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Biomedical subjects

W D Dupont

Publications and source records attributed to W D Dupont.

90 records · Page 5Linked to original sources
PubMed1985

Risk factors for breast cancer in women with proliferative breast disease.

To assess the importance of various risk factors for breast cancer in women with benign proliferative breast lesions, we reevaluated 10,366 consecutive breast biopsies performed in women who had presented at three Nashville hospitals. The median duration of follow-up was 17 years for 3303 women, 1925 of whom had proliferative disease. This sample contained 84.4 per cent of the patients originally selected for follow-up. Women having proliferative disease without atypical hyperplasia had a risk of cancer that was 1.9 times the risk in women with nonproliferative lesions (95 per cent confidence interval, 1.2 to 2.9). The risk in women with atypical hyperplasia (atypia) was 5.3 times that in women with nonproliferative lesions (95 per cent confidence interval, 3.1 to 8.8). A family history of breast cancer had little effect on the risk in women with nonproliferative lesions. However, the risk in women with atypia and a family history of breast cancer was 11 times that in women who had nonproliferative lesions without a family history (95 per cent confidence interval, 5.5 to 24). Calcification elevated the cancer risk in patients with proliferative disease. Although cysts alone did not substantially elevate the risk, women with both cysts and a family history of breast cancer had a risk 2.7 times higher than that for women without either of these risk factors (95 per cent confidence interval, 1.5 to 4.6). This study demonstrates that the majority of women (70 per cent) who undergo breast biopsy for benign disease are not at increased risk of cancer. However, patients with a clinically meaningful elevation in cancer risk can be identified on the basis of atypical hyperplasia and a family history of breast cancer.

Adult↗
PubMed1985

Retrieval of renal function by revascularization. Study of preoperative outcome predictors.

Results of renal revascularization for retrieval of function in poorly functioning kidneys are variable, but criteria for prediction of benefit and patient selection for operation are ill-defined. This report examines preoperative parameters in 64 hypertensive patients who underwent successful revascularization of poorly functioning kidneys as defined by creatinine clearance less than or equal to 15 ml/min (measured by preoperative split renal function studies [SRFS]) or preoperative serum creatinine greater than or equal to 3.5 mg/dl (range: up to 8.9 mg/dl) to identify markers of value in prediction of a beneficial response in renal function. Ages ranged from 35 to 75 years. There were 35 men and 29 women. The renovascular lesion was atherosclerotic in 58 patients and fibrodysplastic in six. Total renal artery occlusion was present in 32 cases. No urine flow was detectable before surgery on SRFS from 13 kidneys. Kidney lengths ranged from 7.7 cm to 15.1 cm. Fifty-four unilateral and 10 bilateral revascularizations were performed. A beneficial blood pressure response to operation was observed in 94%. Benefit in excretory function was determined by comparison of preoperative and postoperative data which included SRFS parameters, renal length, serum creatinine, isotopically derived split functioning renal mass, and glomerular filtration rates. Overall, 56 patients could be classified in regard to functional response. Twenty-two patients received no or minimal benefit; nine patients received modest improvement, and 25 patients exhibited more marked improvement. Statistical evaluation of preoperative anatomic and functional parameters as predictors of functional response suggested that multiple variables influence the probability of function retrieval by revascularization. Useful among these predictive variables are the status of the distal vessel beyond the occlusion, the bilaterality of reconstructable disease in azotemic patients, the amount of residual renal mass available for revascularization, and the degree of hyperconcentration of nonreabsorbable solutes from the involved kidney after surgery.

Adult↗
PubMed1984

Prognostic significance of estrogen receptor status in breast cancer in relation to tumor stage, axillary node metastasis, and histopathologic grading.

