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Biomedical subjects

C B Begg

Publications and source records attributed to C B Begg.

At least 91 records · Page 5Linked to original sources
PubMed1983

Clinical trials and drug toxicity in the elderly. The experience of the Eastern Cooperative Oncology Group.

Nineteen studies of advanced cancer in 8 disease sites have been examined using data from the Eastern Cooperative Oncology Group. The purpose of the investigation was to determine susceptibility of elderly patients (greater than or equal to 70 years of age) to cancer chemotherapy and to compare the results with corresponding figures in control patients (less than 70 years of age). The results indicate that in general, the elderly patients have identical rates of severe toxicity as their younger counterparts. The only exception is for hematologic reactions in a few of the sites studied. On closer examination, the agents that appear to be responsible for these especially adverse effects are methotrexate and methyl-CCNU. It is demonstrated that the elderly patients have similar response rates and survival expectancy to the nonelderly patients. Consequently, it is concluded that the apparent discrimination in not treating elderly patients as aggressively as younger patients, and in excluding elderly patients from protocols, does not appear to be justified. Exclusions should be based on physiologic functional parameters, such as measures of renal, liver and marrow function, or performance status, rather than on an arbitrary age limit. Exceptions should only be made for agents which have a clearly demonstrated adverse effect on the elderly.

Age Factors↗
PubMed1983

Cooperative groups and community hospitals. Measurement of impact in the community hospitals.

The Eastern Cooperative Oncology Group, composed of major cancer treatment centers, has an outreach program which involves community hospitals in ongoing cancer clinical trials. A prevalence survey was carried out in February 1981 among 104 community hospitals and 21 member institutions to determine the characteristics of patients being treated, their staffing, and reasons why patients were not on protocol studies. The survey sampled 25 (50) consecutive patients from community hospitals (member institutions). The purpose of the study was to assess the impact of a community cancer control program. The results of the study demonstrated that 16% of patients surveyed in the affiliated community hospitals were being treated on a research protocol. In addition, a further 35% had their treatment plan influenced by a protocol. Consequently protocols have impacted directly or indirectly on 51% of the patients. The corresponding figures in member institutions were 23% and 38% for a total of 61%. In studying protocol availability, it was found that 66% of all patients were ineligible for any protocol. Of patients eligible for a protocol but not registered on one, 52% were not registered because of physician preference for a specific treatment. The affiliates surveyed were shown to be on average half as large as member institutions in terms of number of beds and staff size. Also, staff/patient ratios are generally smaller in the community hospitals. The median age of patients was considerably lower than SEER incidence data. Also, elderly patients were slightly more prevalent in community hospitals than in member institutions. A clear relationship between disease stage and age in breast cancer patients was noted with the representation of early-stage disease much higher in young women.

Adult↗
PubMed1983

The effects of group size on test ordering for hypertensive patients.

There has been a tremendous increase in the number of patients receiving care from physicians in group practice rather than in solo practice. To determine whether group size influences the number of tests ordered for ambulatory patients, we studied the records of 351 hypertensive patients cared for by 30 internists in group or solo private practice. Patients of physicians who were members of large groups received twice as many tests (6.4 per patient per year) as patients of physicians in small groups (3.5) or in solo practice (3.3) (P less than 0.001). The charges for testing were also nearly double for patients of physicians in large groups ($123 vs. $58 and $71, P less than 0.01). A multiple regression analysis of individual tests showed that large group practices were associated with increased use of electrocardiography (P less than 0.001), blood counts (P less than 0.01), urinalysis (P less than 0.05), and chest radiography (P less than 0.05). These effects were independent of the patient's age and sex, the year the physician graduated from medical school, and the availability of testing machinery at the practice site. These findings suggest that membership in a large group practice is associated with increased test ordering for hypertensive patients. This may be due to self-selection of particular types of physicians or patients, or to a property of the organizational structure itself.

Adult↗
PubMed1983

A comparative clinical trial of adriamycin and 5-fluorouracil in advanced prostatic cancer: prognostic factors and response.

In patients with metastatic hormone-relapsed adenocarcinoma of the prostate, adriamycin was compared to 5-fluorouracil in a randomized trial in 99 patients and adriamycin alone was studied in an open trial in 48 patients. Response to adriamycin was superior as judged by response of measurable disease (25 vs 8%; P less than 0.05) and survival (median 29 vs 24 weeks; Cox analysis, P less than 0.03), but comparable as judged by acid phosphatase response. Ambulatory status and site of metastases influenced rate of response to chemotherapy. Activity level, site of metastases, weight loss, and the symptom of protein aversion were prognostic factors for survival. Hematologic and gastrointestinal toxicity were frequent but were tolerated satisfactorily. Adriamycin therapy may be beneficial in patients with prostatic cancer after hormone therapy.

