Clinical trials are research studies that involve people. These studies test new ways to prevent, detect, diagnose or treat diseases.

Yes. Cancer clinical trials differ according to their primary purpose: 

• Treatment. These trials test the effectiveness of new treatments or new ways of using current treatments in people who have cancer. The treatments tested may include new drugs or new combinations of currently used drugs, new surgery or radiation therapy techniques, vaccines, or other treatments that stimulate a person’s immune system to fight cancer.
• Prevention. These trials test new treatment or action that may lower the risk of developing certain types of cancer. Most cancer prevention trials involve healthy people who have not had cancer; however, they often only include people who have a higher than average risk of developing a specific type of cancer.
• Screening. These trials test new ways of finding cancer early. Cancer screening trials usually involve people who do not have any signs or symptoms of cancer. However, participation in these trials is often limited to people who have a higher than average risk of developing a certain type of cancer because they have a family history of that type of cancer or they have a history of exposure to cancer-causing substances (e.g., cigarette smoke).
• Diagnostic.These trials study new tests or procedures that may help identify, or diagnose, cancer more accurately. Diagnostic trials usually involve people who have some signs or symptoms of cancer.

For more information, visit https://www.cancer.gov/about-cancer/treatment/clinical-trials/what-are-trials/types

Benefits
Clinical trials give eligible participants the opportunity to:

• Have access to promising new treatment that is generally not available outside of a clinical trial. If the clinical trial provides more effective treatment, trial participants may be the first to benefit.
• Receive regular and careful medical attention from a research team that includes doctors, nurses, and other health professionals.
• Play an active role in their own health care.
• Help others by contributing to medical research.

Risks:  

• The new treatment being studied may not be better than standard therapy, or it may have harmful side effects that doctors do not expect or that are worse than those associated with standard therapy.
• Trial participants may be required to make more visits to the doctor than they would if they were not in a clinical trial and/or may need to travel farther for those visits.
• Health insurance may not cover all patient care costs in a trial.

To help you decide if you want to be in a study, U.S. Food and Drug Administration requires that you be given information about the study before you agree to take part. This is known as informed consent. 

The research team provides an informed consent document that includes details about the study, such as its purpose, duration, required procedures, and key contacts, risks and potential benefits.The participant then decides whether or not to sign the document. Informed consent is not a contract, and the participant may withdraw from the trial at any time.