Prevention trials

Cancer prevention trials are studies involving healthy people. In most prevention trials, participants do not have cancer but have high chances of developing cancer. In other studies, participants already have had cancer and are more likely to develop a new cancer. These studies look at cancer risk and ways to reduce that risk.

There are two kinds of prevention trials: action studies and agent studies.

Action studies (“Doing something”) focus on finding out whether actions people take—such as exercising more or eating more fruits and vegetables—can prevent cancer.

Agent studies (“Taking something”) focus on finding out whether taking certain medicines, vitamins, minerals, or dietary supplements (or a combination of them) may lower the risk of a certain type of cancer. Agent studies are also called chemoprevention studies.

Researchers who conduct these studies want to know:

• How safe it is for a person to take this agent or do this activity?
• Does the new approach prevent cancer?