<i>Information from PDQ for Patients 208/03900</i>

<b>What is a clinical trial?</b>
In cancer research, a clinical trial is an organized study conducted in people with cancer to answer specific questions about a new treatment or a new way of using a known treatment. Each study tries to increase medical knowledge and to find new and better ways to help cancer patients. Besides studying new anticancer drugs, clinical trials study new combinations of drugs already used in cancer treatment, new ways of giving treatment, and how changes in lifestyle can help cancer patients or prevent cancer from occurring. Other clinical trials compare the best known standard therapy with a newer therapy to see if one produces more cures and causes fewer side effects than the other.

<b>Why are clinical trials important?</b>
Before a new treatment is tested in patients, it is carefully studied in the laboratory. First, a drug is considered because it changes cells or parts of cells in a way that suggests it will destroy cancer or help the body to deal with the side effects of cancer treatment. Then, the new treatment is tested in animals to learn what it does in the body. But this early research cannot predict exactly how a new treatment will work in people or define all the side effects that might occur. Clinical trials are designed to help us find out how to give a new treatment safely and effectively to people. Each patient who participates in a clinical trial provides information on the effectiveness and risks of the new treatment. Advances in medicine and science are the result of new ideas and approaches developed through research. New cancer treatments must prove to be safe and effective in scientific studies with a certain number of patients before they can be made available to all patients.
Treatments now being used (standard treatments) are the base for building new, hopefully better, treatments. Many standard treatments were first shown to be effective in clinical trials. Clinical trials show researchers which therapies are more effective than others. This is the best way to identify an effective new treatment. New therapies are designed to take advantage of what has worked in the past and to improve on this base. 
You may be interested in participating in a trial. You should learn as much as you can about the trial before you make up your mind.

<b>** TYPES OF TRIALS **</b>
<b>What kinds of clinical trials are there?</b>
There are many kinds of clinical trials. They range from studies of ways to prevent, detect, diagnose, control, and treat cancer to studies of the psychological impact of the disease and ways to improve the patient's comfort and quality of life (including pain control).
Cancer clinical trials deal with new approaches to the treatment of cancer. These treatments most often use surgery (cutting out the cancer), radiation therapy (using x-rays, neutrons, or other invisible beams to kill cancer cells), and/or chemotherapy (using cancer-killing drugs) alone or in combination. Surgery, radiation, and chemotherapy have cured many cancer patients and prolonged the lives of many others. A new area of cancer treatment is biological therapy that use substances that help the body to fight cancer.
Most clinical trials are carried out in steps called phases. Each phase is designed to find different information. Patients may be eligible for studies in different phases, depending on their general condition, the type and stage of their cancer, and what therapy, if any, they have already had. Patients are seen regularly to determine the effect of the treatment, and treatment is always stopped if side effects become too severe.
