11. PREVALENCE OF GERMLINE VARIANTS IN SMARCB1 INCLUDING SOMATIC MOSAICISM IN AT/RT AND OTHER RHABDOID TUMORS

BACKGROUND

Genetic hallmark of atypical teratoid/rhabdoid tumor (AT/RT) is loss-of-function variants or deletions in SMARCB1 gene on 22q11.2 chromosome, which is common to extracranial malignant rhabdoid tumors (MRT). Previous studies demonstrated that approximately one-thirds of AT/RT and extracranial MRT patients harbored germline SMARCB1 variants as the rhabdoid tumor predisposing syndrome. We studied herein intensive analysis of the SMARCB1 gene in AT/RT and extracranial MRT patients focusing on prevalence of germline genetic variants. PROCEDURE: In total, 16 patients were included. Both tumor-derived DNA and germline DNA were obtained from all patients. First, screening for SMARCB1 alterations in the tumor specimens was done by direct sequencing, ddPCR and SNP array analysis. Then, analysis of germline DNA samples focusing on the genomic abnormalities detected in the paired tumors in each case was performed.

RESULTS

In eight of 16 cases (50%), genomic alterations observed in the tumor-derived DNA were also detected in the germline DNA. It is worth noting that three patients had germline mosaicism. Two of three patients had mosaic deletion, including SMARCB1 region, and the average copy number of the deleted region in the SMARCB1 gene in the germline was 1.60 and 1.76. For another patient, the fraction of SMARCB1 variants in normal cells was as low as 1.7%.

CONCLUSIONS

Approximately half the MRT cases in this study had SMARCB1 germline alterations. Considering the presence of low-frequency mosaicisms which conventional methods might overlook, inherited germline variants in predisposition genes are more important than previously assumed for the pathogenesis of pediatric cancers.

RARE-26. RETROSPECTIVE ANALYSIS OF PEDIATRIC CHOROID PLEXUS TUMORS

BACKGROUND

Choroid plexus tumors (CPT) include choroid plexus papilloma (CPP), atypical choroid plexus papilloma (aCPP), and choroid plexus carcinoma (CPC). Because of their rarity, limited data are available on the current status of treatment and outcomes for pediatric CPTs.

METHOD

We retrospectively reviewed clinical information on patients with CPT patients aged between 0 and 30 years at diagnosis and were treated in 8 institutions in Japan.

RESULTS

Of forty-two cases initially diagnosed as CPT, 18 cases were reviewed by central pathologists. As a result, the diagnosis of CPC or aCPP in five cases were changed to other tumors including AT/RT and astroblastoma. The remaining 37 cases were subjected to analysis. Median age at diagnosis was two years (0 to 25) and the mean follow-up period was seven years. All 26 patients with CPP (n=20) or aCPP (n=6) underwent gross-total resection without adjuvant therapy. Of them 24 patients are alive without recurrence. Four patients of patients with CPC (n=11) died of cancer. Five patients including three patients experienced local relapse, achieved complete remission after resection of tumor plus chemoradiotherapy. All three patients with dissemination of CPC at diagnosis or relapse died of the disease. At least three patients were diagnosed with Li-Fraumeni syndrome: one died of medulloblastoma and one patient developed osteosarcoma.

CONCLUSION

Compared with the excellent prognosis of CPP, the survival rates for CPC, especially disseminated CPC are unsatisfactory. Our results also underline the importance of considering genetic testing of TP53 for patients with CPC.

