Secondary acute myelogenous leukemia in patients previously treated for childhood renal tumors: a report from the National Wilms Tumor Study Group

Homoharringtonine-Based Induction Regimen Improved the Remission Rate and Survival Rate in Chinese Childhood AML: A Report From the CCLG-AML 2015 Protocol Study

PURPOSE

Homoharringtonine (HHT) is commonly used for the treatment of Chinese adult AML, and all-trans retinoic acid (ATRA) has been verified in acute promyelocytic leukemia (APL). However, the efficacy and safety of HHT-based induction therapy have not been confirmed for childhood AML, and ATRA-based treatment has not been evaluated among patients with non-APL AML.

PATIENTS AND METHODS

This open-label, multicenter, randomized Chinese Children's Leukemia Group-AML 2015 study was performed across 35 centers in China. Patients with newly diagnosed childhood AML were first randomly assigned to receive an HHT-based (H arm) or etoposide-based (E arm) induction regimen and then randomly allocated to receive cytarabine-based (AC arm) or ATRA-based (AT arm) maintenance therapy. The primary end points were the complete remission (CR) rate after induction therapy, and the secondary end points were the overall survival (OS) and event-free survival (EFS) at 3 years.

RESULTS

We enrolled 1,258 patients, of whom 1,253 were included in the intent-to-treat analysis. The overall CR rate was significantly higher in the H arm than in the E arm (79.9% v 73.9%, P = .014). According to the intention-to-treat analysis, the 3-year OS was 69.2% (95% CI, 65.1 to 72.9) in the H arm and 62.8% (95% CI, 58.7 to 66.6) in the E arm (P = .025); the 3-year EFS was 61.1% (95% CI, 56.8 to 65.0) in the H arm and 53.4% (95% CI, 49.2 to 57.3) in the E arm (P = .022). Among the per-protocol population, who received maintenance therapy, the 3-year EFS did not differ significantly across the four arms (H + AT arm: 70.7%, 95% CI, 61.1 to 78.3; H + AC arm: 74.8%, 95% CI, 67.0 to 81.0, P = .933; E + AC arm: 72.9%, 95% CI, 65.1 to 79.2, P = .789; E + AT arm: 66.2%, 95% CI, 56.8 to 74.0, P = .336).

CONCLUSION

HHT is an alternative combination regimen for childhood AML. The effects of ATRA-based maintenance are comparable with those of cytarabine-based maintenance therapy.

Reproductive outcomes after hydatiform mole and gestational trophoblastic neoplasia

Gestational trophoblastic disease includes complete hydatidiform mole (CHM) or partial hydatidiform mole (PHM) and gestational trophoblastic neoplasia (GTN). Given the very high-curability rate of trophoblastic disease, the risk of further molar pregnancy after CHM or PHM as well as the risk of second primary tumors and fertility compromise after chemotherapy for GTN represent major concerns. The incidence of subsequent molar pregnancy ranges from 0.7 to 2.6% after one CHM or PHM, and is approximately 10% after two previous CHMs. Among patients who have received chemotherapy, there is an increased risk of myeloid leukemia which is mainly related to the cumulative dose of etoposide. Resumption of normal menses occurs in approximately 95% of women treated with chemotherapy, but menopause occurs 3 years earlier compared with those non-treated with chemotherapy. Term live birth rates higher than 70% without increased risk of congenital abnormalities have been reported in these women, and pregnancy outcomes are comparable to those of general population, except a slightly increased risk of stillbirth. Fertility-sparing treatment for placental site trophoblastic tumor is a therapeutic option reserved to highly selected, young women who do not present markedly enlarged uterus or diffuse multifocal disease within the uterus.

Genes and environment: effects on the development of second malignancies in retinoblastoma survivors

Although it is a rare cancer, retinoblastoma has served as an important model in our understanding of genetic cancer syndromes. All patients with a germinal rb1 mutation possess a risk of the development of second malignancies. Approximately 40-50% of all retinoblastoma cases are considered germinal cases and recent work has indicated that nearly all retinoblastoma patients probably demonstrate a degree of mosaicism for the rb1 mutation, and thus are at risk of secondary malignancies. The risk of the development of these cancers continues throughout the patients' lives due to the loss of a functional RB1 protein and its critical tumor suppressive function in all cells. These cancers can develop in diverse anatomic locations, including the skull and long bones, soft tissues, nasal cavity, skin, orbit, brain, breast and lung. Treatments used for retinoblastoma such as external-beam radiation and chemotherapy can have a significant impact on the risk for and pattern of development of these secondary cancers. Second malignancies are the leading cause of death in germinal retinoblastoma survivors in the USA and thus continue to be an important subject of study in this patient population. Second malignancies following the germinal form of retinoblastoma are the subject of this review.

