There are different types of clinical trials.
Natural history studies provide valuable information about how disease and health progress.
Prevention trials look for better ways to prevent a disease in people who have never had the
disease or to prevent the disease from returning. Better approaches may include medicines,
vaccines, or lifestyle changes, among other things.
Screening trials test the best way to detect certain diseases or health conditions.
Diagnostic trials determine better tests or procedures for diagnosing a particular disease or condition.
Treatment trials test new treatments, new combinations of drugs, or new approaches to surgery or radiation therapy.
Quality of life trials (or supportive care trials) explore and measure ways to improve the comfort and quality of life of people with a chronic illness.
Informed consent is the process of providing potential participants with the key facts about a clinical trial before they decide whether to participate. The process of informed consent (providing additional information) continues throughout the study. To help someone decide whether or not to participate, members of the research team explain the details of the study. Translation or interpretive assistance can be provided for participants with limited English proficiency. The research team provides an informed consent document that includes details about the study, such as its purpose, duration, required procedures, and who to contact for further information. The informed consent document also explains risks and potential benefits. The participant then decides whether to sign the document. Informed consent is not a contract. Volunteers are free to withdraw from the study completely or to refuse particular treatments or tests at any time. Sometimes, however, this will make them ineligible to continue the study.