A Multicenter Retrospective Analysis on the Treatment Pattern and Outcome in Relapsed/Refractory Childhood Acute Lymphoblastic Leukemia / 임상소아혈액종양

BACKGROUND: Although the overall survival of childhood acute lymphoblastic leukemia (ALL) approaches 85-90%, the prognosis of relapsed or refractory (R/R) ALL is grave. This study aimed to identify the treatment pattern, treatment response, and overall survival of these patients. METHODS: We reviewed data of 64 patients with R/R ALL whose initial diagnosis of ALL had been made between 1 and 21 years of age. Patients who received clofarabine as part of an induction regimen were excluded. Relapsed patients were limited to those who relapsed after ≥2 prior induction regimens. Treatment patterns, response rates, and overall survival were analyzed. RESULTS: Patients' median age was 15.0 years (range, 6.0-25.0) at the diagnosis of R/R ALL. The most frequently used agents other than steroid were vincristine (54.0%), cytarabine (44.6%), and idarubicin (36.5%), while L-asparaginase was used in only one patient. The complete remission (CR) and overall response (OR) rates were 38.1 and 42.9%, respectively. Sixteen patients (25.4%) underwent allogeneic hematopoietic stem cell transplantation (HSCT). The 5-year overall survival was 6.7%. The survival of patients with HSCT was significantly higher compared with those without HSCT (35.2% vs 0%, P=0.0097). Among 14 patients who achieved CR or CR without platelet recovery (CRp) before HSCT, the 3-year survival was 46.9%. CONCLUSION: The survival of Korean patients with R/R childhood ALL was dismal despite a reasonable CR rate, whereas that of those who received HSCT after CR or CRp was excellent. More treatment options are needed to improve the overall outcome of R/R childhood ALL.

A Multicenter Retrospective Analysis on the Treatment Pattern and Outcome in Relapsed/Refractory Childhood Acute Lymphoblastic Leukemia / 임상소아혈액종양

BACKGROUND: Although the overall survival of childhood acute lymphoblastic leukemia (ALL) approaches 85-90%, the prognosis of relapsed or refractory (R/R) ALL is grave. This study aimed to identify the treatment pattern, treatment response, and overall survival of these patients.METHODS: We reviewed data of 64 patients with R/R ALL whose initial diagnosis of ALL had been made between 1 and 21 years of age. Patients who received clofarabine as part of an induction regimen were excluded. Relapsed patients were limited to those who relapsed after ≥2 prior induction regimens. Treatment patterns, response rates, and overall survival were analyzed.RESULTS: Patients' median age was 15.0 years (range, 6.0-25.0) at the diagnosis of R/R ALL. The most frequently used agents other than steroid were vincristine (54.0%), cytarabine (44.6%), and idarubicin (36.5%), while L-asparaginase was used in only one patient. The complete remission (CR) and overall response (OR) rates were 38.1 and 42.9%, respectively. Sixteen patients (25.4%) underwent allogeneic hematopoietic stem cell transplantation (HSCT). The 5-year overall survival was 6.7%. The survival of patients with HSCT was significantly higher compared with those without HSCT (35.2% vs 0%, P=0.0097). Among 14 patients who achieved CR or CR without platelet recovery (CRp) before HSCT, the 3-year survival was 46.9%.CONCLUSION: The survival of Korean patients with R/R childhood ALL was dismal despite a reasonable CR rate, whereas that of those who received HSCT after CR or CRp was excellent. More treatment options are needed to improve the overall outcome of R/R childhood ALL.

Enhancement of Optic Nerve in Leukemic Patients: Leukemic Infiltration of Optic Nerve versus Optic Neuritis

