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D K Corle

Publications and source records attributed to D K Corle.

12 recordsLinked to original sources
PubMed1992

Aspects of statistical design for the Community Intervention Trial for Smoking Cessation (COMMIT).

We present statistical considerations for the design of the Community Intervention Trial for Smoking Cessation (COMMIT). One outcome measurement, the quit rate in randomly selected cohorts of smokers, is compared with another outcome measurement, the decrease in smoking prevalence, in terms of statistical efficiency and interpretability. The COMMIT study uses both types of outcome measurements. The merits of pair-matching the communities are considered, and sample size calculations take into account heterogeneity among pair-matched communities. In addition to significance tests based on the permutational (randomization) distribution, we also describe approaches for covariate adjustment. The COMMIT design includes 11 pair-matched communities, which should provide good power to detect a 10% or greater difference in quit rates between the intervention and control communities in cohorts of heavy smokers and in cohorts of light or moderate smokers. The power is only moderate to detect intervention effects on the decreases in overall smoking prevalence or in the prevalence of heavy smoking.

Bias↗
PubMed1990

Radical prostatectomy versus expectant primary treatment in stages I and II prostatic cancer. A fifteen-year follow-up.

A fifteen-year follow-up of a prospective, randomized study comparing placebo with radical prostatectomy as the primary treatment of early prostatic cancer is presented. A total of 111 patients with clinical Stage I or II prostatic cancer, normal acid phosphatase levels, and negative findings on skeletal x-ray film were evaluable. Thirty Stage I patients and 20 Stage II patients received placebo only; 31 Stage I and 30 Stage II patients underwent radical prostatectomy. The survival status for 95 patients (86%) was established at the fifteen-year follow-up. No significant differences in crude survival occurred in either stage or in both stages combined. Moreover, the survival curves closely followed reference curves based on expected U.S. mortality for men of comparable ages and races. A statistically significant association between a high Gleason histologic score and poor survival was established. In this study, initial treatment with radical prostatectomy did not yield longer survival than initial placebo treatment alone. However, the findings should be interpreted with caution, since sample size was small and staging procedure was simplified.

Adenocarcinoma↗
PubMed1989

Projecting individualized probabilities of developing breast cancer for white females who are being examined annually.

To assist in medical counseling, we present a method to estimate the chance that a woman with given age and risk factors will develop breast cancer over a specified interval. The risk factors used were age at menarche, age at first live birth, number of previous biopsies, and number of first-degree relatives with breast cancer. A model of relative risks for various combinations of these factors was developed from case-control data from the Breast Cancer Detection Demonstration Project (BCDDP). The model allowed for the fact that relative risks associated with previous breast biopsies were smaller for women aged 50 or more than for younger women. Thus, the proportional hazards models for those under age 50 and for those of age 50 or more. The baseline age-specific hazard rate, which is the rate for a patient without identified risk factors, is computed as the product of the observed age-specific composite hazard rate times the quantity 1 minus the attributable risk. We calculated individualized breast cancer probabilities from information on relative risks and the baseline hazard rate. These calculations take competing risks and the interval of risk into account. Our data were derived from women who participated in the BCDDP and who tended to return for periodic examinations. For this reason, the risk projections given are probably most reliable for counseling women who plan to be examined about once a year.

Adult↗
PubMed1988

A prospective study of the development of breast cancer in 16,692 women with benign breast disease.

The authors studied the relation between benign breast disease and subsequent breast cancer in 16,692 women with biopsy-diagnosed benign breast disease who had participated in the Breast Cancer Detection Demonstration Project throughout the United States. Women were classified into one of five benign breast disease categories: atypical hyperplasia, proliferative disease without atypia, nonproliferative disease, fibroadenoma, and other benign breast disease. A total of 485 incident cases of breast cancer were identified in the women from August 1973 to February 1986 after a median follow-up period of 8.3 years from the diagnosis of benign breast disease. Age-adjusted incidence rates were calculated for benign breast disease types stratified by family history and calcification status. Relative risk (RR) estimates of breast cancer for women in the five benign breast disease categories, compared with the screened women who did not develop recognizable breast disease (normal subjects), were computed using the proportional hazards model. Results indicated that risk was associated with the degree of epithelial atypia. Over all age groups, women with nonproliferative disease, proliferative disease without atypia, and atypical hyperplasia displayed progressively increasing risks of 1.5, 1.9, and 3.0, respectively, compared with normal subjects, with 95% confidence intervals (CI) exceeding unity. Particularly high risk was seen among women under age 46 years with atypical hyperplasia (RR = 5.7, 95% CI 3.0-10.6). Women with fibroadenoma as the only indication of their benign breast disease had a relative risk of 1.7, with a lower 95% confidence limit of 1.0. No increased risk was seen for women with other benign breast disease. Positive family history (RR = 1.8) and calcification (RR = 1.2) significantly increased a woman's risk proportionately over the risk associated with each benign breast disease subtype. The authors conclude that the risk of developing breast cancer varies by category of benign breast disease and is directly related to the degree of epithelial atypia.

