Biomedical subjects

D L Tritchler

Publications and source records attributed to D L Tritchler.

10 recordsLinked to original sources

PubMed1992

High-dose cytosine arabinoside remission induction for acute myelogenous leukemia: comparison of two regimens of remission maintenance.

We report a single institution sequential trial of two maintenance treatment regimens for patients with acute myelogenous leukemia (AML). A total of 175 consecutive patients with AML received initial remission induction therapy with high-dose cytosine arabinoside (ara-C) and glucocorticoids. For the initial 63 patients (group A), the control population, planned maintenance treatment was with conventional-dose ara-C given over 4 days for up to 18 months. The subsequent 107 patients (group B) had planned maintenance therapy of up to 6 courses of daunorubicin, ara-C and prednisone and daily cis-retinoic acid for up to two years. The presenting features of group A and B patients were similar as were the response to remission induction, 60 and 52%, respectively. Severe neurological toxicity was encountered once after high-dose ara-C; no drug-related deaths occurred during maintenance treatment. Median duration of remission for group B patients was 9.9 months compared with 5.5 for group A (p = 0.0685). Median survival duration for the two groups was similar, 9.1 months for group A and 10.4 for group B. Survival of patients in group B who attained a complete remission was significantly better than that of patients in group A (p = 0.0439). The studies confirm our initial experience with remission induction using single agent high-dose ara-C and suggest a positive role for maintenance therapy in AML.

Acute Disease↗

PubMed1991

Communicating probabilistic information to cancer patients: is there 'noise' on the line?

The objective was to examine the way that cancer patients translate verbal descriptors of probability into numerical estimates. A list of words commonly used on consent forms to describe the likelihood for benefits or risks of therapies was provided to 100 cancer patients. Two formats, paper/pencil or computer, were used to provide the list of words. Two methods, magnitude estimation and linear analogue scaling, were used to obtain probability estimates for each word. In addition, two scenarios were developed to study 'context effects' on numerical interpretations of verbal descriptions of probability. All patients provided numerical values for the words on two occasions, separated by one week, and two interviewers collected the data. Regardless of method or format, each word elicited widely variable numerical interpretations. An ANOVA model, including patient, word, interviewer, time, method and format, indicated that patient and interviewer produced major effects on probability estimates. Agreement between methods and across time was good. Paper/pencil and computer formats yielded similar results. Context effects did not appear to influence the numerical probabilities elicited by the 2 scenarios. It was concluded that, within this group of patients, there was no consensus about numerical meaning of a given word, and that interviewers can systematically influence numerical interpretations. There appears to be a great deal of 'noise' in this particular line of communication between patients and health professionals.

Aged↗

PubMed1991

Use of written cases to study factors associated with regional variations in referral rates.

The major purpose was to explore the use of written case scenarios to investigate factors associated with regional variations in referral for consultation. Data were collected in Nova Scotia, where extensive computer-based records of utilization of health services are kept, and the nine health care regions are in sufficient proximity to make visits and interviews feasible. Interviews with 9 x 25 = 225 randomly-selected family physicians, using scenarios analogous to ICD-9 codes, permitted testing of hypotheses about the effects of selected variables on referral rates for hypothetical cases. The family physicians' self-reported referral behavior for the written case scenarios was compared, region by region, with the actual referral of analogous cases by physicians in the same region, as determined from Nova Scotia Health Services and Insurance Commission records. The results indicated that written scenarios provide a useful tool for studies of such variables. Generally, the family physicians responded appropriately to the information that described the hypothetical patients ("case cues"). However, comparisons of hypothetical and actual referral rates indicated that appropriate information about the environment within which referral decisions take place ("environmental cues") may be needed to explain actual regional variations in referral rates.

Attitude of Health Personnel↗

PubMed1989

Measuring satisfaction with health care: a comparison of single with paired rating strategies.