PURPOSE: To identify magnetic resonance imaging (MRI) findings of leukemic infiltration of optic nerve and optic neuritis in leukemic patients with emphasis of clinical findings as reference standard to differentiate them. MATERIALS AND METHODS: MRI and clinical findings of 7 patients diagnosed as leukemic infiltration of optic nerve (n = 5) and optic neuritis (n = 2) in our institution between July 2006 and August 2015were reviewed retrospectively. In particular, MR imaging findings involved perineural enhancement and thickening of optic nerve and its degree, signal intensity, laterality (unilateral/bilateral), intraconal fat infiltration and its degree, and associated central nervous system abnormalities. RESULTS: Of 5 cases of leukemic infiltration of optic nerve, 4 cases showed positive cerebrospinal fluid (CSF) study for leukemia relapse and 1 case was positive on bone marrow (BM) biopsy only. Moreover, of 5 leukemic infiltration of optic nerve, 2 cases showed the most specific MR findings for leukemic central nervous system involvement including 1 prominent leptomeningeal enhancement and 1 chloroma. However, other MR imaging findings of the patients with leukemic infiltration or optic neuritis such as thickening and perineural enhancement of optic nerves are overlapped. CONCLUSION: Enhancement and thickening of optic nerve were overlapped MR findings in leukemic infiltration of optic nerve and optic neuritis. Our findings suggest that enhancing optic nerve thickening with associated central nervous system MR abnormality favors the diagnosis of leukemic infiltration of optic nerve, especially in patients with history of acute lymphoblastic leukemia. However, CSF and BM study were required for differentiation between leukemic infiltration of optic nerve and optic neuritis.

Neurocognitive Outcome in Survivors of Childhood Acute Lymphoblastic Leukemia: Experience at a Tertiary Care Hospital in Korea

This study was conducted to investigate long-term neurocognitive outcomes and to determine associated risk factors in a cohort of Korean survivors of childhood acute lymphoblastic leukemia (ALL). Forty-two survivors of ALL were compared with 42 healthy controls on measures of a neurocognitive test battery. We analysed potential risk factors (cranial irradiation, sex, age at diagnosis, elapsed time from diagnosis, and ALL risk group) on neurocognitive outcomes. ALL patients had lower, but non-significant full-scale intelligence quotient (FSIQ, 107.2 +/- 12.2 vs. 111.7 +/- 10.2), verbal intelligence quotient (VIQ, 107.7 +/- 13.6 vs. 112.2 +/- 11.4), and performance intelligence quotient (PIQ, 106.3 +/- 14.2 vs. 110.1 +/- 10.7) scores than healthy controls. However, patients treated with cranial irradiation performed significantly lower on FSIQ (102.2 +/- 8.1), VIQ (103.3 +/- 11.7), and PIQ (101.4 +/- 13.2) compared to non-irradiated patients and healthy controls. ALL patients also had poor attention, concentration, and executive functions. Among ALL survivors, cranial irradiation was a risk factor for poor FSIQ, being male was a risk factor for poor PIQ, and younger age was a risk factor for poor attention. Therefore, the delayed cognitive effects of ALL treatment and its impact on quality of life require continuing monitoring and management.

Alveolar Soft Part Sarcoma Arising from the Kidney: Imaging and Clinical Features

Alveolar soft part sarcoma (ASPS) is an extremely rare malignant soft tissue sarcoma primarily affecting young patients. It usually occurs in the lower extremities, although it can occur in soft tissue anywhere in the body. However, to our knowledge, there has been no case of primary ASPS originating from the kidney in the literature. We herein present the imaging and clinical features of an ASPS which occurred in a 16-year-old male presented as a palpable mass in the left side of the abdomen.

Langerhans Cell Sarcoma in Two Young Children: Imaging Findings on Initial Presentation and Recurrence

Langerhans cell sarcoma (LCS) is a neoplastic proliferation of Langerhans cells with malignant cytological features and multi-organ involvement that typically has a poor prognosis. We experienced 2 cases of LCS in children less than 2 years of age and report them based primarily on CT and MR findings. Both children had findings of hepatosplenomegaly with low-attenuation nodular lesions, had multiple lymphadenopathy, and had shown recurrent lesions invading the skull during follow-up after chemotherapy.

