Statistics in Oncology Series
Time-To-Event Data: An Overview and Analysis ConsiderationsIn oncology, overall survival and progression-free survival are common time-to-event end points used to measure treatment efficacy. Analyses of this type of data rely on a complex statistical framework and the analysis results are only valid when the data meet certain assumptions. This article provides an overview of time-to-event data, the basic mechanics of common analysis methods, and issues often encountered when analyzing such data. Our goal is to provide clinicians and other lung cancer researchers with the knowledge to choose the appropriate time-to-event analysis methods and to interpret the outcomes of such analyses appropriately.
Statistical Models in Clinical StudiesAlthough statistical models serve as the foundation of data analysis in clinical studies, their interpretation requires sufficient understanding of the underlying statistical framework. Statistical modeling is inherently a difficult task because of the general lack of information of the nature of observable data. In this article, we aim to provide some guidance when using regression models to aid clinical researchers to better interpret results from their statistical models and to encourage investigators to collaborate with a statistician to ensure that their studies are designed and analyzed appropriately.
Statistical Considerations for Subgroup AnalysesRandomized clinical trials (RCTs) are conducted to evaluate the effect of an experimental treatment on outcomes of a target patient population. Eligibility criteria for large trials are often broad to ensure that the trial results can be generalized to a larger patient population. Subgroup analyses, either specified a priori or post hoc, are perfo rmed to evaluate the treatment effect specific to a subgroup of treated patients. Regardless of whether a subgroup analysis is specified a priori or post hoc, investigators must consider inflated false-positive rates, chance differences in observed treatment effects, low power for the comparisons of interest, and interpretation of the subgroup results.
Introducing the Journal of Thoracic Oncology Statistical SeriesThe Journal of Thoracic Oncology (JTO) is excited to introduce a series of brief articles on various statistical topics in the journal this year, starting with the current issue. As the mission of the JTO is to be the “primary educational and informational publication on topics relevant to the prevention, detection, diagnosis, and treatment of thoracic malignancies,” we strive to publish manuscripts of the highest scientific rigor in these areas. Rigorous research requires that studies are thoughtfully conceived, designed, and conducted; with data appropriately analyzed and interpreted; and conclusions meaningfully framed in a context that expands current knowledge.
Clinical Versus Statistical Significance in Studies of Thoracic MalignanciesThe scientific synergy between statistics and medical research often leads to controversy when considering statistical versus clinical significance of findings from studies that are neither overwhelmingly practice-changing nor clearly negative. Studies can reach statistical significance but provide evidence that is not clinically meaningful, or results could not be statistically significant but very clinically relevant. To fully appreciate the debate about studies that fall in this gray area, one must understand how to interpret several features of statistical design and the interpretation of results.
Principles of Good Clinical Trial DesignClinical trials are a fundamental component of medical research and serve as the main route to obtain evidence of the safety and efficacy of treatment before its approval. A trial’s ability to provide the intended evidence hinges on appropriate design, background knowledge, trial rationale to sample size, and interim monitoring rules. In this article, we present some general design principles for investigators and their research teams to consider when planning to conduct a trial.