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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.
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An irreducible ankle dislocation is a rare injury. The cause is a dislocation of the distal fibula anteriorly or posteriorly or the insertion of soft tissue, such as the deltoid ligament or posteromedial tendon. The tibialis posterior tendon can be dislocated through distal tibiofibular diastasis and prevent reduction of the ankle joint. The authors experienced anterolateral ankle fracture dislocation with a diastasis of the distal tibiofibular joint, and reduction was impossible because of impingement of the tibialis posterior tendon dislocated anteriorly through the distal tibiofibular diastasis. This paper reports the treatment of this injury.
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Laundry detergent pod (LDP) exposure has been reported to be fatal in children younger than 2 years, leading to respiratory or central nervous system depression. While gastrointestinal irritation is the most common symptom, there are reported cases of severe acidosis with respiratory depression or pneumonia, resulting in mortality. To our best knowledge, there is no report on a case of LDP exposure presenting with acute respiratory distress syndrome requiring extracorporeal membrane oxygenation support. Here, we present a case of a child with severe acute respiratory distress syndrome following LDP exposure, who was successfully treated with veno-pulmonary extracorporeal membrane oxygenation and steroids.
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Background@#This study was to identify the factors influencing smartphone dependence among late schoolaged children, focusing on grit and family strengths. @*Methods@#A cross-sectional descriptive study was conducted with 218 children in grades 5 and 6 who were recruited from elementary schools in U and Y cities. The data were collected through self-reported questionnaires, including smartphone dependence, grit, family strengths and general characteristics, for the month of December 2019, just before the novel coronavirus pandemic after obtaining approval from IRB. The collected data were analyzed using multiple regression. @*Results@#Smartphone usage time, the main purpose of smartphone usage (game and social networking), and grit were identified as significant factors of smartphone dependence. This model explained 38% of the total variance showing the variable of grit with the greatest variance. @*Conclusions@#A strategy to develop grit is needed to reduce smartphone dependence among late school-age children.
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Background@#Similar to smoking, exposure to secondhand smoke is a risk factor for developing hypertension and cardiovascular diseases; however, there is no standardized method for measuring smoke exposure. Measuring urine cotinine levels is one possible means for determining the degree of exposure to secondhand smoke. This study investigated the association between urinary cotinine levels and blood pressure in Korean adults exposed to secondhand smoke. @*Methods@#Data from the Korea National Health and Nutrition Examination Survey conducted between 2016 and 2018 were used. A total of 9,273 participants aged ≥19 years self-reported as current non-smokers, which was cotinine- verified. A complex sample general linear model regression analysis was performed to analyze the association between urine cotinine and blood pressure. A P-value of <0.05 was considered statistically significant. @*Results@#Corrected urine cotinine levels were positively associated with systolic and diastolic blood pressure in female participants (P<0.001 and P=0.040, respectively). Furthermore, a 10-fold increase in the corrected urine cotinine level of those in contact with secondhand smoke was independently associated with 2.085 mm Hg and 0.575 mm Hg increases in systolic and diastolic blood pressure, respectively. However, there was no association between systolic and diastolic blood pressure in male participants (P=0.226 and P=0.256, respectively). @*Conclusion@#Urinary cotinine levels were positively associated with increased blood pressure in females exposed to secondhand smoke. Therefore, urinary cotinine may be used as an indicator to quantify and monitor the effects of blood pressure elevation in females exposed to secondhand smoke.
