Some facts about clinical trials to keep in mind

Clinical trials are vital in studying all aspects of medicine, not just cancer. The stakes may seem higher when researching medicines to treat cancer, but all new treatments (drugs and medical devices) must go through clinical trials before being approved by the FDA.

Taking part in any clinical trial is voluntary.

You always have the right to choose whether you will take part in a clinical trial for which you meet the criteria. The level of care you get should not be affected by your decision.

You also have the right to leave a clinical trial at any time, for any reason. If you decide to leave the study, talk to your doctor first. You’ll want to know how quitting the study might affect your health and what other treatment options you have. You should also tell the research group that you’re quitting and why. Your health care team may ask that you agree to continue to be watched for a certain length of time to look for any long-term effects of treatment. We discuss these issues further in the section called “What would it be like to take part in a clinical trial?” under “Taking part in the study.”

Not all clinical trials study treatments.

Here we talk about research studies as if they are all about treatments, but many clinical trials look at new ways to detect, diagnose, or learn the extent of disease. Some even look at ways to prevent diseases from happening in the first place. Researchers still use human volunteers to test these methods, and the same general rules apply.

Even among clinical trials that do study treatments, not all of them study drugs.

Many clinical trials test other forms of treatment, such as new surgery or radiation therapy techniques, or even complementary or alternative medicines or techniques.

When clinical trials do look at drugs, not all of them study new ones.

Even after a drug has been approved for use against a type of cancer, doctors sometimes find it works better when given a certain way or when combined with other treatments. It may even work on a different type of cancer. Clinical trials are needed to study these possibilities, too.

Very few cancer clinical trials use a placebo.

A placebo is a sham pill, inactive ingredient, or fake treatment used in some types of clinical trials to help make sure results are unbiased. A placebo pill is sometimes called a “sugar pill.” Over the years, doctors have observed that some people begin to feel better even if they just think they’re being treated. Although this effect tends to be brief, and doesn’t really affect cancer, it can make a new treatment seem to help. Sometimes, people who know they are getting placebo don’t report all the health problems that come up, while those on the treatment do. This can make the treatment look like it has worse side effects than it does. A placebo control group keeps people from knowing if they’re getting the treatment being studied, and makes the results more likely to be valid.

Placebos are rarely used alone in cancer research unless no known effective treatments exist. It’s not ethical to have someone take a placebo if a proven treatment is available. When cancer clinical trials compare treatments, they compare the new treatment against the current standard (proven) treatment. At times, a study may be designed so that patients are not told which one they are getting, but they know they’re getting treatment that at the very least meets the current standard of care.

In some clinical trials, the doctors want to learn if adding a new drug to the standard therapy makes it work better. In these studies, some patients get the standard drug(s) and the new one being tested, while other patients get the standard drug(s) and a placebo. But none of the patients would get only a placebo. Everyone gets standard treatment if there’s a standard treatment available. (See the next section for an example of a phase III study that uses a placebo.) For more information about placebos and how they might be used in some studies, see our document called Placebo Effect.