Tandem High-Dose Chemotherapy and Autologous Stem Cell Transplantation in Young Children with Atypical Teratoid/Rhabdoid Tumor of the Central Nervous System

The feasibility and effectiveness of tandem high-dose chemotherapy and autologous stem cell transplantation (HDCT/autoSCT) were evaluated in children younger than 3 yr of age with atypical teratoid/rhabdoid tumors (ATRT). Tandem HDCT/autoSCT was administered following six cycles of induction chemotherapy. Radiotherapy (RT) was administered if the tumor relapsed or progressed, otherwise, it was administered after 3 yr of age. Tumors relapsed or progressed during induction chemotherapy in 5 of 9 patients enrolled; 3 of these 5 received tandem HDCT/autoSCT as a salvage treatment. One patient died from sepsis during induction chemotherapy. The remaining 3 patients proceeded to tandem HDCT/autoSCT; however, 2 of these patients showed tumor relapse/progression after tandem HDCT/autoSCT. All 7 relapses/progressions occurred at primary sites even in patients with leptomeningeal seeding. Toxicities during tandem HDCT/autoSCT were manageable. A total of 5 patients were alive with a median follow-up of 20 (range 16-70) months from diagnosis. Four of 5 patients who received RT after relapse/progression are alive. The probability of overall survival at 3 yr from diagnosis was 53.3% +/- 17.3%. Our tandem HDCT/autoSCT is feasible; however, early administration of RT prior to tandem HDCT/autoSCT should be considered to improve the outcome after tandem HDCT/autoSCT.

Triple High Dose Chemotherapy Followed by Autologous Stem Cell Transplantation for Pediatric Neuroblastoma / 임상소아혈액종양

BACKGROUND: High-risk group neuroblastoma (HRNB) is one of the most incurable diseases in pediatric oncology field. This report explores the effectiveness, safety and feasibility of triple high dose chemotherapy followed by autologous stem cell transplantation (HDCT/ASCT) in contrast with single HDCT/ASCT for HRNB.METHODS: From Jan. 2001 to Dec. 2009, 25 patients newly diagnosed as HRNB have been analyzed. This study is a retrospective analysis with the medical records of these 25 HRNB patients.RESULTS: Eleven (44%) and the other fourteen (56%) patients were treated with single HDCT/ASCT and triple HDCT/ASCT, respectively. The 5-year event-free survival (EFS) of the whole group in HRNB is 37.2+/-10.0%. The 5-year EFS of single HDCT/ASCT and triple HDCT/ASCT were 27.3+/-13.4% and 46.8+/-13.8%, respectively (P=0.38). Between two groups, there were no statistically significant differences including clinical features, outcome, transplantation-related toxicities, and short-term/long-term complications.CONCLUSION: Triple HDCT/ASCT group showed similar transplantation-related toxicities and long-term complications when compared to single HDCT/ASCT group. We need more exploration to conclude the triple HDCT/ASCT as an optimal treatment for HRNB patients.

Inflammatory Myofibroblastic Tumor in a 3 Months Old Infant / 임상소아혈액종양

Benign intestinal tumors are rare in infancy, however the authors describe an inflammatory myofibroblastic tumor (IMT) of the mesentery in a 3-month-old infant who was diagnosed incidentally. During operation, huge mass which was attached to proximal jejunum was resected, from which a histological diagnosis of IMT was made. A review of the literature for this rare condition was done to delineate the natural history of this tumor. Because of the risk of local recurrence and malignant transformation, IMT cases needed a long-term follow up.

Inflammatory Myofibroblastic Tumor in a 3 Months Old Infant / 임상소아혈액종양

Benign intestinal tumors are rare in infancy, however the authors describe an inflammatory myofibroblastic tumor (IMT) of the mesentery in a 3-month-old infant who was diagnosed incidentally. During operation, huge mass which was attached to proximal jejunum was resected, from which a histological diagnosis of IMT was made. A review of the literature for this rare condition was done to delineate the natural history of this tumor. Because of the risk of local recurrence and malignant transformation, IMT cases needed a long-term follow up.

