Isolated late testicular relapse of B-cell acute lymphoblastic leukemia treated with intensive systemic chemotherapy and response-based testicular radiation: A Children's Oncology Group study.

BACKGROUND: The incidence of isolated testicular relapse (ITR) of acute lymphoblastic leukemia (ALL) has decreased with contemporary treatment strategies, but outcomes are suboptimal with a 58% 5-year overall survival (OS). This study aimed to improve outcome in patients with ITR of B-cell ALL (B-ALL) occurring after 18 months of first clinical remission using intensive systemic chemotherapy and to decrease long-term sequelae by limiting use of testicular radiation. PROCEDURE: Forty patients in first ITR of B-ALL were enrolled. Induction (dexamethasone, vincristine, daunorubicin, and intrathecal triple therapy) was preceded by one dose of high-dose methotrexate (MTX, 5 g/m2 ). Following induction, 25 of 26 patients who had persistent testicular enlargement underwent testicular biopsy. Eleven had biopsy-proven disease and received bilateral testicular radiation (24 Gy), whereas twenty-nine did not. RESULTS: Overall 5-year event-free survival (EFS)/OS was 65.0 ± 8.8%/73.1 ± 8.3%, with 5-year EFS 62.1 ± 11.0% vs. 72.7 ± 14.4% for patients who did not receive radiation therapy (XRT) (n = 29) compared with those who did (n = 11), respectively (P = 0.64). There were six second bone marrow relapses and six second ITRs. The proportion of second relapses was similar in the patients that received testicular radiation and those who did not. However, the 5-year OS was similar for patients who did not receive XRT (72.6 ± 10.2%) compared with those who did (72.7 ± 14.4%) (P = 0.85). CONCLUSIONS: A 5-year OS rate of 73.1 ± 8.3% was obtained in children with first ITR of B-ALL occurring after 18 months of CR1 (length of first clinical remission) using intensive chemotherapy and limiting testicular radiation.

Transplantation-associated thrombotic microangiopathy isolated to a congenital anomaly of the lung.

TA-TMA is a post-hematopoietic stem cell transplant complication with clinical features of hemolytic anemia and thrombocytopenia. A 26-month-old child who had had an allogeneic transplant for treatment of DBA developed severe TA-TMA with heavy red blood cell and platelet transfusion dependence. Incidentally, he was found to have a lung sequestration. TA-TMA resolved and transfusion dependence resolved after resection of the sequestration. The finding suggests the malformation vasculature was selectively vulnerable to the trigger of TA-TMA-raising perhaps a clue to basic pathophysiology of TA-TMA and/or vascular malformations.

Impact of registration on clinical trials on infection risk in pediatric acute myeloid leukemia.

Little is known about the impact of enrollment on therapeutic clinical trials on adverse event rates. Primary objective was to describe the impact of clinical trial registration on sterile site microbiologically documented infection for children with newly diagnosed acute myeloid leukemia (AML). We conducted a multicenter cohort study that included children aged ≤18 years with de novo AML. Primary outcome was microbiologically documented sterile site infection. Infection rates were compared between those registered and not registered on clinical trials. Five hundred seventy-four children with AML were included of which 198 (34.5%) were registered on a therapeutic clinical trial. Overall, 400 (69.7%) had at least one sterile site microbiologically documented infection. In multiple regression, registration on clinical trials was independently associated with a higher risk of microbiologically documented sterile site infection [adjusted odds ratio (OR) 1.24, 95% confidence interval (CI) 1.01-1.53; p = 0.040] and viridans group streptococcal infection (OR 1.46, 95% CI 1.08-1.98; p = 0.015). Registration on trials was not associated with Gram-negative or invasive fungal infections. Children with newly diagnosed AML enrolled on clinical trials have a higher risk of microbiologically documented sterile site infection. This information may impact on supportive care practices in pediatric AML.

Improving diagnostic precision, care and syndrome definitions using comprehensive next-generation sequencing for the inherited bone marrow failure syndromes.

