Clinical trials are research studies that test new treatments to see how well they work. They are an essential part of our quest to find better ways to prevent, treat, and cure cancer. Almost every cancer treatment patients receive today is the result of a clinical trial.

Clinical trials are designed to answer specific questions about:

• Safety
• Benefits
• Side effects
• Whether some people benefit more than others

There are several kinds of clinical trials for cancer. Some look at new therapies that may be able to help treat or potentially cure the disease. Others study therapies to see whether they produce fewer side effects than what’s currently used to treat the disease. Still others may focus on improving quality of life for people who have already had cancer treatment or are living with cancer.

For studies that involve new drugs, cancer researchers organize a clinical trial only after testing the drugs in the laboratory. The treatments that show the most promise are the ones studied in clinical trials.

These are the most common kinds of clinical trials for cancer.

• Cancer treatment trials test new drugs or new combinations of drugs. They also test new approaches to surgery or radiation therapy.
• Cancer prevention trials test new ways to prevent cancer in people who have never had it, or to stop it from coming back in people who have. These approaches may include medicines, vaccines, vitamins, or lifestyle changes.
• Diagnostic trials study new ways to understand an individual person’s disease.
• Screening trials test the best way to detect cancer.
• Quality-of-life trials (also called supportive care trials) explore ways to improve comfort for people who are living with cancer.

Get more in-depth information about clinical trials.