What Is a Clinical Trial?

We understand that some people have mixed emotions about clinical trials and find them confusing. Our goal is to explain clinical trials in plain language to empower you to decide if a clinical trial is a good option for you.

Play Video about myTRIAList: What is a Clinical Trial

Questions to Consider

Let us help you… We’ve answered questions you may have about cancer clinical trials and to provide you with questions to ask your doctor. Click on each question to learn more.

People enroll in clinical trials for many reasons. Clinical trials provide people with cancer the opportunity to access investigational cancer treatments before they are widely available. By participating in a clinical trial, you help with cancer research to provide more options for the future.

Clinical trials identify new cancer treatments, including medicines, surgery, and behavior changes. They provide those diagnosed with cancer the opportunity to access the latest treatments.

Clinical trials typically follow the same enrollment process, but some trials may involve more steps.

Prescreening is the first step in joining a trial. This is to see if you and the study are a good match for each other. The prescreening process may include answering questions about your health, age, and disease type. This is usually done online or by phone.

After that, you meet with a researcher, who is called an investigator, to learn about the study’s purpose and the benefits and risks. They will provide you with an informed consent form with the trial details, such as procedures and contacts. If you decide to join the trial, you will sign the form and move to the next step.

During the screening process, you typically go to the investigator’s office for a physical exam to determine if you meet the eligibility requirements for the trial. This may include having additional tests and/or bloodwork done.

Once you are accepted into the study, a study coordinator will provide you with instructions and next steps, including any follow-up visits.

You can leave the clinical trial at any point.

Clinical trials include new and untested treatments, which may not work as well as expected. The treatment team will explain the risks to you before you start the trial, including possible side effects.

You can enroll in more than one trial at a time through co-enrollment. However, this is not common.

All clinical trials have eligibility requirements based on the clinical trial protocol. This includes rules about who can be in the trial and the details of the treatment procedures and medications. The clinical trial protocol is designed to ensure the trial protects the health of the trial participants.

For the best outcome, researchers want participants who are similar so that reviewing the results is simpler. For example, a study may want people of a certain age range or at a particular disease stage. During the screening process, the researchers will ensure you meet the eligibility criteria for the trial.

Every clinical trial is different, with varying cycles and treatments. Some clinical trials last a short time, while others are longer. So, it is difficult to say how you may be affected. You could also receive inpatient treatment at a hospital or care center. Talk to your doctor or someone from the clinical trial for more details.

Interventional clinical trials that study new treatments often have phases.

Early Phase 1 trials test if the new treatment affects the body and how.

Phase 1  trials test the treatment’s side effects, how it is put into the body, and the timing. They also determine the maximum amount of medicine to give, while keeping the side effects acceptable for participants.

Phase 2  trials test whether the treatment works for a certain cancer type or other diseases, such as shrinking a tumor or improving blood test results. The most effective treatment dosing and way it was put into the body from Phase 1 are typically used as the starting point.

Phase 3  trials test if the new treatment is better than what is currently available, such as which group of patients has better survival rates or fewer side effects. In most cases, treatments move into Phase 3 clinical trials only after they meet the goals of Phase 1 and Phase 2 clinical trials.

Phase 4 trials test the treatment side effects over time after it has been approved by the U.S. Food and Drug Administration (FDA) and is available. Depending on the availability, this treatment may be available to those not participating in a clinical trial.

For more information, please read CancerCare’s clinical trial guide.

  • Interventional studies are where participants are assigned to groups that receive one or more treatments (interventions) or no treatment. Researchers evaluate the outcomes. The group you are assigned to is determined by the study’s protocol.
  • Observational studies are where individuals are observed, or certain outcomes are measured. No attempt is made to change the outcome. For example, no treatment is given.
  • Expanded Access is a program (EAP) that provides investigational therapy that is not available in a clinical trial. It is for patients who have already tried all additional therapies and treatment options. Investigational medicines that are not yet approved by the U.S. Food and Drug Administration (FDA) may be included in these studies and require approval by the doctor and the company providing the medicine.

Immunotherapy is a cancer treatment that boosts the immune system to help destroy cancer cells using the body’s own immune system. It can be used alone or in combination with other cancer treatments. It is administered as an infusion through a port (a tube connected to a vein) or intravenously (IV) (medicine given through a needle into a vein).

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In interventional clinical trials where several treatment (intervention) options are involved, they are often split into groups. Randomization is when a patient is randomly assigned to one of the groups. Some patients receive the new treatment while others receive the currently available treatment. In many studies, the treatment is randomized and “blinded,” meaning the participant and doctor don’t know which treatment group the patient is in. Random assignment to a treatment group ensures each patient has an equal chance of receiving any of the study treatments.