BACKGROUND: Phenotypic overlap among the inherited bone marrow failure syndromes (IBMFSs) frequently limits the ability to establish a diagnosis based solely on clinical features. >70 IBMFS genes have been identified, which often renders genetic testing prolonged and costly. Since correct diagnosis, treatment and cancer surveillance often depend on identifying the mutated gene, strategies that enable timely genotyping are essential. METHODS: To overcome these challenges, we developed a next-generation sequencing assay to analyse a panel of 72 known IBMFS genes. Cases fulfilling the clinical diagnostic criteria of an IBMFS but without identified causal genotypes were included. RESULTS: The assay was validated by detecting 52 variants previously found by Sanger sequencing. A total of 158 patients with unknown mutations were studied. Of 75 patients with known IBMFS categories (eg, Fanconi anaemia), 59% had causal mutations. Among 83 patients with unclassified IBMFSs, we found causal mutations and established the diagnosis in 18% of the patients. The assay detected mutant genes that had not previously been reported to be associated with the patient phenotypes. In other cases, the assay led to amendments of diagnoses. In 20% of genotype cases, the results indicated a cancer surveillance programme. CONCLUSIONS: The novel assay is efficient, accurate and has a major impact on patient care.

The impact of category, cytopathology and cytogenetics on development and progression of clonal and malignant myeloid transformation in inherited bone marrow failure syndromes.

Inherited bone marrow failure syndromes are a group of rare, heterogeneous genetic disorders with a risk of clonal and malignant myeloid transformation including clonal marrow cytogenetic abnormalities, myelodysplastic syndrome and acute myeloid leukemia. The clinical characteristics, risk classification, prognostic factors and outcome of clonal and malignant myeloid transformation associated with inherited bone marrow failure syndromes are largely unknown. The aims of this study were to determine the impact of category, cytopathology and cytogenetics, the three components of the "Category Cytology Cytogenetics" classification of pediatric myelodysplastic syndrome, on the outcome of clonal and malignant myeloid transformation associated with inherited bone marrow failure. We used data from the Canadian Inherited Marrow Failure Registry. Among 327 patients with inherited bone marrow failure syndrome enrolled in the registry, the estimated risk of clonal and malignant myeloid transformation by the age of 18 years was 37%. The risk of clonal and malignant myeloid transformation varied according to the type of inherited bone marrow failure syndrome but was highest in Fanconi anemia. The development of clonal and malignant myeloid transformation significantly affected overall survival. Mortality varied based on cytopathological group. The largest group of patients had refractory cytopenia. Clonal marrow cytogenetic abnormalities were identified in 87% of patients with clonal and malignant myeloid transformation, and different cytogenetic groups had different impacts on disease progression. We conclude that category, cytopathology and cytogenetics in cases of clonal and malignant myeloid transformation associated with inherited bone marrow failure syndromes have an important impact on outcome and that the classification of such cases should incorporate these factors.

Infections in pediatric acute promyelocytic leukemia: from the Canadian infections in acute myeloid leukemia research group.

BACKGROUND: It is not known whether children with acute promyelocytic leukemia (APL) have an infection risk similar to non- APL acute myeloid leukemia. The objective was to describe infectious risk in children with newly diagnosed APL and to describe factors associated with these infections. METHODS: We conducted a retrospective, population-based cohort study that included children ≤ 18 years of age with de novo APL treated at 15 Canadian centers. Thirty-three children with APL were included; 78.8% were treated with APL -specific protocols. RESULTS: Bacterial sterile site infection occurred in 12 (36.4%) and fungal sterile site infection occurred in 2 (6.1%) children. Of the 127 chemotherapy courses, 101 (79.5%) were classified as intensive and among these, the proportion in which a sterile site microbiologically documented infection occurred was 14/101 (13.9%). There was one infection-related death. CONCLUSIONS: One third of children with APL experienced at least one sterile site bacterial infection throughout treatment and 14% of intensive chemotherapy courses were associated with a microbiologically documented sterile site infection. Infection rates in pediatric APL may be lower compared to non- APL acute myeloid leukemia although these children may still benefit from aggressive supportive care during intensive chemotherapy.