Efficacy of vincristine and carboplatin as chemo-reduction for advanced bilateral retinoblastoma, the Saudi experience

PURPOSE

To evaluate the efficacy of a 2-drug chemotherapy regimen without external-beam radiotherapy (EBRT) and/or without enucleation in bilateral retinoblastoma.

METHODS

From 1996 to 2010, 79 patients were diagnosed with bilateral RB and were eligible for chemotherapy. Chemotherapy was administered prior to and/or following local therapy to the eye. All patients received 3 cycles of chemo-reduction with carboplatin and vincristine, additional cycles of the same or other chemotherapy, local therapy, EBRT and enucleation were determined according to re-evaluation by the ophthalmologist.

RESULTS

Advanced disease was seen in 115 (79%) eyes (group IV and V: 96, Group D and E: 19) out of 146 affected eyes. Tumor response after chemotherapy was observed in 78 patients (98.7%); complete response in 25 (32.1%), partial response in 49 (62.8%) Four (5.1%) had progressive disease. A total of 50 (63.3%) patients required EBRT; 38 for persistent disease, 4 for progressive disease, 2 for new lesions, 2 for re-activation and 4 for disease control. Enucleation was required in 15 (19%). Secondary malignancies occurred in two patients who underwent EBRT; one osteogenic sarcoma and one rhabdomyosarcoma then later osteogenic sarcoma. The 10 year overall survival was 96.3% with a median follow-up time of 3.124 ± 0.536 years (95%CI: 2.074-4.174).

CONCLUSIONS

The 2-drug chemotherapy regimen combined with local therapy appears to be adequate therapy for low stage disease but not in patients with advanced disease. The occurrence of secondary cancers in this group of patients is worrisome further highlighting the deleterious effects of EBRT.

Secondary leukemia associated with the anti-cancer agent, etoposide, a topoisomerase II inhibitor

Etoposide is an anticancer agent, which is successfully and extensively used in treatments for various types of cancers in children and adults. However, due to the increases in survival and overall cure rate of cancer patients, interest has arisen on the potential risk of this agent for therapy-related secondary leukemia. Topoisomerase II inhibitors, including etoposide and teniposide, frequently cause rearrangements involving the mixed lineage leukemia (MLL) gene on chromosome 11q23, which is associated with secondary leukemia. The prognosis is extremely poor for leukemias associated with rearrangements in the MLL gene, including etoposide-related secondary leukemias. It is of great importance to gain precise knowledge of the clinical aspects of these diseases and the mechanism underlying the leukemogenesis induced by this agent to ensure correct assessments of current and future therapy strategies. Here, I will review current knowledge regarding the clinical aspects of etoposide-related secondary leukemia, some probable mechanisms, and strategies for treating etoposide-induced leukemia.

Secondary malignant neoplasms after Wilms tumor: an international collaborative study

A combined cohort of 8,884 North American, 2,893 British and 1,574 Nordic subjects with Wilms tumor (WT) diagnosed before 15 years of age during 1960-2004 was established to determine the risk of secondary malignant neoplasms (SMN). After 169,641 person-years (PY) of observation through 2005, 174 solid tumors (exclusive of basal cell carcinomas) and 28 leukemias were ascertained in 195 subjects. Median survival time after a solid SMN diagnosis 5 years or more from WT was 11 years; it was 10 months for all leukemia. Age-specific incidence of secondary solid tumors increased from approximately 1 case per 1,000 PY at age 15 to 5 cases per 1,000 PY at age 40. The cumulative incidence of solid tumors at age 40 for subjects who survived free of SMNs to age 15 was 6.7%. Leukemia risk, by contrast, was highest during the first 5 years after WT diagnosis. Standardized incidence ratios (SIRs) for solid tumors and leukemias were 5.1 and 5.0, respectively. Results for solid tumors for the 3 geographic areas were remarkably consistent; statistical tests for differences in incidence rates and SIRs were all negative. Age-specific incidence rates and SIRs for solid tumors were lower for patients whose WT was diagnosed after 1980, although the trends with decade of diagnosis were not statistically significant. Incidence rates and SIRs for leukemia were highest among those diagnosed after 1990 (p-trend = 0.003). These trends may reflect the decreasing use of radiation therapy and increasing intensity of chemotherapy in modern protocols for treatment of WT.

