Clinical trials are used to evaluate tests
or treatments that have not yet been proven to be effective. Clinical trials
rely on volunteers to take part in them. The June 9, 2004, issue of JAMA includes an article about patients who participate
in cancer clinical trials.
Phase 1 trials are conducted to determine
if a new treatment is safe and what doses can be given and to discover the
main adverse effects of the new treatment. At this first phase, a small number
of patients are enrolled.
Phase 2 trials further evaluate the safety
and potential effectiveness of a therapy and evaluate how it affects the body.
Phase 3 trials provide scientific testing
of the value of a new treatment. Participants are randomly (by chance, like flipping a coin) assigned to receive the new therapy,
the current standard therapy, or a placebo (an inactive
pill or procedure). Most new therapies move on to phase 3 trials only if they
have shown promise during phase 1 and phase 2 trials.
Phase 4 trials evaluate the long-term
safety of the new treatment and take place after the new treatment has been
approved for use.
Every clinical trial has guidelines that outline who can and cannot
participate in the study. These guidelines are called eligibility
criteria. Cancer clinical trials usually require that patients have
a particular type or stage of cancer to participate.
Patients who wish to enroll in a clinical trial must give informed consent before participating. Informed consent ensures that
patients understand the potential risks and benefits of joining a clinical
trial prior to participating. During the informed consent process, participants
are told about what the trial involves and the purpose of the study. Participants
sign an informed consent form to acknowledge that they understand the risks
and benefits of the study, but the form is not binding, and participants can
leave the study at any time for any reason.
Participants may receive promising new therapies that are not
available to the public.
Participants are closely monitored by researchers, doctors, and
other health care professionals during the clinical trial.
Results from the clinical trial may help other patients in the
New therapies are not always better than standard treatments with
which they are compared.
New treatments may have unexpected adverse effects or risks.
Participants in randomized trials may not receive the therapy
Health insurance may not cover all of the costs associated with
participating in a clinical trial. Disclosure about any costs should be part
of the informed consent.
Cancer Information Service 800/4-CANCER (422-6237)http://cis.nci.nih.gov
To find this and other JAMA Patient Pages, go to the Patient Page link
on JAMA's Web site at http://www.jama.com.
A Patient Page on participating in medical research was published in the February
7, 2001, issue.
Sources: National Cancer Institute's Cancer Information Service
The JAMA Patient Page is a public service of JAMA. The information and recommendations appearing on this page are appropriate
in most instances, but they are not a substitute for medical diagnosis. For
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Parmet S, Lynm C, Glass RM. Cancer Clinical Trials. JAMA. 2004;291(22):2778. doi:10.1001/jama.291.22.2778