Association between corticosteroids and infection, sepsis, and infectious death in pediatric acute myeloid leukemia (AML): results from the Canadian infections in AML research group.

BACKGROUND: Infection continues to be a major problem for children with acute myeloid leukemia (AML). Objectives were to identify factors associated with infection, sepsis, and infectious deaths in children with newly diagnosed AML. METHODS: We conducted a retrospective, population-based cohort study that included children ≤ 18 years of age with de novo, non-M3 AML diagnosed between January 1995 and December 2004, treated at 15 Canadian centers. Patients were monitored for infection from initiation of AML treatment until recovery from the last cycle of chemotherapy, conditioning for hematopoietic stem cell transplantation, relapse, persistent disease, or death (whichever occurred first). Consistent trained research associates abstracted all information from each site. RESULTS: 341 patients were included. Median age was 7.1 years (interquartile range [IQR], 2.0-13.5) and 29 (8.5%) had Down syndrome. In sum, 26 (7.6%) experienced death as a first event. There were 1277 courses of chemotherapy administered in which sterile site microbiologically documented infection occurred in 313 courses (24.5%). Sepsis and infectious death occurred in 97 (7.6%) and 16 (1.3%) courses, respectively. The median days of corticosteroid administration was 2 per course (IQR, 0-6). In multiple regression analysis, duration of corticosteroid exposure was significantly associated with more microbiologically documented sterile site infection, bacteremia, fungal infection, and sepsis. The only factor significantly associated with infectious death was days of corticosteroid exposure (odds ratio, 1.05; 95% confidence interval, 1.02-1.08; P = .001). CONCLUSIONS: In pediatric AML, infection, sepsis, and infectious death were associated with duration of corticosteroid exposure. Corticosteroids should be avoided when possible for this population.

Oral 6-mercaptopurine versus oral 6-thioguanine and veno-occlusive disease in children with standard-risk acute lymphoblastic leukemia: report of the Children's Oncology Group CCG-1952 clinical trial.

The Children's Cancer Group 1952 (CCG-1952) clinical trial studied the substitution of oral 6-thioguanine (TG) for 6-mercaptopurine (MP) and triple intrathecal therapy (ITT) for intrathecal methotrexate (IT-MTX) in the treatment of standard-risk acute lymphoblastic leukemia. After remission induction, 2027 patients were randomized to receive MP (n = 1010) or TG (n = 1017) and IT-MTX (n = 1018) or ITT (n = 1009). The results of the thiopurine comparison are as follows. The estimated 7-year event-free survival (EFS) for subjects randomized to TG was 84.1% (+/- 1.8%) and to MP was 79.0% (+/- 2.1%; P = .004 log rank), although overall survival was 91.9% (+/- 1.4%) and 91.2% (+/- 1.5%), respectively (P = .6 log rank). The TG starting dose was reduced from 60 to 50 mg/m(2) per day after recognition of hepatic veno-occlusive disease (VOD). A total of 257 patients on TG (25%) developed VOD or disproportionate thrombocytopenia and switched to MP. Once portal hypertension occurred, all subjects on TG were changed to MP. The benefit of randomization to TG over MP, as measured by EFS, was evident primarily in boys who began TG at 60 mg/m(2) (relative hazard rate [RHR] 0.65, P = .002). The toxicities of TG preclude its protracted use as given in this study. This study is registered at http://clinicaltrials.gov as NCT00002744.

Impact of caring for a child with cancer on single parents compared with parents from two-parent families.