Secondary acute myeloid leukemia after etoposide therapy for haemophagocytic lymphohistiocytosis

Haemophagocytic lymphohistiocytosis (HLH) is an uncommon disease with a high fatality rate. Etoposide is an important component of current HLH treatment regimes. Two patients with HLH developed etoposide-related secondary acute myeloid leukemia (sAML) following therapy for HLH. Etoposide, an epipodophyllotoxin, is a topoisomerase II inhibitor that interacts with DNA to potentiate leukaemogenesis. The risk of developing sAML is estimated to be between 1% and 5%, 2-20 years after exposure to etoposide but may also be related to cumulative drug doses, treatment schedules, host factors and co-administration of other antineoplastic agents.

Secondary B-cell acute lymphoblastic leukemia following Wilms' tumor: Clinical andin vitrochemosensitivity studies

We report the clinical features and in vitro chemosensitivity assay findings of a 13-year-old girl who developed secondary B-cell acute lymphoblastic leukemia (ALL) 7 years after a diagnosis of Wilms' tumor. The patient was treated using the Berlin - Frankfurt - Muenster (BFM) ALL chemotherapy protocol with poor response to initial therapy before succumbing to sepsis. An in vitro chemosensitivity assay on her peripheral blood lymphoblasts was performed while she was undergoing induction therapy and showed a high level of resistance to drugs commonly used for ALL therapy, e.g. steroids, anthracyclines, vincristine and L-asparaginase. The mechanism of chemoresistance was not elicited, but was probably not related to P-glycoprotein (P-gp) over-expression. We believe that the in vitro chemosensitivity assay is a good indicator of cellular response to chemotherapy and may provide reliable information for the basis of the selection of drugs to be used for the treatment of similarly rare patients rather than relying on "standard" protocols.

Radiation dose and relapse are predictors for development of second malignant solid tumors after cancer in childhood and adolescence: a population-based case-control study in the five Nordic countries

The aim of the study was to assess the risk with radiation therapy and chemotherapy of the first cancer in childhood and adolescence for the development of a second malignant solid tumor (SMST). Also, the role of relapse of the primary tumor was studied. It is a nested case-control study within a Nordic cohort of patients less than 20 years of age at first diagnosis 1960-1987. SMSTs were diagnosed in 1960-1991. There were 196 cases and 567 controls. The risk was increased only for radiotherapy given more than five years before the development of the SMST. A significantly increased relative risk of 1.8 was found already at doses below 1 Gy. The risk increased rapidly up to a maximum of 18.3 for doses above 30 Gy. Chemotherapy alone did not increase the risk to develop an SMST. However, in combination with radiotherapy, chemotherapy showed a significant potentiating effect. Relapse was found to be an independent risk factor for development of an SMST, with a higher relative risk for females than for males.

Renal tumours of childhood: an update

The role of the pathologist has been fundamental in the progress of the treatment of paediatric renal tumours. There are different philosophies in the treatment of these tumours, and there have been many recent advances in the areas of chemotherapy, identification of new entities, prognostic histological criteria following treatment and molecular prognostic and diagnostic features. This review discusses the different approaches of the different treatment protocols from Europe and North America, and reviews staging criteria, prognostic criteria and also the different tumour entities.

Second primary neoplasms in survivors of Wilms' tumour--a population-based cohort study from the British Childhood Cancer Survivor Study

