Complication Analysis in Korean Patients With Hemophilia A From 2007 to 2019: A Nationwide Study by the Health Insurance Review and Assessment Service Database.

BACKGROUND: There has been remarkable progress in hemophilia A (HA) treatment in Korea. Viral inactivation products were developed in 1989, use of recombinant factor VIII (FVIII) concentrates started in 2002, and prophylaxis expanded thereafter. This study was conducted to identify the changes in complications in HA before and after 1989 or 2002. METHODS: The study was performed using the 2007-2019 Healthcare Big Data Hub of the Health Insurance Review and Assessment Service. RESULTS: Among 2,557 patients, 1,084 had ≥ 1 complication; 829 had joint problems, 328 had viral infections, 146 had neurologic sequelae, and 87 underwent 113 surgeries or procedures due to complications. Patients born after 1989 had a significantly lower risk of viral infections than those born before 1989; 27.1% vs. 1.4% (P < 0.001, odds ratio [OR], 0.037). Patients born after 2002 had a significantly lower risk of joint problems than those born before 2002; 36.8% vs. 24.7% (P < 0.001, OR, 0.538). Patients born after 2002 had a higher incidence of neurologic sequelae than those born before 2002; 3.7% vs. 11.1% (P < 0.001, OR, 3.210). Medical expenses for complication-associated surgeries or procedures were ₩2,957,557,005. CONCLUSION: Viral infections have significantly decreased in Korean patients with HA. The degree of reduction of joint problems was lower than we expected, because it took > 10 years to expand prophylaxis widely. Neurologic sequelae have not decreased; thus, additional efforts to decrease intracranial hemorrhage are needed. We suggest personalized dosing of FVIII and more meticulous care during childbirth to further reduce the complications.

Incidence and Risk Factors for Totally Implantable Venous Access Device Infections in Pediatric Patients With Cancer: A Study of 25,954 Device-Days.

BACKGROUND: Totally implantable venous access devices (TIVADs) are frequently used in pediatric patients with cancer owing to their multiple benefits. Despite occasional infections with TIVADs, knowledge of the incidence and risk factors is limited. METHODS: This retrospective study included pediatric patients with cancer who received TIVAD at Chungbuk National University Hospital from 2001 to 2021. We collected data on demographics, diagnosis, duration of TIVAD use, pathogens, and other risk factors. RESULTS: During the study period, 55 TIVADs with 25,954 device-days were applied in 49 patients. There were 15 TIVAD infections (15/55, 27.3%), with an infection rate of 0.21 infections per TIVAD per year (0.58 cases/1,000 device-days). TIVAD infections occurred at a median of 5 months (range, 8 days-30 months) after insertion. The most common causative microorganisms were methicillin-resistant coagulase-negative staphylococci (n = 8, 53.3%) followed by Escherichia coli (n = 3, 20.0%). Infection-free TIVAD survival was higher in the group with normal platelet count at insertion (platelet counts ≥ 150,000/µL) than in the group with thrombocytopenia at insertion (platelet counts < 150,000/µL) (81.3% vs. 32.1%, P = 0.004). Device removal was the mainstay of treatment (11/15, 73.3%). CONCLUSION: TIVAD infection may be related to thrombocytopenia at the time of device insertion. Further studies are needed to identify preventive factors against TIVAD infections in children with cancer.

Serum cytokine profiles in infants with infantile hemangiomas on oral propranolol treatment: VEGF and bFGF, potential biomarkers predicting clinical outcomes.