BACKGROUND: It is currently unknown how the intensive and often prolonged treatment of childhood cancer impacts on the lives of single parents. Our aims were to determine whether single parents differ from parents from two-parent families in terms of caregiver demand (the time and effort involved in caregiving), and health-related quality of life (HRQL). PROCEDURES: Forty single parents and 275 parents from two-parent families were recruited between November 2004 and February 2007 from five pediatric oncology centers in Canada. Parents were asked to complete a questionnaire booklet composed of items and scales to measure caregiver demand and HRQL (SF-36). The booklet also measured the following constructs: background and context factors, child factors, caregiving strain, intrapsychic factors, and coping factors. RESULTS: Single parents did not differ from parents from two-parent families in caregiving demand and physical and psychosocial HRQL. Compared with Canadian population norms for the SF-36, both groups reported clinically important differences (i.e., worse health) in psychosocial HRQL (effect size ≥ -2.00), while scores for physical HRQL were within one standard deviation of population norms. CONCLUSION: Our findings suggest that the impact of caregiving on single parents, in terms of caregiving demand and HRQL is similar to that of parents from two-parent families.

A national study of the provision of oncofertility services to female patients in Canada.

OBJECTIVE: This study aimed to gain a better understanding of the fertility preservation services provided by Canadian fertility clinics to women with cancer. METHODS: We invited a total of 76 fertility clinics across Canada to complete a mailed questionnaire related to the availability, accessibility, affordability, and utilization of fertility preservation services for oncology patients. RESULTS: The total response rate was 59.2%: 72.4% for IVF clinics and 51.1% for fertility centres without on-site IVF. Not all the responding IVF centres accepted oncology referrals for women. Six clinics without on-site IVF accepted cancer patients for consultation. The medical consultation fees are covered by public health insurance in all provinces. The majority of respondents expedited the referrals to schedule an initial medical appointment within three days. Despite that, the referral volume reported by respondents was markedly low for all except two facilities. With over 4000 young women of reproductive age given a diagnosis of cancer each year in Canada, the findings suggest that cancer patients are severely under-served by fertility clinics. CONCLUSION: There is a need to develop a stronger partnership between the fields of oncology and reproductive medicine to further improve access of patients with cancer to fertility preservation services. Development of evidence-based practice guidelines covering medical, clinical, psychosocial, ethical, and legal aspects geared to the Canadian health care system would help to avoid ambiguity relating to the roles and responsibilities in the provision of fertility preservation services. Such processes would ensure optimization of services so that all young cancer patients would receive the best care in protecting their fertility.

Quality of life during active treatment for pediatric acute lymphoblastic leukemia.

The objectives of the study were to describe quality of life (QoL), identify predictors of worse QoL and examine QoL during different phases of active therapy for acute lymphoblastic leukemia (ALL). A multiinstitutional cross-sectional study was performed in children with ALL. We included children at least 2 months from diagnosis who were receiving treatment in first remission. Parents described QoL using the PedsQL 4.0 Generic Core Scales and the PedsQL 3.0 Acute Cancer Module. The 206 children on treatment for ALL had overall [median 62.5, 95% confidence interval (CI) 34.8-94.4], physical (median 62.5, 95% CI 18.8-100.0) and psychosocial (median 65.4, 95% CI 38.3-94.2) summary scores that were one to two standard deviations lower than population norms. In high-risk ALL, girls and older children had worse QoL. In standard-risk ALL, those with lower household incomes and unmarried parents had worse QoL. QoL scores were generally constant across phases of ALL therapy. Children on therapy for ALL have lower QoL compared to healthy children. Age and gender predicted QoL in high-risk ALL, whereas socioeconomics predicted QoL in standard-risk ALL. Future efforts should focus on longitudinal studies that describe QoL over time within individual patients.

Parents of children with cancer: which factors explain differences in health-related quality of life.

