A nested case-control study of the effectiveness of screening for prostate cancer: research design.

Although prostate-specific antigen (PSA) and digital rectal examination (DRE) are commonly used to screen for prostate cancer, available data do not confirm that either test improves survival. This report describes the methodological aspects of a nested case-control study addressing the question of whether PSA screening, with or without DRE, is effective in increasing survival. Potential sources of bias are discussed, as well as corresponding strategies used to avoid them. Results are expected in the year 2002.

A stochastic modeling of early HIV-1 population dynamics.

In a recent paper, Tuckwell and Le Corfec [J. Theor. Biol. 195 (1998) 450-463] applied the multi-dimensional diffusion process to model early human immunodeficiency virus type-1 (HIV-1) population dynamics. The purpose of this paper is to assess certain features and consequences of their model in the context of Tan and Wu's stochastic approach [Math. Biosci. 147 (1998) 173-205].

Validation of a staging system for evaluating prognosis in prostate cancer.

BACKGROUND: The purposes of our research were to validate a previously published clinical-anatomic staging system for evaluating prognosis in prostate cancer and to explore the predictive ability of additional factors. METHODS: All patients diagnosed with prostate cancer by physicians affiliated with Yale-New Haven Hospital during 1991 were eligible for the study. Patient and tumor characteristics at baseline were extracted from medical records with up to five-year follow-up for mortality. The original system was validated using Cox proportional hazards analysis and conjunctive consolidation. Prostate specific antigen (PSA) and Gleason score were also explored as factors to be included in an updated staging system. RESULTS: Five-year survival was 76% among 121 patients included in the study. The original staging system, when applied to the current cohort, was validated: Five-year survival ranged from 100% (low-risk) to 27% (high-risk). PSA and Gleason score were associated with survival but did not change results substantially in this population. CONCLUSION: By predicting distinct mortality outcomes in men with prostate cancer, prognostic staging systems can be used to help patients and physicians make informed treatment decisions.

Informed consent for PSA screening: does it happen?

CONTEXT: Screening for prostate cancer with serum prostate-specific antigen (PSA) is controversial. Ideally, patients should be aware of the potential benefits and risks related to testing. PURPOSE: To assess whether patients remembered having PSA screening and to determine whether they recalled having a discussion with their primary care provider about the pros and cons of such testing. METHODS: A questionnaire was sent to patients who had PSA screening ordered by a primary care practitioner during a 2-month period at a university-affiliated Veterans Affairs medical center. Approximately 3 months after the PSA test was done, patients were asked about their baseline health as well as their knowledge of and attitudes toward screening with PSA and treatment for prostate cancer. RESULTS: The overall response rate was 197 out of 421 (46%) patients. Among 173 eligible respondents without prostate cancer, 53 (31%) were unaware that their physician had ordered a PSA test. Among the 120 patients who were aware of receiving the test, only 56 (47%) recalled having a discussion with their primary care provider about the risks and benefits of screening. Support for the test was more common among patients who recalled having PSA screening than those who did not recall having the test (91% vs. 70%, respectively; P = 0.003). CONCLUSIONS: Patients who have PSA screening often are unable to recall relevant facts about the test and may have no knowledge of its associated risks and benefits. The role and effectiveness of obtaining verbal informed consent for PSA screening should be re-evaluated.

Twenty-two-year follow-up in the VA Cooperative Study of Coronary Artery Bypass Surgery for Stable Angina.

We evaluated the 22-year results of initial coronary artery bypass surgery with saphenous vein grafts compared with initial medical therapy on survival, incidence of myocardial infarction, reoperation, and symptomatic status in 686 patients (average age 51) with stable angina in the Veterans Affairs Cooperative Study of Coronary Artery Bypass Surgery. Between 1972 and 1974, 354 patients were assigned to medical treatment and 332 to surgical revascularization. In the surgical cohort, 312 patients underwent operation (operative mortality 5.8%) and 25% subsequently underwent repeat operation (operative mortality 10.3%). In the medical cohort, 160 patients crossed over to surgery (operative mortality 4.4%) and 21% of these patients had reoperation (operative mortality 9.1%). Neither crossover nor reoperation was predictable by angiographic or clinical risk factors measured at baseline. The overall 22-year cumulative survival rates were 25% and 20% in the medical and surgical cohorts (p = 0.24). Corresponding rates in low-risk patients who had 1 or 2 vessels diseased, or 3 vessels diseased with normal left ventricular function were 31% and 24% (p = 0.024). Although significant at 10 years, there was also no long-term survival benefit for high-risk patients assigned to bypass surgery. The probabilities of remaining free of myocardial infarction and of being alive without infarction were significantly higher with initial medical therapy, 57% versus 41% (p = 0.02) and 18% versus 11% (p = 0.0031), respectively. This trial provides strong evidence that initial bypass surgery did not improve survival for low-risk patients, and that it did not reduce the overall risk of myocardial infarction. Although there was an early survival benefit with surgery in high-risk patients (up to a decade), long-term survival rates became comparable in both treatment groups. In total, there were twice as many bypass procedures performed in the group assigned to surgery without any long-term survival or symptomatic benefit.