One of the central problems in studies of patient satisfaction with health care is the development of reliable and valid methods to determine the relative importance of different aspects of health care. Two techniques, paired comparisons and rating on a visual analogue scale, were compared in terms of their consistency with logical assumptions, test-retest reliability, and convergent validity. Thirty women with breast cancer were asked to assess brief hypothetical scenarios describing out-patient clinic visits to a tertiary cancer care centre. Each scenario incorporated three variables related to satisfaction with care: staff attitude, control over treatment decisions, and continuity of medical supervision. The paired choice method showed marginally better reliability and logical consistency than the rating method. Of the three variables assessed, continuity of medical supervision was consistently ranked highest in importance, and control over treatment decisions lowest. These preference assessment techniques appear to be suitable for use in the development of patient satisfaction indices, and for studies designed to examine variations in the priority given to different aspects of satisfaction with care.

Attitude of Health Personnel↗

PubMed1989

Cancer patients: their desire for information and participation in treatment decisions.

The relationship between cancer patients' desire for information and their preference for participation in decision making has been examined. Approximately 77% of the 52 patients reported that they had participated in decision making to the extent that they wished, while most of the remaining 23% would have preferred an opportunity to have greater input. Although many of the patients actively sought information, a majority preferred the physician to assume the role of the primary decision maker. Ethically, the disclosure of information has been assumed to be necessary for autonomous decision making. Nevertheless, the results of this study indicate that patients may actively seek information to satisfy an as yet unidentified aspect of psychological autonomy that does not necessarily include participation in decision making.

Canada↗

PubMed1987

Response to 5-azacytidine of leukemic blast cells in suspension: a biological parameter associated with response to chemotherapy.

Sensitivities to drugs acting on cells in culture can be measured as dose-response curves, provided a quantitative assay is available for a relevant cell function. We have used two such assays in the study of the blast cells of acute myeloblastic leukemia. Colony formation in culture with methylcellulose detects principally terminal divisions, while growth of clonogenic cells in suspension reflects self-renewal. In a previous study different cytosine arabinoside and 5-azacytidine dose-response curves were obtained with the two assays. For the former the slope of the dose-response curve measured in suspension was steeper than that obtained using the clonogenic assay. For the latter, 5-azacytidine, the relationship between sensitivity in suspension and in methylcellulose was reversed. Further, for cytosine arabinoside, sensitivity in suspension but not in methylcellulose was associated with successful remission-induction. In this article we report an association between 5-azacytidine sensitivity in suspension and successful remission induction, for patients treated only with high-dose cytosine arabinoside. There was no correlation between the 5-azacytidine dose-response curve in methyl-cellulose and clinical outcome. A model is presented that may explain these findings, based on the hypothesis that there are genetic mechanisms responsible for blast cell renewal.

Adult↗

PubMed1986

The sensitivity to cytosine arabinoside of the blast progenitors of acute myeloblastic leukemia.

Two culture methods are available for the study of the blast cells of acute myeloblastic leukemia (AML). One is an assay for clonogenic precursors; it depends on their ability to form blast colonies in culture in the presence of methylcellulose and suitable growth factors. The other assesses the growth of blast cells in suspension culture, where growth is measured by increasing numbers of clonogenic cells. We have compared the two methods as assays for the cytotoxic effects of the chemotherapeutic drug cytosine arabinoside (Ara-C). Marked patient-to-patient variation was found using either method; however, the slopes of the dose-response curves were usually greater when cells were exposed to drug in suspension rather than in methylcellulose. Control experiments showed that the difference could not be explained by drug carry-over from the suspension cultures to the methylcellulose plates when clonogenic cells in the suspensions were assessed. Further, the survival curves for Adriamycin were very similar, regardless of which assay was used. No correlation was found between D10 Ara-C values measured in suspension or in methylcellulose. However, a significant association with outcome was found between D10 Ara-C in suspension and response to treatment with a regimen in which Ara-C was the only chemotherapeutic agent used. No such association was detected when the D10 values obtained with the clonogenic assay were compared with outcome for the same group of 15 patients. Finally, a feasibility experiment was performed in which blast cells were exposed to Ara-C repeatedly during exponential growth over 238 days. A dose-related inhibition of growth was observed; no evidence was seen of emerging drug-resistant cells. Nor did the morphology of the cells change as a result of drug exposure. We conclude that drug sensitivities of AML blast cells in culture are dependent on measurement methods, even when techniques affecting cell proliferation are compared. Measurements of drug sensitivity in culture may best be interpreted when the bases of the assay systems are understood.