Research with parents of children with cancer has identified factors related to their adjustment and coping, but it is not fully understood why some parents do well and others do not. Guided by a stress process model, we examined the interrelationships among a comprehensive set of factors to identify the most important determinants of health-related quality of life (HRQoL) in parents of children in active treatment for cancer. A cross-sectional survey of 411 parents (80% response rate) of children receiving cancer treatment in Canada was conducted between November 2004 and February 2007. The following constructs were measured: background and context factors, child characteristics, family-centered service delivery, caregiver strain, intrapsychic factors, coping/supportive factors and parental HRQoL. The model was evaluated using structural equation modeling. Analysis was stratified by time since diagnosis (i.e., <12 months and ≥12 months). For those within 12 months of their child's diagnosis, family-centred service provision, caregiver strain, and self-perception accounted for 58% of the variation in psychosocial health, whereas caregiver strain and social support explained 50% of the variation in physical health. For parents in the >12 month group, caregiving strain was the only factor with a direct relationship with parental psychosocial and physical health, accounting for 66% and 55% of the variance in these constructs, respectively. Our findings reinforce the need for health professionals to be particularly attuned to family caregivers in the early stages of treatment and identify potential areas for interventions to promote parental health.

Caregiving demands in parents of children with cancer: psychometric validation of the Care of My Child with Cancer questionnaire.

A comprehensive evaluation of the psychometric properties of Care of My Child With Cancer (CMCC) was performed in a sample of 411 parents of children undergoing treatment of cancer at five Canadian pediatric oncology centers. Psychometric tests used to assess data quality, targeting, reliability, and construct validity demonstrated that the CMCC is a scientific sound measure. The CMCC will be helpful for assessing increasing parental responsibility for caregiving tasks associated with cancer care.

Parental optimism in poor prognosis pediatric cancers.

OBJECTIVE: The objectives were to describe parent-rated and physician-rated prognosis in a wide range of pediatric cancers and to describe the prevalence and predictors of parental prognostic optimism in poor prognosis pediatric cancer patients. METHODS: This Canadian multi-institutional cross-sectional study included children with cancer receiving any type of active treatment. The primary caregiver rated child prognosis on a 5-point categorical rating scale. For each child, five pediatric oncologists rated prognosis according to child- and disease-related characteristics. RESULTS: Of the 395 included families, 42 (10.6%) of parents rated prognosis as excellent or very good for children in whom physicians rated prognosis as poor. In multiple regression analysis, in comparison to parents of children with leukemia and lymphoma, parents of children with solid tumors (odds ratio (OR) 11.3, 95% CI 4.6, 27.8; P=0.0009) and brain tumors (OR 7.5, 95% CI 2.7, 21.1; P=0.09), parents of children with relapsed disease (OR 10.7, 95% CI 3.6, 31.3; P<0.0001) and parents with greater dispositional optimism (OR 1.1, 95% CI 1.0, 1.2; P=0.008) were more likely to have optimistic prognostic estimates in the setting of physician-rated poor prognosis. CONCLUSION: Approximately 10% of parents have optimistic prognostic estimates in the setting of physician-rated poor prognosis. Families of children with solid tumors and relapsed cancer and parents who were more optimistic were more likely to be optimistic in the poor prognosis setting. More research is needed to understand the impact of such discrepancies in prognosis on processes and outcomes.

Ataxia-telangiectasia: atypical presentation and toxicity of cancer treatment.

BACKGROUND: The onset of progressive cerebellar ataxia in early childhood is considered a key feature of ataxia-telangiectasia (A-T), accompanied by ocular apraxia, telangiectasias, immunodeficiency, cancer susceptibility and hypersensitivity to ionizing radiation. METHODS: We describe the clinical features and course of three Mennonite children who were diagnosed with A-T following the completion of therapy for lymphoid malignancies. RESULTS: Prior to cancer therapy, all had non-progressive atypical neurological abnormalities, with onset by age 30 months, including dysarthria, dyskinesia, hypotonia and/or dystonia, without telangiectasias. Cerebellar ataxia was noted in only one of the children and was mild until his death at age eight years. None had severe infections. All three children were "cured" of their lymphoid malignancies, but experienced severe adverse effects from the treatments administered. The two children who received cranial irradiation developed supratentorial primitive neuroectodermal tumors of the brain, an association not previously described, with fatal outcomes. CONCLUSIONS: The range of neurological presentations of A-T is broad. Ataxia and telangiectasias may be minimal or absent and the course seemingly non-progressive. The diagnosis of A-T should be considered in all children with neuromotor dysfunction or peripheral neuropathy, particularly those who develop lymphoid malignancies. The consequences of missing the diagnosis may be dire. Radiation therapy and radiomimetic drugs should be avoided in individuals with A-T.