The value of estrogen receptor (ER) measurements for predicting recurrence and survival rates in primary breast cancer was examined in 121 women who were followed from 5 to 12 years after mastectomy with a median follow-up of 64 months. The prognostic significance of the ER status was evaluated independently and in association with tumor stage, axillary node metastasis, and histopathologic grade. The independent evaluation demonstrated no statistically significant difference in prognosis between women with ER-negative and ER-positive cancers, although the latter group tended to have a longer time to recurrence and longer survival. Multivariate analysis of the data by Cox's proportional hazard regression techniques revealed a synergistic effect of ER status on the risk associated with axillary node metastasis. Patients with nodal metastasis were at 2.8 times the risk of recurrence compared to patients without metastasis. For women with nodal metastasis whose primary cancer was ER-negative, this risk increased to 4.6 times compared to women without metastasis and ER-positive tumors (P = 0.0003). The risk of cancer-related death was 5.6 times more likely for poorly differentiated tumors than for highly differentiated tumors. Patients with poorly differentiated ER-negative tumors were at an even higher risk (7.0) of dying than women with highly differentiated ER-positive carcinomas (P = 0.009). In conjunction with tumor stage, axillary node metastasis and histopathologic grade ER determination is useful for identifying subpopulations at increased risk of tumor recurrence or mortality.

Adenocarcinoma↗
PubMed1984

Aortic and renal vascular disease. Factors affecting the value of combined procedures.

Assessment of the predictive value of preoperative factors in the determination of operative risk in 50 patients who underwent simultaneous aortic and renovascular procedures over a 10-year period is reported. There were six operative mortalities (12%). Factors associated with increased mortal risk were azotemia (43% vs. 7%), associated complex renal or visceral procedures (31% vs. 5%), treatment of aortic aneurysm vs. occlusive disease (17% vs. 5%), positive EKG (19% vs. 4%), age over 60 years (20% vs. 4%), and a history of diffuse peripheral vascular disease (18% vs. 7%). None of these differences, by themselves, had statistical significance. Through discriminate analysis with assignment of weighted scores to the five most powerful predictors of operative death (complex procedure--4, azotemia--4, aortic aneurysm repair--3, positive electrocardiogram--2, history of diffuse vascular disease--2), a weighted score of greater than or equal to 10 predicted operative death with an 83% sensitivity and 93% specificity (p = 0.003). Although advanced age, diabetes, severity of hypertension, and history of heart disease were associated with increased operative risk, they contributed minimal discriminate value to that provided by the preceding five variables. This was because these weaker risk factors were usually found in association with the predictors in the discriminant score. This study suggests that in patients with high weighted discriminant scores (greater than or equal to 10), consideration of operative risk is particularly important in evaluation of the proposed value of combined procedures.

Adult↗
PubMed1984

Carcinoembryonic antigen expression and patient survival in carcinoma of the breast.

Immunoperoxidase staining was used to examine carcinoembryonic antigen (CEA) expression in 167 breast cancer cases. Patients with histological evidence of regional or localized breast cancer who lived less than 3 years or greater than 10 years were assessed. Overall expression of CEA was 65%. There was no significant correlation in CEA expression and survival in either regional or localized breast cancer cases. There was no association between CEA expression and number of lymph nodes involved, size of tumor, parity, gravidity, blood type, or menopausal status of the patients in either group. When the lymph nodes of cases with regional breast cancer were examined, there was a statistically significant number of short survivors whose primary tumor was negative for CEA, but whose metastatic tumor expressed the marker when compared to long survivors with regional lymph node involvement.

Adult↗
PubMed1983

Sequential stopping rules and sequentially adjusted P values: does one require the other?

