Consider a randomized clinical trial to evaluate the benefit of screening an asymptomatic population. Suppose that subjects are randomized into a usual care and a study group. The study group receives one or more periodic early detection examinations aimed at diagnosing disease early, when there are no signs or symptoms. Early detection clinical trials differ from therapeutic trials in that power is affected by: (i) the number of exams, (ii) the time between exams and (iii) the optimal time of analysis and length of follow-up. These design options do not exist in therapeutic trials. Furthermore long-term follow-up may result in a reduction of power. In general power increases with number of examinations, and the optimal follow-up time is dependent on the spacing between examinations. Clinical trials in which the usual care group receives benefit are also briefly discussed. Two designs are presented, i.e. The “Up-front Design” in which all subjects receive an initial exam and then are randomized to the usual care and study groups and the “Close-out Design” in which the usual care group receives an exam which is timed to be given at the same time as the last exam in the study group. Both families of designs significantly reduce the power. The optimization criterion is to maximize the power of the statistical test for comparing mortalities. Application is made to National Lung Screening Trials (NLST).

Citation Format: Ping Hu, Philip Prorok. Planning, design, and execution of cancer screening and early detection trials: Application to the National Lung Screening Trial (NLST). [abstract]. In: Proceedings of the Eleventh Annual AACR International Conference on Frontiers in Cancer Prevention Research; 2012 Oct 16-19; Anaheim, CA. Philadelphia (PA): AACR; Cancer Prev Res 2012;5(11 Suppl):Abstract nr ED01-03.

©2012 American Association for Cancer Research.
2012