RARE-16. SEVEN CASES OF RETINOBLASTOMA WITH CNS INVOLVEMENTS

Treatment strategy for trilateral retinoblastoma (TRb: very rare RB with brain tumor) or retinoblastoma with central nervous system (CNS) involvement is not established yet. We retrospectively reviewed our seven cases of these rare almost fatal tumors. Their ages at diagnosis are 0y3m-1y10m (median 1y3m) (Male 4, Female 3). Only one had RB family history. Their affected eyes were bilateral 3, unilateral 3 and no 1. Their CNS involvements were suprasellar tumor 4, pineal tumor 1 and cerebrospinal fluid (CSF) cytology positive 2. Three of the suprasellar tumor patients had spinal metastasis. Four of the seven patients were TRb and one were genetically classified suprasellar retinoblastoma. All of them were treated with chemotherapy and four received high-dose chemotherapy. Three brain tumors of four TRb almost disappeared with chemotherapy. Two of them also received radiotherapy but relapsed. Although one radiation-free long-term TRb survivor developed secondary osteosarcoma, he got remission again and live 5 more years. One CSF positive Rb patient with chiasm invasion died of disease 11 months later. The other patient had no chiasm invasion nor CSF involvement at diagnosis, but his CSF cytology turned to positive after his second cycle of chemotherapy. He got remission with radiotherapy and high-dose chemotherapy, and alive without disease for 4 years. 2-year RFS and 2-year OS of all patients were 40% and 60%. Although our TRb patients responded to chemotherapy, it was difficult to avoid radiotherapy except one. Data accumulation is necessary for better treatment of these cancer-predisposed patients.

ETMR-11. A CASE OF PRIMARY DIFFUSE LEPTOMENINGEAL PRIMITIVE NEUROECTODERMAL TUMOR

BACKGROUND

Primary diffuse leptomeningeal primitive neuroectodermal tumor (PDL PNET) is a rare embryonal brain tumor which arises primarily in the meninges without an intraparenchymal mass. Few previous reports of this condition exist, and the clinical outcomes are poor. We herein report a case of a child with PDL PNET and present a cursory review of the literature. CASE: A 3-year-old female patient was seen at a local clinic due to vomiting, headaches, and seizures. As a head MRI revealed hydrocephalus but no mass, acute encephalopathy was initially diagnosed. She received steroid pulse therapy, but the symptoms progressed to hallucination and lethargy. Another MRI at the 1-month follow-up revealed diffuse leptomeningeal enhancement. Thereafter she was transferred to our hospital. A spine MRI revealed spinal dissemination. She underwent a dura mater biopsy, and the pathological analysis led to the diagnosis of PDL PNET. She received chemotherapy consisting of vincristine, cyclophosphamide, etoposide, cisplatin, and intrathecal methotrexate injections two months after the initial presentation. The progressive hydrocephalus was managed with external ventricular drainage. Two weeks after the first cycle of chemotherapy the hydrocephalus resolved, and the external ventricular drainage was removed. A follow-up MRI showed that the leptomeningeal enhancement decreased during the four cycles of chemotherapy without radiotherapy. The patient is scheduled to receive high-dose chemotherapy as consolidation therapy.

CONCLUSION

PDL PNET is extremely rare, and its diagnosis is often delayed. Treatment of PDL PNET is very difficult due to its aggressive course, and surgical resection is impossible. Early diagnosis may help improve outcomes.

HGG-49. A PEDIATRIC THALAMIC HIGH-GRADE GLIOMA WITH H3F3A K27M AND BRAF V600E DOUBLE MUTATIONS

CASE

A 18-month-old boy presented with approximately 2 months history of progressive left hemiparesis and left exotropia. MRI study showed a 3–4 cm T1-iso, T2-high tumor at right thalamus to midbrain with little contrast enhancement. The patient underwent endoscopic biopsy of the tumor, which showed relatively dense proliferation of small cells with round nuclei, mitosis of the tumor cell, but no necrosis. Immunohistochemical showed positive stain of GFAP and Olig2. Ki-67 was 34%. The histopathological diagnosis was compatible with high grade glioma. Chemotherapy with vincristine, cyclophosphamide, cisplatin and etoposide was initiated. Molecular testing of the tumor revealed H3F3A K27M and BRAF V600E double mutations in DNA from frozen tumor tissue.

DISCUSSION

The concurrent mutation of H3F3A K27M and BRAF V600E in pediatric glioma is very rare, but there are several cases previously reported in literature. Interestingly those cases are heterogenous in age, location, histopathological subtypes and clinical outcome.