Adult↗

PubMed1985

Eliciting preferences for alternative cancer drug treatments. The influence of framing, medium, and rater variables.

In oncology there is increasing interest in the development of techniques to help patients choose between alternative therapies in ways that are consistent with their preferences. The purpose of this study was to examine some methodological problems associated with the elicitation of preferences. Preferences for alternative drug therapies were sought from 208 visitors to an open house at the Ontario Cancer Institute and from 216 university nursing students. Preferences were not significantly dependent on the sex, age or professional status of the respondents, nor on the medium used for elicitation of preferences (computer terminal versus pencil-and-paper questionnaire). In contrast, the importance of the way decision problems are framed was confirmed. Comparison of a positive frame (outcomes expressed as the probability of surviving) with a negative frame (outcomes expressed as the probability of dying) and a mixed frame (probabilities of surviving and dying were both given) pointed to the presence or absence of the word "survive" in the outcome description as the main source of framing bias. The framing effect was in the opposite direction to that hypothesized.

Adolescent↗

PubMedDate not supplied

Whose utilities for decision analysis?

The goal of this study was to examine sources of variation in the utilities assigned to health states. The authors selected a common clinical problem, carcinoma of the rectum, and examined the utilities assigned to colostomy, a common outcome of treatment for that disease. After preparing and validating a description of colostomy and its effects on patients' lives, utilities for the state were obtained from five groups of individuals. These comprised two groups of patients who received treatment for rectal cancer, a group of physicians and surgeons specializing in the treatment of this disease, and two groups of healthy subjects, none of whom were health professionals. Of the patients who had been treated for rectal cancer, one group had been treated surgically with the formation of colostomies and the other had been treated with radiotherapy and none had a colostomy. Utilities for colostomy were elicited using the standard gamble, category rating, and a treatment choice questionnaire. The groups differed substantially in the utilities assigned to colostomy. In general, patients with colostomies and physicians assigned significantly higher utilities than did patients who did not themselves have a colostomy. The clinical significance of these differences was examined in a simplified clinical decision problem that compared surgery (with colostomy) and radiotherapy (without colostomy) as primary treatment. The expected clinical value of these treatment alternatives was substantially influenced by the differences observed in utilities for colostomy. These results emphasize the importance of patient utilities in clinical decision making and the need to gain greater understanding of the factors that influence the utilities that patients assign to health states.

Attitude of Health Personnel↗

PubMedDate not supplied

Benign and malignant breast disease: the relationship between women's health status and health values.

The study purpose was to determine whether differences in the weights assigned to various dimensions of health by 90 women in three subgroups (benign breast disease, breast cancer receiving chemotherapy, and breast cancer receiving other therapies) were associated with differences in self-reported health status in these dimensions. Two methods, one direct and the other indirect, were used to elicit values for mobility, depression, and social support. Two different scales also provided self-reports of health status in each of these dimensions. These measures, in conjunction with sociodemographic variables, were used to test for status-value relationships. No statistically significant association between health values and health status was observed. The absence of any detectable association may have been a result of methodologic difficulties in assessing broadly defined dimensions of health. A possible solution would be to use "individualized" dimensions that are uniquely important to the individual, and to take into account such factors as possible influences of past health status and values, and possible gaps between expected health status and health status actually experienced.

Activities of Daily Living↗