Epidemiologic and Clinical Outcomes of Pediatric Renal Tumors in Korea: A Retrospective Analysis of The Korean Pediatric Hematology and Oncology Group (KPHOG) Data / Journal of the Korean Cancer Association, 대한암학회지

Purpose@#Renal tumors account for approximately 7% of all childhood cancers. These include Wilms tumor (WT), clear cell sarcoma of the kidney (CCSK), malignant rhabdoid tumor of the kidney (MRTK), renal cell carcinoma (RCC), congenital mesoblastic nephroma (CMN) and other rare tumors. We investigated the epidemiology of pediatric renal tumors in Korea. @*Materials and Methods@#From January 2001 to December 2015, data of pediatric patients (0–18 years) newly-diagnosed with renal tumors at 26 hospitals were retrospectively analyzed. @*Results@#Among 439 patients (male, 240), the most common tumor was WT (n=342, 77.9%), followed by RCC (n=36, 8.2%), CCSK (n=24, 5.5%), MRTK (n=16, 3.6%), CMN (n=12, 2.7%), and others (n=9, 2.1%). Median age at diagnosis was 27.1 months (range 0-225.5) and median follow-up duration was 88.5 months (range 0-211.6). Overall, 32 patients died, of whom 17, 11, 1, and 3 died of relapse, progressive disease, second malignant neoplasm, and treatment-related mortality. Five-year overall survival and event free survival were 97.2% and 84.8% in WT, 90.6% and 82.1% in RCC, 81.1% and 63.6% in CCSK, 60.3% and 56.2% in MRTK, and 100% and 91.7% in CMN, respectively (p < 0.001). @*Conclusion@#The pediatric renal tumor types in Korea are similar to those previously reported in other countries. WT accounted for a large proportion and survival was excellent. Non-Wilms renal tumors included a variety of tumors and showed inferior outcome, especially MRTK. Further efforts are necessary to optimize the treatment and analyze the genetic characteristics of pediatric renal tumors in Korea.

The Role of Neurologists in Pain Management – Based on the Survey Conducted by the Korean Neurological Association in 2020

Background@#Pain is one of the most common chief complaints in neurological field. Authors try to inform the current situation of pain medicine in neurological practice and present an effective method for pain-related education during neurology residency and for practicing neurologists. @*Methods@#A survey was conducted from November 16 to November 27, 2020 for members of the Korean Neurological Association, and the results were analyzed. @*Results@#About two-thirds of neurologists replied that more than 25% of their patients were suffered from diverse pain including headache, spine pain or neuropathic pain. Despite many patients are visiting to neurologist for pain treatment, most neurologists are aware that they have not received sufficient practical pain education in the past and present. Therefore, they want more educational opportunities in pain medicine including interventional pain management and physical and pharmacologic therapies for more effective treatment. @*Conclusions@#More follow-up studies on pain treatment and education should be conducted. It is also essential that the members of the society continue to interest and participate in the change of the pain education program.

The Role of Neurologists in Pain Management – Based on the Survey Conducted by the Korean Neurological Association in 2020

Background@#Pain is one of the most common chief complaints in neurological field. Authors try to inform the current situation of pain medicine in neurological practice and present an effective method for pain-related education during neurology residency and for practicing neurologists. @*Methods@#A survey was conducted from November 16 to November 27, 2020 for members of the Korean Neurological Association, and the results were analyzed. @*Results@#About two-thirds of neurologists replied that more than 25% of their patients were suffered from diverse pain including headache, spine pain or neuropathic pain. Despite many patients are visiting to neurologist for pain treatment, most neurologists are aware that they have not received sufficient practical pain education in the past and present. Therefore, they want more educational opportunities in pain medicine including interventional pain management and physical and pharmacologic therapies for more effective treatment. @*Conclusions@#More follow-up studies on pain treatment and education should be conducted. It is also essential that the members of the society continue to interest and participate in the change of the pain education program.

