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Featured researches published by David Dix.


Journal of Clinical Oncology | 2008

Impact of Caring for a Child With Cancer on Parents’ Health-Related Quality of Life

Anne F. Klassen; Robert J. Klaassen; David Dix; Rochelle Yanofsky; Maureen O'Donnell; Amie M. Scott; Lillian Sung

PURPOSE To compare the health-related quality of life (QOL) of parents of children who are undergoing treatment for cancer with that of Canadian population norms and to identify important parent and child predictors of parental QOL. PATIENTS AND METHODS A total of 411 respondents of 513 eligible parents were recruited from five pediatric oncology centers in Canada between November 2004 and February 2007. Parents were asked to complete a questionnaire booklet that included a measure of adult QOL (SF-36), a measure of child health status (functional status IIR), and questions to assess health-promoting self-care actions (eg, sleep, diet, and exercise habits) and characteristics of the child with cancer (eg, relapse status, time since diagnosis, prognosis, treatment intensity). RESULTS Compared with population norms, parents of children with cancer reported poorer physical and psychosocial QOL in all psychosocial domains (effect sizes range, -0.71 to -1.58) and in most physical health domains (effect sizes range, -0.08 to -0.63). Parent characteristics associated with better parental QOL included better eating, exercise and sleep habits, younger age, and higher income. Child characteristics associated with better parental QOL included better child health status (functional status IIR scores), lower treatment intensity, and longer time since diagnosis. CONCLUSION Parents of children with cancer report poorer QOL compared with population norms. Interventions directed at parents should be included as part of the treatment plan for a child with cancer. Modifiable variables associated with poorer parental QOL, such as sleep quality and diet and exercise habits, indicate those parents most likely to experience poor QOL and may be potential areas for intervention.


Journal of Bone and Mineral Research | 2009

Advanced Vertebral Fracture among Newly Diagnosed Children with Acute Lymphoblastic Leukemia: Results of the Canadian STeroid-associated Osteoporosis in the Pediatric Population (STOPP) Research Program

Jacqueline Halton; Isabelle Gaboury; Ronald Grant; Nathalie Alos; Elizabeth A. Cummings; M. Matzinger; Nazih Shenouda; Brian Lentle; Sharon Abish; Stephanie A. Atkinson; Elizabeth Cairney; David Dix; Sara J. Israels; David Stephure; Beverly Wilson; John Hay; David Moher; Frank Rauch; Kerry Siminoski; Leanne M. Ward

Vertebral compression is a serious complication of childhood acute lymphoblastic leukemia (ALL). The prevalence and pattern of vertebral fractures, as well as their relationship to BMD and other clinical indices, have not been systematically studied. We evaluated spine health in 186 newly diagnosed children (median age, 5.3 yr; 108 boys) with ALL (precursor B cell: N = 167; T cell: N = 19) who were enrolled in a national bone health research program. Patients were assessed within 30 days of diagnosis by lateral thoraco‐lumbar spine radiograph, bone age (also used for metacarpal morphometry), and BMD. Vertebral morphometry was carried out by the Genant semiquantitative method. Twenty‐nine patients (16%) had a total of 75 grade 1 or higher prevalent vertebral compression fractures (53 thoracic, 71%; 22 lumbar). Grade 1 fractures as the worst grade were present in 14 children (48%), 9 patients (31%) had grade 2 fractures, and 6 children (21%) had grade 3 fractures. The distribution of spine fracture was bimodal, with most occurring in the midthoracic and thoraco‐lumbar regions. Children with grade 1 or higher vertebral compression had reduced lumbar spine (LS) areal BMD Z‐scores compared with those without (mean ± SD, −2.1 ± 1.5 versus −1.1 ± 1.2; p < 0.001). LS BMD Z‐score, second metacarpal percent cortical area Z‐score, and back pain were associated with increased odds for fracture. For every 1 SD reduction in LS BMD Z‐score, the odds for fracture increased by 80% (95% CI: 10–193%); the presence of back pain had an OR of 4.7 (95% CI: 1.5–14.5). These results show that vertebral compression is an under‐recognized complication of newly diagnosed ALL. Whether the fractures will resolve through bone growth during or after leukemia chemotherapy remains to be determined.