SURG-17. CLINICAL CHARACTERISTICS AND OUTCOMES OF EPILEPSY-RELATED BRAIN TUMOR IN CHILDREN

OBJECTIVE

Epilepsy is one of the earliest symptoms in pediatric brain tumor. Gross total resection (GTR) of the tumor does not necessarily achieve seizure free, therefore it is controversial whether surrounding epileptic foci should be resected at the initial surgery. The aims of this study are to report clinical characteristics and outcome of pediatric epilepsy-related brain tumor (ERBT) and to discuss treatment strategy.

METHODS

Subjects were children less than 18 years old who underwent surgery for ERBT. Patients in whom epilepsy had been controlled before surgery were excluded. Data were collected from medical record and retrospectively reviewed.

RESULTS

Twenty-one children (8 boys and 13 girls) were analyzed in this study. The mean age at surgery was 6.8 years. Tumor was astrocytic tumor in 10, gangliogioma in 4 and dysembryoplastic neuroepithelial tumor in 3. Intracranial subdural electrodes were placed prior to tumor resection in 5 cases. GTR was achieved in 14 (67%). Seizure free was achieved in 15 (71.4%). GTR was significantly associated with seizure free (p=0.002).

CONCLUSION

In most of ERBT, seizure free can be achieved by lesionectomy alone. However, the resection of surrounding epileptic foci is required in some cases. Detailed examinations to detect the epileptic foci should be performed in ERBT, particularly in case of drug-resistant intractable epilepsy.

Definitive Tumor Resection after Myeloablative High Dose Chemotherapy Is a Feasible and Effective Option in the Multimodal Treatment of High-Risk Neuroblastoma: A Single Institution Experience

BACKGROUND/PURPOSE

The delayed local treatment approach (DL) in high-risk neuroblastoma (HR-NB) refers to the process in which tumor resection is performed after the completion of all the courses of chemotherapy, including myeloablative high-dose chemotherapy (HDC). Alternatively, in the conventional local treatment approach (CL), tumor resection is performed during induction chemotherapy. In this study, we compared the surgical outcomes in HR-NB patients treated by CL and DL.

METHOD

Forty-seven patients with abdominal HR-NB underwent primary tumor resection from 2002 to 2018. The timing of surgery was generally determined by following the trials and guidelines available at the time. The outcomes and surgical complications between the two strategies were compared.

RESULT

Operation time, blood loss, and postoperative WBC counts were lower in the DL group (n = 25) when compared to the CL group (n = 22), statistical significance notwithstanding. Major vascular structures were less frequently encased in the DL group tumors, while immediate surgical complications were significantly more frequent in the CL group (P < 0.05). Furthermore, the 3-year EFSs were 50.0% and 53.9% in the DL and CL groups, respectively.

CONCLUSION

DL appears to be a feasible and effective treatment option for HR-NB. Nonetheless, further verifications using larger cohorts are warranted.

LEVEL OF EVIDENCE

Treatment study, Level III.

Hematopoietic Cell Transplantation for Chronic Granulomatous Disease in Japan

Hematopoietic cell transplantation (HCT) is established as a curative treatment for severe chronic granulomatous disease (CGD). However, outcomes of HCT for CGD in Japan had not been precisely reported. We evaluated the outcome of HCT for CGD in Japan by means of a nationwide survey. A total of 91 patients (86 males and 5 females) with CGD who received HCT between 1992 and 2013 was investigated. Their median age at HCT was 11 years (0–39). Sixty-four patients had X-linked CGD caused by CYBB gene mutations, 13 had autosomal recessive CGD (7 CYBA and 6 NCF2), and 14 were genetically undetermined. Seventy patients are still alive at a median follow-up of 38.9 (3.7–230) months. Three-year OS and EFS was 73.7 and 67.6%, respectively. Twenty-one patients died mainly from transplant-related mortality. The cumulative incidence of grade II to IV acute GVHD and extensive chronic GVHD was 27.2 and 17.9%, respectively. Risk factors for EFS after HCT for CGD were age >30 years (P < 0.01), non-CYBB gene mutations (P < 0.01) and CBT (P < 0.01). Regarding the reduced intensity conditioning (RIC) regimen, risk factors for EFS included anti-thymocyte globulin (P = 0.048) and not using low-dose irradiation therapy (P < 0.01), in addition to the preceding risk factors. We report outcomes of HCT for CGD in Japan. Future studies are needed to improve such outcomes, especially for patients harboring non-CYBB gene mutations and suffering from adult CGD. A RIC regimen including low-dose irradiation may be a good option to explore further.

