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2006 by the Societe Internationale de Chirurgie World J Surg (2006) 30: 11841189Published Online: 16 June 2006 DOI: 10.1007/s00268-006-0073-xClinical Trial Results Applied to Management of
the Individual Cancer PatientIsmail Jatoi, MD, PhD,1 Michael A. Proschan, PhD21Department of Surgery, National Naval Medical Center and the Uniformed Services University, 4301 Jones Bridge Road,Bethesda, Maryland 208142Biostatistics Branch, National Institute of Allergy and Infectious Diseases, Bethesda, Maryland 20814, USAAbstractThe application of clinical trial results to the management of the individual cancer patient is notalways straightforward. The results of a clinical trial indicate the average effect of an intervention, often expressed in terms of an absolute risk reduction, which is an estimate of the likelihoodof benefit for a particular patient. However, within any clinical trial, there might be differencesbetween groups of patients in underlying pathology, genetics, or biology, and some patients mightbenefit more from a new treatment than others. Thus, within a clinical trial, it might also be usefulto group together patients with similar characteristics, and test for subgroup interaction. The testfor interaction will indicate whether the magnitude of benefit differs from one prognostic subgroupto the next (a quantitative interaction). Much less common are qualitative interactions, in which anew treatment is beneficial in one subgroup but harmful in another. If the test for subgroupinteraction is significant, then the effects of treatment may indeed differ between subgroups ofpatients, but this should be confirmed in other trials before a treatment is implemented in clinicalpractice.During much of the 20th century, the surgical management of cancer was based on retrospectivestudies and anecdotal experiences. In recent years, surgical oncology has evolved into an evidence-based discipline, and management is increasingly predicated onresults from randomized clinical trials. Of equal importance, randomized trials have provided valuable insightsinto the natural history of cancer, forcing the medicalcommunity to discard many old dogmas.1 Yet, thetranslation of clinical trial results to the management of
the individual cancer patient is not always straightforward.For instance, it may seem that the participants in a trialare not representative of the general population, and thata particular patient may not respond to an intervention inthe same manner as the majority of the trial participants.Alternatively, a clinical trial may contain a large mix ofindividuals, and one might argue that the results of aparticular trial should be refined from an...