Triple High Dose Chemotherapy Followed by Autologous Stem Cell Transplantation for Pediatric Neuroblastoma / 임상소아혈액종양

BACKGROUND: High-risk group neuroblastoma (HRNB) is one of the most incurable diseases in pediatric oncology field. This report explores the effectiveness, safety and feasibility of triple high dose chemotherapy followed by autologous stem cell transplantation (HDCT/ASCT) in contrast with single HDCT/ASCT for HRNB. METHODS: From Jan. 2001 to Dec. 2009, 25 patients newly diagnosed as HRNB have been analyzed. This study is a retrospective analysis with the medical records of these 25 HRNB patients. RESULTS: Eleven (44%) and the other fourteen (56%) patients were treated with single HDCT/ASCT and triple HDCT/ASCT, respectively. The 5-year event-free survival (EFS) of the whole group in HRNB is 37.2+/-10.0%. The 5-year EFS of single HDCT/ASCT and triple HDCT/ASCT were 27.3+/-13.4% and 46.8+/-13.8%, respectively (P=0.38). Between two groups, there were no statistically significant differences including clinical features, outcome, transplantation-related toxicities, and short-term/long-term complications. CONCLUSION: Triple HDCT/ASCT group showed similar transplantation-related toxicities and long-term complications when compared to single HDCT/ASCT group. We need more exploration to conclude the triple HDCT/ASCT as an optimal treatment for HRNB patients.

Efficacy and safety of deferiprone (Ferriprox), an oral iron-chelating agent, in pediatric patients / 대한혈액학회지

BACKGROUND: Iron overload is a predictable and life-threatening complication in patients dependent on the regular transfusion of RBCs. The aims of this study were to investigate the efficacy and safety of deferiprone in a variety of pediatric hematologic and/or oncologic patients with a high iron overload. METHODS: Seventeen patients (age: 1.1-20.4 years; median: 10.6 years) from 7 hospitals who were treated with deferiprone from 2006 to 2009 were enrolled in this study. Medical records of enrolled patients were reviewed retrospectively. RESULTS: Serum ferritin levels were 4,677.8+/-1,130.9 microgram/L at baseline compared to 3,363.9+/-1,149.7 microgram/L at the end of deferiprone treatment (P=0.033). Only 1 patient developed neutropenia as a complication. CONCLUSION: Deferiprone treatment is relatively safe for pediatric patients suffering from various hematologic and oncologic diseases that require RBC transfusions as part of treatment. However, the potential development of critical complications such as agranulocytosis and/or neutropenia remains a concern.

Efficacy of Tandem High-Dose Chemotherapy and Autologous Stem Cell Rescue in Patients Over 1 Year of Age with Stage 4 Neuroblastoma: The Korean Society of Pediatric Hematology-Oncology Experience Over 6 Years (2000-2005)

The efficacy of tandem high-dose chemotherapy and autologous stem cell rescue (HDCT/ASCR) was investigated in patients with high-risk neuroblastoma. Patients over 1 yr of age who were newly diagnosed with stage 4 neuroblastoma from January 2000 to December 2005 were enrolled in The Korean Society of Pediatric Hematology-Oncology registry. All patients who were assigned to receive HDCT/ASCR at diagnosis were retrospectively analyzed to investigate the efficacy of single or tandem HDCT/ASCR. Seventy and 71 patients were assigned to receive single or tandem HDCT/ASCR at diagnosis. Fifty-seven and 59 patients in the single or tandem HDCT group underwent single or tandem HDCT/ASCR as scheduled. Twenty-four and 38 patients in the single or tandem HDCT group remained event free with a median follow-up of 56 (24-88) months. When the survival rate was analyzed according to intent-to-treat at diagnosis, the probability of the 5-yr event-free survival+/-95% confidence intervals was higher in the tandem HDCT group than in the single HDCT group (51.2+/-12.4% vs. 31.3+/-11.5%, P=0.030). The results of the present study demonstrate that the tandem HDCT/ASCR strategy is significantly better than the single HDCT/ASCR strategy for improved survival in the treatment of high-risk neuroblastoma patients.

Clinical Role of Bone Marrow Angiogenesis in Childhood Acute Lymphocytic Leukemia

