There are two types of studies, interventional and

observational. Interventional studies are those in

which the research subjects are assigned by the

investigator to a treatment or other intervention, and

their outcomes are measured. Observational studies

are those in which individuals are observed and their

outcomes are measured by the investigators.

All clinical trials have criteria for enrollment that include

the type and stage of cancer, the patient’s age and sex,

and previous treatment history. By participating,

patients can play a more active role in their own

healthcare, gain access to new research treatments

before they are widely available, and help others by

contributing to medical research.