Comparison of Neuropathic Pain in Neuromyelitis Optica Spectrum Disorder and Multiple Sclerosis

3) of the pain in domains of tingling/prickling sensation (p=0.024), mechanical allodynia (p=0.027), sudden pain attacks (p=0.018), and thermal hyperalgesia (p=0.002) were significantly more frequent in NMOSD compared to MS patients. Among the patients experiencing pain with a neuropathic component, total pain-related interference (p=0.045) scores were significantly higher in NMOSD patients than in MS patients. In daily life, pain interfered with normal work (p=0.045) and relationships with other people (p=0.039) more often in NMOSD patients than in MS patients. Although pain medication was prescribed more frequently in NMOSD patients, the percentage of patients experiencing medication-related pain relief was lower in those patients.CONCLUSIONS: The severity of neuropathic pain and the pain-related interference in daily life were greater in NMOSD patients than in MS patients. Individualized analgesic management should be considered based on a comprehensive understanding of neuropathic pain in these patients.

Four-Week, Home-Based, Robot Cognitive Intervention for Patients with Mild Cognitive Impairment: a Pilot Randomized Controlled Trial

Background@#and Purpose: Previous studies suggest that cognitive intervention can mitigate the development of dementia in patients with mild cognitive impairment (MCI). However, the previous cognitive intervention was mostly provided as a group session, in which MCI patients sometimes had difficulty in regularly attending sessions or were reluctant to participate in group-based classes. Additionally, experienced instructors for traditional cognitive intervention may be unavailable in some chronic-care facilities or community centers. Considering these reasons, we have developed 5 programs for home-based cognitive intervention using a personal robot for MCI patients. In this preliminary study, we aimed to demonstrate the effects of our newly developed home-based cognitive intervention with robots on cognitive function in MCI patients. @*Methods@#We conducted a single-blind randomized controlled trial enrolling 46 MCI patients. Participants were randomized into 2 groups: the robot cognitive intervention (robot) (n=24) group and without cognitive intervention (control) (n=22) group. The interventions comprised 60-min sessions per day for 4 weeks. The primary outcome was the change in cognitive function measured using the Cambridge Neuropsychological Test Automated Battery. @*Results@#There were no significant baseline demographic or clinical differences between the robot and control groups. After the 4-week cognitive intervention, the robot group showed greater improvement in working memory than did the control group. @*Conclusions@#Our home-based cognitive intervention with a personal robot improved the working memory in MCI patients. Further studies with larger samples and longer study periods are required to demonstrate the effects of these programs in other cognitive domains in MCI patients.

Clinical Characteristics and Treatment Outcomes in Children, Adolescents, and Young-adults with Hodgkin's Lymphoma:a KPHOG Lymphoma Working-party, Multicenter, Retrospective Study

Background@#Hodgkin's lymphoma (HL) constitutes 10%–20% of all malignant lymphomas and has a high cure rate (5-year survival, around 90%). Recently, interest has increased concerning preventing secondary complications (secondary cancer, endocrine disorders) in long-term survivors. We aimed to study the epidemiologic features and therapeutic outcomes of HL in children, adolescents, and young adults in Korea. @*Methods@#We performed a multicenter, retrospective study of 224 patients aged < 25 years diagnosed with HL at 22 participating institutes in Korea from January 2007 to August 2016. @*Results@#A higher percentage of males was diagnosed at a younger age. Nodular sclerosis histopathological HL subtype was most common, followed by mixed cellularity subtype.Eighty-one (36.2%), 101 (45.1%), and 42 (18.8%) patients were classified into low, intermediate, and high-risk groups, respectively. Doxorubicin, bleomycin, vinblastine, dacarbazine was the most common protocol (n = 102, 45.5%). Event-free survival rate was 86.0% ± 2.4%, while five-year overall survival (OS) rate was 96.1% ± 1.4%: 98.7% ± 1.3%, 97.7% ± 1.6%, and 86.5% ± 5.6% in the low, intermediate, and high-risk groups, respectively (P = 0.021). Five-year OS was worse in patients with B-symptoms, stage IV disease, highrisk, splenic involvement, extra-nodal lymphoma, and elevated lactate dehydrogenase level.In multivariate analysis, B-symptoms and extra-nodal involvement were prognostic factors for poor OS. Late complications of endocrine disorders and secondary malignancy were observed in 17 and 6 patients, respectively. @*Conclusion@#This is the first study on the epidemiology and treatment outcomes of HL in children, adolescents, and young adults in Korea. Future prospective studies are indicated to develop therapies that minimize treatment toxicity while maximizing cure rates in children, adolescents, and young adults with HL.