BACKGROUND: Oral propranolol has become first-line treatment for infantile hemangiomas (IHs). This study focused on identifying cytokines related to the biology of IH and early regression indicators of IH after propranolol treatment. METHODS: For inclusion, the patients had to be aged less than 1 year and have an IH with a largest diameter ≥2 cm. Patients were scheduled to receive 1 year of propranolol treatment. Serum cytokines involved in angiogenesis, vasculogenesis, and/or chronic inflammation were analyzed at 0, 1, and/or 12 months after treatment using Multiplex Luminex assays. RESULTS: Among the 49 evaluable patients, 33 completed the 1-year treatment: 16 showed excellent response and 12 had good response to propranolol. Significant decreases in serum MMP-2, bFGF, VEGF-α, and MCP-1 levels were observed after 1 year of treatment compared to pretreatment values. The maximal diameters of the lesions significantly correlated with pretreatment serum VEGF-α, bFGF, and MMP-9. Patients with higher bFGF and VEGF levels showed better response to propranolol at 1 year. CONCLUSION: MMP-2, VEGF-α, bFGF, and MCP-1 may involve in the biology of IH and their downregulation may be associated with involution processes of IH. Pretreatment bFGF and VEGF could be novel biomarkers for predicting response to propranolol. IMPACT: We found that decreases in the concentrations of MMP-2, bFGF, VEGF, and MCP-1 were associated with regression of the hemangioma, which indicates that one of the mechanisms of propranolol in the treatment of proliferative hemangiomas may involve downregulation of those cytokines. Patients with higher bFGF and VEGF levels showed better response to propranolol at 1 year. Importantly, serum bFGF higher than 37.07 pg/mL may predict an excellent response to propranolol. Therefore, along with the patient's age and the size and visual characteristics of the lesion, bFGF levels could help determine the viability of propranolol use in the treatment of IHs. Our study represented extensive serum profiling in IH, reporting the indicators and molecules clearly related to IH regression with propranolol treatment. The authors believe that monitoring serum cytokines, including MMP-2, bFGF, VEGF, and MCP-1, in IH patients could be important, in addition to clinical follow-up, for determining when to start and end propranolol treatment.

Changes in hepatitis B antibody status after chemotherapy in children with acute lymphoblastic leukemia.

BACKGROUND: Children with cancer may be at an increased risk of infection with hepatitis B virus (HBV) when levels of hepatitis B antibodies are reduced owing to chemotherapy-induced immunosuppression. This study evaluated the changes in HBV antibody status and HBV infections after chemotherapy in children with acute lymphoblastic leukemia (ALL). PROCEDURE: The data of patients with ALL diagnosed between April 2007 and March 2013 were retrospectively collected. Hepatitis B surface antibody (HBsAb) titers were defined as negative at levels <10 IU/L. The HBsAb titers were individually compared before and after chemotherapy. RESULTS: A total of 88 patients were included in this study. At the time of diagnosis, 32 (36.4%) and 56 (63.6%) patients were HBsAb negative and HBsAb positive, respectively. The 56 HBsAb-positive patients were categorized into two groups, namely, group A with 44 patients (78.6%, 44/56) who became HBsAb negative after chemotherapy, and group B with 12 patients (21.4%) who remained HBsAb positive. On multivariate analysis, lower initial levels of HBsAb titers were associated with HBsAb negativity after chemotherapy (relative risk: 1.003, 95% confidence interval: 1.001-1.006; P = .009). CONCLUSION: This study demonstrated that patients with a low level of prechemotherapy HBsAb titers were likely to become HBsAb negative after chemotherapy. Therefore, evaluation of HBsAb status may be necessary after the completion of chemotherapy in children with ALL.

Unrelated donor hematopoietic stem cell transplantation for pediatric de novo acute myeloid leukemia with intermediate- or high-risk cytogenetics.

The role of unrelated donor HSCT for children with de novo AML in CR1 is controversial. We performed this study to investigate the feasibility of unrelated donor HSCT who initially had intermediate- or high-risk cytogenetics. We retrospectively reviewed medical records of patients with AML who received unrelated HSCT in CR1 at Samsung Medical Center between November 2001 and January 2012. Patients were allocated based on karyotype at diagnosis as follows: (a) low-risk: inv(16), t(16;16), t(8;21), and t(15;17); (b) high-risk: -5, 5q-, -7, 3q abnormalities, t(8;16), t(6;9), t(6;11), t(6;21), t(10;11), complex karyotype (≥3 abnormalities), and acute megakaryocytic leukemia without t(1;22); and (c) IR: all the other karyotypes including normal. Patients in intermediate- or high-risk group who were transplanted with either unrelated CB or matched unrelated BM/mobilized PB in their CR1 were included in this study. The projected OS and EFS rates were 74.9% and 71.1%, respectively, with a median follow-up of 87.3 months after transplantation. The EFS was 70.1%, 80.7%, and 73.9% for CB, BM, and mobilized PB groups, respectively (P = 0.89), and 73.9% and 70.6% for IR and high-risk groups (P = 0.76). The leading cause of death was relapse (n = 8), and only one patient died from non-relapse cause. Unrelated donor HSCT seems a feasible approach for children with intermediate- or high-risk AML in CR1. Relapse remains the leading cause of treatment failure among these patients.