Acute Appendicitis in Children with Acute Leukemia: Experiences of a Single Institution in Korea

PURPOSE: Acute appendicitis has been reported to be relatively rare in pediatric leukemia patients but there is no official data for this in Korea. And there is no consensus for its treatment in this population. MATERIALS AND METHODS: We conducted a retrospective study of 7 patients diagnosed with appendicitis among 1209 pediatric patients who were diagnosed with leukemia from 1996 to 2008 at a single institution in Korea. RESULTS: The median age at the time of the diagnosis of appendicitis was 12 years (range: 3-15 years), and 3 of the patients were male. The median absolute neutrophil count (ANC) at the time of diagnosis was 0.99x10(9)/L (range: 0-3x10(9)/L). The mean time from the onset of symptoms to the diagnosis was 4 days. All 7 leukemia patients with appendicitis underwent surgery and they demonstrated a survival of 100% without significant complications. CONCLUSION: The incidence of appendicitis in pediatric leukemia patients was 0.57% in our study. Early diagnosis with abdominal ultrasound or computed tomography and early surgical resection in leukemic patient with acute appendicitis may be a safer and more effective treatment option. Even when perforation has already occurred and when the patient has an ANC of 0x10(9)/L, surgical treatment may improve overall survival without incurring significant complications.

A Case of Therapy of Aerosolized Ribavirin in a Leukemia Infant with RSV Infection / 소아감염

Respiratory syncytial virus (RSV) is the major cause of lower respiratory tract infection in infants. Life-threatening RSV infection is often reported in young children and immunocompromised hosts. Since there is no report on ribavirin therapy for RSV pneumonia in pediatric cancer patients in Korea, we report one case of RSV pneumonia that developed in an infant with acute lymphoblastic leukemia (ALL). Despite administration of oral ribavirin and intravenous immunoglobulin, the patient's respiratory distress worsened and admission to an intensive care unit was necessary. Chest x-ray showed multifocal consolidation, pneumothorax, and pneumomediastinum. Treatment with aerosolized ribavirin led to significant clinical improvement. The role of aerosolized ribavirin is still controversial, but it might have a therapeutic potential for severe RSV pneumonia in children with leukemia.

Assessment of Serologic Immunity to Diphtheria-Tetanus-Pertussis After Treatment of Korean Pediatric Hematology and Oncology Patients

The aim of this study was to investigate the diphtheria-tetanus-pertussis antibody titers after antineoplastic treatment and to suggest an appropriate vaccination approach for pediatric hemato-oncologic patients. A total of 146 children with either malignancy in remission after cessation of therapy or bone marrow failure were recruited. All children had received routine immunization including diphtheria-tetanus-acellular pertussis vaccination before diagnosis of cancer. The serologic immunity to diphtheria, tetanus and pertussis was classified as: completely protective, partially protective, or non-protective. Non-protective serum antibody titer for diphtheria, tetanus and pertussis was detected in 6.2%, 11.6%, and 62.3% of patients, respectively, and partial protective serum antibody titer for diphtheria, tetanus and pertussis was seen in 37%, 28.1%, and 8.9% of patients. There was no significant correlation between the severity of immune defect and age, gender or underlying disease. Revaccination after antineoplastic therapy showed significantly higher levels of antibody for each vaccine antigen. Our data indicates that a large proportion of children lacked protective serum concentrations of antibodies against diphtheria, tetanus, and pertussis. This suggests that reimmunization of these patients is necessary after completion of antineoplastic treatment. Also, prospective studies should be undertaken with the aim of devising a common strategy of revaccination.

Clinical and hematologic manifestations in patients with Diamond Blackfan anemia in Korea

BACKGROUND: Diamond Blackfan anemia (DBA), characterized by impaired red cell production, is a rare condition that is usually symptomatic in early infancy. The purpose of this study was to assess nationwide experiences of DBA encountered over a period of 20 years. METHODS: The medical records of 56 patients diagnosed with DBA were retrospectively reviewed from November 1984 to July 2010. Fifteen institutions, including 13 university hospitals, participated in this study. RESULTS: The male-to-female ratio of patients with DBA was 1.67:1. The median age of diagnosis was 4 months, and 74.1% were diagnosed before 1 year of age. From 2000 to 2009, annual incidence was 6.6 cases per million. Excluding growth retardation, 38.2% showed congenital defects: thumb deformities, ptosis, coarctation of aorta, ventricular septal defect, strabismus, etc. The mean hemoglobin concentration was 5.1+/-1.9 g/dL, mean corpuscular volume was 93.4+/-11.6 fL, and mean number of reticulocytes was 19,700/mm3. The mean cellularity of bone marrow was 75%, with myeloid:erythroid ratio of 20.4:1. After remission, 48.9% of patients did not need further steroids. Five patients with DBA who received hematopoietic transplantation have survived. Cancer developed in 2 cases (3.6%). CONCLUSION: The incidence of DBA is similar to data already published, but our study had a male predilection. Although all patients responded to initial treatment with steroids, about half needed further steroids after remission. It is necessary to collect further data, including information regarding management pathways, from nationwide DBA registries, along with data on molecular analyses.

