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S J Pocock

Publications and source records attributed to S J Pocock.

14 recordsLinked to original sources
PubMed1979

Long-term survival of patients with breast cancer: a study of the curability of the disease.

A retrospective analysis was made of 3878 cases of breast carcinoma first seen in Edinburgh from 1954 to 1964. During this time there was a policy to treat breast cancer by simple mastectomy and x-ray therapy, and over 90% of cases classified as international stages I and II were so treated. The mortality in these women was compared with that in an equivalent normal population using Scottish national age-specific death rates. For every year of follow-up within 20 years of initial treatment there was an excess mortality from all causes. There was an overall excess mortality of 58% among patients with breast cancer 15-20 years after initial treatment, and 20 times more deaths occurred in this period from breast cancer than in a normal population. For patients disease-free after 15 years there was still a 28% excess mortality from all causes. Factors known to be of major prognostic significance for five-year survivorship had less influence than might have been expected when the ratio of observed to expected deaths was considered for longer periods of follow-up. The effect of clinical staging (I, II, or III), though initially marked, largely disappeared by the 10th year of follow-up, and after allowing for age there was no evidence beyond 10 years of an effect on survival of the original stage of the disease. Similarly, the effect of tumour size on survival disappeared after 10 years. Women who were premenopausal at presentation still had a significant excess of deaths in the fourth quinquennium of follow-up. In the menopausal and postmenopausal groups combined there was still a small non-significant excess of deaths from all causes after 15 years but this almost disappeared when patients who had already relapsed were excluded. In terms of overall mortality only patients who have undergone the menopause before presentation and who are disease-free 15 years after primary treatment may prove to be cured by conventional techniques such as simple mastectomy and postoperative radiotherapy.

Adult↗
PubMed1979

The contribution of drinking water lead to maternal blood lead concentrations.

The association between domestic water lead concentrations and blood lead concentrations has been examined in 232 mothers at delivery. The blood lead was found to vary significantly with the cube root of the water lead. This association was stronger for first flush water lead rather than for running water lead. This study emphasises the danger to mothers and to their children of environmental lead over-exposure in areas of soft acid plumbosolvent water.

Adolescent↗
PubMed1979

Allocation of patients to treatment in clinical trials.

This article is intended as a practical guide to the various methods of patient assignment in clinical trials. Topics discussed include a critical appraisal of non-randomized studies, methods of restricted randomization such as random permuted blocks and the biased coin technique, the extent to which stratification is necessary and the methods available, the possible benefits of randomization with a greater proportion of patients on a new treatment, factorial designs, crossover designs, randomized consent designs and adaptive assignment procedures. With all this diversity of approach it needs to be remembered that the effective implementation and reliability of a relatively straightforward randomization scheme may be more important than attempting theoretical optimality with more complex designs.

Clinical Trials as Topic↗
PubMed1978

Size of cancer clinical trials and stopping rules.

A recent international survey on the size of clinical trials in cancer showed the frequent problem of slow patient accrual, which remains a major hindrance to progress. The survey also revealed that, although the design of most trials specified a fixed number of patients, subsequent experience revealed a much more flexible approach, with analysis of results, say, every 4--6 months. Conventional sequential methods are hardly ever used and unfortunately most trials proceed without any predetermined stopping rules. Some trial organizers use repeated significance tests on accumulating data as a guide to the detection of treatment differences, an approach that can be adapted to a more rigorous statistical framework as a "group sequential design". The major statistical principle involved is that the more often one analyses the data the greater is the probability of achieving a statistically significant result, even when the two treatments are equally effective. Group sequential designs require the adoption of a more stringent significance level to allow for repeated testing. If one intends up to 10 repeated analyses of the data, only a treatment difference significant at the 1% level would merit a decision to stop the trial. For any trial to implement a stopping rule successfully there must also be prompt feedback and processing of response and survival data ready for up-to-date analysis. Such efficiency is often lacking. The repeated presentation of interim results of a trial to participating investigators can seriously affect their future reaction, especially if there are interesting but non-significant differences. Thus, some secrecy about ongoing results is advisable if trials are to achieve an unbiased conclusion.

Clinical Trials as Topic↗
PubMed1977

Prognosis of patients with acute myocardial infarction admitted to a coronary care unit. I: Survival in hospital.

On a basis of history, clinical examination, and the electrocardiogram it was possible to identify groups of patients with acute myocardial infarction with good and bad prognoses as regards hospital survival. Individual adverse factors were age, prevous history of ischaemic heart disease, anterior infarction, persistent sinus tachycardia, pulmonary crepitations, hypotension, and raised venous pressure. Multivariate analysis showed four factors remaining significant--age, tachycardia, hypotension, and pulmonary crepitations. As a result of treatment of cardiac arrest, hospital mortality, which would otherwise have been 20 percent, was 17 percent. Preceding unstable angina did not worsen the immediate prognosis.

Adult↗
PubMed1977

Prognosis of patients with acute myocardial infarction admitted to a coronary care unit. II. Survival after hospital discharge.

The factors adversely affecting long-term prognosis differed from those affecting outcome of acute infarction. Individual factors were previous history of infarction or hypertension, tachycardia, cardiac arrest, ventricular arrhythmia, atrial fibrillation, 3rd heart sound, raised venous pressure, and pulmonary crepitations. Multivariate analysis reduced these to 6--previous infarct or hypertension, sinus tachycardia, cardiac arrest, ventricular arrhythmia, and artial fibrillation. Of those who survived 5 years, approximately half had angina. Two-thirds of the under 60 survivors were at their normal work.

Coronary Care Units↗
PubMed1977

Chemotherapy of non-Hodgkin's lymphomas: Eastern Cooperative Oncology Group experience.

The addition of prednisone to the two-drug combination of cyclophosphamide and vincristine increases the number of complete remissions (CR). Patients who had CRs in at least two of the studies, EST 0168 and EST 3472, lived significantly longer than those who had partial remissions. In EST 0168, the survival time correlated strongly with the nodal pattern and cell type, confirming results of Rosenberg and co-workers. EST 1472 confirmed the activity of BCNU in lymphocytic lymphomas; when both agents are combined with prednisone, the induction potential of BCNU is equal to that of cyclophosphamide. In the histiocytic lymphomas, BCNU added to CVP increases the percentage of CRs but it does so at the expense of considerable toxicity. EST 0871 demonstrated that low-dose bleomycin and hexamethylmelamine are active agents in lymphoma and should be combined with other effective combinations in an attempt to improve the CR rate. Finally, our current studies demonstrate that the failure rate in the diffuse or unfavorable lymphomas is higher than that in the more favorable nodular forms.

Altretamine↗
PubMed1975

Clinical studies of 5-fluorouracil + premarin in the treatment of breast cancer.

Sixty patients with metastatic or primary inoperable breast cancer not suitable for hormone alteration therapy were blindly randomized between weekly 5-fluorouracil, intravenously, and daily physiologic doses of conjugated estrogens by mouth against weekly 5-fluorouracil, intravenously, and placebo. There was no difference in the survival or the effect on the tumor in the two groups. Numerous factors were analyzed as to their effect on the course of the disease. The number of organ sites of tumor involvement, age of the host, and previous treatment for the disseminated disease were not shown to influence the survival or the results of therapy of either group. However, the duration of the clinical cancer-free period from primary treatment to recurrence, the sites of organ involvement, and the performance status of the patients at the time of entry into the study significantly did influence the survival. There is no evidence in this study that physiologic doses of conjugated estrogens deleteriously influenced the course of the disease.

Adult↗