Diffuse hemangiomatosis with predominant central nervous system involvement.

Diffuse neonatal hemangiomatosis presents with multiple, progressive, rapidly growing cutaneous hemangiomas associated with widespread visceral hemangiomas in the liver, lungs, gastrointestinal tract, brain, and meninges. Described here is a case of diffuse neonatal hemangiomatosis with predominant central nervous system involvement. The early appearance of central nervous system lesions on imaging can overlap with that of cavernous malformations, confounding diagnosis; however, rapid growth, response to steroids, cystic appearance with sedimentation levels of the mature lesions, and involvement of other visceral organs can help confirm the diagnosis.

Germline SAMD9 and SAMD9L mutations are associated with extensive genetic evolution and diverse hematologic outcomes.

Germline SAMD9 and SAMD9L mutations cause a spectrum of multisystem disorders that carry a markedly increased risk of developing myeloid malignancies with somatic monosomy 7. Here, we describe 16 siblings, the majority of which were phenotypically normal, from 5 families diagnosed with myelodysplasia and leukemia syndrome with monosomy 7 (MLSM7; OMIM 252270) who primarily had onset of hematologic abnormalities during the first decade of life. Molecular analyses uncovered germline SAMD9L (n = 4) or SAMD9 (n = 1) mutations in these families. Affected individuals had a highly variable clinical course that ranged from mild and transient dyspoietic changes in the bone marrow to a rapid progression of myelodysplastic syndrome (MDS) or acute myeloid leukemia (AML) with monosomy 7. Expression of these gain-of-function SAMD9 and SAMD9L mutations reduces cell cycle progression, and deep sequencing demonstrated selective pressure favoring the outgrowth of clones that have either lost the mutant allele or acquired revertant mutations. The myeloid malignancies of affected siblings acquired cooperating mutations in genes that are also altered in sporadic cases of AML characterized by monosomy 7. These data have implications for understanding how SAMD9 and SAMD9L mutations contribute to myeloid transformation and for recognizing, counseling, and treating affected families.

Childhood brain cancer and its psychosocial impact on survivors and their parents: A qualitative thematic synthesis.

PURPOSE: The multiple late-effects experienced by survivors of childhood brain tumors, are not only a source of great distress for survivors, but also for their parents and siblings. The aim of this review is to systematically identify and synthesize qualitative evidence on how survivors of childhood brain tumors and their parents experience life after surviving childhood brain tumors. METHODS: Based on literature search in seven databases, 10 qualitative studies, published between 2004 and 2014 were included. RESULTS: Surviving a childhood brain tumor was experienced as paradox for survivors and their parents. While parents and survivors celebrated making it through the cancer experience, they nonetheless encountered a world with loss and new challenges. In short, the experience of survival was a bittersweet experience for survivors and their parents. Survivors and their parents experienced change that included living with uncertainty, intensification of the parenting role, a changing social world, a different way of being, and the need for additional help. CONCLUSION: Results from this synthesis reinforce that surviving a childhood brain tumor should be viewed as a point on a continuum of living with a brain tumor. Psychosocial effects of surviving brain cancer affect the entire family unit. A need for psychosocial support is evident, although development of such supports necessitates a more full understanding of challenges face by the child affected, their parents, and siblings. The limitations noted in this synthesis reinforce that more qualitative research is needed in this subject area.

