Being Part of a Clinical Trial
If you decide to join a clinical trial, here’s some information to help you know what to expect.
Informed consent or informed permission
The first thing you’ll 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.
You’ll then be given a written consent form that usually includes the following information:
- 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 because 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. Consent forms are not always easy to understand. Be sure someone from the research team goes over what’s involved and what’s expected of you. You may want to bring someone along with you to help make sure all your concerns are addressed. 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’ll have the right to choose if you will take part. The level of care you get should not be affected by your decision.
You can take the consent form home with you. 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.
Informed permission
If you’re looking at a study for your child, this process is much the same but may be called informed permission. 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 similar to those of adults, including the right to leave the study any time they want.
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’ll be asked about your medical history and have a physical exam. These are needed to be sure that you can safely join the clinical trial.
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 or adverse events while being treated.
Because the side effects may not be fully 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 clinical trial early?
You’ll be told many times before you agree to be in a clinical trial that taking part is always voluntary. You (or your child) have the right to stop taking part in the study at any time. 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. Your doctors will still take care of you to the best of their ability.
If you decide to leave the clinical trial, 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 trial team that you’re quitting and why.
The clinical trial 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.
The clinical trial may end early if the treatment being studied is proven to work better or worse than the standard treatment. Sometimes, the new treatment is found to have side effects that cannot be managed.
Who ensures safety in clinical trials?
Researchers and government groups have put many safeguards in place to protect people in clinical trials.
One important guide is The Belmont Report, a set of ethical rules created in 1979 to help protect people in studies. It outlines 3 values for research involving people:
- Respect: All people should be respected. They have the right to choose what treatments they get.
- Beneficence: Protect people from harm by giving the most benefit with limited risks.
- Justice: Try to make sure that all people share the benefits and burdens equally.
Internal and independent oversight
Institutional review boards (IRBs) make sure that people in clinical trials are protected and that federal laws are followed. The IRB also makes sure that the informed consent form is accurate, complete, and easy to understand. Once a clinical trial begins, the IRB watches over it to look for problems. If you’re in a clinical trial, you can contact the IRB with any questions or concerns.
Data and safety monitoring boards (DSMBs) are used for phase III (and some earlier phase) clinical trials. The job of the DSMB is to watch the progress and results of the clinical trial. The DSMB can stop a clinical trial before it’s done if:
- It becomes clear that the new treatment is much more (or less) effective than the standard treatment to allow all people on the clinical trial to get the better treatment.
- Safety concerns come up, such as risks being much greater than benefits, so that no one else is exposed to possible harm.
The clinical investigator or principal investigator is responsible for patient safety. They must let the study sponsor (the group or company that funds the trial) know right away when severe side effects occur.
Government agencies that oversee clinical trials
Several government agencies help make sure clinical trials are safe and follow the rules:
- The Office of Human Research Protections (OHRP) makes sure that the rules of informed consent, IRBs, and participation of people with special needs are followed. OHRP can stop clinical trials when problems are found. They also teach research sites and individuals to follow current clinical trial standards.
- The US Food and Drug Administration (FDA) must approve any new medicine, treatment, or device before clinical trials can begin. They may also inspect (audit) sites doing clinical trials to make sure proper procedures are followed. Lastly, the FDA has the final say about whether a new treatment is approved and can be given to people.
- The National Cancer Institute (NCI) pays for many clinical trials after careful review. They also audit sites to make sure rules are followed.
- Written by
- References
Developed by the American Cancer Society medical and editorial content team with medical review and contribution by the American Society of Clinical Oncology (ASCO).
American Society of Clinical Oncology. Patient safety in clinical trials. Cancer.net. Content is no longer available.
Children’s Oncology Group. Research. 2023. Accessed at https://childrensoncologygroup.org/research on April 22, 2025.
National Cancer Institute (NCI). Cancer clinical trial information for patients and caregivers. Cancer.gov. Accessed at https://www.cancer.gov/research/participate/clinical-trials on April 22, 2025.
National Institutes of Health (NIH). NIH clinical research trials and you: The basics. Nih.gov. 2025. Accessed at https://www.nih.gov/health-information/nih-clinical-research-trials-you/basics on April 21, 2025.
National Institutes of Health (NIH). NIH clinical research trials and you. Nih.gov. 2025. Accessed at https://www.nih.gov/health-information/nih-clinical-research-trials-you on April 22, 2025.
U.S. Dept of Health and Human Services (HHS). The Belmont Report. Hhs.gov. Updated August 26, 2024. Accessed at https://www.hhs.gov/ohrp/regulations-and-policy/belmont-report/index.html on April 22, 2025.
U.S. Dept of Health and Human Services (HHS). Office for human research protections. Hhs.gov. Accessed at https://www.hhs.gov/ohrp/ on April 22, 2025.
Wong AR, Sun V, George K, et al. Barriers to participation in therapeutic clinical trials as perceived by community oncologists. JCO Oncol Pract. 2020;16(9): e849-e858. doi:10.1200/JOP.19.00662
Last Revised: June 3, 2025
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