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Biomedical subjects

Ronald D Barr

Publications and source records attributed to Ronald D Barr.

At least 19 recordsLinked to original sources
PubMed2007

Common cancers in adolescents.

Adolescence, spanning 15-19 years of age, is a time of developmental transition from childhood to adult life. The spectrum of cancers affecting this age group reflects a similar transition. The common malignant diseases of childhood - leukemias, lymphomas, tumors of the central nervous system and embryonal solid tumors (such as nephroblastoma and neuroblastoma) - are replaced in relative frequency by sarcomas of bone and soft tissue, and tumors of the male and female genital tracts. Moreover, the epithelial tumors (carcinomas), so prevalent in adults, occur (albeit at much lower frequencies) in adolescents. Within individual tumor types, biological features may be distinctive in this age group. Examples are the high prevalence of poor prognostic determinants in acute lymphoblastic leukemia and histologically higher grade forms of astrocytic/glial tumors. Particular challenges in addressing the common tumors of adolescence include the development of better categorization, especially of soft tissue sarcomas, and exploring these diseases in this age group within the developing world where most adolescents reside.

Adolescent↗
PubMed2007

Implementation of a data management program in a pediatric cancer unit in a low income country.

INTRODUCTION: Pediatric cancer units in low-income countries lack data on which to base quality improvement initiatives. We implemented a data management program in the oncology unit of the children's hospital of Tegucigalpa, Honduras, and then we assessed training and supervision of data managers, data accuracy, and completeness as well as obstacles encountered. METHODS: Training included 2 days of off-site hands-on instruction in the use of an online database, daily on-site supervision by physicians, periodic online meetings for education and problem-solving, and continuous e-mail support. RESULTS: Of the 652 patients diagnosed with acute leukemia between July 1995 and June 2005, 150 (23%) had not yet been registered in the database at the time of audit and 65 (10%) had missing medical records. The remaining 437 charts (67%) were reviewed by an external auditor and compared to the data entered previously by the two trained data managers. Protocol information was incomplete in 30% of cases, and the cause of death was inaccurate in 18%. All other data were 99% accurate and 93%-100% complete. Obstacles included a limited medical records system, poor organization of the charts, missing records, inconsistently documented protocol information, data managers who lack a medical background, and slow or unreliable internet connections. CONCLUSION: Data managers can be trained to effectively collect basic pediatric oncology data in a low-income country. Addressing inadequacies in the medical record system while providing specific training in protocol-based care and determination of cause of death for both physicians and data managers will improve data quality.

Clinical Protocols↗
PubMed2007

Protocol-based treatment for children with cancer in low income countries in Latin America: a report on the recent meetings of the Monza International School of Pediatric Hematology/Oncology (MISPHO)--part II.

Pediatric cancer programs in low-income countries (LIC) can improve outcomes. However, treatment must be tailored to the patient's living conditions and the availability of supportive care. In some cases, a more intense regimen will decrease survival since the increase in death from toxicity may exceed any decrease in relapse. Attempts to practice evidence-based pediatric oncology are thwarted by the lack of evidence derived from local experience in LIC to determine optimal therapy. This report summarizes treatment regimens used by pediatric oncologists from 15 countries of the Caribbean, Central and South America who participate in the Monza International School of Pediatric Hematology/Oncology (MISPHO). Patients with hepatoblastoma, Wilms tumor, and histiocytosis treated on unmodified published protocols had outcomes comparable to those in high-income countries (HIC). Those with rhabdomyosarcoma, osteosarcoma, Hodgkin lymphoma, and acute myeloid leukemia treated with unmodified regimens had event-free survival estimates 10%-20% lower than those reported in HIC due to higher rates of toxic death, abandonment of therapy, and relapse. Treatment of retinoblastoma is complicated by advanced stages and extraocular disease at diagnosis; improved outcomes depend on education of pediatricians and the public to recognize early signs of this disease. Use of unmodified protocols for Burkitt lymphoma and acute lymphoblastic leukemia have been associated with unacceptable toxicity in LIC, so MISPHO centers have modified published regimens by giving lower doses of methotrexate and reducing use of anthracyclines. Despite the use of all-trans-retinoic acid during induction for acute promyelocytic leukemia, the incidence of fatal hemorrhage remains unacceptably high.