Neoadjuvant chemotherapy for atypical teratoid rhabdoid tumors (AT/RTs)

PURPOSE

Atypical teratoid rhabdoid tumor (AT/RT) is a rare, clinically highly malignant tumor. The extent of the surgical resection may affect survival. However, it is often difficult to perform gross total resection (GTR) at an initial surgery because of the large tumor size and high vascularity. Neoadjuvant chemotherapy may reduce not only the size but also the vascularity. We report our experience, review the literature, and analyze its effectiveness.

METHODS

A retrospective chart review of patients who underwent neoadjuvant chemotherapy and second-look surgery was performed. Demographic data, treatment courses, changes in tumor after the chemotherapy, extent of resection and estimated blood loss (EBL) during the second-look surgery, and outcome of each children were evaluated.

RESULTS

There are 4 cases. The average age at diagnosis was 13.3 months (2-30 months). Two to 4 courses of neoadjuvant chemotherapy were performed. MRI after the chemotherapy showed reduction of tumor volume, and tumor vascularity at the second-look surgery decreased in all cases. GTR was achieved in 3 cases, and NTR in 1 case. The mean EBL/estimated blood volume (EBL/EBV) was 21.3% (1.5-39%). The mean follow-up period was 23 months (2-48 months). At the last follow-up, 2 patients were alive without recurrence of the tumor (the follow-up periods were 48 and 16 months).

CONCLUSIONS

Neoadjuvant chemotherapy for AT/RTs might reduce both tumor size and vascularity, which enabled the maximal tumor resection. It may contribute to improve the prognosis of AT/RT through facilitating the tumor resection.

Tacrolimus blood concentration increase depends on administration route when combined with voriconazole in pediatric stem cell transplant recipients

BACKGROUND

Understanding of TAC pharmacokinetics is required to avoid both overdosing and underdosing. VRCZ is known to increase the TAC blood concentration by inhibiting CYP3A4; however, detailed, practical information on pediatric cases is still scarce. Herein, we investigated the association between the TAC blood concentration and dosage focusing on the administration route and concomitant use of VRCZ in children.

METHODS

In total, 38 children who received TAC during stem cell transplantation at our hospital between January 2013 and April 2018 were included. The ratio of the TAC blood concentration (ng/mL) to dosage (mg/kg/day) (C/D) was calculated at the last continuous intravenous infusion (C/Div) and after switching to oral administration (C/Dpo).

RESULTS

Patients with VRCZ (n = 14) showed a higher C/D regardless of administration route (median C/Div: with VRCZ/without VRCZ = 832/643, median C/Dpo: with VRCZ/without VRCZ = 339/45). Additionally, the (C/Div)/(C/Dpo) was about one-fourth in cases with VRCZ; the median (C/Div)/(C/Dpo) was 3.3 for cases with VRCZ and 13.5 for cases without VRCZ. Interestingly, the increase in the TAC blood concentration due to VRCZ was higher when TAC was administered orally, especially in adolescent patients.

CONCLUSIONS

To obtain an optimal TAC blood concentration, dose adjustment based on multiple factors, such as administration route, concomitant use of VRCZ, and age, is required.