During the course of a clinical trial it is normally necessary to conduct periodic reviews of the data in order to determine whether the trial should be terminated. Since these reviews affect the probability of the final outcome, many statisticians recommend that the P values quoted for a clinical trial be sequentially adjusted to account for the possibility of premature termination. In this article it is argued that the sequentially adjusted P value is an inappropriate measure of the strength of evidence justified by a clinical trial. This is because the size of sequentially adjusted P values will vary according to actions that might have been taken if the trial had gone differently than it in fact did. Although such contingencies will effect the frequency of occurrence of certain events in hypothetical sequence of trial replications, it is hard to see why decisions that would have been made in response to outcomes that did not occur should have any bearing on the strength of evidence that can be attributed to the results that were actually observed. The credibility merited by a clinical trial depends not only on the implausibility of the observed results under the null hypothesis, but also on factors such as the medical plausibility of hypothesis well supported by the data, and the extent to which observed results have been predicted in advance. It is argued that publishing these factors along with fixed sample P values is the best way to indicate the degree of certainty that should be attributed to the conclusions of a clinical trial.

Clinical Trials as Topic↗
PubMed1983

A stochastic catch-effort method for estimating animal abundance.

A method for estimating the size of a heavily exploited animal population from catch data and relative-harvest-effort data is presented. The method assumes a competing-risk model of adult deaths and captures that is similar to the hazard-regression model of Cox (1972, Journal of the Royal Statistical Society, Series B 34, 187-220). This model avoids making any assumptions about birth rates or juvenile mortality rates, and allows the user to incorporate an arbitrary number of time-dependent covariates into the natural and catch hazard functions. Estimates of the population's size, together with asymptotic error bounds and predictions of subsequent catches, are derived from maximum likelihood estimates of the parameters of the model. A simulation study is presented which indicates that this method is far more accurate than previously available catch-effort techniques. The method is illustrated with some fisheries data. A series of models is fitted to the data with the objective of improving the goodness of fit while maintaining biologic plausibility of the model. In this example a 68% reduction in the mean sum of squares for error is obtained and the accuracy of future catch predictions is greatly improved. This method is particularly appropriate for estimating the sizes of commercially exploited aquatic populations whose sizes are too large to make mark-recapture techniques feasible, and which are not amenable to line-transect techniques.

Animals↗
PubMed1982

A retrospective cohort study of Histologic risk factors in breast cancer patients.

A retrospective cohort study was performed with a ten-year follow-up of 70 consecutive patients who were diagnosed as having invasive, operable ductal breast cancer of no special histologic type and without lymph node metastases. All tumors were evaluated by using established histopathologic criteria that reflected either the growth potential of the tumor or the host defense reaction in form of a cellular immunologic response. The evaluation was undertaken to study the interrelationship of the various histopathologic factors and to assess the risk of subsequent breast cancer mortality associated with histopathologic factors and to assess the risk of subsequent breast cancer mortality associated with different constellations of these factors. Multivariate analysis of the data by Cox's proportional hazard regression techniques confirmed the importance of the histologic risk factors reflecting the tumor growth potential and demonstrated that lack of tubule formation was the most important single risk factor. Patients with absent tubule formation were at 6.7 times the risk of cancer mortality than women with tubule formation (P = 0.002). Patients with frequent mitotic figures were at 4.2 times the risk of patients with infrequent mitoses (P = 0.014). Interactions between these two risk factors and nuclear grade were striking. Women who either lacked tubule formations or had tumors with anaplastic nuclei were at 20 times the risk of women with neither of these variables (P = 0.004). The pathologic parameters reflecting the immunologic host defense response were of much less importance. The multivariate classification of all examined histopathologic parameters was helpful in predicting the prognosis of the individual breast cancer patient.

Breast Neoplasms↗
PubMed1982

Intraductal carcinoma of the breast: follow-up after biopsy only.

Twenty-eight women with ductal carcinoma in situ (DCIS) of the breast treated by biopsy only were identified in a histologic review of 11,760 biopsies performed between 1950 and 1968. Seven of the 25 women followed for more than three years developed invasive breast carcinoma, all in the same breast with a previously detected DCIS. Average follow-up interval for the 18 women not developing invasive carcinoma was 16 years. The invasive carcinomas presented clinically from three to ten years (average, 6.1) after the biopsies demonstrating DCIS. Four women with invasive carcinoma developed distant metastases following mastectomy. This study suggests that 28% of women treated with biopsy only for DCIS presenting as an incidental histologic finding will develop invasive carcinoma in a follow-up period of approximately 15 years.