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Background@#Data on the status of long-term follow-up (LTFU) care for childhood cancer survivors (CCSs) in Korea is lacking. This study was conducted to evaluate the current status of LTFU care for CCSs and relevant physicians’ perspectives. @*Methods@#A nationwide online survey of pediatric hematologists/oncologists in the Republic of Korea was undertaken. @*Results@#Overall, 47 of the 74 board-certified Korean pediatric hematologists/oncologists currently providing pediatric hematology/oncology care participated in the survey (response rate = 63.5%). Forty-five of the 47 respondents provided LTFU care for CCSs five years after the completion of primary cancer treatment. However, some of the 45 respondents provided LTFU care only for CCS with late complications or CCSs who requested LTFU care. Twenty of the 45 respondents oversaw LTFU care for adult CCSs, although pediatric hematologists/ oncologists experienced more difficulties managing adult CCSs. Many pediatric hematologists/oncologists did not perform the necessary screening test, although CCSs had risk factors for late complications, mostly because of insurance coverage issues and the lack of Korean LTFU guidelines. Regarding a desirable LTFU care system for CCSs in Korea, 27 of the 46 respondents (58.7%) answered that it is desirable to establish a multidisciplinary CCSs care system in which pediatric hematologists/oncologists and adult physicians cooperate. @*Conclusion@#The LTFU care system for CCS is underdeveloped in the Republic of Korea. It is urgent to establish an LTFU care system to meet the growing needs of Korean CCSs, which should include Korean CCSs care guidelines, provider education plans, the establishment of multidisciplinary care systems, and a supportive national healthcare policy.
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Background@#Glomus tumors are benign vascular tumors derived from the glomus body, a neuromuscular vascular tissue responsible for regulating the temperature and blood flow of the skin. Ultrasonography (USG) is a useful tool for diagnosing glomus tumors; nevertheless, data on Korean patients with glomus tumors are limited. @*Objective@#This study aimed to describe USG findings of subungual glomus tumors in Korean patients. @*Methods@#We retrospectively reviewed the medical records and USG readings of 20 cases of glomus tumors in the nail apparatus diagnosed from January 2015 to December 2021. @*Results@#Twenty patients were included in this study. Four patients (20.0%) were male and 16 (80.0%) were female. The age of onset ranged from 18∼86 years, with a mean of 45.2 years. USG findings showed hypoechoic echogenicity in all cases. Tumor size ranged from 2.3∼10 mm (mean±standard deviation, 5.5±1.9 mm). The tumor shape observed on USG was oval in 16 cases (80.0%), lobulated in three cases (15.0%), and round in one case (5.0%). Tumor boundaries were well-defined in 18 cases (90.0%) and ill-defined in two cases. Posterior acoustic enhancement and cortical erosion were observed in 19 (95.0%) and 17 cases (85.0%), respectively. Increased vascularity was observed in 19 cases (95.0%). @*Conclusion@#This study revealed characteristic USG features of glomus tumors. USG is a helpful tool for the diagnosis and management of glomus tumors.
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Purpose@#This study aimed to evaluate clinical significance and imaging findings of newly detected lesions on breast MRI while monitoring patients’ response to neoadjuvant chemotherapy (NAC). @*Materials and Methods@#We identified 291 patients with newly diagnosed breast cancer who underwent breast MRI to assess their response to NAC between January 2017 and August 2021. We evaluated 26 new lesions in 24 women (mean age, 49.8 years; range, 35–63 years) who were included in this study. Two radiologists assessed imaging findings of new lesions according to Breast Imaging Reporting and Data System (BI-RADS) lexicon 5th edition and evaluated follow-up MRI during NAC. Outcomes of new lesions were determined based on pathologic examination or imaging follow-up after surgery. @*Results@#All 26 new lesions were found on the first follow-up imaging. They disappeared or decreased in size on the second follow-up imaging. Lesion types included mass (n = 22, 84.6%) and non-mass enhancement (n = 4, 15.4%). The majority of the mass types showed oval to round shapes (22/22, 100%), circumscribed margins (21/22, 95.5%), and rim enhancement (18/22, 81.8%). Seven (26.9%) new lesions were ipsilateral to the index cancer, 7 (26.9%) were contralateral, and 12 (46.2%) were bilateral. None of these new lesions were malignant. @*Conclusion@#New lesions were detected in 4.7% of breast MRI during NAC. Most new lesions tended to
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Background@#Recent genomic studies identified four discrete molecular subgroups of medulloblastoma (MB), and the risk stratification of childhood MB in the context of subgroups was refined in 2015. In this study, we investigated the effect of molecular subgroups on the risk stratification of childhood MB. @*Methods@#The nCounter® system and a customized cancer panel were used for molecular subgrouping and risk stratification in archived tissues. @*Results@#A total of 44 patients were included in this study. In clinical risk stratification, based on the presence of residual tumor/metastasis and histological findings, 24 and 20 patients were classified into the average-risk and high-risk groups, respectively. Molecular subgroups were successfully defined in 37 patients using limited gene expression analysis, and DNA panel sequencing additionally classified the molecular subgroups in three patients. Collectively, 40 patients were classified into molecular subgroups as follows: WNT (n = 7), SHH (n = 4), Group 3 (n = 8), and Group 4 (n = 21). Excluding the four patients whose molecular subgroups could not be determined, among the 17 average-risk group patients in clinical risk stratification, one patient in the SHH group with the TP53 variant was reclassified as very-high-risk using the new risk classification system. In addition, 5 of 23 patients who were initially classified as high-risk group in clinical risk stratification were reclassified into the low- or standard-risk groups in the new risk classification system. @*Conclusion@#The new risk stratification incorporating integrated diagnosis showed some discrepancies with clinical risk stratification. Risk stratification based on precise molecular subgrouping is needed for the tailored treatment of MB patients.