Risk Factor Analysis for Secondary Malignancy in Dexrazoxane-Treated Pediatric Cancer Patients / Journal of the Korean Cancer Association, 대한암학회지

PURPOSE: Dexrazoxane has been used as an effective cardioprotector against anthracycline cardiotoxicity. This study intended to analyze cardioprotective efficacy and secondary malignancy development, and elucidate risk factors for secondary malignancies in dexrazoxane-treated pediatric patients. MATERIALS AND METHODS: Data was collected from 15 hospitals in Korea. Patients who received any anthracyclines, and completed treatment without stem cell transplantation were included. For efficacy evaluation, the incidence of cardiac events and cardiac event-free survival rates were compared. Data about risk factors of secondary malignancies were collected. RESULTS: Data of total 1,453 cases were analyzed; dexrazoxane with every anthracyclines group (D group, 1,035 patients) and no dexrazoxane group (non-D group, 418 patients). Incidence of the reported cardiac events was not statistically different between two groups; however, the cardiac event-free survival rate of patients with more than 400 mg/m2 of anthracyclines was significantly higher in D group (91.2% vs. 80.1%, p=0.04). The 6-year cumulative incidence of secondary malignancy was not different between both groups after considering follow-up duration difference (non-D, 0.52%±0.37%; D, 0.60%±0.28%; p=0.55). The most influential risk factor for secondary malignancy was the duration of anthracycline administration according to multivariate analysis. CONCLUSION: Dexrazoxane had an efficacy in lowering cardiac event-free survival rates in patients with higher cumulative anthracyclines. As a result of multivariate analysis for assessing risk factors of secondary malignancy, the occurrence of secondary malignancy was not related to dexrazoxane administration.

Spontaneous Repetitive Constriction and Dilatation of a Unilateral Pupil in a Brain Death Patient

In brain death state, bilateral pupil light reflexes are disappeared, and pupils are fixed with dilated. However, spontaneous movements such as ocular microtremor or bilateral cyclical constriction-dilatation of pupils have been rarely reported in brain death patients. We present a brain death patient whose right pupil displayed spontaneously repetitive constriction and dilatation regardless of external stimuli such as light and pain. Early recognition of this phenomenon may prohibit the delay in the diagnosis of brain death and organ transplantation.

APEX1 Polymorphism and Mercaptopurine-Related Early Onset Neutropenia in Pediatric Acute Lymphoblastic Leukemia / Journal of the Korean Cancer Association, 대한암학회지

PURPOSE: Mercaptopurine (MP) is one of the main chemotherapeutics for acute lymphoblastic leukemia (ALL). To improve treatment outcomes, constant MP dose titration is essential to maintain steady drug exposure, while minimizing myelosuppression. We performed two-stage analyses to identify genetic determinants of MP-related neutropenia in Korean pediatric ALL patients. MATERIALS AND METHODS: Targeted sequencing of 40 patients who exhibited definite MP intolerance was conducted using a novel panel of 211 pharmacogenetic-related genes, and subsequent analysis was performed with 185 patients. RESULTS: Using bioinformatics tools and genetic data, four functionally interesting variants were selected (ABCC4, APEX1, CYP1A1, and CYP4F2). Including four variants, 23 variants in 12 genes potentially linked to MP adverse reactions were selected as final candidates for subsequent analysis in 185 patients. Ultimately, a variant allele in APEX1 rs2307486was found to be strongly associated with MP-induced neutropenia that occurred within 28 days of initiating MP (odds ratio, 3.44; p=0.02). Moreover, the cumulative incidence of MP-related neutropenia was significantly higher in patients with APEX1 rs2307486 variants, as GG genotypes were associated with the highest cumulative incidence (p < 0.01). NUDT15 rs116855232 variants were strongly associated with a higher cumulative incidence of neutropenia (p < 0.01), and a lower median dose of tolerated MP throughout maintenance treatment (p < 0.01). CONCLUSION: We have identified that APEX1 rs2307486 variants conferred an increased risk of MP-related early onset neutropenia. APEX1 and NUDT15 both contribute to cell protection from DNA damage or misincorporation, so alleles that impair the function of either gene may affect MP sensitivities, thereby inducing MP-related neutropenia.