Development of Bullous Acrodermatitis Enteropathica during the Course of Chemotherapy for Acute Lymphocytic Leukemia

Acrodermatitis enteropathica (AE) is an uncommon autosomal recessive genetic disorder of zinc malabsorption. The acquired form may be associated with inadequate intake, impaired absorption, and increased excretion of zinc. Those afflicted present with diarrhea, stomatitis, psychiatric symptoms, non-scarring alopecia, and nail dystrophy accompanied by erythematous which appears as scaly patches with erosion vesicles and pustules mostly affecting the extremities, perineal, and periorificial areas. Due to the variable findings of most case reports, the clinical and histopathological features of AE are often regarded as non-specific. We report an unusual case of bullous AE secondary to total parenteral nutrition for the treatment of acute pancreatitis occurring in a six-year-old male with acute lymphocytic leukemia who underwent chemotherapy. He presented with periorificial, reddish, eroded bullae with multiple vesicles and blisters on his fingers, toes, and buttock, showing necrotic keratinocytes with multiple intraepidermal vesicles and perivascular infiltration with predominant lymphocytes and few neutrophils within the dermis. To the best of our knowledge, this is the first case report of bullous AE in the Korean dermatologic literature.

Clinical Investigation of Bacteremia in Children with Hemato-Oncologic Diseases / 감염과화학요법

BACKGROUND: The purpose of this study was to determine the spectrum of locally prevalent pathogens and their susceptibility patterns responsible for bacteremia in pediatric hemato-oncologic patients for empiric antimicrobial therapy. MATERIALS AND METHODS: A one-year retrospective study of pediatric hematooncologic patients with bacteremia in Seoul St. Mary's Hospital, the Catholic University of Korea, from April 2009 to March 2010 was conducted using previous medical records. The findings were compared with our previous data obtained from 2004 to 2006. RESULTS: Sixty-five episodes of bacteremia were recorded in 41 patients. Of them, 55 (84.6%) occurred in neutropenic and 10 (15.4%) in non-neutropenic patients. Gram-positive organisms were more commonly isolated than Gram-negative organisms (56.9% vs. 41.5%) in the following order: viridans streptococci (23.1%), Klebsiella pneumoniae (21.6%), coagulase-negative staphylococci (12.3%), Staphylococcus aureus (7.7%), Enterococcus faecium (7.7%). Susceptibility rates of viridans streptococci to penicillin, cefotaxime and vancomycin were 33.3%, 60% and 100%, and those of Enterobacteriaceae to amikacin, ceftazidime, piperacillin/ tazobactam and meropenem were 94.7%, 73.7%, 78.9%, and 100%, respectively. Compared to our previous data, infection still contributed towards a major fraction of mortality and morbidity in the management of patients with cancer. No differences in mortality rate were observed between isolated organisms from bacteremia. CONCLUSIONS: Gram-positive organisms were more prevalent than Gram-negative organisms in our population. The monitoring of causative agents and antimicrobial resistance should be considered in therapeutic strategies of pediatric hemato-oncologic infection.

The role of B cells in acute graft-versus-host disease

No abstract available.

A Study of Mixed Phenotype Acute Leukemia Based on the 2008 World Health Organization Classification / 대한진단검사의학회지

