Clinical Trials Information for Patients
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.
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.
What kinds of clinical trials are there?
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.
The purpose of a phase I study is to find the best way to give a new treatment and how much of it can be given safely. In a phase I study, a new treatment is given to a small number of patients. For a new drug, the study starts by giving a very low dose of the drug, then the dose is slowly increased as new patients enter the trial. The dose can be increased by giving more at one time or by giving the same dose more often. Physicians watch patients carefully for any harmful side effects. Although the research treatment has been well tested in laboratory and animal studies, the side effects in patients can not be completely known ahead of time. Phase I studies may involve significant risks for this reason. They are offered only to patients whose cancer cannot be helped by other known treatments. Phase I treatments may or may not produce anticancer effects, but some patients have been helped by these treatments. Once the best dose is chosen, the drug is studied for its ability to shrink tumors in phase II trials.
Phase II studies are designed to find out if the treatment actually kills cancer cells in people. Usually groups of 20 to 50 patients with one type of cancer receive a phase II treatment. For example, patients with breast cancer that no longer responds to accepted therapy (it has become resistant to standard therapy) may be treated on a phase II study. Patients are closely observed for anticancer effect by repeated measurement of tumor size to see if it has shrunk since the beginning of the study. When the tumor gets a lot smaller and stays smaller for at least a month, the patient is said to have “responded” to the treatment. If at least one-fifth of the patients in the phase II study respond to treatment, the treatment is judged active against their tumor type. In addition to monitoring patients for response, any side effects of the treatment are carefully recorded and assessed. Since larger numbers of patients receive the treatment in phase II studies than in phase I studies, there is more chance to observe unusual side effects. Each new phase of a clinical trial depends on and builds on information from an earlier phase. If a treatment has shown activity against cancer in a phase II study, it becomes part of a phase III study.
Phase III studies usually compare standard treatments (the treatment most accepted) with treatments that appeared to be good in the small phase II studies. Phase III studies require large numbers of patients; some studies use thousands of patients. Patients are usually randomized, which means they are assigned by chance to one of the treatments being studied. The group that receives the standard treatment is called the “control” group. The researchers know that a certain number of these patients will be helped by the treatment. Another patient group receives the newer therapy to see if it will help the patients more. Phase III studies look for longer life, better quality of life, fewer side effects, and fewer cases of the cancer returning.
Adjuvant studies are conducted to determine if additional therapy will improve the chance for cure in patients at risk for the cancer coming back after surgical removal of all visible disease. An example is a study for patients with large bowel cancer. The standard therapy for large bowel cancer is surgery. An adjuvant study could be run in which one group of patients with large bowel cancer received surgery and the other group received surgery and then chemotherapy. If the study shows that surgery plus chemotherapy is better than surgery alone, surgery plus chemotherapy will become the new, standard therapy. Adjuvant studies progress through phase I, II, and III trials like other treatment studies.
Clinical Trials Information for Patients