Clinical similarities between influenza A and B in children: a single-center study, 2017/18 season, Korea.

BACKGROUND: The global burden of seasonal influenza on medical care has been one of the greatest in the pediatric population. The attention drawn to influenza B was relatively low compared to influenza A, probably because the influenza B virus was thought to be less virulent and have a lower pandemic potential. This study aimed to compare the clinical features of influenza A and B in children. METHODS: This retrospective study included children diagnosed and treated for influenza as inpatients or outpatients during the 2017/18 influenza season at a tertiary referral hospital. Data regarding clinical characteristics, diagnoses, laboratory results, and vaccination histories were collected and reviewed. RESULTS: Over the study period, 128 patients with influenza A and 109 patients with influenza B were identified. The mean age of patients with influenza B was significantly higher than that of patients with influenza A (5.6 ± 4.4 vs 4.1 ± 4.4 years, p = 0.010). Fever was the most common manifestation of influenza followed by respiratory symptoms. No single symptom was specifically associated with either type of influenza. The total duration of fever (4.3 ± 2.3 vs 3.7 ± 2.6 days), 'time from fever onset to initiation of antivirals', and 'time from initiation of antivirals to defervescence' were similar between the two influenza types, even though all three time periods tended to be longer for influenza B. The platelet counts and proportions of neutrophils were higher for influenza A than for influenza B infections, although the values were within normal limits for both influenza types. CONCLUSIONS: We found overall clinical similarities between influenza A and B with no less clinical significance or severity of influenza B compared to those of influenza A. Equal levels of awareness and attention should be paid to both influenza types.

Impact of Day 14 Peripheral Blood Chimerism after Allogeneic Hematopoietic Stem Cell Bone Transplantation on the Treatment Outcome of Non-Malignant Disease.

BACKGROUND: The impact of early peripheral blood chimerism on the outcome of allogeneic hematopoietic stem cell transplantation (allo-HSCT) is unclear. We aimed to determine whether day 14 peripheral blood chimerism after allo-HSCT predicts outcomes in patients with non-malignant diseases. METHODS: Data from 56 patients who received allo-HSCT between April 2007 and March 2016 were retrospectively analyzed. Chimerism was evaluated using short-tandem repeat polymerase chain reaction, with mixed chimerism (MC) defined as greater than 1% recipient cells which was further categorized into low-level MC (> 1% and < 15% of recipient-derived cells) and high-level MC (≥ 15% of the recipient-derived cells). RESULTS: Thirty-six patients showed complete donor chimerism (CC), 14 low-level MC, and 6 high-level MC at day 14 post-transplant. The estimated 5-year event-free survival (EFS) was higher in the CC or low-level MC groups than in the high-level MC group (86.1% vs. 71.4% vs. 33.3%; P = 0.001). In BM or peripheral blood stem cell (BM/PBSC) transplants, the 5-year EFS was higher in the CC or low-level MC group than in the high-level MC group (93.1% vs. 66.7% vs. 0%; P < 0.001). However, in cord blood transplants, the 5-year OS and EFS according to the day 14 peripheral blood chimerism did not reach statistical significance. CONCLUSION: Although CC is not always necessary after allo-HSCT for non-malignant diseases, our data suggest that day 14 peripheral blood chimerism may predict outcomes in patients with non-malignant diseases who underwent BM/PBSC transplants.

Erratum: Correction of Title: Impact of Day 14 Peripheral Blood Chimerism after Allogeneic Hematopoietic Stem Cell Bone Transplantation on the Treatment Outcome of Non-Malignant Disease.

[This corrects the article e46 in vol. 34, PMID: 30787679.].