BACKGROUND: We evaluated the clinical significance of revised 2008 WHO classification needed to diagnose mixed phenotype acute leukemia (MPAL). METHODS: A total of 22 MPAL patients, previously diagnosed by applying the scoring system of the European Group for Immunological Classification of Acute Leukemias (EGIL) were reclassified based on the 2008 WHO classification. RESULTS: In 2008 WHO classification, the number of monoclonal antibodies (mAbs) required for assigning more than one lineage was markedly decreased, from 26 to 11, compared with that of EGIL. Seventeen of the 22 MPAL patients were reclassified as MPAL with following details: 6 MPAL with t(9;22)(q34;q11.2); BCR-ABL1, 1 MPAL with t(v;11q23); MLL rearranged, 7 MPAL, B/Myeloid, not otherwise specified (NOS) and 3 MPAL, T/Myeloid, NOS. Five patients were excluded from MPAL in the revised classification: 4 cytoplasmic myeloperoxidase (cMPO)-negative and 1 CD19-negative. The failure of complete remission achievement and occurrence of relapse were associated with poor prognosis (P=0.0002 and P=0.009, respectively). But the presence of Philadelphia chromsome was not significantly related with patient outcome (P=0.082). One patient with cCD79a, CD20, CD38, cMPO and CD15, whose diagnosis was reclassified from MPAL to AML has survived during the study period. CONCLUSIONS: Because of decreased number of mAbs needed, it is possible that acute leukemia panel is designed to include all mAbs required to diagnose MPAL according to 2008 WHO classification. When diagnosing MPAL, it is critical to figure out positivity in either cMPO or CD19, and AML expressing more than 2 lymphoid antigens are considered as MPAL.

Idarubicin Plus Behenoyl Cytarabine and 6-thioguanine Compares Favorably with Idarubicin Plus Cytarabine-based Regimen for Children with Previously Untreated Acute Myeloid Leukemia: 10-Year Retrospective, Multicenter Study in Korea

We investigated the outcome of idarubicin plus N4-behenoyl-1-beta-D-arabinofuranosyl cytosine (BHAC)-based chemotherapy (BHAC group, n=149) compared to idarubicin plus cytarabine-based chemotherapy (cytarabine group, n=191) for childhood acute myeloid leukemia (AML). Between January 1996 and December 2005, 340 children with AML from 5 university hospitals in Korea received the BHAC-based or cytarabine-based chemotherapy, with or without hematopoietic stem cell transplantation. After induction therapy, 264 (77.6%) of 340 children achieved a complete remission (CR) and 43 (12%) achieved a partial remission (PR). The CR rate in the BHAC group was higher than in the cytarabine group (85.2% vs. 71.7%, P=0.004). However, the overall response rate (CR+PR) was not different between the two groups (93.3% vs. 87.9%, P=0.139). The 5-yr estimates of overall survival (OS) of children in the two groups were similar (54.9% for the BHAC group vs. 52.4% for the cytarabine group, P=0.281). Although the results were analyzed according to the treatment type and cytogenetic risk, the OS showed no significant difference between the BHAC group and the cytarabine group. In the present study, the clinical outcomes of the BHAC-based chemotherapy, consisting of BHAC, idarubicin, and 6-TG, are comparable to that of the cytarabine-based chemotherapy for childhood AML.

Diamond-Blackfan Anemia Confirmed by RPS19 Gene Mutation Analysis: A Case Study and Literature Review of Korean Patients / 대한진단검사의학회지

Diamond-Blackfan anemia (DBA) is a rare congenital erythroid hypoplastic anemia that usually presents early in infancy and is inherited in up to 45% of cases. It is characterized by red cell aplasia, congenital anomalies, and a predisposition to cancer. Corticosteroids and red blood cell transfusions are the mainstays of therapy. We describe a case of 3-month-old infant who presented with severe anemia, elevated levels of HbF and adenosine deaminase and bilateral hydronephrosis, who was later confirmed as DBA by mutation analysis using the direct sequencing method. Direct sequencing analysis of RPS19 gene was performed with both cDNA and genomic DNA extracted from peripheral blood and a c.3G>A point mutation of exon 2 resulting in p.Met1Ile was identified in this patient. The patient showed an inadequate response to steroid therapy and a partial response to RBC transfusion with a follow-up Hb level of 8.3 g/dL on her last visit to the outpatient clinic. DBA is a genetically and phenotypically heterogeneous disease, and we have reviewed the clinical characteristics of 25 Korean patients thus far reported in the literature. To our knowledge, this is the first case of DBA confirmed by mutation analysis in Korea, and mutation identification using molecular method is recommended for confirmation of this genetically and phenotypically heterogeneous disease.