PEDT-04 SIX CASES OF RETINOBLASTOMA WITH CNS INVOLVEMENT

Although the survival rate of intraocular retinoblastoma (RB) is nearly 100%, the outcome of central nervous system (CNS) involvement or Trilateral retinoblastoma (TRb: very rare RB which associated with brain tumor) is dismal. We retrospectively reviewed our six cases of these rare tumors. Their ages at diagnosis are 0y3m-1y10m (median 1y3m) (Male 4, Female 2). Only one had RB family history. Their affected eyes were bilateral 2, unilateral 3 and no 1. Their CNS diseases were suprasellar tumor 3, pineal tumor 1 and cerebrospinal fluid (CSF) cytology positive 2. Two of the suprasellar tumor patients had spinal metastasis. Three of the six patients were TRb. One TRb patient was treated with chemotherapy and high-dose chemotherapy without radiotherapy. Although he suffered with secondary osteosarcoma seven years later, he got complete remission and alive 5 years more without any tumor recurrence. The second TRb patient was treated with chemotherapy and local radiotherapy but relapsed 20 months later. The third TRb patient was chemotherapy resistant. Two CSF positive patients had optic nerve invasion. One patient with chiasm invasion died 11 months later because of treatment resistance. The other patient with optic nerve invasion before optic canal had no CNS tumor nor CSF involvement at diagnosis. Chemotherapy before enucleation was given to avoid dissemination. However, CSF cytology became positive after enucleation and remained even with intensified chemotherapy. Finally, he got remission with radiotherapy and high-dose chemotherapy, and alive without disease for 3.8 years. The last patient had suprasellar genetically classified retinoblastoma tumor and cerebrospinal metastasis. This patient showed good chemotherapy response and is still under treatment. Even with &quotso called° fatal RB cases, some case could survive with intensified therapy. Data accumulation is necessary for better survival of these tumors.

Clinical characteristics, treatment, and survival outcome in pediatric patients with atypical teratoid/rhabdoid tumors: a retrospective study by the Japan Children's Cancer Group

OBJECTIVE

The prognosis of atypical teratoid/rhabdoid tumors (ATRTs) has improved in recent years with the use of multimodal therapy, mainly in cases not involving metastatic disease. The authors wanted to obtain historical control data and evaluate the suitable treatments in Japanese children with ATRTs that were proven negative for INI-1 immunostaining.

METHODS

The authors retrospectively collected clinical information on 38 pediatric patients with ATRTs treated from 2005 to 2016 and analyzed the data for this series.

RESULTS

The median age of the patient population was 1.3 years, and the male/female ratio was approximately 2:1. Twenty-three patients (60.5%) had metastases. The effects of treatment on prognosis were analyzed for 34 patients after exclusion of 4 patients who could not receive curative treatment. At a median follow-up of 40.9 months, the mean (± SD) progression-free survival (PFS) and overall survival (OS) were 66.6% ± 8.3% and 45.9% ± 8.7% at 2 years and 44.2% ± 9.9% and 34.2% ± 8.9% at 5 years, respectively. The metastasis stage at diagnosis (M0-1 vs M2-4) (HR 2.68, 95% CI 1.08-6.65; p = 0.0338) and gross tumor resection (yes vs no) (HR 3.49, 95% CI 1.01-12.1; p = 0.0481) were prognostic factors for PFS but not for OS. Postoperative chemotherapy was performed in all 34 cases. High-dose chemotherapy was performed in 19 (55.8%) of 34 patients and showed a positive impact on OS (HR 0.31, 95% CI 0.11-0.86; p = 0.0254); the most commonly used regimen was a double-conditioning regimen of thiotepa plus melphalan. Local radiotherapy had a positive impact on both PFS and OS; however, craniospinal irradiation (CSI) performed in 12 patients as the primary therapy was associated with a poor outcome. Disseminated recurrence within 12 months from diagnosis was the most common pattern of treatment failure regardless of CSI.

CONCLUSIONS

There has been an improvement in outcomes for pediatric ATRT patients since the introduction of multimodal therapy in Japan, mainly in patients without metastases. Even if selection bias is taken into consideration, CSI did not contribute to an improved prognosis. Novel treatment approaches are required for pediatric ATRT patients with metastases.

