GENERAL DESCRIPTIONWhat is a clinical trial? 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. Why are clinical trials important? 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. TYPES OF TRIALSWhat 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. Phase I studies 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 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 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 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. Neoadjuvant studies Neoadjuvant treatment is given first to try to reduce the cancer to a size where standard therapy is effective. For example, the standard therapy for head and neck cancer is radiotherapy and/or surgery. Sometimes the cancer is too large to safely treat by either of these methods. The chemotherapy may make the tumor shrink to a size that can be treated with radiotherapy or that can be removed surgically. Neoadjuvant studies progress through phase I, II, and III trials like other treatment studies. Supportive care studies Clinical trials also try to find better ways of caring for the side effects caused by cancer treatment (such as nausea and vomiting) and the side effects of the cancer itself (such as pain or sleeplessness). Some supportive care studies use drugs to treat side effects, and such studies will have phases (phase I, II, or III) like cancer therapy clinical trials. Other studies look at whether support groups help ease the discomfort of the patient. Supportive care studies sometimes try to find better ways to help the families of patients with cancer cope with the illness of a loved-one. Prevention and early detection studies Often people in prevention studies are considered likely to develop cancer (high risk) because several family members have related cancers. Prevention studies usually compare a group of people that receive no special treatment to a group that is given a drug or a change in diet to try to prevent cancer from developing. People in both groups are contacted for many years to see if there is a difference in how many of them get cancer. Early detection studies assess methods of screening people for cancer to try to find the cancer when it is still very small. If the cancer can be found when it is small, the cancer may be more easily treated, increasing the chance for survival. These methods may use x-rays, blood tests, or touch (among others) to find cancer. Early detection studies may or may not run over many years. Group C and Treatment Referral Center studies These types of studies make drugs available to some cancer doctors. These drugs have been through clinical trials, have been shown to work for some tumors, and may soon be approved by the Food and Drug Administration for sale. Group C drugs can be used by a wider group of doctors than drugs used in either modified Group C or Treatment Referral Center studies. Patients who receive drugs by any of these means are checked regularly by their doctor as if they were on a clinical trial. How can you find out about clinical trials? The National Cancer Institute (NCI) has created a computer file about cancer and clinical trials called Physicians Data Query (PDQ). The information in PDQ is updated monthly and can give you or your doctor the latest information on clinical trials being offered around the country, as well as the names of doctors running the trials and the names of the hospitals treating patients on the trials. Patients can obtain PDQ information from their physicians or by contacting the Cancer Information Service (CIS). The CIS answers cancer-related questions from the public, cancer patients and their families, and health professionals. If you have questions, call the toll-free number 1-800-4-CANCER and you will be connected to the CIS office serving your area. PDQ contains summaries of over 1,500 cancer clinical trials that are available to patients. Treatment studies are grouped by the site of disease (for example, lung, kidney, breast, or bone), by the type of treatment (surgery, radiotherapy, chemotherapy, biological therapy), by the study phase (I, II, III, adjuvant, neoadjuvant, Group C, or Treatment Referral Center), by the drug used in the study, and by the city where the study is done. Supportive care studies are grouped by the cancer-related problem (for example, pain, anemia, infection), while prevention/early detection studies are grouped by the type of cancer like the treatment studies. TREATMENT OPTIONSWhat is best for you? Finding answers and making decisions are often hard for a cancer patient. The diagnosis of cancer followed by decisions about therapy can be confusing, and you may be frightened and upset. It is important to discuss your possible choices with medical experts, including your own doctor, and with those close to you. Your personal doctor and cancer specialists can advise you about your choices for standard treatment or clinical trials. PDQ provides detailed information for patients and physicians about the recent, best, standard treatment for most types of cancer. When there is no standard therapy that works, PDQ advises that physicians and patients consider clinical trials. What is informed consent? Anyone entering a clinical trial in the United States is required to sign a form indicating that they understand what will happen to them during the study. If the patient is a child, a parent or guardian must sign the form. This form will tell you what treatment will be given, what kind of problems might occur, and what other treatments might work for your condition. The amount of help expected from the study will be given. In phase I studies, it is usually not known whether any help will occur. The informed consent form also indicates which costs are covered by the study and which must be paid by you (or your insurance). After you have signed the consent form, a copy of it is given to you. Included on the form is the name and telephone number of someone to call if you have questions. Informed consent also tells you that you have the right to leave the study at any time. You cannot be refused other treatment that may help you if you decide not to become part of the study. Before you sign the informed consent form, you need to ask the doctor questions about the study. What are important questions to ask about a clinical trial? If you are thinking about taking part in a clinical trial, here are some important questions to ask:
If you want to know more about cancer and how it is treated, or if you wish to know about clinical trials for your type of cancer, you can call the NCI's Cancer Information Service at 1-800-422-6237, toll free. A trained information specialist can talk with you and answer your questions. |
