What are clinical trials?

Clinical trials (intervention studies) are research studies that involve people. They are the final step in a long process that begins with research that is done in a lab. Clinical trials to develop new methods to prevent, find, and treat all types of diseases. It is through clinical trials that researchers can find out whether new treatments are safe and work better than current treatments. When you take part in a clinical trial, you add to our knowledge about cancer and help improve cancer care.

Learn more about:

Treatment trials
Supportive care trials
Prevention trials
Screening trials

Treatment trials

Most cancer clinical trials are treatment studies that involve people who have cancer. These studies test new treatments or new ways of using existing treatments, such as medicines, vaccines, ways of doing surgery or methods for doing radiation therapy, or combinations of treatments.

There is another type of treatment trial that involves testing cancer cells for the presence of specific molecular markers. These markers can include changes in certain genes or proteins. These changes may help us to further classify cancers. This can help researchers find better treatments for these specific cancers.

Treatment trials are designed to answers questions such as:

• What new treatment methods can help people who have cancer?
• What is the most effective treatment for people who have cancer?
• Does the new treatment work as well as the old treatment?
• What are the new treatment’s side effects?

Supportive care trials

These trials look for ways to improve the quality of life of cancer patients, especially those who have side effects from cancer and its treatment. They find new ways to help people cope with pain, nutrition problems, infection, nausea and vomiting, sleep problems, depression, and other health issues.

These trials might test drugs, such as those that help with depression or nausea. Or, they might test the effect of certain activities, such as going to support groups, exercising, or talking with a counselor. Other quality of life studies test ways to help families and caregivers cope with their own needs, as well as those of the person with cancer.

Researchers who conduct these studies want to know:

• How does cancer and its treatment affect patients and their loved ones?
• What can improve the comfort and quality of life of people who have cancer?

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?

Screening trials

The goal of cancer screening trials is to test new ways to find disease early. An effective screening test will reduce the number of deaths from the specific type of cancer being screened for.

Researchers who conduct cancer screening studies want to know:

• Does finding disease earlier, before people have any symptoms, save lives?
• Is one screening test better than another?
• How many people who receive the screening test go through follow-up tests and procedures that were unnecessary because they didn’t have cancer?

Other Types of Research Studies
Some clinical research studies do not provide a treatment to patients, but instead try to improve our understanding of a disease. Some examples of these studies are called non-intervention studies or non-therapeutic studies. These clinical research studies often lead to new treatments. Specific examples of non-therapeutic research studies are:

• Collection of tissue samples to learn more about a disease.
• Studies that track anonymous data on large groups of people to collect information such as the long-term health effects of a treatment for a disease.