Adenofibroma↗
PubMed1988

Hormone therapy for prostate cancer: results of the Veterans Administration Cooperative Urological Research Group studies.

Between 1960 and 1975, the Veterans Administration Cooperative Urological Research Group conducted a consecutive series of 3 major randomized clinical trials comparing various endocrine treatments for newly diagnosed prostate cancer patients. Six major conclusions concerning hormonal treatment emerged from these studies: 1) increased hazard of cardiovascular death after therapy with 5 mg diethylstilbestrol (DES); 2) orchiectomy plus DES no better than orchiectomy or DES alone; 3) equivalent effect of 1.0 and 5.0 mg DES on cancer; 4) reduced cardiovascular hazard from therapy with 1.0 mg DES; 5) Premarin and Provera no better than 1.0 mg DES at doses studied; 6) decisions about hormone treatment at diagnosis dependent on patient characteristics, mainly age and Gleason grade. In this paper, these studies are reviewed briefly and data are presented to support these conclusions. Some tentative treatment recommendations are proposed.

Cardiovascular Diseases↗
PubMed1976

Response of serum cholesterol and triglycerides to hormone treatment and the relation of pretreatment values to mortality in patients with prostatic cancer.

Cholesterol and triglycerides were measured in plasma samples from patient with cancer of the prostate before and after 3 months treatment with either Premarin, Provera, Provera and diethylstilbestrol, or diethylstilbestrol alone. Cholesterol was also measured before and after one of three doses of diethylstilbestrol or placebo. Pretreatment cholesterol levels at 196 +/- 1.3 mg per 100 ml (X +/- SE, N = 1093) were significantly lower than these reported for similar age group noncancer controls. Significant increases occurred with some of the estrogen treatments. Pretreatment cholesterol levels showed a significant negative correlation with age in Stage III and IV patients of both studies and a positive correlation with hemoglobin in Stage III patients of both studies. Pretreatment triglyceride levels at 120 +/- 1.9 mg per 100 ml (X +/- SE, N = 1089) were similar to levels reported for noncancer controls of similar age. Estrogen treatment produced a significant increase in triglyceride levels. Serum triglycerides were significantly correlated with hemoglobin, weight, and cholesterol and negatively correlated with age, Analysis of covariance for both cholesterol and triglycerides showed highly significant treatment effects, but no stage effects and no stage-treatment interactions. It showed that the pretreatment value is of extreme importance for predicting or explaining the 3-month value. Death rates were calculated by level of pretreatment cholesterol or pretreatment triglycerides for all Stage II and IV patients, all treatments combined, and for Study 2 and Study 3 separately. No consistent trends were evident for cholesterol. Spearman correlation coefficients between category of initial triglyceride value and rank of death rate were computed to test for a quadratic effect. When the absolute values of the initial triglyceride values minus the overall mean were correlated with the death rate, a significant negative correlation was found for all causes of death and for deaths due to cardiovascular disease and prostatic cancer. These results indicate that the death rate is highest near the overal mean for initial triglyceride values and decreases as the initial values deviate above or below the mean. Initial triglyceride levels appear to have potential as indicators of risk of death in patients with prostatic cancer. The percentage of patients dead at 1 year by initial triglyceride levels, measured only in Study 3, revealed a pattern similar to that observed for the death rate, that is, the highest percentages were associated with values near the overall mean.

Cholesterol↗
PubMed1976

Response of plasma fibrinogen and plasminogen to hormone treatment and the relation of pretreatment values to mortality in patients with prostatic cancer.

Fibrinogen and plasminogen were measured in plasma samples from prostatic cancer patients before and after 3 months of treatment with either Premarin, Provera, Provera and diethylstilbestrol, one of three doses of diethylstilbestrol, or placebo. Plasminogen levels generally were increased significantly with the estrogens but were unchanged following placebo or Provera treatment. Pretreatment plasminogen levels in Study 3 were significantly lower (p less than .001) than in Study 2. Plasminogen pretreatment levels were significantly correlated with age, hemoglobin, body weight, and blood pressure. Fibrinogen pretreatment levels were significantly elevated above normal. They were not significantly with age, hemoglobin, body weight, or blood pressure. Fibrinogen levels generally were significantly decreased by the estrogens. Comparisons of means of pretreatment fibrinogen and plasminogen levels from patients dying during the first year of the study with the mean pretreatment levels of the patient group alive after 1 year on study yielded no significant differences. Death rates were calculated by pretreatment plasminogen or fibrinogen for all treatments of all Stage III and Stage IV patients combined for Study 2 and Study 3 separately. Such rates were calculated for all causes combined and for deaths from prostatic cancer or cardiovascular disease separately. The levels of plasminogen were significnatly negatively correlated with death rate from all causes combined and with cardiovascular disease considered separately, but not with death from prostatic cancer. The levels of fibrinogen were signigicantly positively correlated with death rates from all cuses and nearly significantly with prostatic cancer, but not cardiovascular disease. Elvated pretreatment fibrinogen levels were associated with an increased proportion of deaths at 1 year from all causes and from cancer of the prostate.

Age Factors↗