Clinical Courses and Outcome of Newly Diagnosed Immune Thrombocytopenia in Infants / 임상소아혈액종양

BACKGROUND: Infants with immune thrombocytopenia (ITP) are at increased risk of high risk bleeding and vaccination-associated ITP. Infants with ITP respond favorably to treatment and are less likely to develop chronic ITP compared to older children. However the characteristics of this entity in infants have rarely been analyzed. We investigated the clinical characteristics and response to treatment of newly diagnosed ITP in infants under 1 year of age. METHODS: We retrospectively reviewed the medical records of newly diagnosed ITP infants between 1 month to 11 months of age at Chonbuk National University Hospital from 2002 to 2017. The demographics, complete blood count, absolute lymphocyte count (ALC), absolute neutrophil count, vaccination history, upper respiratory infection, viral study (cytomegalovirus) and treatment of patients with ITP were reviewed. RESULTS: A total of 85 patients satisfied the criteria for newly diagnosed ITP. Of these patients, 83 were in complete remission, 6 were in persistent remission, and 2 progressed to chronic ITP. As a result of the study, 57 patients (67%) were male. 71 patients (83.5%) were secondary ITP. Among secondary ITP, vaccination related ITP was the most common cause with 60 patients (84.5%). The mean at diagnosis was 4.3±3.2 month. There was no statistically significant difference in ALC between the time of diagnosis and treatment. Hemoglobin was 10.8 g/dL at diagnosis and increased significantly to 12.3 g/dL after treatment. CONCLUSION: Ninety-seven percent of ITP patients diagnosed under 1 year of age were in remission.

The Novel Neuroprotective Compound KMS99220 Has an Early Anti-neuroinflammatory Effect via AMPK and HO-1, Independent of Nrf2

We have previously reported a novel synthetic compound KMS99220 that prevented degeneration of the nigral dopaminergic neurons and the associated motor deficits, suggesting a neuroprotective therapeutic utility for Parkinson's disease. Microglia are closely associated with neuroinflammation, which plays a key role in the pathogenesis of neurodegenerative diseases. In this study, we investigated the effects of KMS99220 on the signaling involving AMP-activated protein kinase (AMPK) and heme oxygenase-1 (HO-1), the enzymes thought to regulate inflammation. KMS99220 was shown to elevate the enzyme activity of purified AMPK, and phosphorylation of cellular AMPK in BV2 microglia. It increased the level of HO-1, and this was attenuated by AMPK inhibitors. KMS99220 lowered phosphorylation of IκB, nuclear translocation of NFκB, induction of inducible nitric oxide synthase, and generation of nitric oxide in BV2 cells that had been challenged with lipopolysaccharide. This anti-inflammatory response involved HO-1, because both its pharmacological inhibition and knockdown of its expression abolished the response. The AMPK inhibitors also reversed the anti-inflammatory effects of KMS99220. The induction of HO-1 by KMS99220 occurred within 1 h, and this appeared not to involve the transcription factor Nrf2, because Nrf2 knockdown did not affect the compound's HO-1 inducing- and anti-inflammatory effects in this time window. These findings indicated that KMS99220 leads to AMPK-induced HO-1 expression in microglia, which in turn plays an important role in early anti-inflammatory signaling. Together with its neuroprotective property, KMS99220 may serve as a feasible therapeutic agent against neuroinflammation and neurodegeneration.

