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Being in a Clinical Trial

People usually don’t think about being in a clinical trial until they have a serious illness. Medical advances often make the news but you usually don’t hear about the thousands of people who are helped each year because they took part in a clinical trial. You also aren’t likely to hear about the millions of others who benefit because of the people who were in clinical trials.

Sometimes clinical trials are slowed or do not get completed because not enough people are enrolled. This is especially true for clinical trials that need to enroll racial minorities and those with other diseases (such as HIV infection and kidney disease). Clinical trial groups are taking steps to recruit a more diverse group of people.

Eligibility, or inclusion and exclusion criteria

Before you can join a clinical trial, you must meet the requirements (eligibility criteria). All clinical trials have criteria about who can and cannot be in them.

  • The factors that allow a person to sign up for a study are called inclusion criteria.
  • The factors that can prevent a person from joining a study are called exclusion criteria.

These criteria are used to make sure that only people who can safely take part in the clinical trial are included.

For cancer clinical trials, the inclusion and exclusion criteria usually have to do with:

  • The type of cancer a person has
  • The stage (extent) of the cancer
  • Previous treatments a person had
  • The length of time since a person last had treatment
  • Results of certain lab tests
  • The medicines a person is taking
  • Other medical conditions the person has
  • Any previous history of another cancer
  • A person’s activity level (often called the performance status)

Other factors, such as a person’s age or sex, may also be part of the criteria. There are usually other criteria for each study as well.

The first thing you will be asked to do is provide written, informed consent. During the informed consent process, the researchers (doctors or nurses) will explain the details of the trial to you and answer your questions and concerns. If you’re looking at a study for your child, this process is much the same but may be called informed permission.

You will then be given a written consent form. Consent forms for clinical trials usually include the following:

  • The reason for the study (what the researchers hope to find out)
  • Who is eligible to take part
  • What’s known about the new treatment
  • The possible risks and benefits of the new treatment
  • Other treatments that may be an option for you
  • The design of the study (whether it’s randomized, double blinded, etc.)
  • How many and what types of tests and doctor’s visits will be needed
  • Who must pay for the costs of the clinical trial (tests, doctor’s visits, etc.) and for costs if you need extra care as a result of the clinical trial
  • A statement about how your identity will be protected
  • A statement about the study being voluntary and your right to leave the study at any time without fear of losing care that you would receive outside of the trial
  • Contact information in case you have questions before, during or after the study

Before you sign the consent form, ask questions. Be sure someone from the research team goes over the form with you. Consent forms are not all easy to understand, and there may be words or ideas that are confusing. You may want to bring someone along with you to help make sure all your concerns are addressed.

Parents must sign the form for their child, and in most cases older children must also agree before they take part. (This is called assent.) In general, children’s rights are very like those of adults, including the right to leave the study any time they want.

Be sure you understand what’s involved and what’s expected of you. Review what you understand about the study with your doctor or nurse to make sure you’ve got it right.

Finally, don’t feel rushed to make a decision. If you are eligible for a clinical trial, you always have the right to choose if you will take part. The level of care you get should not be affected by your decision.

Take the consent form home with you if you want to. Ask trusted family members and friends what they think. Some people may want to get a second opinion about the study from another doctor, too.

Taking part in the study

Once you’ve signed the consent form, you’ll probably need to have blood tests and/or imaging tests before you start treatment. Usually, you will be asked about your medical history and examined physically. These are needed to be sure that you meet the eligibility criteria and help ensure your safety.

What happens next may seem like getting a normal treatment, but you may need more tests and visits to the doctor. These tests are to find out how the treatment is going and how you’re doing. The doctors and nurses may examine you more often and will want to know if you’re having any side effects (called adverse events) while being treated.

Because the possible problems may not fully be known, it’s very important to let the research team know if you have any symptoms that are not normal for you..The research team will decide if symptoms you’re having are related to the clinical trial, and if they need to be treated or your treatment needs to be changed.

What if I want to leave the study early?

You will be told many times before you agree to be in a clinical trial that taking part is always voluntary. This is an important point. You (or your child) have the right to stop taking part in the study at any time, for any reason. 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 clinical trials team that you’re quitting and why. The clinical trials team may ask to continue to follow up with you for a certain length of time to look for any long-term effects of treatment. This helps find unexpected problems and can make sure you are safe, even though you’re no longer part of the clinical trial. Your doctors will still take care of you to the best of their ability.

People stop being part of clinical trials for many reasons. You might quit because it’s not working for you. You might leave the trial because of severe side effects. Or you just decide you no longer want to be in it. THIS IS YOUR CHOICE and not a problem.

Also, the clinical trial itself may be ended early if the treatment being studied is proven to work or NOT work as well as the standard treatment. Sometimes, the new treatment is found to have side effects that cannot be managed.

What if I’m not eligible for a clinical trial?

Some people are too sick or have other problems that keep them from taking part in clinical trials.

Other people may be interested in a certain treatment that’s only available in clinical trials, but they don’t meet the eligibility criteria. In some of these cases, a person’s doctor may ask the study sponsor if they can get an eligibility waiver or special exception to allow the person into the study, even though they don’t meet all of the criteria. This decision is usually made by the trial's clinical investigator, who may consult with others involved in the study about the request. If the clinical investigator agrees to allow a waiver, the person is treated according to the study protocol (the same tests, doctor’s visits, follow-up, etc.), but that person's results are not included in the final study results.

In some cases, studies may have already enrolled enough people and aren’t taking any more participants.

Sometimes, there are ways to get access to treatments that are in late-phase clinical trials but not yet approved by the FDA. These are usually referred to as expanded access or compassionate use programs. In recent years the FDA has broadened these programs to allow some patients who urgently need these treatments to be able to get them. For more, see Compassionate Drug Use.

The American Cancer Society medical and editorial content team

Our team is made up of doctors and oncology certified nurses with deep knowledge of cancer care as well as editors and translators with extensive experience in medical writing.

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Last Revised: August 18, 2020

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