Copper deficiency-induced bicytopenia caused by poor compliance in a paediatric patient with chronic malnutrition: A case report.

A 12-year-old boy who underwent gastric wedge resection was transferred to our hospital because of vomiting, growth failure, and weight loss in January, 2016. We tried to restore his general condition by maintaining additional nutritional supply through peripheral parenteral nutrition (PN). However, continuous vomiting, weight loss, and superior mesenteric artery syndrome persisted because of low treatment compliance. The findings of hyponatraemia and bicytopenia did not improve. Bone marrow biopsy was performed, and it revealed copper deficiency. PN with additional micronutrient agents, including copper, were administered. In particular, invasive diagnosis and treatment, and adequate education improved the treatment compliance of the child. His copper deficiency and bicytopenia improved, and his weight and dietary intake also increased. We confirmed that treatment compliance is important in paediatric patients with malnutrition. In chronic malnutrition, attention should also be paid to deficiency of micronutrients such as copper, which can lead to haematologic problems.

Allogeneic Hematopoietic Cell Transplantation in Patients with Primary Immunodeficiencies in Korea: Eleven-Year Experience in a Single Center.

PURPOSE: We aimed to report our single-center experience of allogeneic hematopoietic cell transplantation (HCT), which has been the only curative option for certain patients with lethal primary immunodeficiencies (PIDs). METHODS: We summarized the results of HCT performed for patients with PIDs for 11 consecutive years from 2006 to 2016 at Samsung Medical Center, Seoul, Korea. Twenty-six patients with PIDs received HCT. Most had chronic granulomatous disease (42.3%), Wiskott Aldrich syndrome (15.4%), or severe combined immunodeficiency (11.5%). RESULTS: Nine patients (34.6%) received HCT during the former half period and 17 patients (65.4%) during the latter half period. Donor types were categorized as: matched sibling donor (n = 5), unrelated donor (n = 17), and familial mismatched donor (FMMD) (n = 4). Unrelated HCT and FMMD transplantation were increasingly performed in the latter half period compared to the first (5 vs. 16, P = 0.034). Five patients experienced initial engraftment failure, but all of them were eventually engrafted after additional HCTs. The 3-year probability of overall survival was 72.0%. Seven patients (26.9%) died, and the causes of death were bacterial sepsis (n = 4), pneumonia (n = 1), chronic graft-versus-host disease (GVHD) (n = 1), and diffuse alveolar hemorrhage (n = 1). Two patients with bacterial sepsis and a patient with pneumonia also had chronic GVHD. Unrelated HCT and use of methotrexate were associated with poor outcome. Complete chimerism was attained in 85.0% at 1 year after HCT. CONCLUSION: PID candidates have been increasingly identified for allogeneic HCT in Korea, and the majority of them could be cured by HCT. Establishment of a systematic registry of PID patients for HCT is needed.

Correction to: Allogeneic Hematopoietic Cell Transplantation in Patients with Primary Immunodeficiencies in Korea: Eleven-Year Experience in a Single Center.

The original version of this article unfortunately contained a mistake in the 7th author's given name. The correct version is presented above.

Splenic embolization for a giant splenic hemangioma in a child: a case report.

BACKGROUND: Splenic hemangioma is the most common benign tumor of the spleen. However, it remains a rare medical condition in children. Although the natural course of splenic hemangioma is slow growth, treatment for large splenic hemangiomas has been recommended due to the risk of spontaneous rupture causing life-threating hemorrhage. However, the optimal treatment for splenic hemangioma in children is unclear. CASE PRESENTATION: An 11-year-old girl had an enhancing mass, 61 × 54 × 65 mm in size and numerous daughter nodules throughout the entire spleen on a contrast-enhanced computed tomography scan of the abdomen and angiography. The patient was treated by complete embolization at the distal level of splenic artery, which resulted in total splenic infarction. Treatment-related complications were thrombocytosis and postembolization syndrome, including abdominal pain and, intermittent fever below 39 °C. There were no other serious complications, including bleeding. CONCLUSION: Splenic embolization may be a safe and less invasive intervention for children with a large splenic hemangioma. Further studies are needed to confirm the effectiveness of our approach.