Lymphomatoid Papulosis Followed by Anaplastic Large Cell Lymphoma in a Pediatric Patient

Lymphomatoid papulosis (LyP) is a benign, self-healing, papular eruption that can wax and wane over time. Transformation to T-cell lymphoma has been well documented in 10% to 20% of adults with LyP. However, this transformation rarely occurs in patients younger than 20 years of age. Here, we present the first known pediatric patient in Korea, a 12-year-old boy who developed a subcutaneous nodule on the scrotum 13 months after papulonecrotic lesions of LyP were identified on both lower extremities and face. Histological and immunohistochemical examination of the subcutaneous nodule revealed anaplastic large cell lymphoma (ALCL). A T-cell receptor gene rearrangement analysis demonstrated an identical rearranged pattern in the two specimens, indicating that a common T-cell clone had proliferated over time in both the LyP and ALCL lesions.

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

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.

Neostigmine for the treatment of acute colonic pseudo-obstruction (ACPO) in pediatric hematologic malignancies

BACKGROUND: Acute colonic pseudo-obstruction (ACPO) refers to dilatation of the colon and decreased bowel motility without evidence of mechanical obstruction. Neostigmine, an acetylcholinesterase inhibitor, has been used in patients in whom supportive therapy failed to resolve ACPO. Here, we report the results of administering neostigmine to treat ACPO in children with hematologic malignancies. METHODS: Between September 2005 and December 2009, 10 patients (8 male and 2 female) were diagnosed with ACPO at the Department of Pediatrics, Catholic University of Korea. Diagnosis of ACPO was based on typical clinical features as well as colonic dilatation found on abdominal CT imaging. Neostigmine was administered subcutaneously at a dosage of 0.01 mg/kg/dose (maximum 0.5 mg) twice daily for a maximum of 5 total doses. ACPO was determined to be responsive to neostigmine if the patient showed both stool passage and improvement of clinical symptoms. RESULTS: The study group included 8 acute lymphoblastic leukemia patients, 1 patient with malignant lymphoma, and 1 patient with juvenile myelomonocytic leukemia. The median age at ACPO diagnosis was 8.5 years (range, 3-14). Overall, 8 patients (80%) showed therapeutic response to neostigmine at a median of 29 hours after the initial administration (range, 1-70). Two patients (20%) showed side effects of grade 2 or above, but none complained of cardiovascular symptoms that required treatment. CONCLUSION: In this study, ACPO was diagnosed most often in late-childhood ALL patients. Subcutaneous neostigmine can be used to effectively treat ACPO diagnosed in children with hematologic malignancies without major cardiovascular complications.

Outcome of childhood acute promyelocytic leukemia treated using a modified AIDA protocol

BACKGROUND: Combination treatment with all-trans-retinoic acid (ATRA) and anthracycline-based chemotherapy has led to major advances in the treatment of acute promyelocytic leukemia (APL). METHODS: In this study, we reviewed the outcome of pediatric APL patients treated using a modified AIDA protocol at our institution. RESULTS: Between May 1999 and December 2007, 23 patients were diagnosed with APL at the Department of Pediatrics, Saint Mary's Hospital, The Catholic University of Korea. Eleven patients were male (48%) (median age at diagnosis, 11 (range, 2-14) years). The treatment protocol consisted of remission induction (achieved by coadministration of ATRA and idarubicin), 3 courses of consolidation treatment, and 2 years of maintenance treatment during which ATRA was also administered. Three patients died early during remission induction due to CNS hemorrhage. The remaining 20 patients achieved complete remission (CR), with an overall CR rate of 87%. Two patients relapsed and died, and another patient died of pneumonia unrelated to APL. Four patients (17%) were diagnosed with ATRA syndrome, and all patients showed resolution of symptoms. The event-free survival (EFS) and overall survival (OS) of the cohort were 78.3+/-8.6% and 76.3+/-9.5%, respectively. Initial WBC count at diagnosis was the only significant prognostic factor for the rate of CR (P=0.039) and OS (P=0.039). CONCLUSION: A modified AIDA protocol for the treatment of childhood APL leads to improved EFS and OS, with limited ATRA syndrome-associated toxicity. Active monitoring and treatment of patients with high initial WBC counts may help in reducing mortality.