Incidence of advanced symptomatic disease as primary endpoint in screening and prevention trials.

Abstract

Randomized clinical trials (RCTs) using disease-specific mortality as the primary outcome are the gold standard for evaluating the efficacy of screening tests. These trials require thousands of subjects and 8-10 years of follow-up; often the imaging technology has changed by the end of the trial. We propose the incidence of symptomatic disease as an alternative to disease-specific mortality. This endpoint is sensitive to the benefit of screening, correlates with patients' quality of life and societal costs, and can dramatically reduce the sample size and follow-up requirements of RCTs.