Changes in hepatitis B virus antibody titers over time among children: a single center study from 2012 to 2015 in an urban of South Korea.

BACKGROUND: Hepatitis B virus (HBV) infection is the most common cause of liver disease in endemic areas such as South Korea. After HBV vaccination, hepatitis B surface antibody (HBsAb) titers gradually decrease. Trends in HBsAb titers have not been evaluated among children in South Korea over the past decade. METHODS: We screened 6155 patients (aged 7 months to 17 years) who underwent HBV antigen/antibody testing at Chung-Ang University Hospital from May 2012 to April 2015. Titer criteria were defined as follows: positive, titer ≥100 IU/L; weakly positive, titer 10-99 IU/L; and negative, titer <10 IU/L. We also compared titers before and 1 month after a single booster vaccination. RESULTS: Of the 5655 patients included, 3016 were male and 5 (0.09%) tested positive for HBV surface antigen. A marked reduction in antibody titer was observed until 4 years of age. Thereafter, the titers showed fluctuating decreases. HBsAb titers reached their lowest levels by 14 years of age. After 7 years of age, 50% of patients tested negative for HBsAb. Simple linear analysis showed that the titer reached levels of <10 IU/L and zero at 12.9 and 13.4 years of age, respectively. 1 month after a single booster vaccination was administered to those who were HBsAb-negative (n = 72), 69 children (96%) had developed antibodies while 3 (4%) remained HBsAb-negative. CONCLUSIONS: In conclusion, the continuous reduction in HBsAb titers over time and in each age group was confirmed. The titer level was shown significant decline until age 4. More than half of the sample had negative titers after age 7 years. After booster vaccination, most of child significantly increase titer level.

Measurement and Estimation of Renal Size by Computed Tomography in Korean Children.

Adequate organ growth is an important aspect of growth evaluation in children. Renal size is an important indicator of adequate renal growth; computed tomography (CT) can closely estimate actual kidney size. However, insufficient data are available on normal renal size as measured by CT. This study aimed to evaluate the relationships of anthropometric indices with renal length and volume measured by CT in Korean pediatric patients. Renal length and volume were measured using CT images in 272 pediatric patients (age < 18 years) without renal disease. Data for anthropometric indices-including height, weight, and body surface area (BSA)-were obtained using medical records. Using the equation for an ellipsoid, renal volume was calculated in cubic centimeters. Height showed greatest correlation with renal length on stepwise multiple linear regression analysis; BSA showed the strongest significant correlation with renal volume. The mean renal size for each age group and height group was determined; it showed a tendency to increase with age and height. This is the first Korean study to report the relationship between body indices and renal size measured by CT. These results can serve as normative standards for assessing adequate renal growth.

High-Dose Chemotherapy and Autologous Stem Cell Transplantation in Children with High-Risk or Recurrent Bone and Soft Tissue Sarcomas.

Despite increasing evidence that high-dose chemotherapy and autologous stem cell transplantation (HDCT/auto-SCT) might improve the survival of patients with high-risk or recurrent solid tumors, therapy effectiveness for bone and soft tissue sarcoma treatment remains unclear. This study retrospectively investigated the feasibility and effectiveness of HDCT/auto-SCT for high-risk or recurrent bone and soft tissue sarcoma. A total of 28 patients (18 high-risk and 10 recurrent) underwent single or tandem HDCT/auto-SCT between October 2004 and September 2014. During follow-up of a median 15.3 months, 18 patients exhibited disease progression and 2 died of treatment-related toxicities (1 veno-occlusive disease and 1 sepsis). Overall, 8 patients remained alive and progression-free. The 3-year overall survival (OS) and event-free survival (EFS) rates for all 28 patients were 28.7% and 26.3%, respectively. In the subgroup analysis, OS and EFS rates were higher in patients with complete or partial remission prior to HDCT/auto-SCT than in those with worse responses (OS, 39.1% vs. 0.0%, P = 0.002; EFS, 36.8% vs. 0.0%, P < 0.001). Therefore, careful selection of patients who can benefit from HDCT/auto-SCT and maximal effort to reduce tumor burden prior to treatment will be important to achieve favorable outcomes in patients with high-risk or recurrent bone and soft tissue sarcomas.

