POTENTIAL IMPACT OF GENETIC TESTING ON CANCER PREVENTION TRIALS, USING BREAST-CANCER AS AN EXAMPLE

Using breast cancer as an example, we explored the potential impact th at a highly predictive genetic test could have on the design and analy sis of cancer prevention trials. We discuss three situations in this a rticle: 1) trials that are in progress when the genetic test first bec omes available as a research tool but is not available for general use , 2) trials in progress when the genetic test becomes generally availa ble to the public, and 3) trials that begin after the test becomes gen erally available. We have concluded that the availability of a highly predictive genetic test will provide impediments to prevention trials in the form of increased noncompliance and also will provide opportuni ties in the form of new trials that include only persons at very high risk of developing cancer. Such trial designs could, under favorable c ircumstances, substantially reduce the size, duration, and cost of can cer prevention trials. The availability of a highly predictive genetic test will make the discovery of effective interventions even more urg ent, and the randomized trial will still provide the most reliable met hod of evaluating prevention strategies.