Preoperative diagnosis of clear cell sarcoma of the kidney by detection of BCOR internal tandem duplication in circulating tumor DNA

Clear cell sarcoma of the kidney (CCSK) is the second most common renal malignancy in children. The prognosis is poorer in CCSK than in Wilms' tumor, and multimodal treatment including surgery, intensive chemotherapy, and radiation is required to improve the outcome for children with CCSK. Histological evaluation is required for the diagnosis. However, biopsies of tumors to obtain diagnostic specimens are not routinely performed because of the risk of spreading tumor cells during the procedure. Recently, internal tandem duplication (ITD) of BCOR has been recognized as a genetic hallmark of CCSK. We herein established a novel BCOR-ITD-specific polymerase chain reaction method with well-designed primers, and then performed a liquid biopsy for cell-free DNA (cfDNA) obtained from plasma of three children with nonmetastatic renal tumors (stage II) and from one control. BCOR-ITD was positively detected in the cfDNA of two cases, both of which were later diagnosed as CCSK based on histological feature of the resected tumor specimen, while it was not detected for a normal control and a patient diagnosed with Wilms' tumor. Our study is the first one of preoperative circulating tumor DNA assay in pediatric renal tumors. The liquid biopsy method enables less invasive, preoperative diagnosis of CCSK with no risk of tumor spillage, which can avoid iatrogenic upstaging.

Integrated Molecular Characterization of the Lethal Pediatric Cancer Pancreatoblastoma

Pancreatoblastoma is a rare pediatric pancreatic malignancy for which the molecular pathogenesis is not understood. In this study, we report the findings of an integrated multiomics study of whole-exome and RNA sequencing as well as genome-wide copy number and methylation analyses of ten pancreatoblastoma cases. The pancreatoblastoma genome was characterized by a high frequency of aberrant activation of the Wnt signaling pathway, either via somatic mutations of CTNNB1 (90%) and copy-neutral loss of heterozygosity (CN-LOH) of APC (10%). In addition, imprinting dysregulation of IGF2 as a consequence of CN-LOH (80%), gain of paternal allele (10%), and gain of methylation (10%) was universally detected. At the transcriptome level, pancreatoblastoma exhibited an expression profile characteristic of early pancreas progenitor-like cells along with upregulation of the R-spondin/LGR5/RNF43 module. Our results offer a comprehensive description of the molecular basis for pancreatoblastoma and highlight rational therapeutic targets for its treatment.Significance: Molecular genetic analysis of a rare untreatable pediatric tumor reveals Wnt/IGF2 aberrations and features of early pancreas progenitor-like cells, suggesting cellular origins and rational strategies for therapeutic targeting. Cancer Res; 78(4); 865-76. ©2017 AACR.

Atypical intravitreal growth of retinoblastoma with a multi-branching configuration

Purpose

To report the clinical and histopathological findings of atypical intravitreal growth of a retinoblastoma with a multi-branching configuration.

Observations

A 7-month-old boy was referred to our hospital due to leukocoria in the right eye. Ophthalmic examinations identified multi-branching vessels surrounded by diaphanous tissue behind the lens in the right eye. Imaging modalities showed microphthalmos, band-shaped calcification, and cystic lesions in that eye. Because it was difficult to rule out congenital anomalies such as persistent fetal vasculature due to the atypical clinical features of retinoblastoma, we performed a biopsy using a limbal approach. An intraoperative rapid pathological examination led to the definitive diagnosis of retinoblastoma. The right eye was enucleated and postoperative adjuvant chemotherapy was administered. Immunohistochemical staining of the enucleated eyeball showed that the tumoral cells and diaphanous tumoral tissue around the vessels were positive for neuron-specific enolase and Ki-67 and partially positive for glial fibrillary acidic protein (GFAP). The vessels of the diaphanous tissues near the tumoral mass were stained by GFAP and those behind the lens were stained faintly.

Conclusions and importance

We described an atypical retinoblastoma of pseudo-persistent fetal vasculature with a multi-branching configuration, which expanded the clinical spectrum of retinoblastoma. Such a specific growth pattern of the embryonic tumor might occur with a combination of retinal development, retinal vasculature, and hyaloid vascular system.

[LMB chemotherapy for mature B-cell neoplasms in children: a single-center experience]

BACKGROUND

LMB chemotherapy based on the FAB LMB96 study is internationally accepted as one of the standard treatments for pediatric B-cell non-Hodgkin lymphoma (B-NHL), though experience with this regimen in Japan is very limited. Since 2009, we have administered LMB chemotherapy to children with B-NHL at the National Center for Child Health and Development. Thus, we herein report the clinical characteristics and outcomes of 13 children with B-NHL given LMB chemotherapy.

