Treatment trials test new treatments (like a new cancer drug, new approaches to surgery or radiation therapy, new combinations of treatments, or new methods such as gene therapy).

Prevention trials test new approaches, such as medicines, vitamins, minerals, or other supplements that doctors believe may lower the risk of a certain type of cancer. These trials look for the best way to prevent cancer in people who have never had cancer or to prevent cancer from coming back or a new cancer in people who have already had cancer.

Screening trials test the best way to find cancer, especially in its early stages.

Quality of Life trials (also called Supportive Care trials) explore ways to improve comfort and quality of life for cancer patients.