Acid Phosphatase↗
PubMed1983

Methodology for the differential diagnosis of a complex data set. A case study using data from routine CT scan examinations.

Data from routine CT scan examinations are employed to illustrate the use of the polychotomous logistic regression model as a statistical diagnostic tool. The assumptions of the model, the interpretation of its parameters, and its capabilities are described in detail. In carrying out the analysis on the CT data, a large, relatively sparse data set, many technical difficulties were encountered. Modifications to the methodology that were necessary to permit its implementation are described, and it is demonstrated that an unbiased analysis of T + 1 diagnostic categories can be implemented by separately performing T individual simple logistic analyses. The limitations of the methodology are discussed. It is hoped that this paper may serve as a basis for the practical implementation of the polychotomous logistic model in similar diagnostic settings.

Adult↗
PubMed1983

Assessment of diagnostic tests when disease verification is subject to selection bias.

In the assessment of the statistical properties of a diagnostic test, for example the sensitivity and specificity of the test, it is common to derive estimates from a sample limited to those cases for whom subsequent definitive disease verification is obtained. Omission of nonverified cases can seriously bias the estimates. In order to adjust the estimates it is necessary to make assumptions about the mechanism for selecting cases for verification. Methods for making the necessary adjustments can then be derived.

Biometry↗
PubMed1982

Participation of community hospitals in clinical trials: analysis of five years of experience in the Eastern Cooperative Oncology Group.

The Eastern Cooperative Oncology Group (ECOG) initiated a program in 1976 to involve community hospitals in multi-institutional clinical trials. The community hospitals can be characterized as generally having no tradition of participating in clinical trials of cancer therapy, whereas the ECOG member institutions are university hospitals or major treatment centers. More than 100 community hospitals participated in 97 randomized trials involving 4506 patients from November 1976 through February 1981. Comparisons between the community hospitals and the ECOG member institutions indicate that the quality of participation was similar, as measured by rates of ineligibility, compliance with the protocol, and submission of data. Objective measures of outcome, such as survival, response, and toxicity, were also comparable. We conclude that under the mechanism adopted by the ECOG, it is possible to include community hospitals in clinical trials of cancer therapy without reducing the quality of the data or compromising the therapeutic outcomes.

Clinical Trials as Topic↗
PubMed1982

A study of the use of the probability-of-being-in-response function as a summary of tumor response data.

The probability-of-being-in-response function (PBRF), proposed by Temkin (1978, Biometrics 34, 571-588) as a vehicle for analyzing transient response data, is examined using the simplified parametric model in which each of the failure processes is assumed to be exponential. Properties of the PBRF under these assumptions are discussed. It is demonstrated that the PBRF is a very complete summary of the data and has attractive properties for its intended use as a visual display. The model is extended to incorporate covariates, and it is demonstrated that the desired properties can be generalized under specific conditions for the covariates.

Antineoplastic Agents↗
PubMed1982

Surface marker identification of small cleaved follicular center cell lymphomas with a highly favorable prognosis.

Between 1976 and 1980, 143 cases of non-Hodgkin's lymphoma have been prospectively analyzed for correlations between surface marker phenotype, histomorphology, and prognosis. This study analyzed 44 adults with tumors classified by Lukes-Collins criteria as small cleaved follicular center cell lymphomas. Two surface marker phenotypic subsets were membrane immunoglobulin, immunoglobulin D (IgD), or a receptor for the third component of the complement system (C'3) (Group I = IgD+ and/or C'3+, group II = IgD-C'3-). Eleven of the 44 patients have died with a projected median survival of 58 months. Four patients in Group I have died with a median survival of 58 months while seven patients in Group II have died with a median survival of 30 months. The difference in the survival curves for the two subgroups is statistically significant (p = 0.01). An analysis of variables such as stage, age, sex, and sites of involvement revealed no differences between the two groups. When classified histologically, the two groups were morphologically indistinguishable and had similar distributions of nodular (follicular) and diffuse variants. Of interest, five patients in Group I were judged to require no initial therapy whereas none in Group II remained untreated initially. The expression of the second heavy chain delta and/or a receptor for C'3 appears to define a subgroup of small cleaved follicular center cell lymphomas with an indolent course and an excellent prognosis.