Adolescent↗
PubMed2007

Improving outcomes for children with cancer in low-income countries in Latin America: a report on the recent meetings of the Monza International School of Pediatric Hematology/Oncology (MISPHO)-Part I.

The difference in survival for children diagnosed with cancer between high- and low-income countries (LIC) continues to widen as curative therapies are developed in the former but not implemented in the latter. In 1996, the Monza International School of Pediatric Hematology/Oncology (MISPHO) was founded in an attempt to narrow this survival gap. During its sixth and seventh meetings, members recognized the problem of lack of affordability of essential drugs to treat childhood cancer in many LIC, and initiated an advocacy program. In 1998, MISPHO spawned a collaboration of Central American pediatric oncology centers: the Asociación de Hemato-Oncología Pediátrica Centroamericana (AHOPCA). AHOPCA members reported preliminary findings from several of the 10 cooperative protocols that are currently in progress. In 2003, a second regional collaborative group was formed that includes seven centers in South America. Twinning programs between MISPHO centers and centers in high-income countries (HIC) have proven invaluable to harness the resources of these centers to improve pediatric oncology care in LIC. MISPHO educational efforts include oncology nursing, supportive care, cancer-specific updates, epidemiology, and clinical research methods. Educational efforts are facilitated by educational content and online conferencing via www.cure4kids.org. Identifying preventable causes of abandonment of therapy and documenting the nutritional status of patients treated at MISPHO centers are areas of active research.

Adolescent↗
PubMed2006

Osteonecrosis in children and adolescents with cancer - an adverse effect of systemic therapy.

Osteonecrosis (ON) is recognised increasingly as a complication of the treatment of cancer in children and adolescents. It is especially prevalent among survivors of acute lymphoblastic leukaemia and non-Hodgkin lymphoma, in whom as many as 1/3 may be affected, likely reflecting the cumulative exposure to glucocorticosteroid therapy. The pathogenesis is complex and includes suppression of bone formation, expansion of the intra-medullary lipocyte compartment and a direct effect on nutrient arteries. Children > or =10 years of age are at particular risk and the disorder is substantially more common in Whites than in Blacks. Genetic predispositions have been identified. ON is often multi-articular and bilateral, affecting weight-bearing joints predominantly. Surgical management options are of concern in young growing subjects, although injection of autologous marrow into affected sites offers promising results. Other novel approaches include the use of anti-resorptive drugs and strategies for prevention, such as with lipid-lowering agents, are being explored.

Adolescent↗
PubMed2006

Commentary on Cox CL, Lensing S, Rai SN et al. Proxy assessment of quality of life in pediatric clinical trials: application of the Health Utilities Index 3. Qual Life Res 2005; 14: 1045-1056.

The paper by Cox et al. offers an important potential for informing designs of future studies. The rates of missing measurements in the study are much greater than those reported by other investigators. This is not surprising because the nurse assessors were restricted explicitly by the study protocol from collecting required information, had little contact with many of the patients, and some had a poor understanding of the measurement system. Standard multi-attribute system questionnaires, such as the one used in the Cox et al. study, have been designed carefully and require assessments of aspects of health that are not always readily observable (e.g. emotional status). There is an abundance of published evidence, from studies conducted around the world, of acceptable measurement properties for these instruments. However, the published evidence also indicates that measurement properties are compromised with the use of proxy assessors who have little day-to-day knowledge of patients. We conclude that the Cox et al. study results provide evidence that multi-attribute system assessments should be elicited from patients themselves or, failing that, from proxy assessors known to be well-informed about the patients' capacity on all relevant attributes.

Clinical Trials as Topic↗
PubMed2006

Health status measurements at diagnosis as predictors of survival among adults with brain tumors.

