RANDOMIZED CLINICAL-TRIALS IN ONCOLOGY - PRINCIPLES AND OBSTACLES

Cancer clinical trials have two broad objectives: To identify promisin g treatments and to determine whether such treatments really do reduce morbidity and mortality. These two objectives generally require diffe rent types of clinical trials. The guiding principle of clinical trial s is to ask an important question and get a reliable answer. Asking an important question generally means asking a question that has the pot ential for influencing medical practice, using a control treatment tha t is widely accepted, using an experimental treatment that is widely a pplicable, using an endpoint that is a direct measure of patient benef it, and studying a group of patients who are broadly representative. G etting a reliable answer also has many components, including randomize d treatment assignment, adequate sample size, intent-to-treat analysis , and testing of prestated hypotheses on mature data. These components are discussed. Several recent developments in clinical trials methodo logy: interim monitoring boundaries, large simple trials, and metaanal ysis, are highlighted here. Major obstacles to conducting randomized c linical trials are also described.