All clinical trials must follow a specific protocol , or plan, that is designed to answer specific questions and to guard a patient's health and well-being. Patients are admitted to a clinical trial only if their medical conditions meets the specifics of the protocol. Those who take part must sign an informed-consent form to indicate that they understand the potential benefits and risks involved. Each participant's medical progress is monitored on an ongoing basis. Trials take many different forms.
Some trials test a single treatment on a single group of people.
Others compare a new treatment with the best known standard therapy, using two groups of patients with similar disease characteristics. In such trials, the group receiving the standard therapy is called the control group . Phase I trials are meant to determine safe dosage and side effects. They are conducted with a small number of patients. Only people with advanced cancer who cannot be helped with standard treatments take part.