PURPOSE: The intent of this study was to determine whether baseline measures of functional capacity and performance could be used to predict survival in adults following the diagnosis of brain tumors. PATIENTS AND METHODS: Comprehensive health status and health-related quality of life (HRQL) were measured using the Health Utilities Index (HUI; McMaster University, Hamilton, Canada) system by a self-assessment questionnaire in a survey of 100 consecutive patients. The Karnofsky Performance Score (KPS) and Folstein's Mini-Mental State Examination (MMSE) scores were measured by a physician blinded to the HUI results. The patients were observed for up to 5 years to recorded dates of death. RESULTS: An HUI questionnaire was completed for 93% of the patients and 69% died within 5 years of assessment. The HUI revealed a burden of morbidity and complexity of disability that far exceeded that reported for the general population. KPS and MMSE correlated strongly with each other (r = 0.52; P < .001). A decrease of 0.1 units in HUI Mark 2 (HUI2) self-care single-attribute utility score was associated with an increased hazard of death of 30% (P = .023) for patients with low-grade tumors (n=25). For patients with high-grade tumors (n=56), a 10 unit decrease in the KPS, a 5 unit decrease in MMSE, and a 0.1 decrease in HUI Mark 3 (HUI3) speech and dexterity single-attribute scores were associated with an increased hazard of death of 20% (P = .022), 26% (P = .015), 36% (P = .021), and 18% (P = .035), respectively. CONCLUSION: Scores derived from the measurement of HRQL following diagnosis can predict survival in adults with brain tumors.

Adult↗
PubMed2006

Cancer surveillance and control in adolescents--similarities and contrasts between Canada and the United States.

Opportunities for cancer prevention in adolescents range from limitation of sun exposure to the use of human papillomavirus vaccines. Those who develop malignant disease experience longer waiting times for diagnosis and treatment than do children, especially when referred to adult treatment centers, and they are less frequently enrolled in clinical trials. More attention to developmentally appropriate psychological support, enhancement of compliance/adherence, health promotion, and palliative care is needed. Improving cancer surveillance and control in adolescents in North America will require co-ordinated national efforts, involving pediatric and adult health care providers, institutions, and multiple levels of government.

Adolescent↗
PubMed2006

Health status in survivors of cancer in childhood and adolescence.

BACKGROUND: Assessing health status in survivors of childhood cancer is increasingly important due to improved survival rates. However, there are limited estimates available for this population based on large samples and compared to population controls. METHODS: In a retrospective cohort study, 2,152 long-term survivors and 2,432 controls, aged 5-37, who had survived cancer during childhood or adolescence were compared on the Health Utilities Index Mark III (HUI3). Descriptive and logistic regression analyses were used to assess the effect of age at diagnosis, type of cancer and therapy received on HUI3 domains. MAJOR FINDINGS: More survivors than controls showed deficits in dexterity, ambulation, hearing, speech and cognition but not in vision, emotion or pain. The largest numbers of survivors reporting excess impairment was found in the cognition attribute. Survivors of central nervous system tumors were most likely to show impairments across multiple domains. Lastly, impairments in cognition were found most commonly in survivors exposed to cranio-spinal radiation at young ages. CONCLUSIONS: Seventy-five percent of childhood cancer survivors and 80% of controls were found to have two or fewer impaired attributes. Those reporting impairments that were most likely to be of clinical relevance were among survivors diagnosed with central nervous system and bone tumours, and those exposed to cranial radiation as young children. Tools assessing health status should be included in prospective trials to more clearly assess the contribution of therapy to reduced long-term health status.

Adolescent↗
PubMed2006

Measurement of health-related quality of life in survivors of cancer in childhood in Central America: feasibility, reliability, and validity.