RESULTS

Median age was 7.5 years. Five patients were girls and 8 were boys. Nine were subclassified as having Burkitt lymphoma and 4 as having diffuse large B-cell lymphoma. According to the St. Jude staging system, 3, 4, 2, 1, and 3 patients had stages 1, 2, 3, 4, and B-ALL disease, respectively. According to the LMB group classification system, nine patients were classified into Group B and four into Group C. At a median follow-up of 2.3 years, all patients are alive without lymphoma relapse. In Group C, myelosuppression and severe mucositis were the main adverse events especially during induction therapy. High-dose methotrexate at a dose of 8 g/m2 was manageable using standard supportive therapy even with 24-hour infusion.

CONCLUSION

Our experience indicates the feasibility of LMB chemotherapy for Japanese children with B-NHL.

Secondary cancers after a childhood cancer diagnosis: a nationwide hospital-based retrospective cohort study in Japan

BACKGROUND

The epidemiology of secondary cancers in childhood cancer survivors has been unknown in Asian countries. Our aim is to assess the incidence and risk factors for secondary cancers through a nationwide survey in Japan.

METHODS

A retrospective cohort study comprising 10,069 children who were diagnosed with cancer between 1980 and 2009 was conducted in 15 Japanese hospitals. The cumulative incidence rate was calculated using death as the competing risk and compared by the Gray method. The standardized incidence ratio (SIR) was defined as the ratio of the number of observed cancers divided by the number of expected cancers. The risk factors were analyzed using Cox regression analysis.

RESULTS

One hundred and twenty-eight patients (1.3 %) developed secondary cancers within a median follow-up of 8.4 years. The cumulative incidence rate was 1.1 % (95 % confidence interval [CI] 0.9-1.4) at 10 years and 2.6 % (95 % CI 2.1-3.3) at 20 years after primary cancer diagnosis. Sensitivity analysis, limited to 5-year survivors (n = 5,387), confirmed these low incidence rates. The SIR of secondary cancers was 12.1 (95 % CI 10.1-14.4). In the Cox analysis, the hazard ratios for secondary cancers were 3.81 (95 % CI 1.53-9.47) for retinoblastoma, 2.78 (95 % CI 1.44-5.38) for bone/soft tissue sarcomas, and 1.81 (95 % CI 1.16-2.83) for allogeneic stem cell transplantation.

CONCLUSIONS

The cumulative incidence of secondary cancers in children in Japan was not high; however, the SIR was relatively high. Retinoblastoma or sarcoma in addition to allogeneic stem cell transplantation were significant risk factors for secondary cancers.

Second-Look Surgery for Intracranial Germ Cell Tumors

BACKGROUND:

The role of second-look surgery in intracranial germ cell tumors (GCTs) needs to be reviewed.

OBJECTIVE:

To present our experience of second-look surgery in patients with intracranial GCTs who showed less than complete response despite normalizing or decreasing tumor markers after chemotherapy.

METHODS:

Retrospective review of 7 patients who underwent second-look surgery for an intracranial GCT was performed.

RESULTS:

Of 23 consecutive patients with newly diagnosed intracranial GCTs treated between August 2003 and August 2013, 7 patients (30%) underwent second-look surgery. The mean age was 9.4 years. The initial diagnoses were mixed germ cell tumor in 5 and immature teratoma in 2. Second-look surgery was performed after 1 to 3 courses of chemotherapy. Magnetic resonance imaging at the surgery demonstrated increasing residual tumor in 4 and stable residual tumor in 3. Tumor markers were normalized in 5 and nearly normalized in 2. Gross total resection was achieved in all patients. Histopathology at second-look surgery revealed mature teratoma in 5, fibrosis with atypical cells in 1, and fibrosis in 1. All patients subsequently underwent additional chemoradiation therapy according to the initial diagnosis. All patients are alive with no evidence of recurrence, with a mean follow-up of 48 months.

CONCLUSION:

Second-look surgery plays an important role in the treatment of intracranial GCTs. Surgery may be encouraged at a relatively early phase after chemotherapy when the residual tumor increases or does not change size despite normalized or nearly normalized tumor markers in order to achieve complete resection and improve outcome.