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Purpose@#We performed this study to determine whether the degree of neutropenia after the first chemotherapy cycle can be used as a surrogate marker of individual susceptibility to chemotherapeutic agents affecting treatment outcome in patients with neuroblastoma. @*Materials and Methods@#The study included 313 patients who received the first cycle chemotherapy with a CEDC (cisplatin+etoposide+doxorubicin+cyclophosphamide) regimen and had absolute neutrophil count (ANC) data available. The cumulative incidences of progression and treatment-related mortality (TRM) were estimated. To identify genetic variations associated with the ANC, a genome-wide association study (GWAS) was performed. @*Results@#An ANC of 32.5/μL was determined as the cutoff point to categorize patients into the good and poor prognosis subgroups in terms of progression. Patients with a high nadir ANC had a higher cumulative incidence of progression than those with a low nadir ANC (p < 0.001). In multivariate analysis, high nadir ANC, age, bone marrow involvement, and unfavorable histology were poor prognostic factors. With regard to the TRM, patients with a low nadir ANC (ANC < 51.0/μL) had a higher cumulative incidence of TRM than those with a high nadir ANC (p=0.010). In GWAS, single-nucleotide polymorphisms of LPHN2 and CRHR1 were significantly associated with the nadir ANC. @*Conclusion@#In neuroblastoma patients, the degree of neutropenia after the first chemotherapy cycle can be used as a surrogate marker to predict an individual’s susceptibility to chemotherapeutic agents. Tailoring of treatment based on the degree of neutropenia needs to be considered.
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Recurrent respiratory papillomatosis (RRP) is a chronic disease related to human papillomavirus infection. The standard treatment of RRP is surgical resection of the lesion, but due to frequent recurrence, a combination of various adjuvant therapies has been attempted. Herein, we present the first case of RRP to whom intravenous cidofovir was administered as an adjuvant therapy in Korea. A 9-year-old boy was admitted due to hoarseness, stridor and breathing difficulty. At 10 months of age, he was diagnosed with RRP in the upper airway and thereafter he had repeatedly undergone surgical removal. During this hospitalization, papilloma was found again from the superior glottis to the inferior glottis and surrounding the trachea at the age of 9 years. In addition, well-defined nodular lesions were newly found on both lung fields, and a pathologic examination revealed a squamous papilloma with highgrade dysplasia, human papilloma virus types 6, 11, and 40 (low-risk type). Because of the frequent recurrence of papilloma in the upper airway as well as lung involvement, he underwent 38 injections of intravenous cidofovir for 2 years. During treatment, the intervals required for surgical removal of the mass causing upper airway obstruction were prolonged from an average of 37.3 to 74.6 days without serious side effects. However, intravenous cidofovir treatment had no effect on the lung lesion. This case shows that an intravenous cidofovir administration can be used as an adjuvant therapy in a child with RRP to relieve the upper airway obstruction, although this treatment does not cure the disease.