Cancer is the commonest cause of disease-related death in children over 5 years of age in various parts of Latin America, but the survival rates are improving. This study assessed the health status and health-related quality of life (HRQL) of more than 200 survivors of cancer in childhood in the countries of a Central American consortium devoted to pediatric hematology-oncology. Patients' self-reports and parental proxy assessments were collected using interviewer-administered Spanish-language questionnaires, and physicians provided assessments using self-complete questionnaires, based on the complementary Health Utilities Index (HUI) Mark 2 (HUI2) and Mark 3 (HUI3) health status classification systems. Inter-rater agreement, measured by intra-class correlation (ICC), was fair to moderate (0.34 0.60) for all 3 pairs of assessors for readily assessable attributes: HUI2 sensation, HUI3 vision, HUI3 hearing, and HUI3 ambulation. Less than 40% of the patients reported being in perfect health. More than 20% reported being in health states with HRQL scores corresponding to moderate or severe disability, notably in the attributes of emotion and cognition. The results reflect a common profile in survivors of cancer in childhood, including those from industrialized societies. This study illustrates the feasibility of collecting reliable and valid information on HRQL in the developing country context, raising the prospect that such information could be used to influence clinical practice.

Adolescent↗
PubMed2006

Impact of age and diagnosis on waiting times between important healthcare events among children 0 to 19 years cared for in pediatric units: the Canadian Childhood Cancer Surveillance and Control Program.

BACKGROUND: The objectives were to describe and compare waiting times to diagnosis and treatment of children and adolescents who accessed pediatric oncology centers in Canada for healthcare, and to assess the effects and relative contributions of age, sex, and diagnosis to waiting times. METHODS: Waiting times were assessed for 2,365 children (0 to 14 y) and 375 adolescents (15 to 19 y) diagnosed with cancer between 1995 and 2000 inclusive and followed by the Treatment and Outcome Surveillance system of the Canadian Children's Cancer Surveillance and Control Program. Differences were assessed using the chi2 test, Fisher exact test, and Wilcoxon test statistic. RESULTS: Median waiting times between first assessment by treating oncologist or surgeon and definitive diagnostic procedure, and the subsequent interval to first therapeutic event, were 2 days each. Significant variation existed in both periods when stratified by age and diagnosis but not sex. The most significant differences between age groups were eliminated when stratified by diagnosis. INTERPRETATION: This analysis suggests that once they enter the healthcare system, children and adolescents treated in pediatric centers in Canada experience short waiting times to key diagnostic and treatment events. Differences in wait times between the 2 age groups are not clinically significant and can be attributed to the differences in the types of cancer experienced by adolescents compared with children.

Adolescent↗
PubMed2005

Patient-focused measures of functional health status and health-related quality of life in pediatric orthopedics: a case study in measurement selection.

The objectives of this report are to review the assessment of patient-focused outcomes in pediatric orthopedic surgery, to describe a framework for identifying appropriate sets of measures, and to illustrate an application of the framework to a challenging orthopedic problem.A detailed framework of study design and measurement factors is described. The factors are important for selecting appropriate instruments to measure health status and health-related quality of life (HRQL) in a particular context. A study to evaluate treatment alternatives for patients with neurofibromatosis type 1 and congenital tibial dysplasia (NF1-CTD) provides a rich illustration of the application of the framework. The application involves great variability in the instrument selection factors. Furthermore, these patients and their supportive caregivers face numerous complex health challenges with long-term implications for HRQL. Detailed summaries of important generic preference-based multi-attribute measurement systems, pediatric health profile instruments, and pediatric orthopedic-specific instruments are presented. Age-appropriate generic and specific measures are identified for study of NF1-CTD patients. Selected measures include the Activities Scale for Children, Gillette Functional Assessment Questionnaire Walking Scale, Health Utilities Index, and Pediatric Inventory of Quality of Life. Reliable and valid measures for application to pediatric orthopedics are available. There are important differences among measures. The selected measures complement each other. The framework in this report provides a guide for selecting appropriate measures. Application of appropriate sets of measures will enhance the ability to describe the morbidity of pediatric orthopedic patients and to assess the effectiveness of alternative clinical interventions. The framework for measurement of health status and HRQL from a patient perspective has relevance to many other areas of orthopedic practice.