Adult↗
PubMed1981

Eastern Cooperative Oncology Group study of the cytochemistry of adult acute myeloid leukemia by correlation of subtypes with response and survival.

A study of over 300 adult patients with acute myeloid leukemia has been completed by member institutions of the Eastern Cooperative Oncology Group. A complete remission rate of 51% was achieved. The FAB classification was used with an overall concordance of 61% between investigators and the repository center. Acute monocytic leukemia (M5) and acute erythroleukemia (M6) accounted for 12% of the cases accessioned and had the worst median survival with no patients surviving 2 years. The longest response duration occurred in hypergranular promyelocytic leukemia (M3).

Adult↗
PubMed1980

Randomized clinical trial comparing two dose regimens of ICRF-159 in refractory malignant lymphomas.

A clinical trial of ICRF-159 was done in patients with Hodgkin's disease and non-Hodgkin's lymphomas whose tumors had become resistant to conventional chemotherapy. Antitumor effect and toxicity were compared in patients who were randomly assigned to receive either a loading course or a weekly regimen. Among 82 evaluable cases, five of 39 (13%) treated with the loading course schedule and six of 43 (14%) treated with the weekly schedule experienced objective tumor regressions. Response duration tended to be brief (median, 7 weeks). Life-threatening myelosuppression was more frequent in patients receiving the loading course regimen. Survival was somewhat longer among patients receiving the weekly schedule (median survival, 24 versus 12 weeks; P = 0.04). ICRF-159 demonstrated definite but limited therapeutic activity in this population of patients with advanced malignant lymphomas. The weekly schedule was associated with fewer episodes of life-threatening toxicity and longer patient survival.

Adult↗
PubMed1980

A treatment allocation procedure for sequential clinical trials.

A dynamic treatment allocation procedure is proposed for clinical trials which require balancing across several prognostic factors. The treatment allocation decision is based on the minimization of a function which is an easily evaluated approximation to the variance of the treatment effect in a linear model relating the outcome variable to the chosen prognostic factors and selected interactions. By use of simulations, the procedure is shown to be superior to ad hoc procedures proposed by Pocock and Simon (1975, Biometrics 31, 103-115), over a variety of reasonable experimental situations. It is shown that it is feasible to evaluate the procedure by hand calculations and that it is extremely easy if a small programmable calculator is available. Practical problems relating to implementation of the procedure are discussed with special reference to multi-institutional clinical trials.

Clinical Trials as Topic↗
PubMed1980

Are the elderly predisposed to toxicity from cancer chemotherapy? An investigation using data from the Eastern Cooperative Oncology Group.

Cancer management of the elderly is a topic which has received relatively little attention. This is surprising in view of the fact that approximately 50% of all cancers occur in patients over 65 years of age. In this paper, six terminated studies of the Eastern Cooperative Oncology Group involving approximately 3000 cancer patients have been examined to characterize the nature and extent of the susceptibility to toxicity of elderly patients undergoing chemotherapy for cancer. The six studies were restricted to three primary sites: lung, breast, and colorectum. The results indicate that elderly cancer patients in the study did not experience any increase in the frequency or severity of the toxicity of chemotherapy. The data do not indicate any systematic bias in patient selection with respect to important clinical variables such as performance status, prior treatment, and presence of liver metastases. Compliance with dosage regimen as prescribed by the protocol was similar for each age group during the course of studies. Comparability was further indicated by the fact that the response rates among the elderly were equivalent to the rest of the patient population. The results have important implications for cancer management of the elderly.

Adult↗
PubMed1979

VM-26, a new anticancer drug with effectiveness in malignant lymphoma: an Eastern Cooperative Oncology Group Study (EST 1474).

Thirty-six patients with stage III and IV Hodgkin's disease and non-Hodgkin's lymphoma, who had become refractory to conventional chemotherapy, were treated with VM-26. Complete remissions were documented in two patients with diffuse histiocytic lymphoma. Six patients (four with non-Hodgkin's lymphomas and two with Hodgkin's disease) had partial remissions. The overall response rate was 22% (eight of 36 patients). Hematologic toxicity was the most frequent dose-limiting toxicity. Nonhematologic toxic effects were mild and acceptable. This study demonstrates that VM-26 can produce tumor responses in refractory lymphomas. The Eastern Cooperative Oncology Group is currently planning two new phase II studies to incorporate VM-26 with other active new agents, one involving hexamethylmelamine and the other involving cis-dichlorodiammineplatinum(II).

Adult↗