PURPOSE: Vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF) are associated with increased angiogenesis, growth, and metastasis in solid tumors. But, until today, the importance of theses factors on leukemia, especially childhood acute lymphocytic leukemia (ALL) has received limited attention. Therefore, this study examined the bone marrow plasma VEGF and bFGF levels in ALL patients and normal controls. PATIENTS AND METHODS: Bone marrow plasmas at diagnosis from 33 ALL patients (median age 5.9 years; range 1.8-13.9 years) were used for analysis. The bone marrow levels of bFGF and VEGF were determined by enzyme-linked immunosorbent assay (R & D Systems) and compared with the bone marrow levels of 7 healthy control subjects (median age 11.98 years; 6 months -13.6 years). RESULTS: Average VEGF was higher in relapse ALL (N=7, 216.6 +/- 79.9pg/mL) compared to standard (N=9, 36.8 +/- 12.1pg/mL) (p=0.013) or high risk ALL (N=17, 80.0 +/- 12.2pg/mL) (p=0.023). bFGF levels were also significantly higher in relapse than standard-, or high-risk ALL patients (relapse ALL; 48.6 +/- 15.4pg/mL, standard risk ALL; 18.9 +/- 5.5pg/mL, high risk ALL; 19.0 +/- 3.5pg/mL, normal control; 18.6 +/- 4.0pg/mL) (p=0.003). Three patients with refractory relapse and death had much higher VEGF and bFGF values (VEGF; 420.0 +/- 81.6pg/ mL, bFGF; 85.6 +/- 3.2pg/mL). CONCLUSION: Our data suggest that the increased levels of VEGF and bFGF in bone marrow may play an important role in prognosis of childhood ALL.

Hematopoietic Stem Cell Transplantation for Children with Malignant Lymphoma in Korea: Multicenter Retrospective Study / 대한소아혈액종양학회지

PURPOSE: Children with Malignant lymphoma who is in the advanced stage at diagnosis or relapses during treatment have a poor prognosis. Recently, hematopoietic stem cell transplantation (HSCT) for advanced stage or refractory/relapsed lymphoma performed frequently. However, the role for HSCT for children with malignant lymphoma is still controversial. In this study, we reviewed children with malignant lymphoma who received HSCT and analyzed the results. METHODS: Questionnaires were made and sent to a group of teaching hospitals, with a return of 37 questionnaires from 11 hospitals. 33 patients with Non-Hodgkin lymphoma (NHL) and 4 patients with Hodgkin disease (HD) who received HSCT from 1997 to 2004 in Korea were enrolled in this study. Disease state at diagnosis, relapses during treatment, disease state at HSCT, and survival record were analyzed. All Data were reviewed with the questionnaires from the 11 teaching hospitals. RESULTS: Four patients with HD received HSCT at the 2nd complete remission after relapse. Survival rate for HD was 100% and their follow up duration ranged from 0.2 to 6.2 years (median 2.4 years). The 2-year survival rate for NHL was 68.1+/-9.0% and their follow up duration ranged from 0.1 to 7.6 years (median 1.5 years). The 2-year survival rate in patients with advanced stage at diagnosis and in relapsed/refractory patients were 83.6+/-1.1% and 55.9+/-12.9%, respectively (P=0.12). The mortality asssociated with HSCT was only 1 case, and most of the transplantation related complications did not resulted in death. CONCLUSION: Our results suggest that high dose chemotherapy followed by HSCT in children with malignant lymphoma is a safe procedure, which at the same time improves the results of standard treatment.

Follow-up Studies and Clinical Significance of Chromosomal Rearrangement in Childhood Acute Lymphocytic Leukemia / 소아과

PURPOSE: Through routine screening for chromosomal defects present in patients with acute lymphocytic leukemia(ALL) by means of reverse transcription-polymerase chain reaction(RT-PCR), we aimed for earlier detection of recurrences, hence evaluating the progress of the disease after treatment, and forecasting the need for further testing. METHODS: We analyzed 30 patients who visited the Pediatrics Department of Severance Hospital, from January 2002 to July 2003, in whom pre- and post-chemotherapy(post remission induction, post consolidateion and during maintenance) bone marrow samples were available. Among them, periodic RT-PCR examinations were performed in five bcr/abl positive cases, five TEL/AML1 positive cases, and seven dupMLL positive cases to follow the changes in genetic markers. RESULTS: In patients with bcr/abl, all five cases reached complete remission in hematologic examination after induction chemotherapy, but bcr/abl RT-PCR was positive in one case after the treatment, with complete remission reached in just four patients. In the group with TEL/AML1, all five cases reached both hematologic and molecular complete remission after induction chemotherapy. In seven cases with dupMLL, hematologic complete remission was reached in all patients, except one patient who was six months old at diagnosis, who exhibited positive findings for abnormal precursor after induction chemotherapy. CONCLUSION: Earlier detection of recurrence was possible through hematologic and chromosomal anaylsis of patients during follow-up. The most essential factor to detect recurrence considered the timing of bone marrow biopsy. So the procedure must be performed at critical intervals in a patient's course of treatment. In patients with ALL, recurrences by drug-resistant cells occur primarily after one year from the initiation of treatment, so we propose that bone marrow acquisitions to detect recurrences are recommended at one year after the start of treatment, and just before the discontinuation of treatment.