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Placebos are inactive treatments that look the same and are given the same way as the drug being tested in a clinical trial. Placebos may be used in a cancer clinical trial that compares the standard treatment plus a placebo with the standard treatment plus a new treatment. This is a way to determine if the new treatment works better than the standard treatment.

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A double-blind clinical trial means that neither the researchers nor participants know which treatment they are receiving until the trial is over. A double-blind trial is used to prevent biased results.

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Some clinical trials test an already approved drug that is used in a different way or to treat a different disease. Other clinical trials evaluate a new drug or drug combination to ensure the treatment is safe and will benefit patients. In some cases, the clinical trial could include surgery, chemotherapy, radiation, or immunotherapy. The clinical trial team will explain any tests, treatments, and/or procedures involved in their clinical trial.

For more information, visit CancerCare’s clinical trial resources.

You have many rights when enrolling in a U.S. clinical trial. This includes signing up for the trial, asking any questions you have about the trial, and leaving the trial at any time.

For more information, visit CancerCare’s clinical trial rights and protection page.

People from other countries may be able to enroll in U.S. cancer clinical trials if they meet the medical criteria. Contact your doctor or the study researcher.

Yes, the clinical trial will provide a translator at the treatment facility for those who do not speak English.

Biomarker testing is when doctors take samples from your body like blood or saliva and measure specific biological molecules called biological markers or biomarkers for short. These tests may provide useful information about how to treat your cancer.

Not all cancers have known biomarkers, so you may not have had biomarker testing before. You may be asked to have further testing if a clinical trial needs information about a particular biomarker for research or to see if you meet the trial eligibility requirements. The trial usually provides financial support for required biomarker testing. Ask your doctor or the trial contact for more information.

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Biomarker testing is when doctors take samples from your body like blood or saliva and measure specific biological molecules called biological markers or biomarkers for short.

Genetic testing is looking for a certain type of biomarker for changes in a person’s genes, gene expression, or chromosomes at the cellular level. The testing can also be done on tumor tissues, helping diagnose cancer, plan treatment, or monitor a treatment. Genetic testing may give information about your risk of developing a certain cancer type or if people in the same family may be at higher risk than most other people for a cancer type.

Some clinical trials may require and may pay for you to have biomarker or genetic testing done before you can be accepted into the trial.

Most patients should have no out-of-pocket costs for a clinical trial other than travel costs. Either your insurance company or the trial sponsor usually pays for the treatment costs. If you do not have insurance or the sponsor of the trial does not pay, CancerCare may offer some financial resources if available for patients, and they may be able to help with travel costs.

You can leave a clinical trial at any time and for any reason. Leaving a trial will not impact your ongoing care.

You can be asked to leave a trial if you do not follow the protocols outlined in the informed consent form you signed, or the investigator no longer thinks the treatment is right for you.

Also, clinical trials can end early if the treatment is shown not to work, doesn’t work as well as the standard treatment, or has unexpected side effects. If the trial ends early, all participants will be removed from it.

Consult with your doctor and/or the clinical trial investigator/doctor when you notice any changes in your condition.

Yes, a cancer clinical trial can impact fertility. Ask your doctor or the clinical trial investigator about any concerns you may have about fertility before joining a clinical trial to empower your future decisions.

Investigational treatments may be dangerous to a fetus. Most clinical trials exclude people who are pregnant to avoid risk to the fetus.

The more details you have about your cancer, the more accurate your search results will be. You may need additional information from your doctor. This could include details on your specific cancer type, results from past tests, and any previous cancer treatment you may have received.

Medical terms can be challenging to understand. By asking your doctor to explain a trial you found on myTRIAList, you can learn more about some of the things you may not fully understand. You can also email or call the study contact yourself to receive more information to share with your doctor. 

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Most clinical trials pay for special testing and costs related to the research. Depending on your insurance company, they may pay for part of or all treatment costs. If you do not have insurance or the cost of the trial is not covered, CancerCare may have financial resources you can access.

Some clinical trials add to your current or suggested treatment plan. Ask your doctor if the trial you are interested in will allow you to continue your current treatment plan.

This is an important question to ask your doctor. They can provide the information you need about your treatment options and if the trial can be added to your current treatment plan. This will empower you to make informed decisions.

The clinical trial length depends on the trial and the cancer type. It’s important to discuss the timeline with your doctor and/or the clinical trial Principal Investigator to understand how long the trial will last.

U.S. clinical trials are carefully designed to maximize the benefits and minimize participant risks. It’s important to discuss the potential side effects of any treatment you might receive during a clinical trial with your doctor because they differ depending on the treatment. 

The clinical trial may include your doctor, another care team, or a combination. By talking with these people, you will know who you can ask additional questions to, empowering your decision-making.

In some trials, your doctor may be able to continue treating you. However, in some cases, you may need to see another doctor who is more familiar with the clinical trial. 

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