Journal of Clinical Oncology | 2012

High Incidence of Vertebral Fractures in Children With Acute Lymphoblastic Leukemia 12 Months After the Initiation of Therapy

Nathalie Alos; Ronald Grant; Timothy Ramsay; Jacqueline Halton; Elizabeth A. Cummings; Paivi Miettunen; Sharon Abish; Stephanie A. Atkinson; Ronald D. Barr; David A. Cabral; Elizabeth Cairney; Robert B. Couch; David Dix; Conrad V. Fernandez; John Hay; Sara J. Israels; Caroline Laverdière; Brian Lentle; Victor Lewis; M. Matzinger; Celia Rodd; Nazih Shenouda; Robert Stein; David Stephure; Shayne Taback; Beverly Wilson; Kathryn Williams; Frank Rauch; Kerry Siminoski; Leanne M. Ward

PURPOSE Vertebral fractures due to osteoporosis are a potential complication of childhood acute lymphoblastic leukemia (ALL). To date, the incidence of vertebral fractures during ALL treatment has not been reported. PATIENT AND METHODS We prospectively evaluated 155 children with ALL during the first 12 months of leukemia therapy. Lateral thoracolumbar spine radiographs were obtained at baseline and 12 months. Vertebral bodies were assessed for incident vertebral fractures using the Genant semiquantitative method, and relevant clinical indices such as spine bone mineral density (BMD), back pain, and the presence of vertebral fractures at baseline were analyzed for association with incident vertebral fractures. RESULTS Of the 155 children, 25 (16%; 95% CI, 11% to 23%) had a total of 61 incident vertebral fractures, of which 32 (52%) were moderate or severe. Thirteen (52%) of the 25 children with incident vertebral fractures also had fractures at baseline. Vertebral fractures at baseline increased the odds of an incident fracture at 12 months by an odds ratio of 7.3 (95% CI, 2.3 to 23.1; P = .001). In addition, for every one standard deviation reduction in spine BMD Z-score at baseline, there was 1.8-fold increased odds of incident vertebral fracture at 12 months (95% CI, 1.2 to 2.7; P = .006). CONCLUSION Children with ALL have a high incidence of vertebral fractures after 12 months of chemotherapy, and the presence of vertebral fractures and reductions in spine BMD Z-scores at baseline are highly associated clinical features.


International Journal of Cancer | 2011

Quality of life during active treatment for pediatric acute lymphoblastic leukemia

Lillian Sung; Rochelle Yanofsky; Robert J. Klaassen; David Dix; Naomi J. Winick; Sarah Alexander; Anne F. Klassen

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.


Pediatric Blood & Cancer | 2013

Children's Oncology Group's 2013 blueprint for research: renal tumors.

Jeffrey S. Dome; Conrad V. Fernandez; Elizabeth Mullen; John A. Kalapurakal; James I. Geller; Vicki Huff; Eric J. Gratias; David Dix; Peter F. Ehrlich; Geetika Khanna; Marcio H. Malogolowkin; James R. Anderson; Arlene Naranjo; Elizabeth J. Perlman

Renal malignancies are among the most prevalent pediatric cancers. The most common is favorable histology Wilms tumor (FHWT), which has 5‐year overall survival exceeding 90%. Other pediatric renal malignancies, including anaplastic Wilms tumor, clear cell sarcoma, malignant rhabdoid tumor, and renal cell carcinoma, have less favorable outcomes. Recent clinical trials have identified gain of chromosome 1q as a prognostic marker for FHWT. Upcoming studies will evaluate therapy adjustments based on this and other novel biomarkers. For high‐risk renal tumors, new treatment regimens will incorporate biological therapies. A research blueprint, viewed from the perspective of the Childrens Oncology Group, is presented. Pediatr Blood Cancer 2013; 60: 994–1000.


British Journal of Cancer | 2009

Identification of paediatric cancer patients with poor quality of life

Lillian Sung; Robert J. Klaassen; David Dix; S Pritchard; R Yanofsky; B Dzolganovski; R Almeida; A Klassen

The primary objective was to describe predictors of physical, emotional and social quality of life (QoL) in children receiving active treatment for cancer. This Canadian multi-institutional cross-sectional study included children with cancer receiving any type of active treatment. The primary caregiver provided information on child physical, emotional and social QoL according to the PedsQL 4.0 Generic Core scales. Between November 2004 and February 2007, 376 families provided the data. In multiple regression, children with acute lymphoblastic leukemia had better physical health (OR: 0.37, 95% CI 0.23, 0.60; P<0.0001) while intensive chemotherapy treatment (OR: 2.34, 95% CI: 1.42, 3.85; P=0.0008) and having a sibling with a chronic condition (OR: 2.53, 95% CI: 1.54, 4.15; P=0.0002) were associated with poor physical QoL. Better emotional health was associated with good prognosis, less intensive chemotherapy treatment and greater household savings, whereas female children and those with a sibling with a chronic condition had poor social QoL. Physical, emotional and social QoL are influenced by demographic, diagnostic and treatment variables. Sibling and household characteristics are associated with QoL. This information will help to identify children at higher risk of poor QoL during treatment for cancer.