Polymorphisms within Glutathione S-transferase Genes in Childhood Acute Lymphoblastic Leukemia / 대한소아혈액종양학회지

PURPOSE: Glutathione S-transferases (GSTs) are polymorphic genes. Absence of enzyme activity due to homozygous or heterozygous deletion of the gene is associated with reduced detoxification of carcinogens and potentially increasing the risk of cancer. METHODS: DNA was extracted from bone marrow aspirates of 26 acute lymphoblastic leukemia (ALL) patients and from peripheral blood of 13 controls. PCR amplification was used to assess GSTM1, GSTT1, and GSTP1 at codon 105 and 114 genotypes for cases and controls. RESULTS: We investigated the polymorphisms within the GSTM1, GSTT1, and GSTP1 genes in children with ALL. The null (absence of both alleles) genotype for GSTM1 was 2.6-fold [odd ratio (OR), 0.38; 95% confidence interval (CI), 0.1-1.5; P=0.043] increased in children with ALL, whereas the frequency of GSTT1 null genotype in ALL cases was not statistically different from that of controls. GSTP1 Val105/Val105 genotype showed a 1.6-fold (OR, 0.63; 95% CI, 0.16-2.43; P=0.38) increase in ALL in comparison to the combined category of Ile105/Val105 and Ile105/Ile105 genotypes. CONCLUSION: Our results suggest that polymorphisms within genes of the GST superfamily (especiallly GSTM1 null type) may be increased in childhood ALL.

Influence of Prognostic Factors on Survival Rate of Medulloblastoma Patient with Chemotherapy

PURPOSE: Brain tumors are the second most common tumor in childhood, and medulloblastomas comprise 15-25% of brain tumors. The well known prognostic factors are age at diagnosis, stage of disease, and extent of surgical excision. In this study, we analysed the prognostic factors in patients who received chemotherapy after excision. METHODS: We reviewed the medical records of 61 patients who received chemotherapy among the 94 patients who were diagnosed and treated between Jan 1985 and Sep 2001 in the Department of Pediatrics and Neurosurgery at Severance Hospital. RESULTS: Among the total survival rate of patients who underwent chemotherapy, the 3-yr progression-free survival rate was 66.5+/-6.3% and the 15-yr progression-free survival rate was 60.3+/-6.7%. The progression-free survival rate for patients with age at diagnosis over 3 yrs old and under 3 yrs old, was 64.5+/-7.7% and 48.2+/-12.9% respectively and there was no statistically significant difference. The survival rate of the high vs low risk group by staging was 72.7+/-10.5% and 54.6+/-8.3% respectively, and there was no significant difference. The survival rate of patients with total removal vs subtotal removal was 65.8+/-11.8% and 56.8+/-8.2% respectively, showing no statistical difference. CONCLUSION: The reason there is no difference in survival rate according to the traditional prognostic factors is that chemotherapy has improved not only the total survival rate but also the survival rate in patients with poor traditional prognostic factors. So, sufficient removal of tumor followed by proper chemotherapy and radiotherapy is an important factor which influences the survival rate of medulloblastoma patients.

A Clinical Study on Childhood Hemolytic Anemia According to Etiological Classification

PURPOSE: The etiology of hemolytic anemia can be classified as either cellular or extracellular defects of red blood cells. The aim of this study was to investigate the clinical and laboratory findings of hemolytic anemia concerning its etiological classification. METHODS: Clinical and laboratory findings of the patients with hemolytic anemia treated from January 1987 to May 2002 at Severance Hospital were analyzed retrospectively. They were divided into two groups based on the types of red cell defects(group I : erythrocytic defect, group II : extraerythro cytic defect). RESULTS: Twenty one cases were included in group I, thirty four cases in group II, and three cases were unclassified. In group I, nineteen cases(90.5%) were diagnosed as hereditary spherocytosis and were proved to have red cell membrane disorders while two cases(9.5%) were shown to have red cell enzyme deficiencies. In group II, thirteen cases(38.2%) were noted as autoimmune hemolytic anemia, eleven cases(32.4%) as traumatic or microangiopathic hemolytic anemia, four cases(11.8%) as drug induced hemolytic anemia, two cases(5.9%) were related with systemic lupus erythematosus and one case(2.9%) with malignancy. Hemoglobin at the time of diagnosis(7.5 g/dL vs. 6.2 g/dL, P< 0.05) and the incidence of splenomegaly(85.7% vs. 18.2%, P<0.05) were higher in group I though blood urea nitrogen(9.0/0.4 mg/dL vs. 27.8/1.6 mg/dL, P<0.05) was higher in group II. CONCLUSION: Comparing the clinical features of pediatric hemolytic anemia, we concluded as following: In cases associated with extraerythrocytic defect, blood tests revealed significant initial lower hematocrit with higher level of BUN and Cr while cases with erythrocytic defect, splenomegaly were more common noted.