Neoadjuvant chemotherapy for brain tumors in infants and young children

OBJECT

Because of their large size and high vascularity, complete removal of brain tumors in infants and young children is often difficult. In most cases the degree of resection is associated with prognosis. Neoadjuvant chemotherapy may facilitate resection by reducing the vascularity of the tumor. The authors evaluated the effectiveness of neoadjuvant chemotherapy in the management of these tumors.

METHODS

The authors performed a retrospective review of infants and young children who underwent tumor removal after neoadjuvant chemotherapy.

RESULTS

Nine consecutive patients underwent resection after neoadjuvant chemotherapy during the period February 2004 to December 2012. The mean age at diagnosis was 18 months (range 2-50 months). The average largest tumor diameter was 71 mm (range 30-130 mm) at initial surgery. Five patients underwent partial resection, and 4 underwent biopsy as the initial surgery. The histopathological diagnoses were ependymoma in 2 patients, anaplastic ependymoma in 1, primitive neuroectodermal tumor (PNET) in 2, choroid plexus carcinoma in 1, atypical teratoid/rhabdoid tumor (AT/RT) in 1, glioblastoma in 1, and embryonal tumor with abundant neuropil and true rosettes in 1. After 2-4 courses of multiagent chemotherapy (mainly with vincristine, cyclophosphamide, etoposide, and cisplatin), the second-look surgery was performed. In 1 patient with a PNET, intratumoral hemorrhage was observed after 2 courses of chemotherapy. The mean interval between the initial and the second-look surgery was 3 months. The tumor volume was reduced to varying degrees in 5 patients (56%) after chemotherapy. Intraoperatively, the vascularity of the tumor was considerably reduced, and the tumor was more circumscribed in all cases. Gross-total resection was achieved in 8 patients (89%) and neartotal resection in 1 (11%). Histopathological examination demonstrated fibrotic tissue circumscribing the tumor in 6 of 9 cases (67%). The average blood loss was 20% of the estimated blood volume, and 3 patients (33%) required a blood transfusion. There was no surgical mortality. One patient had transient dysphasia postoperatively. The mean follow-up period was 28 months. At the last follow-up, 2 patients (22%) had died (1 died of tumor progression and 1 of sepsis), and 4 patients (44%) had no tumor recurrence.

CONCLUSIONS

Neoadjuvant chemotherapy for brain tumors in infants and young children was effective in reduction of tumor vascularity and clarification of the tumor-brain interface, which significantly facilitated maximal tumor resection.

Pharmacokinetics of Carboplatin in a One-Year-Old Anuric Boy Undergoing Hemodialysis and a Review of the Literature

There have been few reports of carboplatin-based chemotherapy for anuric infants. As we had a chance to treat a one-year-old anuric hepatoblastoma patient with carboplatin, we performed a pharmacokinetic analysis and examined the optimal treatment strategy. A one-year-old anuric boy under peritoneal dialysis was diagnosed with hepatoblastoma. Surgical resection was performed, and administration of carboplatin was scheduled postoperatively aiming at 5 mg·min/mL of the area under the curve from the time of dosing to the time of the last observation (AUC(0-t)). We set the initial dose at 50 mg, higher than that calculated by the Calvert formula (34 mg); the time from the end of carboplatin infusion to the initiation of hemodialysis at 2 h; and the hemodialysis duration at 24 h. The actual AUC0-t was 3.05 mg·min/mL because the elimination half-lives before and during hemodialysis were shorter than expected. The AUC(0-t) after the second dose (100 mg) and the third dose (80 mg) were 7.00 and 4.68 mg·min/mL, respectively. The Calvert formula is not suitable for hemodialysis patients because removal of platinum by hemodialysis is not taken into account. It appears that extrarenal clearance in anuric infants is different from that in adults. We obtained an optimal AUC(0-t) using a dose of 80 mg (200 mg/m(2)), setting the time from the end of carboplatin infusion to the initiation of hemodialysis at 2 h, and performing 8-h hemodialysis. Further accumulation of the pharmacokinetic data of carboplatin is necessary for anuric children.