Cancer therapy and the randomized clinical trial. Good medicine?

True improvements in the treatment of cancer--by the introduction of new drugs or novel drug combinations, new therapeutic modalities, or technologic improvements of old modalities--result in higher response rates and prolonged survival when compared with existing therapies. When a new treatment convincingly meets the test of improving survival rates or, at worst, improving patients' quality of life, it becomes the accepted standard of care if its side effects are acceptable and its cost is not prohibitive. Improved therapeutic results can be demonstrated only by clinical trials with an adequate numbers of patients, appropriate control subjects, and a sufficient duration of follow-up. Therapeutic breakthroughs are revolutionary advances in treatment, usually rapidly and dramatically obvious in comparison with historic controls; demonstration of benefit in these cases does not usually require randomized trials. Much more common, however, are new therapies that represent modest, incremental advances over existing treatment and that usually require randomized comparison trials to demonstrate convincingly statistically significant improvement. A randomized clinical trial should test an important hypothesis. It must be carefully designed to ensure that both groups of patients are comparable in terms of various prognostic variables and to minimize subtle sources of bias. An honest belief that both arms of the trial are a priori equal must be maintained. Meeting these criteria, the randomized clinical trial offers to the individual cancer patient treatment that should be at least equal to the best available nonexperimental therapy. This equates with Good Medicine.