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Background@#Fixed-dose combinations have the advantage of improving patient compliance, but may increase the risk of duplicate prescriptions. As the use of fixed-dose combination antihypertensives increases, it is necessary to investigate the current status of class duplication prescriptions (CDP) in patients taking fixed-dose combination antihypertensives in Korea and to identify factors associated with CDP. @*Methods@#We conducted a retrospective observational study using nationally representative claim data. Hypertensive patients aged 20 years or older taking fixed-dose combination antihypertensives were extracted. Among these patients, patients with CDP were identified. A chi-square test was applied to determine the differences between patients with CDP and nonCDP. The associated factors of CDP were identified through multiple logistic regression. @*Results@#Of the 74,165 patients who were prescribed fixed-dose combination antihypertensives, 426 patients (0.6%) with CDP were identified. The most common antihypertensive class associated with CDP was calcium channel blockers (194 patients, 45.5%), followed by angiotensin II receptor blockers (136 patients, 31.9%). Patients aged 75 years or older (odds ratio [OR] 1.83, 95% confidence interval [CI] 1.02-3.52), chronic kidney disease (OR 4.45, 95% CI 2.15-8.25), chronic heart failure (OR 2.71, 95% CI 1.93-3.72), coronary artery disease (OR 2.22, 95% CI 1.60-3.03) and Medical Aid/Patriots and Veterans Insurance (OR 1.49, 95% CI 1.04-2.07) were significantly associated with increased CDP. @*Conclusions@#The factors associated with CDP were the elderly, comorbidities, and low socioeconomic status. Since CDP can result in negative clinical outcomes, active intervention by the pharmacist is warranted.
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Purpose@#This study aimed to assess the factors influencing aortic unfolding (AU) defined by aortic width on coronary artery calcium (CAC) scan and determine the normal limits for AU. @*Materials and Methods@#In this retrospective study, we measured AU in 924 asymptomatic subjects who underwent CAC scanning during routine health screening from June 2015 to June 2018. Multivariate regression analysis was used to evaluate the factors influencing AU. After the exclusion of subjects with risk factors associated with AU, 283 subjects were included in the analysis of normal values of AU. Mean AU, standard deviation, and upper normal limit were calculated. @*Results@#Sex, age, CAC score, body mass index, body surface area, hypertension, left ventricular hypertrophy, plasma creatinine, and smoking were significantly associated with AU. The mean AU was 102.2 ± 12.8 mm for men and 93.1 ± 10.7 mm for women. AU increased with advancing age (9.6 mm per decade). @*Conclusion@#AU determined from a single measurement on CAC scans was associated with cardiovascular risk factors. The normal limits of AU were defined by age, sex, and body surface area in low-risk subjects in this study.
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Objectives@#Adolescent suicide is a serious social problem. Adolescent alcohol use is one of the most important risk factors for adolescent suicide. This study aimed to identify the relationship between drinking habits and suicide among Korean adolescents. @*Methods@#Data from the 14th and 15th Korean Youth Risk Behavior Web-based Survey, conducted in 2018 and 2019, were used for analysis. Multiple logistic regression analysis was used to identify the relationship between drinking habits—including the age of drinking initiation, frequency of drinking, average drinking amount, frequency of drunkenness—and suicidal ideation, plans, and attempts. @*Results@#Even after adjusting for age, sex, school grade, academic achievement, socioeconomic status, depression, stress, and drinking habits, the frequencies of drinking and drunkenness increased the risk of suicide attempts. Suicide attempts were associated with the frequency of drinking in girls and middle school students, and with the frequency of drunkenness in boys and high school students. @*Conclusion@#This study identified associations between drinking habits (the age of drinking initiation, frequency of drinking, average amount of drinking, frequency of drunkenness) and suicidal behavior in adolescents. Our findings suggest that to prevent adolescent suicide, it might be necessary to investigate drinking habits, including the frequencies of drinking and drunkenness. Moreover, considering the differences in sex and school grade, it is important to include the individual group characteristics when evaluating drinking habits.
