Introduction

Clinical trials are research studies in which people help doctors find ways to improve health and cancer care. Each study tries to answer scientific questions and to find better ways to prevent, diagnose, or treat cancer. 

If you or someone you know has cancer, you might want to learn what the best research has to say about its prevention, diagnosis, or treatment. But what constitutes the "best" research? If it's well designed, any clinical trial can produce reliable findings. But reliable findings aren't always definitive.

Research findings that are most likely to set the standard of cancer care usually come from phase III clinical trials that have been randomized and controlled, and that have enrolled enough participants to yield statistically significant results.

This article explains what these terms mean, and why a phase III randomized, controlled clinical trial with a specific number of participants is considered the gold standard in cancer research. With this knowledge, you'll be better able to tell which cancer studies are the most definitive, and therefore the most helpful, in guiding your medical decisions.