International Journal of Cancer | 2011

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

Anne F. Klassen; Parminder Raina; Cameron McIntosh; Lillian Sung; Robert J. Klaassen; Maureen O'Donnell; Rochelle Yanofsky; David Dix

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 childs 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.


Blood | 2009

The impact of prophylactic fresh-frozen plasma and cryoprecipitate on the incidence of central nervous system thrombosis and hemorrhage in children with acute lymphoblastic leukemia receiving asparaginase

Lesleigh S. Abbott; Mariana Deevska; Conrad V. Fernandez; David Dix; Victoria Price; Hao Wang; Louise Parker; Margaret Yhap; Colleen Fitzgerald; Dorothy R. Barnard; Jason N. Berman

Asparaginase (ASP) therapy is associated with depletion of antithrombin (AT) and fibrinogen (FG). Potential toxicities include central nervous system thrombosis (CNST) and hemorrhage. Historical practice at the Izaak Walton Killam Health Centre (IWK) involves measuring AT and FG levels after ASP administration and transfusing fresh-frozen plasma (FFP) or cryoprecipitate (CRY) to prevent thrombotic and hemorrhagic complications. To determine whether this reduced these complications in children with acute lymphoblastic leukemia (ALL), incidence, outcome, and clinical characteristics of ASP-related CNST in ALL patients at IWK were compared with a similar cohort from BC Childrens Hospital (BCCH), where prophylaxis was not performed. Costs associated with preventative versus expectant management were estimated. From 1990 to 2005, 240 patients were treated at IWK and 479 at BCCH. Seven BCCH patients developed venous CNST (1.5%), compared with none at IWK. CNST occurred exclusively during induction. Six patients received anticoagulation and continued ASP. All 7 patients remain in remission. National Cancer Institute high-risk ALL predicted CNST risk (P = .02), whereas sex, age, race, and body mass index did not. Neither FFP nor CRY protected against CNST, suggesting prophylaxis is unwarranted for unselected ALL patients. However, prophylactic replacement for HR patients in induction may be cost-effective.


Clinical Infectious Diseases | 2012

Association Between Corticosteroids and Infection, Sepsis, and Infectious Death in Pediatric Acute Myeloid Leukemia (AML): Results From the Canadian Infections in AML Research Group

David Dix; Sonia Cellot; Victoria Price; Biljana Gillmeister; Marie-Chantal Ethier; Donna L. Johnston; Victor Lewis; Bruno Michon; David Mitchell; Kent Stobart; Rochelle Yanofsky; Carol Portwine; Mariana Silva; Lynette Bowes; Shayna Zelcer; Josee Brossard; Jeffrey Traubici; Upton Allen; Joseph Beyene; Lillian Sung

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.


Journal of Pediatric Hematology Oncology | 2004

An assessment of published pediatric dosage guidelines for enoxaparin: a retrospective review.

Sharon H. Ho; John Wu; Donald P. Hamilton; David Dix; Louis D. Wadsworth

Objective To evaluate the ability of published dosage guidelines for enoxaparin to achieve therapeutic anticoagulation and to determine whether the routine monitoring of anti-Xa levels is still necessary at a tertiary care pediatric institution. Methods Consecutive charts and laboratory records were reviewed for all patients receiving treatment doses of enoxaparin for thrombosis in the authors’ institution over a 4-year period (1998–2002). Results Sixty-six percent (25/38) of the anti-Xa levels were within the recommended therapeutic range (0.5–1.0 [± 10%] U/mL) after two doses. The success rates of achieving therapeutic levels were 1/6, 2/3, 6/9, 10/11, and 6/9, for patients 2 months or younger, more than 2 months to 1 year, more than 1 year to 6 years, more than 6 years to 12 years, and more than 12 years of age, respectively. Patients with cardiac or renal disease were more likely to achieve high anti-Xa levels. Thirty-seven percent of patients reported adverse effects. The most common effects were injection site-related bruising and minor bleeding. One patient experienced a major bleed that was not life-threatening. Conclusions Most patients achieved therapeutic anticoagulation when dosed according to the published guidelines. Children with cardiac conditions or renal insufficiency or those younger than 2 months were more likely to require dosage adjustments to achieve the therapeutic range. Routine monitoring of anti-Xa levels is still necessary in these patient populations, particularly when the early establishment of therapeutic anticoagulation may be critical. Enoxaparin appears to be well tolerated in the authors’ patient population.

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Robert J. Klaassen

Children's Hospital of Eastern Ontario

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Donna L. Johnston

Children's Hospital of Eastern Ontario

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Carol Portwine

McMaster Children's Hospital

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Victor Lewis

Alberta Children's Hospital

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David Mitchell

Montreal Children's Hospital

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Sonia Cellot

Université de Montréal

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