Adult↗
PubMed1980

Chronic pulmonary histoplasmosis following the excavation of a bird roost.

The clinical and epidemiologic characteristics of chronic pulmonary histoplasmosis, as compared with the more familiar acute pulmonary histoplasmosis, are relatively unknown. Opinions vary as to the pathogenesis, and only the severe forms of the disease are readily recognized. Over a 22 month period following the excavation of blackbird roost, an unusual outbreak of chronic pulmonary histoplasmosis occurred in a town in southern Kentucky. Thirteen of the cases developed over a span of only four months. An associated outbreak of acute pulmonary histoplasmosis did not occur. During the course of the ensuing investigation, the residential addresses of the affected persons were noted to be clustered about the previously excavated blackbird roost. A case-control study was initiated; the median distance of the residential addresses of the affected persons was found to be 1.0 miles from the roost, compared with 3.2 miles for the control subjects (P less than 0.001). It was concluded that (1) the excavated blackbird roost had served as the common source of the epidemic; (2) the inhalation of exogenous spores accounted for the infections; (3) the spectrum of clinical illness ranged from asymptomatic and mild illness to cavitary disease with considerable morbidity; and (4) following excavation, blackbird roosts may remain an infection hazard for an indefinite period of time.

Animals↗
PubMedDate not supplied

Sensitivity of Fisher's exact test to minor perturbations in 2 x 2 contingency tables.

The two tailed Fisher's exact P value is extremely sensitive to small perturbations in 2 x 2 contingency tables. An example indicates that a 1 per cent increase in the denominator of one treatment group results in a 32 per cent drop in the exact P value, but a mere 0.1 per cent decrease in the treatment success rate. This is equivalent to the increase in significance obtained by a 20 per cent increase in the sample size of both treatments without changing the observed success rates. This drop results from small changes in the probabilities of unobserved events. A systematic evaluation of 920 pairs of similar contingency tables shows that these fluctuations occur frequently over a wide range of sample sizes and significance levels. Doubling the one tailed exact P value provides a more consistent measure of inferential strength. We discuss various chi-squared continuity corrections.

Biometry↗
PubMedDate not supplied

A survey of 251 patients with acute syphilis treated in the collaborative penicillin study of 1943-1950.

The dramatic and apparently curative effect of penicillin for the treatment of acute syphilis led to follow-up studies for only comparatively brief periods, and the acceptance of the long-term benefit of penicillin has rested on uncontrolled clinical impressions. More certainty about the efficacy of penicillin was sought by a follow-up review of 251 patients treated between March 1944 and December 1950 under the Penicillin Study of the Office of Scientific Research and Development (OSRD) and continued under U. S. Public Health Service after World War II. Eighty-eight patients were interviewed and examined. Telephone conversation or correspondence was had with 43 subjects; an additional nine are known to be living but did not respond to letters. Thirty-two patients died greater than or equal to 20 years after treatment, and 21 patients died within less than 20 years of treatment. Fifty-eight patients could not be found. Treatment failures were documented. Syphilis was not shown to be the cause of disability or death, except for a patient with meningovascular syphilis who died soon after initial treatment. Disabilities recorded and deaths documented revealed only diseases common to any middle-aged population. The outcomes of 17 pregnancies of women treated for acute syphilis were documented. Blood samples obtained from the 88 subjects examined were tested at the Center for Disease Control (Atlanta, Ga.); the results are recorded and discussed. Methods for locating the patients are described, and the psychosocial findings for the 88 patients interviewed are presented. The study has confirmed the clinical impressions of the therapeutic effectiveness of penicillin, which have been accepted for greater than 30 years.

Acute Disease↗