Neuromyopathy caused by long term colchicine therapy

Colchicine-induced neuromyopathy is an extremely rare complication, and can develop in the setting of acute overdose or chronic administration in therapeutic doses. A 72-year-old man presented with proximal muscle weakness and myalgia. He had angina pectoris and Behçet’s disease, leading to the treatment of colchicine (1.2 mg daily for about 6 years), cyclosporine, methylprednisolone, simvastatin, and aspirin. A biceps brachii muscle biopsy was performed and electron microscopic examination revealed scattered autophagic vacuoles. He was initially treated with steroid pulse therapy. However, muscle weakness did not improve. After the discontinuation of colchicine, muscle power and myalgia improved steadily. There should be heightened awareness of colchicine-induced neuromyopathy because that clinical suspicion is the most important diagnostic clue, and termination of colchicine is the only treatment.

Thyroid dysfunction in patients with childhood-onset medulloblastoma or primitive neuroectodermal tumor

PURPOSE: We investigated the clinical characteristics of patients who developed thyroid dysfunction and evaluated the risk factors for hypothyroidism following radiotherapy and chemotherapy in pediatric patients with medulloblastoma or primitive neuroectodermal tumor (PNET). METHODS: The medical records of 66 patients (42 males) treated for medulloblastoma (n=56) or PNET (n=10) in childhood between January 2000 and December 2014 at Seoul National University Children’s Hospital were retrospectively reviewed. A total of 21 patients (18 high-risk medulloblastoma and 3 PNET) underwent high-dose chemotherapy and autologous stem cell rescue (HDCT/ASCR) RESULTS: During the median 7.6 years of follow-up, 49 patients (74%) developed transient (n=12) or permanent (n=37) hypothyroidism at a median 3.8 years of follow-up (2.9–4.6 years). Younger age ( < 5 years) at radiation exposure (P=0.014 vs. ≥9 years) and HDCT (P=0.042) were significantly predictive for hypothyroidism based on log-rank test. However, sex, type of tumor, and dose of craniospinal irradiation (less vs. more than 23.4 Gy) were not significant predictors. Cox proportional hazard model showed that both younger age (< 5 years) at radiation exposure (hazard ratio [HR], 3.1; vs. ≥9 years; P=0.004) and HDCT (HR, 2.4; P=0.010) were significant predictors of hypothyroidism. CONCLUSIONS: Three-quarters of patients with pediatric medulloblastoma or PNET showed thyroid dysfunction, and over half had permanent thyroid dysfunction. Thus, frequent monitoring of thyroid function is mandatory in all patients treated for medulloblastoma or PNET, especially, in very young patients and/or high-risk patients recommended for HDCT/ASCR.

Pathogenic Variant of REEP1 in a Korean Family with Autosomal-Dominant Hereditary Spastic Paraplegia

No abstract available.

ALK Protein Expression Is Related to Neuroblastoma Aggressiveness But Is Not Independent Prognostic Factor / Journal of the Korean Cancer Association, 대한암학회지

PURPOSE: In this study, anaplastic lymphoma kinase (ALK) mutation and amplification, ALK protein expression, loss of the nuclear alpha thalassemia/mental retardation syndrome X-linked (ATRX) protein, and telomerase reverse transcriptase (TERT) protein expressionwere studied to investigate potential correlations between these molecular characteristics and clinical features or outcomes in neuroblastoma. MATERIALS AND METHODS: Seventy-two patients were enrolled in this study. Polymerase chain reaction amplification and direct sequencing were used for mutation analysis. ALK and MYCN amplifications were detected by fluorescence in situ hybridization. Protein expressionwas evaluated by immunohistochemical (IHC) staining. RESULTS: ALK mutation was found in only two patients (4.1%); ALK amplification was not detected. ALK positivity, loss of nuclear ATRX protein, TERT positivity by IHC were detected in 40 (55.6%), nine (13.0%), and 42 (59.2%) patients, respectively. The incidence of ALK expression increased in accordance with increasing tumor stage (p=0.001) and risk group (p < 0.001). The relapse rate was significantly higher in ALK+ patients compared to that of other patients (47.5% vs. 11.3%, p=0.007). However, there was no significant difference in relapse rate when the survival analysis was confined to the high-risk patients. CONCLUSION: Although ALK mutation was rare and no amplification was observed, ALK protein expression was found in a significant number of patients and was correlated with advanced stage and high-risk neuroblastoma. ALK protein expression could be considered as a marker related to the aggressive neuroblastoma, but it was not the independent prognostic factor for the outcome.

