Analysis of combined data from heterogeneous study designs: an applied example from the patient navigation research program.

Background: The Patient Navigation Research Program (PNRP) is a cooperative effort of nine research projects, with similar clinical criteria but with different study designs. To evaluate projects such as PNRP, it is desirable to perform a pooled analysis to increase power relative to the individual projects. There is no agreed-upon prospective methodology, however, for analyzing combined data arising from different study designs.

Celecoxib for the prevention of sporadic colorectal adenomas.

Background: Studies showing that drugs that inhibit cyclooxygenase-2 (COX-2) reduce the number of colorectal adenomas in animals and patients with familial adenomatous polyposis suggest that COX-2 inhibitors may also prevent sporadic colorectal neoplasia.

Methods: We randomly assigned patients who had adenomas removed before study entry to receive placebo (679 patients) or 200 mg (685 patients) or 400 mg (671 patients) of celecoxib twice daily. Randomization was stratified for the use of low-dose aspirin.

The fallacy of enrolling only high-risk subjects in cancer prevention trials: is there a "free lunch"?

Background: There is a common belief that most cancer prevention trials should be restricted to high-risk subjects in order to increase statistical power. This strategy is appropriate if the ultimate target population is subjects at the same high-risk. However if the target population is the general population, three assumptions may underlie the decision to enroll high-risk subject instead of average-risk subjects from the general population: higher statistical power for the same sample size, lower costs for the same power and type I error, and a correct ratio of benefits to harms.

Non-steroidal anti-inflammatory drug use is associated with reduction in recurrence of advanced and non-advanced colorectal adenomas (United States).

Objective: To prospectively examine the association between non-steroidal anti-inflammatory drugs (NSAIDs) use (including dose and dosage schedule) and the recurrence of colorectal adenomas among individuals who were diagnosed with an adenoma at entry into a clinical trial.

Methods: For this analysis, participants who completed the full follow-up (n = 1905) for the Polyp Prevention Trial (PPT) were evaluated. Information on current use and dose of NSAIDs and other drugs was obtained at baseline and at each subsequent study visit over the duration of the trial.

Lack of effect of a low-fat, high-fruit, -vegetable, and -fiber diet on serum prostate-specific antigen of men without prostate cancer: results from a randomized trial.

Purpose: To determine whether a diet low in fat and high in fruits, vegetables, and fiber may be protective against prostate cancer by having an impact on serial levels of serum prostate-specific antigen (PSA).

Methods: Six hundred eighty-nine men were randomized to the intervention arm and 661 to the control arm. The intervention group received intensive counseling to consume a diet low in fat and high in fiber, fruits, and vegetables.