Results of Treatment for Children with Primary Brain Tumors: Long-Term Follow Up Results of a Single Institute

PURPOSE: Brain tumors are the most common solid tumor in children. We retrospectively investigated the clinical characteristics of pediatric brain tumors, such as age, sex, tumor site and survival, as seen in a single institution over the last 15 years. We tried to evaluate the role of chemotherapy on the survival of some brain tumors. METHODS: Three hundred fifty four children with primary brain tumor who were treated at Severance Hospital from Jan. 1985 to Sep. 2001 were enrolled. RESULTS: Pediatric brain tumors were found most frequently in 10-15 years of age group(35.3%) and the ratio of male to female was 1.3 : 1. Supratentorial tumors(52%) were more frequent than infratentorial tumors(48%). Medulloblastoma/primitive neuroectodermal tumor(PNET) was the most common type(24.6%), followed by cerebellar astrocytoma(14.1%). Ten year survival rate of medulloblastoma, cerebellar astrocytoma and cerebral astrocytoma were 59.4%, 79.3% and 71%, respectively. The prognosis for brain stem glioma and glioblastoma multiforme were still grim with a 10 year survival rate of 12.7% and 13.3%, respectively. The addition of chemotherapy for high grade medulloblastoma led to an improved 10 year survival rate of 54.5%, compared with 40% without chemotherapy. CONCLUSION: The combined use of chemotherapy and radiation and surgery improved survival rate of pediatric brain tumors in our study. Chemotherapy for high grade medulloblastoma improved the 10 year survival rate. Further data analysis of the treatment modalities will lead to better comparisons.

A Case of Subcutaneous Panniculitis-like T Cell Lymphoma in Childhood

Subcutaneous pannicultis-like T cell lymphoma is a rare cutaneous T cell lymphoma. It presents with multiple subcutaneous nodules or plaques involving the extremities or trunk, and with constitutional symptoms that include fever, malaise, fatigue, myalgia, chills and weight loss. Histologically, the lesions of this disease are reminiscent of panniculitis and are composed of a mixture of small and large atypical lymphoid cells infiltrating between adipocytes. The optimal treatment for this disease is undefined and prognosis of this disease is poor, even when treated with multiagent chemotherapy regimens considered optimal for agressive lymphoma of other types. Poor prognosis factors include clinical features such as anemia, leukocytopenia, hepatosplenomegaly, lymphadenopathy and coagulopathy, which are suggestive of hemophagocytosis. Much of the mortality of this disease is due not to disseminated lymphoma with organ failure, but rather to complications of the cytopenias associated with the hemophagocytic syndrome. We report a case of subcutaneous panniculitis-like T cell lymphoma in a 12 year-old boy who presented with initial complaints of fever and multiple subcutaneous nodules, and briefly review the related literature.

A Comparative Analysis between Flow Cytometry and RT-PCR Methods for the Detection of Minimal Residual Disease in Neuroblastoma / 대한소아혈액종양학회지

PURPOSE: A sensitive assay to detect minimal residual disease in neuroblastoma is necessary for accurate assessment of disease status and optimal treatment. In this study, we compared the usefulness of sensitive methods, flow cytometry and RT-PCR for the detection of minimal residual disease in neuroblastoma. METHODS: Eighteen patients who were newly diagnosed and treated at Severance Hospital since 1999 were included in this study. Samples from bone marrow, peripheral blood, and peripheral blood stem cell product were examined for tumor cell contamination by RT-PCR (TH RT-PCR) to detect tyrosine hydroxylase mRNA and by flow cytometry identifying CD9+/CD56+/CD45- cells. RESULTS: We analyzed 20 cases from 18 patients, which were assayed by both methods at the same time. Among 20 cases, 16 cases showed same results, which were compatible with histologic results and clinical course, and 4 cases showed different results. One case of them showed positive result in histology and flow cytometry, but negative result in TH RT-PCR. The other 3 cases showed negative results in flow cytometry, but positive results in TH RT-PCR, and 1 patient of them relapsed. Among 16 patients, 2 patients, showing positive results in only TH RT-PCR, relapsed. CONCLUSION: Detection of minimal residual disease using TH RT-PCR and flow cytometry was effective and useful in evaluating disease status and deciding for proper treatment.