Detection of MYCN Amplification in Serum DNA Using Conventional Polymerase Chain Reaction.

Neuroblastoma (NB) is the most common extra-cranial solid tumor of childhood and is characterized by a wide range of clinical behaviors. Amplification of MYCN is a well-known poor prognostic factor in NB patients. As the MYCN amplification status is usually tested using tumor specimens, lengthy and invasive procedures are unavoidable. To evaluate the possibility of detecting MYCN amplification without invasive procedure, we performed conventional polymerase chain reaction (PCR) analysis to identify MYCN amplification using the preserved serum DNA. PCR of serum DNA was done in 105 NB patients whose MYCN status had been confirmed by fluorescence in situ hybridization. MYCN amplification was evaluated as the ratio of signal intensities between MYCN and NAGK (M/N ratio). When regarding the tissue FISH results as a reference, 10 patients had MYCN-amplified (MNA) NB, and 95 had non-MNA NB. The M/N ratio of the MNA group (median 2.56, range 1.01-3.58) was significantly higher than that of the non-MNA group (median 0.97, range 0.67-5.18) (P < 0.001). In the receiver operating characteristic curve analysis, the area under the curve was 0.957 (95% confidence interval 0.898-1.000; P < 0.001), and it showed 90.9% sensitivity and 97.9% specificity with the selected cut-off value set as 1.6. The detection of MYCN amplification using conventional PCR analysis of serum samples seems to be a simple and promising method to evaluate the MYCN status of NB patients. Further study with a larger set of patients is needed to confirm the accuracy of this result.

Clinical Significance of Persistent Tumor in Bone Marrow during Treatment of High-risk Neuroblastoma.

The records of 63 high-risk neuroblastoma patients with bone marrow (BM) tumors at diagnosis were retrospectively reviewed. All patients received nine cycles of induction chemotherapy followed by tandem high-dose chemotherapy and autologous stem cell transplantation (HDCT/auto-SCT). Follow-up BM examination was performed every three cycles during induction chemotherapy and every three months for one year after the second HDCT/auto-SCT. BM tumor cells persisted in 48.4%, 37.7%, 23.3%, and 20.4% of patients after three, six, and nine cycles of induction chemotherapy and three months after the second HDCT/auto-SCT, respectively. There was no difference in progression-free survival (PFS) rate between patients with persistent BM tumor and those without during the induction treatment. However, after tandem HDCT/auto-SCT, the PFS rate was worse in patients with persistent BM tumor than in those without (probability of 5-yr PFS 14.7% ± 13.4% vs. 64.2% ± 8.3%, P = 0.009). Persistent BM tumor during induction treatment is not associated with a worse prognosis when intensive tandem HDCT/auto-SCT is given as consolidation treatment. However, persistent BM tumor after tandem HDCT/auto-SCT is associated with a worse prognosis. Therefore, further treatment might be needed in patients with persistent BM tumor after tandem HDCT/auto-SCT.

Toxicity of tandem high-dose chemotherapy and autologous stem cell transplantation using carboplatin-thiotepa-etoposide and cyclophosphamide-melphalan regimens for malignant brain tumors in children and young adults.

The number of studies examining the use of tandem high-dose chemotherapy and autologous stem cell transplantation (HDCT/auto-SCT) to treat high-risk or recurrent brain tumors is increasing. However, studies addressing the toxicity associated with tandem HDCT/auto-SCT, particularly during the second HDCT/auto-SCT, are very limited. For this reason, we retrospectively evaluated the toxicity of tandem HDCT/auto-SCT with carboplatin-thiotepa-etoposide (CTE) and cyclophosphamide-melphalan (CM) regimens when used to treat high-risk or recurrent brain tumors. A total of 109 patients who received a first HDCT/auto-SCT and 100 who proceeded to a second HDCT/auto-SCT between May 2005 and December 2013 were included. Hematologic recovery was rapid during both the first and second HDCT/auto-SCT. In the first HDCT/auto-SCT, mucositis-related gastrointestinal toxicity was frequent, and two (1.8 %) patients died from toxicity [one hepatic veno-occlusive disease (VOD) and one sepsis]. In the second HDCT/auto-SCT, mucositis-related toxicity was milder than in the first round. However, hepatic VOD frequency was high (20.0 %), and six (6.0 %) patients died from toxicity (four hepatic VODs, one asphyxia, and one sepsis). Multivariate analysis indicated that age younger than 8 years was the only significant predictor for hepatic VOD. All six patients who died from toxicity during the second HDCT/auto-SCT were younger than 9 years of age. This study demonstrates that tandem HDCT/auto-SCT using CTE/CM regimens was generally feasible. However, dose reduction during the second HDCT/auto-SCT in young children might be needed to decrease the death rate from toxicity.