A British population-based cohort study was carried out to determine the risk of second primary neoplasms in survivors of Wilms' tumour. The cohort was obtained from the British Childhood Cancer Survivor Study, a population-based cohort study of treatment toxicities in 18,044 individuals diagnosed with childhood cancer, at an age of less than 15 years, between 1940 and 1991 in Britain. There were 1,441 Wilms' tumour survivors in the cohort: 732 males (50.8%) and 709 females (49.2%). Total follow-up from 5-year survival was 27,841 person years, mean follow-up of 19.3 years per survivor. There were 81 second primary neoplasms, including 52 solid neoplasms, 3 acute myeloid leukaemias and 26 basal cell carcinomas. Thirty-five of the 39 solid neoplasms that developed in the thoracic, abdominal or pelvic region occurred within irradiated tissue. The standardised incidence ratio for all solid second primary neoplasms was 6.7 (95% CI: 5.0-8.8). Cumulative incidence for all solid second primary neoplasms by ages 30, 40 and 50 years was 2.3% (1.4-3.5%), 6.8% (4.6-9.5%) and 12.2% (7.3-18.4%). The overall risk of second primary neoplasms in survivors of Wilms' tumour treated between 1940 and 1991 was substantial, and solid second tumours tended to develop in the irradiated tissue. Continued follow-up of these survivors is important to monitor such late effects of treatment. It is also important to evaluate the risk of second primary neoplasms following more recent lower radiation dose treatment practices.

A study of soft tissue sarcomas after childhood cancer in Britain

Among 16 541 3-year survivors of childhood cancer in Britain, 39 soft tissue sarcomas (STSs) occurred and 1.1 sarcomas were expected, yielding a standardised incidence ratio (SIR) of 16.1. When retinoblastomas were excluded from the cohort, the SIR for STSs was 15.9, and the cumulative risk of developing a soft tissue tumour after childhood cancer within 20 years of 3-year survival was 0.23%. In the case-control study, there was a significant excess of STSs in those patients exposed to both radiotherapy (RT) and chemotherapy, which was five times that observed among those not exposed (P=0.02). On the basis of individual radiation dosimetry, there was evidence of a strong dose-response effect with a significant increase in the risk of STS with increasing dose of RT (P<0.001). This effect remained significant in a multivariate model. The adjusted risk in patients exposed to RT doses of over 3000 cGy was over 50 times the risk in the unexposed. There was evidence of a dose-response effect with exposure to alkylating agents, the risk increasing substantially with increasing cumulative dose (P=0.05). This effect remained after adjusting for the effect of radiation exposure.

Secondary acute myeloid leukemia after etoposide therapy for retinoblastoma

Retinoblastoma is the most common eye tumor in children and is highly curable. Patients with hereditary retinoblastoma, have an increased risk of developing additional tumors, predominantly sarcomas. Most chemotherapy regimens used in retinoblastoma include etoposide, an epipodophyllotoxin associated with a risk of secondary myeloid leukemia. The use of etoposide in patients with a cancer predisposition syndrome such as retinoblastoma is potentially harmful, however, reports of secondary acute myeloid leukemia in patients treated with etoposide for retinoblastoma are rare. We report a case of a patient who developed secondary acute myeloid leukemia after etoposide treatment for retinoblastoma.

Wilms tumor: progress and considerations for the surgeon

Wilms tumor (WT) or nephroblastoma is the most common tumor of renal origin found in children. It accounts for 6% of all pediatric tumors and is the second most frequent intrabdominal solid organ tumor found in children. Initial survival rates in the early part of the last century was only 30%, but now long-term survival in both North America and European trials is approaching 85% with many low-stage tumors significantly higher. Treatment is now progressing towards "risk-based management"- based not only on stage and histology but also incorporating genetic markers [Dome JS, Grundy PE, Perlman EJ, Ehrlich PF, et al. Protocols for the renal tumors study. Childrens Oncology Group. [www.childrensoncologygroup.org. 2007.]. Within the multidisciplinary treatment team the surgeon plays a critical role in the diagnosis, staging and the surgeon's technical skills and judgment directs therapy and impacts outcome. The next generation of treatment for children with WT will focus on identifying subsets of patients who can be defined by some criterion as having a different outcome than their similar stage peers and who therefore require a variation in management. These include children with WT that have unsatisfactory long-term survival (less then 75%), patients of good survival but high potential for late effects and a final challenge are those children with both a poor survival and a high potential for late effects. This article presents a review of the most recent treatment considerations for WT with a focus on the surgeon's role to ensure a good outcome.