A Successful Transplant of HLA-3 Loci Mismatched Umbilical Cord Blood into a Patient with Acute Myeloid Leukemia from an Unrelated Donor

Cord blood is a useful source of allogeneic hematopoietic stem cells for bone marrow reconstitution. The number of umbilical cord blood transplants is increasing worldwide. In this a case 15- month-old boy with acute myeloid leukemia was treated with umbilical cord blood transplant from an HLA-3 loci mismatched unrelated donor. Granulocyte recovery greater than 500/mm3 occurred at day 49, and the platelet recovered greater than 20,000/mm3 independent of transfusion at day 81 after stem cell infusion.

A Case of Wilms Tumor with Thrombi which Invaded the Right Ventricule

Wilms tumor is the second most common malignant retroperitoneal tumor. Inferior vena cava and right atrial involvement is found in about 4-10% and 0.5-3% of cases, respectively. But, right ventricular involvement has not been reported. We experienced a case of Wilms tumor with right ventricular invasion in a 2 year-old male who presented intermittent hematuria and abdominal pain. Computed tomogram and echocardiogram showed a homogeneous mass extended to right ventricle via inferior vena cava. He received pre-operative chemotherapy followed by operation, radiation therapy including heart, and post-operative chemotherapy.

Therapeutic Leukapheresis for Acute Lymphoblastic Leukemia with Severe Hyperleukocytosis in a Six-Week-Old Infant (4.7 kg) / 대한소아혈액종양학회지

We report a 4.7 kg infant who received a therapeutic leukapheresis as an immediate treatment for acute lymphoblastic leukemia with severe hyperleukocytosis. By decreasing the number of circulating white blood cells, therapeutic leukapheresis helps prevent the risks of hyperviscosity and cerebrovascular and pulmonary leukostasis. In addition, it potentially reduces metabolic and renal complications associated with rapid cell lysis when applied before chemotherapy. This six-week-old female presented with vomiting for 15 days. Initial WBC count was 1,532,800/muL. After placement of 4 french two-lumen central venous catheter in both femoral vein, the CS 3000 plus was primed with 250 mL of paternal whole blood mixed with 150 mL of normal saline. After therapeutic leukapheresis, the CBC showed WBC count of 560,000/muL. Our successful experience in performing this procedure suggests that therapeutic leukapheresis be a feasible treatment even for very young infants with hyperleukocytosis.

Patterns of Relapse and Survival for Neuroblastoma / 대한소아혈액종양학회지

PURPOSE: Nowadays, survival of neuroblastoma patients has improved by high dose chemotherapy followed by autologous peripheral blood stem cell transplantation (PBSCT). But, many of these patients experienced treatment failure, and relapse was the most important factor of treatment failure. The aim of this study was to investigate the relation between pattern of relapse and survival of neuroblastoma for 10 years. METHODS: Fifty nine neuroblastoma patients were enrolled in the study. Retrospective investigation of medical records was performed. RESULTS: Twenty two patients experienced relapse among total 59 patients. Two patients had relapse two times, and another two patients had two or more relpase sites. Median time from diagnosis to relapse is 16.8 months (2~40 months). According to International Neuroblastoma Staging System (INSS), stage of patients with relapse at diagnosis is as follows; Stage II-2 patients, Stage III-4 patients, and Stage IV-16 patients. 11 patients received high dose chemotherapy followed by autologous PBSCT, and 7 patients (63.6%) of them experienced relapse. 48 patients received only chemotherapy, and 17 patients (35.4%) of them experienced relapse. Sites of relapse are as follows; central nervous system (CNS) 6 patients (22.2%), primary site 4 patients (14.8%), bone 4 patients (14.8%), bone marrow 4 patients (14.8%), distant lymph node 2 patients (7.4%), liver 2 patients (7.4%), and others 5 patients (18.5%). CONCLUSION: In this study, relapses were observed in about 37% of cases. And, the more relapse, the lesser survivals are observed. Although this single institution result had limitation to generalize, CNS was the most common site of relapse. However, multi-center study for relapse sites of neuroblastoma should be evaluated further.