What Are Clinical Trials?
In cancer research, a clinical study is designed to show how a particular anti-cancer strategy -- for instance, a promising drug, a new diagnostic test, or a possible way to prevent cancer -- affects the people who receive it.
A "clinical trial" refers to medical studies with people. These studies are the final step in the process of developing new drugs and other means to fight disease. Once a drug has shown promise, first in laboratory and then in animal studies, it may move on to studies with people if the U.S. Food and Drug Administration (FDA) approves. At this stage, FDA approval is to conduct the study -- not for the drug itself. Only after a drug proves safe and effective in clinical studies does FDA grant approval for marketing the drug.
All over the country. These trials take place in cancer centers, other major medical centers, community hospitals and clinics, and veterans' and military hospitals in numerous cities and towns around the U.S. Hundreds of clinical trials are carried out by large networks, called cooperative clinical trial groups, that are funded by the National Cancer Institute (NCI). The cancer specialists, or oncologists, who belong to these networks conduct joint studies simultaneously in many different places and pool their data.
Prevention trials look at lifestyle changes or drugs that may help prevent cancer. One study, for example, is testing a drug that may prevent breast cancer in women at high risk.
Diagnostic trials look at ways of detecting cancer or finding out more about a tumor. For instance, a large study is looking a new ways to analyze Pap tests, the common screening test for cervical cancer, along with different ways of following up on Pap test abnormalities.
Treatment trials may study new drugs or other ways of treating cancer, or they may look at new combinations of established treatments. They fall into three categories:
- Phase I trials test the safety of a new treatment.
- Phase II trials assess how effective a treatment is against various kinds of cancer.
- Phase III trials, which usually involve many patients in different places, compare two or more different treatments.
One advantage is the possibility that a new treatment, diagnostic test, or preventive measure will turn out to be better than a more established procedure. Patients who take part in procedures that do proves to be better have the first chance to benefit from them. In Phase III clinical trials where one treatment is compared to another, patients receive either the most advanced and accepted treatment for the kind of cancer they have -- known as the "standard" treatment -- or a new treatment that has shown promise of being at least as beneficial as the standard treatment, if not better.
People who take part in trials receive specialized care under a very detailed set of directions or protocol. Highly trained and experienced cancer specialists design, review, and approve each protocol. In addition, all clinical trial patients are carefully monitored during a study and followed afterwards. They often become part of a network of clinical trials carried out around the country. In this network, doctors and researchers share their ideas and experience, so patients receive the benefit of their pooled knowledge.
Many cancer patients have said that they take part in trials also because it is an opportunity to contribute to new knowledge that may benefit others with cancer.
Medical studies can carry unknown dangers and side effects, as well as hoped-for benefits. Many medical treatments have known side effects, but because clinical trials are testing new treatments, the risks involved are not always known ahead of time. The risks and benefits of each study are explained in a document, called an Informed Consent Form, that patients discuss with their doctors or nurses before agreeing to participate.
Any well-run clinical trial is carefully reviewed for medical ethics, patient safety, and scientific merit. An Institutional Review Board (IRB), located at the institution where the trial is to take place, must review the trial before it begins. Made of up scientists, doctors, clergy, and other people from the community, IRBs focus on minimizing risks to patients. They also ensure that any patient interested in the study will be able to make an informed decision about participation. Careful monitoring of side effects during the trial is another safeguard. In addition, the NCI conducts regular reviews of studies it sponsors, and the FDA requires regular reports on all clinical trials, including those that are investigating cancer treatments.
Costs are a major concern of cancer patients and their families. Different arrangements and policies exist at different research institutions. Health insurance programs also vary; some cover part or all of the cost of care in a trial, some make decisions on a case-by-case basis, and some never or rarely cover clinical study costs. NCI is now working with major managed care and health insurance programs to encourage coverage for cancer patients who want to enroll on a trial.
Clinical trials are under way for nearly every kind of cancer. To find out what they are and where they are taking place:
- Call NCI's Cancer Information Service (CIS) at 1-800-4-CANCER (1-800-426-6237). Ask for a customized search of the PDQ database, which provides information on current studies. Also ask for the pamphlet, "What Are Clinical Trials All About?", which includes questions to ask before deciding to participate.
- Log onto the Internet and visit NCI's International Cancer Information Center (ICIC). This site provides access to the PDQ database, as well as current information on preventing, diagnosing, and treating cancer.
- Contact patient advocacy and voluntary organizations that may have information on studies of specific cancers. Some cancer patient organizations have prepared succinct, non-technical summaries of clinical trials in conjunction with the NCI.