Pinpointing the Importance of Clinical Trials
Research studies in all fields of medicine are known as clinical trials. These studies are conducted with an eye to the future, in hopes of finding safer or more effective methods to screen for, prevent, diagnose, or treat a variety of diseases.
Realizing the scope of cancer trials
Just how many clinical trials on cancer are there? Here's some perspective: In June 2004, more than 25,000 cancer specialists attended the conference for the American Society of Clinical Oncologists. At that conference, participants could learn about the results of 3,700 different cancer research studies.
These studies — and others in related fields — are conducted on many fronts. For example, many cancer research studies address the following areas:
- New techniques for screening for, diagnosing, or staging cancer
- New anticancer drugs
- New methods of surgery
- New approaches to radiation therapy
- New combinations of standard treatments
- New technologies, such as gene therapy
Tests are carried out according to standard procedures used to evaluate new drugs and methods of treatment. Powerful treatments in use today for breast cancer, colon cancer, rectal cancer, and childhood cancers all began in clinical trials. The results of clinical trials have allowed many people with cancer to live longer, and these scientific tests also have pointed the way to future research.
Understanding the development of clinical trials
A clinical trial is not the first step in the development of a new drug or treatment. In fact, it is one of the last. Research and development generally begins in a scientific laboratory. After extensive testing, scientists may test a promising drug or technique on animals. Later, a small number of volunteers willing to undergo experimental treatments takes part in studies. Based on the results of these studies, drugs and treatments that have been shown to be effective are made available for larger clinical trials.
According to the National Cancer Institute, which is part of the National Institutes of Health, cancer clinical trials include research at three different phases, each designed to answer different questions about the new treatment or technique.
The first two phases generally are made available only to a limited number of patients who are not benefiting from standard treatment.
Here are the three phases of research:
- Phase I: This is the first step in testing a new treatment on humans. Researchers may study whether the best way to give a new treatment is by mouth, IV drip, or injection. They may try to determine the best dose and how many times a drug or treatment should be given each day. They also watch for harmful side effects.
- Phase II: Trials conducted in Phase II determine whether the new treatment has an anticancer effect. For instance, does the treatment shrink tumors? What types of tumors does it shrink? Does it improve the results of blood tests for some cancers but not others?
- Phase III: After a treatment has demonstrated promising results in Phases I and II, Phase III studies compare the results of people taking standard treatments for specific cancers in specific stages with people taking the new treatment. Researchers all over the country conduct Phase III clinical trials, and thousands of people take part.
In Phase III clinical trials, participants are assigned at random to receive either the new treatment or a standard cancer treatment. Participants in clinical trials are divided into the two groups to help avoid bias. In this instance, bias is defined as an effect on the results of the study due to personal choices. In most cases, the treatment group receives the drug or method being tested, and the control group receives a time-tested standard treatment for cancer. All patients, of course, are carefully monitored.
In single blind studies, participants are unaware of which group they are in. In double blind studies — which are not done in the majority of cases — neither the participant nor the doctor knows whether the participant is in the experimental group or the control group (the group receiving standard treatment). These studies are designed to protect against bias, because participants (and their doctors) may act differently if they know whether they are taking the experimental drug or receiving standard treatment.
Comparing the results of two different treatments for the same type of cancer allows researchers to document the study results and show which treatment is more effective and has fewer side effects.
A small number of clinical trials involve the use of placebos for participants in the control group. Placebos are pills or injections that look like the drug or substance being tested but contain no drug. Everyone participating is informed if placebos are in use. Again, most clinical trials do not use placebos, and only if a patient agrees to participate in a placebo-controlled clinical trial can she receive a placebo.