Activities of Daily Living↗
PubMed2005

Quality-adjusted survival: a rigorous assessment of cure after cancer during childhood and adolescence.

Survivors of cancer in childhood and adolescence, while increasing gratifyingly in number with ever more effective therapy, have a life expectancy that is compromised all-too-often in both duration and value as a result of adverse treatment-related sequelae. Accounting for this burden of morbidity and mortality is essential for a proper appreciation of cure. Adjusting estimates of survival by measures of its quality affords a means of accomodating this requirement. It can be accomplished by "weighting" the length of survival according to preference-based assessments of health-related quality of life (HRQL), which allow the calculation of quality-adjusted life years. Inclusion of measures of HRQL in clinical trials is imperative as we reach to the ultimate objective; the truly cured child restored to normal health.

Adolescent↗
PubMed2005

Waiting times for cancer care in Canadian children: impact of distance, clinical, and demographic factors.

BACKGROUND: The objective of this study was to evaluate the impact of distance from residence to pediatric oncology centers on waiting times to diagnostic assessment and treatment in Canadian children with cancer. PROCEDURE: Two thousand three hundred sixteen children (< 15 years of age) captured by the Canadian Childhood Cancer Surveillance and Control Program's (CCCSCP) Treatment and Outcome Surveillance (TOS) system were included in the analysis. The number of days between onset of symptoms and first anti-cancer therapy was compared for those living less than 25, 25-99, and more than 100 kilometers from their treating center. For each time period, the adjusted odds of falling into the longest time quartiles were estimated using logistic regression analysis. RESULTS: Thirty-four percent (n = 786) of children lived more than 100 kilometers from their treating center. There were no significant differences in age at diagnosis (P = 0.33), sex (P = 0.68), or ICCC diagnosis (P = 0.02) by distance from center, though there was a significant difference in region of residence (P < 0.01) and the first health care professional contacted (P < 0.01). Except for waiting time from first health care contact to first assessment by treating oncologist which increased with increasing distance (P < 0.01), there were no significant differences in waiting times by distance. When adjusted for important demographic and clinical characteristics, distance to center did not affect the odds of waiting longer for any event. CONCLUSIONS: Distance to treating center had no significant impact on waiting times for important diagnostic and treatment events, when adjusted for age at diagnosis, diagnosis, region, and first health care professional seen.

Adolescent↗
PubMed2005

Translation and cultural adaptation of Health Utilities Index (HUI) Mark 2 (HUI2) and Mark 3 (HUI3) with application to survivors of childhood cancer in Brazil.

INTRODUCTION: There are few publications reporting health-related quality of life (HRQL) in developing nations. Most instruments measuring HRQL have been developed in English-speaking countries. These instruments need to be culturally adapted for use in non-English-speaking countries. The HUI2 and HUI3 are generic, preference-based systems for describing health status and HRQL. Developed in Canada, the systems have been translated into more than a dozen languages and used worldwide in hundreds of studies of clinical and general populations. METHODS: The Brazilian-Portuguese translation of the HUI systems was supervised by senior HUInc staff having experience with both the HUI systems and translations. The process included two independent forward translations of the multi-attribute health status classification systems and related questionnaires, consensus between translators on a forward translation, back-translation by two independent translators of the forward translation, and review of the back-translations by original developers of the HUI. The final questionnaires were tested by surveying a sample of convenience of 50 patients recruited at the Centro de Tratamento e Pesquisa-Hospital do Cancer in São Paulo, Brazil. RESULTS: Fifty patients were enrolled in the study. No assessor, patient or nurse or physician, reported problems answering the HUI questionnaires. No significant differences were found in mean overall HUI2 or HUI3 utility scores among types of assessors. Variability in scores are similar to those from other studies in Latin America and Canada. CONCLUSION: Test results provide preliminary evidence that the Brazilian-Portuguese translation is acceptable, understandable, reliable and valid for assessing health-status and HRQL among survivors of cancer in childhood in Brazil.

Adult↗