What Are Clinical Trials?

A clinical trial is a research project that looks at how well a new treatment or medical procedure works in people. Other studies that are done on just cells in petri dishes or on animals are called preclinical trials. Clinical trials are started only after preclinical trials suggest that the new treatment or procedure will help people and also will be safe for people.

Preclinical trials can offer researchers a lot of good information. But studying how a treatment or procedure works in humans is different than studying mice or certain cells in a lab. So clinical trials are needed to answer two major questions:

• Does the new treatment or procedure work in people? Is what's being tested better than what's being used now? Does it cause more or fewer side effects? Does it work in a group of people who can't use or don't benefit from current treatments or procedures?
• Is the new treatment or procedure safe for people to use? All treatments for breast cancer and some diagnostic procedures have side effects. In clinical trials, researchers try to figure out if the benefits of a new treatment or procedure outweigh the potential side effects.