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Background@#The optimal conditioning regimen in cord blood transplantation (CBT) needs to be determined. This study aimed to identify the impact of conditioning regimen on the outcome of CBT in children with acute leukemia. @*Methods@#Medical records of patients with acute leukemia who received CBT were retrospectively reviewed. @*Results@#A total of 71 patients were allocated into 2 groups; patients who received total body irradiation 10 Gy, cyclophosphamide 120 mg/kg, and fludarabine 75 mg/m 2 were named as the TCF group (n = 18), while the non-TCF group (n = 53) included patients conditioned with regimens other than the TCF regimen. All patients in the TCF group were successfully engrafted, while 22.6% in the non-TCF group (n = 12) failed to achieve donor-origin hematopoiesis (P = 0.028). The incidence of cytomegalovirus diseases was 5.6% in the TCF group and 30.2% in the non-TCF group (P = 0.029). The 5-year overall survival rates of the TCF and non-TCF groups were 77.8% and 44.2%, respectively (P = 0.017). @*Conclusion@#Patients conditioned with the TCF regimen achieved better engraftment and survival rates, less suffering from cytomegalovirus disease. Our data suggest that the TCF regimen is a preferred option for CBT in children with acute leukemia.
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Purpose@#Atypical teratoid/rhabdoid tumor (ATRT) is a highly aggressive malignancy with peak incidence in children aged less than 3 years. Standard treatment for central nervous system ATRT in children under the age of 3 years have not been established yet. The objective of this study was to analyze characteristics and clinical outcomes of ATRT in children aged less than 3 years. @*Materials and Methods@#A search of medical records from seven centers was performed between January 2005 and December 2016. @*Results@#Forty-three patients were enrolled. With a median follow-up of 90 months, 27 patients (64.3%) showed at least one episode of disease progression (PD). The first date of PD was at 160 days after diagnosis. The 1- and 3-year progression-free survivals (PFS) were 51.2% and 28.5%, respectively. The 1- and 3-year overall survivals were 61.9% and 38.1%, respectively. The 3-year PFS was improved from 0% in pre-2011 to 47.4% in post-2011. Excluding one patient who did not receive any further therapy after surgery, 27 patients died due to PD (n=21), treatment-related toxicity (n=5), or unknown cause (n=1). In univariate analysis, factors associated with higher 3-year PFS were no metastases, diagnosis after 2011, early adjuvant radiotherapy, and high-dose chemotherapy (HDCT). In multivariate analysis, the use of HDCT and adjuvant radiotherapy remained significant prognostic factors for PFS (both p < 0.01). @*Conclusion@#Aggressive therapy including early adjuvant radiotherapy and HDCT could be considered to improve outcomes of ATRT in children under the age of 3 years.
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Objectives@#Adolescent suicide is a serious social problem. Adolescent alcohol use is one of the most important risk factors for adolescent suicide. This study aimed to identify the relationship between drinking habits and suicide among Korean adolescents. @*Methods@#Data from the 14th and 15th Korean Youth Risk Behavior Web-based Survey, conducted in 2018 and 2019, were used for analysis. Multiple logistic regression analysis was used to identify the relationship between drinking habits—including the age of drinking initiation, frequency of drinking, average drinking amount, frequency of drunkenness—and suicidal ideation, plans, and attempts. @*Results@#Even after adjusting for age, sex, school grade, academic achievement, socioeconomic status, depression, stress, and drinking habits, the frequencies of drinking and drunkenness increased the risk of suicide attempts. Suicide attempts were associated with the frequency of drinking in girls and middle school students, and with the frequency of drunkenness in boys and high school students. @*Conclusion@#This study identified associations between drinking habits (the age of drinking initiation, frequency of drinking, average amount of drinking, frequency of drunkenness) and suicidal behavior in adolescents. Our findings suggest that to prevent adolescent suicide, it might be necessary to investigate drinking habits, including the frequencies of drinking and drunkenness. Moreover, considering the differences in sex and school grade, it is important to include the individual group characteristics when evaluating drinking habits.