FAT1 Gene Alteration in Facioscapulohumeral Muscular Dystrophy Type 1

Facioscapulohumeral muscular dystrophy type 1 (FSHD1) is caused by contraction of the D4Z4 repeat array. Recent studies revealed that the FAT1 expression is associated with disease activity of FSHD, and the FAT1 alterations result in myopathy with a FSHD-like phenotype. We describe a 59-year-old woman with both contracted D4Z4 repeat units and a FAT1 mutation. Shoulder girdle muscle weakness developed at the age of 56 years, and was followed by proximal leg weakness. When we examined her at 59 years of age, she displayed asymmetric and predominant weakness of facial and proximal muscles. Muscle biopsy showed increased variation in fiber size and multifocal degenerating fibers with lymphocytic infiltration. Southern blot analysis revealed 8 D4Z4 repeat units, and targeted sequencing of modifier genes demonstrated the c.10331 A>G variant in the FAT1 gene. This FAT1 variant has previously been reported as pathogenic variant in a patient with FSHD-like phenotype. Our study is the first report of a FAT1 mutation in a FSHD1 patient, and suggests that FAT1 alterations might work as a genetic modifier.

Outcome of Reinduction Chemotherapy with a Modified Dose of Idarubicin for Children with Marrow-Relapsed Acute Lymphoblastic Leukemia: Results of the Childhood Acute Lymphoblastic Leukemia (CALL)-0603 Study

This multicenter, prospective trial was conducted to develop an effective and safe reinduction regimen for marrow-relapsed pediatric acute lymphoblastic leukemia (ALL) by modifying the dose of idarubicin. Between 2006 and 2009, the trial accrued 44 patients, 1 to 21 years old with first marrow-relapsed ALL. The reinduction regimen comprised prednisolone, vincristine, L-asparaginase, and idarubicin (10 mg/m²/week). The idarubicin dose was adjusted according to the degree of myelosuppression. The second complete remission (CR2) rate was 72.7%, obtained by 54.2% of patients with early relapse < 24 months after initial diagnosis and 95.0% of those with late relapse (P = 0.002). Five patients entered remission with extended treatment, resulting in a final CR2 rate of 84.1%. The CR2 rate was not significantly different according to the idarubicin dose. The induction death rate was 2.3% (1/44). The 5-year event-free and overall survival rates were 22.2% ± 6.4% and 27.3% ± 6.7% for all patients, 4.2% ± 4.1% and 8.3% ± 5.6% for early relapsers, and 43.8% ± 11.4% and 50.0% ± 11.2% for late relapsers, respectively. Early relapse and slow response to reinduction chemotherapy were predictors of poor outcomes. In conclusion, a modified dose of idarubicin was effectively incorporated into the reinduction regimen for late marrow-relapsed ALL with a low toxic death rate. However, the CR2 rate for early relapsers was suboptimal, and the second remission was not durable in most patients.

