What are the types of studies?

• Treatment studies test investigational drugs and devices, new combinations of drugs, or new approaches to surgery or radiation therapy
• Prevention studies look for better ways to prevent disease in people who do not have the disease or to prevent the disease from returning. These trials may include medicines, vaccines, vitamins and minerals, or lifestyle changes
• Diagnostic studies are conducted to find better tests or procedures for diagnosing a particular disease or condtion
• Quality of Life studies explore ways to improve comfort and the quality of life for individuals with a chronic illness