Survival of Children with Acute Lymphoblastic Leukemia with Risk Group-Based Protocol Changes: A Single Center Experience with 460 Patients over a 20-Year Period.

Purpose: Recent treatments for pediatric acute lymphoblastic leukemia (ALL) are founded on risk stratification. We examined the survival rates and prognostic factors of patients over a 20-year period at a single institution. Materials and Methods: This study analyzed patients diagnosed with ALL and treated at the Pediatric Department of Samsung Medical Center (SMC). Patients were categorized into standard-risk (SR), high-risk (HR), and very high-risk (VHR) groups. The SMC protocol for the HR group underwent two changes during the study period: A modified Children's Cancer Group (CCG)-1882 protocol was used from 2000 to 2005, the Korean multicenter HR ALL-0601 protocol from 2006 to 2014, and the Korean multicenter HR ALL-1501 protocol from 2015 to 2019. Results: Of the 460 patients, complete remission was achieved in 436 patients (94.8%). The 10-year overall survival rate (OS) was 83.8±1.9% for all patients. OS according to the SMC risk group was as follows: 95.9±1.4% in the SR group, 83.8±3.6% in the HR group, and 66.2±6.9% in the VHR group. The 5-year OS within the HR group varied according to the treatment protocol: 73.9±7.5%, in the modified CCG-1882 protocol, 83.0±3.9%, in the 0601 protocol, and 96.2±2.6%, in the 1501 protocol. For those aged 15 years and older, the OS was only 56.5±13.1%. Relapse occurred in 71 patients (15.4%), and the OS after relapse was 37.7±6.0%. Conclusion: The treatment outcomes of patients with ALL improved markedly. However, there is a need to further characterize adolescents and young adult patients, as well as those who have experienced relapses.

The Effect of Hematopoietic Stem Cell Transplantation on Treatment Outcome in Children with Acute Lymphoblastic Leukemia.

Purpose: Hematopoietic stem cell transplantation (HSCT) has been an important method of treatment in the advance of pediatric acute lymphoblastic leukemia (ALL). The indications for HSCT are evolving and require updated establishment. In this study, we aimed to investigate the efficacy of HSCT on the treatment outcome of pediatric ALL, considering the indications for HSCT and subgroups. Materials and Methods: A retrospective analysis was conducted on ALL patients diagnosed and treated at a single center. Risk groups were categorized based on age at diagnosis, initial white blood cell count, disease lineage (B/T), and cytogenetic study results. Data on the patients' disease status at HSCT and indications of HSCT were collected. Indications for HSCT were categorized as upfront HSCT at 1st complete remission, relapse, and refractory disease. Results: Among the 549 screened patients, a total of 418 patients were included in the study; B-ALL (n=379) and T-ALL (n=39). HSCT was conducted on a total of 106 patients (25.4%), with a higher frequency as upfront HSCT in higher risk groups and specific cytogenetics. The overall survival (OS) was significantly better when done upfront than in relapsed or refractory state in T-ALL patients (p=0.0016). The KMT2A-rearranged ALL patients showed superior event-free survival (p=0.0023) and OS (p=0.0221) when HSCT was done as upfront treatment. Conclusion: HSCT had a substantial positive effect in a specific subset of pediatric ALL. In particular, frontline HSCT for T-ALL and KMT2A-rearranged ALL offered a better prognosis than when HSCT was conducted in a relapsed or refractory setting.