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Background@#The optimal conditioning regimen in cord blood transplantation (CBT) needs to be determined. This study aimed to identify the impact of conditioning regimen on the outcome of CBT in children with acute leukemia. @*Methods@#Medical records of patients with acute leukemia who received CBT were retrospectively reviewed. @*Results@#A total of 71 patients were allocated into 2 groups; patients who received total body irradiation 10 Gy, cyclophosphamide 120 mg/kg, and fludarabine 75 mg/m 2 were named as the TCF group (n = 18), while the non-TCF group (n = 53) included patients conditioned with regimens other than the TCF regimen. All patients in the TCF group were successfully engrafted, while 22.6% in the non-TCF group (n = 12) failed to achieve donor-origin hematopoiesis (P = 0.028). The incidence of cytomegalovirus diseases was 5.6% in the TCF group and 30.2% in the non-TCF group (P = 0.029). The 5-year overall survival rates of the TCF and non-TCF groups were 77.8% and 44.2%, respectively (P = 0.017). @*Conclusion@#Patients conditioned with the TCF regimen achieved better engraftment and survival rates, less suffering from cytomegalovirus disease. Our data suggest that the TCF regimen is a preferred option for CBT in children with acute leukemia.
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Background@#We developed an assay to measure DNA-incorporated 6-thioguanine (DNATG) and validated its clinical applicability in Korean pediatric patients with acute lymphoblastic leukemia (ALL) in order to improve individualized thiopurine treatment and reduce the life-threatening cytotoxicity. @*Methods@#The DNA-TG assay was developed based on liquid chromatography-tandem mass spectrometry, with isotope-labeled TG-d3 and guanine-d3 as internal standards.This method was applied to 257 samples of pediatric ALL patients. The DNA-TG level was compared with erythrocyte TG nucleotide (RBC-TGN) level in relation to the TPMT and NUDT15 genotypes, which affect thiopurine metabolism, using Spearman’s rank test and repeated measure ANOVA. @*Results@#For DNA-TG quantification, a linearity range of 10.0-5,000.0 fmol TG/µg DNA;bias for accuracy of –10.4% –3.5%; coefficient of variation for intra- and inter-day precision of 3.4% and 5.8% at 80 fmol TG/µg DNA and of 4.9% and 5.3% at 800 fmol TG/µg DNA, respectively; and recovery of 85.7%–116.2% were achieved without matrix effects or carry-over. The median DNA-TG level in the 257 samples was 106.0 fmol TG/µg DNA (interquartile range, 75.8–150.9). There was a strong correlation between DNA-TG and RBC-TGN levels (ρ = 0.68,ρ < 0.0001). The DNA-TG/RBC-TGN ratio was significantly higher in NUDT15 intermediate metabolizers (*1/*2 and *1/*3) than in patients with wildtype alleles (ρ < 0.0001). @*Conclusions@#This simple and sensitive method for measuring DNA-TG level can improve therapeutic drug monitoring for thiopurine treatment.
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Purpose@#Atypical teratoid/rhabdoid tumor (ATRT) is a highly aggressive malignancy with peak incidence in children aged less than 3 years. Standard treatment for central nervous system ATRT in children under the age of 3 years have not been established yet. The objective of this study was to analyze characteristics and clinical outcomes of ATRT in children aged less than 3 years. @*Materials and Methods@#A search of medical records from seven centers was performed between January 2005 and December 2016. @*Results@#Forty-three patients were enrolled. With a median follow-up of 90 months, 27 patients (64.3%) showed at least one episode of disease progression (PD). The first date of PD was at 160 days after diagnosis. The 1- and 3-year progression-free survivals (PFS) were 51.2% and 28.5%, respectively. The 1- and 3-year overall survivals were 61.9% and 38.1%, respectively. The 3-year PFS was improved from 0% in pre-2011 to 47.4% in post-2011. Excluding one patient who did not receive any further therapy after surgery, 27 patients died due to PD (n=21), treatment-related toxicity (n=5), or unknown cause (n=1). In univariate analysis, factors associated with higher 3-year PFS were no metastases, diagnosis after 2011, early adjuvant radiotherapy, and high-dose chemotherapy (HDCT). In multivariate analysis, the use of HDCT and adjuvant radiotherapy remained significant prognostic factors for PFS (both p < 0.01). @*Conclusion@#Aggressive therapy including early adjuvant radiotherapy and HDCT could be considered to improve outcomes of ATRT in children under the age of 3 years.