Unilateral Ptosis with Bilateral Incomplete Ophthalmoplegia as the Initial Presentation in Metastatic Cancer / 이화의대지

Orbital metastases are rare and predominantly unilateral occurrences. Bilateral metastases affecting the extraocular muscles are extremely rare. A few case reports of bilateral metastases to extraocular muscles described binocular diplopia with conspicuous bilateral external ophthalmoplegia as an initial symptom. We report a case in which unilateral ptosis was an initial symptom and bilateral incomplete ophthalmoplegia was found on initial neurologic examination in invasive ductal carcinoma of the breast. The patient had hormone receptor-positive breast cancer, and so was treated by hormonal therapies and closely monitored. The presence of a secondary orbital lesion presents many difficulties of differential diagnosis and treatment. A thorough neurologic examination to detect ocular manifestations is most important for localization and broad differential diagnosis including mechanical orbital metastatic lesion.

A Case of Severe Hypercalcemia Causing Acute Kidney Injury: An Unusual Presentation of Acute Lymphoblastic Leukemia

Severe hypercalcemia is rarely encountered in children, even though serum calcium concentrations above 15-16 mg/dL could be life-threatening. We present a patient having severe hypercalcemia and azotemia. A 14-year-old boy with no significant past medical history was referred to our hospital with hypercalcemia and azotemia. Laboratory and imaging studies excluded hyperparathyroidism and solid tumor. Other laboratory findings including a peripheral blood profile were unremarkable. His hypercalcemia was not improved with massive hydration, diuretics, or even hemodialysis, but noticeably reversed with administration of calcitonin. A bone marrow biopsy performed to rule out the possibility of hematological malignancy revealed acute lymphoblastic leukemia. His hypercalcemia and azotemia resolved shortly after initiation of induction chemotherapy. Results in this patient indicate that a hematological malignancy could present with severe hypercalcemia even though blast cells have not appeared in the peripheral blood. Therefore, extensive evaluation to determine the cause of hypercalcemia is necessary. Additionally, appropriate treatment, viz., hydration or administration of calcitonin is important to prevent complications of severe hypercalcemia, including renal failure and nephrocalcinosis.

Etiology of Bacteremia in Children with Hemato-oncologic Diseases from a Single Center from 2011 to 2015

PURPOSE: The aim of this study was to identify the pathogens of blood stream infection (BSI) in children with hemato-oncologic disorders, to analyze susceptibility patterns of microorganisms to guide empirical antimicrobial therapy, and to compare temporal trends of the pathogen and antimicrobial susceptibility with those of previous studies. METHODS: We retrospectively analyzed the medical records of children with hemato-oncologic disorders whose blood culture grew pathogens at the Seoul National University Children's Hospital between 2011 and 2015. RESULTS: A total of 167 patients developed 221 episodes of bacteremia. Among 229 pathogens, gram-negative bacteria (GNB) accounted for 69.0% (64.0% in 2002 to 2005, 63.4% in 2006 to 2010); gram-positive bacteria (GPB) accounted for 28.8% (31.3% in 2002 to 2005, 34.6% in 2006 to 2010); and fungus accounted for 2.2%. Among GNB, Klebsiella species (53.2%, 84/158) and Escherichia coli (19.6%, 31/158) were common. Staphylococcus aureus (48.5%, 32/66) and viridans streptococci (21.2%, 14/66) were frequently isolated among GPB. The susceptibilities of oxacillin and vancomycin in GPB were 54.8% and 96.9% (51.5% and 95.5% in 2002 to 2005; 34.1% and 90.5% in 2006 to 2010), respectively, whereas in GNB, the susceptibilities of cefotaxime, piperacillin/tazobactam, and imipenem were 73.2%, 77.2%, and 92.6% (75.9%, 82.8%, and 93.4% in 2002 to 2005; 62.8%, 82.9%, 93.8% and in 2006 to 2010), respectively. There were no significant differences in the proportion of etiologic agents or the antimicrobial susceptibilities between the current study and that of the previous two studies from 2002 to 2010. Overall fatality rate was 13.1%. CONCLUSIONS: GNB predominated in BSI among children with hemato-oncologic disorders. The etiology of bacteremia and antimicrobial susceptibility were comparable to those of the previous studies. Thus, piperacillin/tazobactam can be used as the initial empirical antimicrobial agent in febrile neutropenia.