A different perspective to approaching cancer symptoms in children.

A sound and comprehensive knowledge base about symptoms in children experiencing cancer is necessary if health care professionals hope to effectively manage their symptoms. To date, there is still much to be discovered about how children with cancer and their families experience childhood cancer symptoms. Accordingly, a longitudinal qualitative study was undertaken between July 1998 and December 2000 to explore and describe the childhood cancer symptom course from the perspectives of children and their families. The study was conducted in three settings: the participants' homes and both an inpatient and outpatient pediatric cancer unit located in Western Canada. Thirty-nine children (4 1/2- to 18-year-old males and females) with mixed cancer diagnoses and their families (parents and siblings) participated in the study. The majority of the children were diagnosed with either leukemia or lymphoma (72%), had siblings (87%), and two parents (87.2%), and remained in remission at the completion of the study (90%). All the children received chemotherapy either alone (56%) or in combination with surgery (18%), radiation (5%), radiation and bone marrow transplant (8%), radiation and surgery (10%), and surgery, radiation, and bone marrow transplant (3%). Multiple methods of data collection were used including open-ended formal interviewing and participant observation. Interview and participant observation data were analyzed by the constant comparative method of data analysis. The creation of illness narratives added to the understanding of children's and families' experiences. In addition to providing a description of how the symptoms affected children's and families' daily living, findings related to how to health professionals can better understand and approach children's cancer symptoms emerged. When families, physicians, nurses, and other health professionals approached children's symptoms solely as side effects (e.g., nausea) or singular physical and psychological states, children provided minimal description of what they were actually experiencing. However, a greater understanding was achieved when the symptoms were approached as dynamic multidimensional experiences that occurred within a particular context. Children experienced symptoms as feeling states. Critical to children's feeling states were the meanings that children and their families assigned to the symptoms. Viewing cancer symptoms in the context of assigned meanings has implications for how symptoms are assessed and managed. The need to develop a children's symptom assessment tool based on assigned meanings is recommended.

Second Bacteremia During Antibiotic Treatment in Children With Acute Myeloid Leukemia: A Report From the Canadian Infections in Acute Myeloid Leukemia Research Group.

BACKGROUND: The risk of second bacteremia during antibiotic treatment for initial bacteremia is unknown in high-risk populations. Our objectives were to describe the prevalence of second bacteremia during treatment and identify risk factors in children with acute myeloid leukemia (AML). METHODS: We conducted a retrospective, population-based cohort study that included children and adolescents with de novo, non-M3 AML who were diagnosed and treated between January 1, 1995 and December 31, 2004 at 15 Canadian centers. Patients were monitored for bacteremia during chemotherapy until completion of treatment, hematopoietic stem cell transplantation, relapse, refractory disease, or death. RESULTS: There were 290 episodes of bacteremia occurring in 185 (54.3%) of 341 children. Eighteen (6.2%) had a second bacteremia while receiving antibiotic treatment. Two episodes of second bacteremia were complicated by sepsis; there were no infection-related deaths. Eleven episodes (61.1%) had either an initial Gram-positive and subsequent Gram-negative bacteremia or initial Gram-negative followed by Gram-positive bacteremia. Days receiving corticosteroids (odds ratio [OR], 1.09; 95% confidence interval [CI], 1.07-1.12; P < .0001), cumulative dose of corticosteroids (OR, 1.04; 95% CI, 1.00-1.08; P = .035), and days of neutropenia from start of course to initial bacteremia (OR, 1.07; 95% CI, 1.02-1.12; P = .007) were significantly associated with second bacteremia. CONCLUSIONS: In pediatric AML, 6% of patients will experience a second bacteremia during antibiotic treatment; duration of corticosteroid exposure and neutropenia are risk factors. These patients remain at high risk for second bacteremia after identification of the initial bacteremia and warrant continued broad-spectrum treatment during profound neutropenia.