The role of the Wilms tumour gene (WT1) in normal and malignant haematopoiesis

In addition to its loss playing a pivotal role in the development of a childhood kidney malignancy, the Wilms tumour 1 gene (WT1) has emerged as an important factor in normal and malignant haematopoiesis. Preferentially expressed in CD34+ haematopoietic progenitors and down-regulated in more-differentiated cells, the WT1 transcription factor has been implicated in regulation of apoptosis, proliferation and differentiation. Putative target genes, such as BCL2, MYC, A1 and cyclin E, may cooperate with WT1 to modulate cell growth. However, the effects of WT1 on target gene expression appear to be isoform-specific. Certain WT1 isoforms are over-represented in leukaemia, but the exact mechanisms underlying the role of WT1 in transformation remain unclear. The ubiquity of WT1 in haematological malignancies has led to efforts to exploit it as a marker for minimal residual disease and as a prognostic factor, with conflicting results. In vitro killing of tumour cells by WT1-specific CD8+ cytotoxic T lymphocytes facilitated design of Phase I vaccine trials that showed clinical regression of WT1-positive tumours. Alternative methods employing WT1-specific immunotherapy are being investigated and might ultimately be used to optimise multimodal therapy of haematological malignancies.

Pharmacogenetics of alkylator-associated acute myeloid leukemia

Therapy-related acute myeloid leukemia (t-AML) is a lethal late complication of alkylator chemotherapy. The genetic basis of susceptibility to t-AML is poorly understood. Both t-AML and de novo AML are complex genetic diseases, requiring cooperating mutations in interacting pathways for disease initiation and progression. Germline variants of these ‘leukemia pathway’ genes may cooperate with somatic mutations to induce both de novo and therapy-related AML. Several cancer susceptibility syndromes have been identified that cause an inherited predisposition to de novo and t-AML. The genes responsible for these syndromes are also somatically mutated in sporadic AML. We reason that germline polymorphism in any gene somatically mutated in AML could contribute to t-AML risk in the general population. Identification of these susceptibility alleles should help clinicians develop tailored therapies that reduce the relative risk of t-AML.

Treatment of anaplastic histology Wilms' tumor: results from the fifth National Wilms' Tumor Study

PURPOSE

An objective of the fifth National Wilms' Tumor Study (NWTS-5) was to evaluate the efficacy of treatment regimens for anaplastic histology Wilms' tumor (AH).

PATIENTS AND METHODS

Prospective single-arm studies were conducted. Patients with stage I AH were treated with vincristine and dactinomycin for 18 weeks. Patients with stages II to IV diffuse AH were treated with vincristine, doxorubicin, cyclophosphamide, and etoposide for 24 weeks plus flank/abdominal radiation.

RESULTS

A total of 2,596 patients with Wilms' tumor were enrolled onto NWTS-5, of whom 281 (10.8%) had AH. Four-year event-free survival (EFS) and overall survival (OS) estimates for assessable patients with stage I AH (n = 29) were 69.5% (95% CI, 46.9 to 84.0) and 82.6% (95% CI, 63.1 to 92.4). In comparison, 4-year EFS and OS estimates for patients with stage I favorable histology (FH; n = 473) were 92.4% (95% CI, 89.5 to 94.5) and 98.3% (95% CI, 96.4 to 99.2). Four-year EFS estimates for patients who underwent immediate nephrectomy with stages II (n = 23), III (n = 43), and IV (n = 15) diffuse AH were 82.6% (95% CI, 60.1 to 93.1), 64.7% (95% CI, 48.3 to 77.7), and 33.3% (95% CI, 12.2 to 56.4), respectively. OS was similar to EFS for these groups. There were no local recurrences among patients with stage II AH. Four-year EFS and OS estimates for patients with bilateral AH (n = 29) were 43.8% (95% CI, 24.2 to 61.8) and 55.2% (95% CI, 34.8 to 71.7), respectively.

CONCLUSION

The prognosis for patients with stage I AH is worse than that for patients with stage I FH. Novel treatment strategies are needed to improve outcomes for patients with AH, especially those with stage III to V disease.

Treatment-related myelodysplastic syndrome/acute myeloid leukemia in survivors of childhood cancer--an update

Treatment-related myelodysplastic syndrome/acute myeloid leukemia (t-MDS/t-AML) is a devastating complication of treatment for childhood cancer. However, the major cause of premature death of children treated for cancer remains their primary cancer. The understanding of the presentation, incidence, predisposing risk factors and pathobiology of t-MDS/t-AML is increasing. This increased understanding has not yet been translated into improved outcomes of therapy for t-MDS/t-AML. However, newer approaches are under study.

