Journal of the National Cancer Institute
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J. Natl. Cancer Inst. · Jul 2011
ReviewRandomized phase II trials: a long-term investment with promising returns.
Given the multitude of novel anticancer drugs and the limited resources available to study them, phase II trials should identify drugs with the highest probability of succeeding in subsequent phase III trials. Currently, single-arm phase II trial results are interpreted relative to historical control subjects, introducing selection bias and confounding that may limit the validity of the conclusions. The rate of success (defined as a statistically significant difference between arms) in phase III oncology trials is only 40%, suggesting that current phase II trials are insufficiently informative. ⋯ There are a wide variety of randomized phase II designs that can be used, including the randomized discontinuation design, the delayed-start design, adaptive (Bayesian) designs, selection designs, and phase II/III designs. The barriers to widespread adoption of randomized phase II trials include time to completion, sample size considerations, and ethical concerns, but none are insurmountable. We conclude that randomized phase II trials are a worthy investment considering finite patient and financial resources and should be the rule rather than the exception for evaluating novel therapies in oncology.
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J. Natl. Cancer Inst. · Jul 2011
Inconsistencies in findings from the early lung cancer action project studies of lung cancer screening.
Long-standing guidelines against screening high-risk individuals for lung cancer may change following the publication of the randomized National Lung Screening Trial (NLST), which shows a benefit of computed tomography compared with chest x-ray screening. Guideline panels will likely also seek additional information from nonrandomized studies of computed tomography screening, such as the Early Lung Cancer Action Project (ELCAP). ⋯ Specifically, some of the reports from ELCAP appear to contradict others in terms of important endpoints, and several findings from ELCAP appear to be statistically improbable or outliers when compared with analyses and studies by other research groups. Clarification of both internal and external inconsistencies is a prerequisite for evaluation of the body of work published by ELCAP investigators.