Neuropeptide Y receptors in renal cell carcinomas and nephroblastomas

Numerous peptide receptors are overexpressed in human cancer, permitting in vivo tumor targeting. Among such receptors, those for the neurotransmitter neuropeptide Y (NPY) are overexpressed in various tumors. Since NPY can play a role in the kidney, NPY receptor expression and/or endogenous production of peptides of the NPY family (NPY, PYY, PP) were evaluated in 40 renal cell carcinomas (RCCs) and 18 nephroblastomas. NPY receptor protein expression was investigated by in vitro autoradiography using (125)I-labeled PYY in competition with NPY receptor subtype-selective analogs. NPY, PYY and PP production was assessed immunohistochemically. Fifty-six percent of RCCs expressed the Y1 receptor subtype in moderate density, and 80% of nephroblastomas expressed Y1 and Y2 subtypes in moderate to high density. Y1 was also highly expressed in intratumoral blood vessels. In selected cases, NPY was observed in nerve fibers in close association with intratumoral blood vessels and in the vicinity of tumor cells, while no PYY or PP was detected immunohistochemically in these sites. NPY receptors on renal tumor cells and tumor blood vessels may therefore be the molecular targets of endogenous NPY released by intratumoral nerve fibers. With regard to clinical applications, NPY receptors may act as in vivo targets for receptor-directed therapy of RCCs and nephroblastomas for which alternative therapeutic approaches are still required.

Management of Wilms' tumour: current practice and future goals

Most patients with Wilms' tumour in Europe and North America can be cured with treatment and subsequently lead a normal adulthood. However, for some, therapy as applied today results in long-term side-effects and creates a substantial burden on quality of life. Therefore, investigators involved in the management of patients with Wilms' tumour are increasingly focusing their efforts on curtailing the long-term sequelae of therapy. This aim has been achieved by lowering the total amount of chemotherapy, radiotherapy, or both administered to patients who have characteristics associated with favourable outcome. Although excellent survival has been maintained, many patients receive less therapy today than patients with similar characteristics did a decade or two ago. Better understanding of the biological processes that lead to this childhood cancer will allow further improvements in its management.

Late effects of childhood cancer therapy

This study reviews the common long-term sequalae of childhood cancer and its therapy. It discusses the clinical and research challenges posed by such late effects. The authors address related topics of late effects research and clinical care, methodological issues, barriers and directions for the future.

Pediatric genitourinary tumors

Each year advances are made in the clinical evaluation and treatment of genitourinary tumors in children. Understanding of cellular, molecular, and genetic processes in tumorigenesis is evolving rapidly. In addition, information is accumulating about the long-term outcome and complications associated with treatment modalities. This article reviews the 2001 literature on pediatric Wilms tumor, other renal tumors, rhabdomyosarcoma of the pelvis, paratesticular rhabdomyosarcoma, and testicular tumors. The emphasis in molecular biology is to identify molecular or genetic markers that predict outcome. The National Wilms' Tumor Study Group reported on the complications of surgery and the decreased complication rate when these procedures are performed by pediatric surgical specialists. Long-term complications of treatment are also discussed, including short stature and leukemia. The Intergroup Rhabdomyosarcoma Study Group reported on the results of treatment for nonmetastatic disease and the goals of the upcoming Study V, reduction of chemotherapy and radiotherapy. They also presented data from Study IV and discussed the findings on improved prognosis.

Risk of etoposide-related acute myeloid leukemia in the treatment of Epstein-Barr virus-associated hemophagocytic lymphohistiocytosis

We studied the impact of etoposide on the prognosis of 81 patients (77 of whom were children <15 years old) with Epstein-Barr virus-associated hemophagocytic lymphohistiocytosis (EBV-HLH). The study group received a median cumulative dose of 1,500 mg/m2 etoposide (range, 0-14,550 mg/m2), with a median follow-up period of 44 months (range, 20-88 months) from the diagnosis. Only 1 patient, who received 3150 mg/m2 etoposide, developed therapy-related acute myeloid leukemia (t-AML), at 31 months after diagnosis. Excluding 9 patients who underwent hemopoietic stem cell transplantation during the course of treatment, the prognosis was poorer for those patients who received less than a 1,000 mg/m2 cumulative dose of etoposide. Our results indicate that the risk of etoposide-related t-AML is low. An appropriate dosage of etoposide for the treatment of EBV-HLH would be in the range of 1,000 to 3,000 mg/m2. However, even at these doses, care must be taken to prevent the rare risk of t-AML.