Joining a Clinical Trial
A plain-language guide to the possible risks and benefits of joining a cancer clinical trial and questions to ask first, based on National Cancer Institute resources.
Source: National Cancer Institute · NCI reviewed 2024-11-18 · Verified 2026-07-02
The 30-second version
If you are thinking about joining a cancer clinical trial, it helps to understand the possible risks and benefits and to ask questions first. Trials may offer access to a treatment under study and close monitoring, but the study treatment may not be better than standard care and could have serious side effects. Asking questions helps you decide what is right for you.
Key takeaways
- Every clinical trial is different, so its risks and benefits can differ too.
- Possible benefits include access to a treatment under study and close monitoring by the research team.
- Possible risks include that the study treatment may not be better than standard treatment and may have serious side effects.
- Trials may involve extra visits, tests, and expenses such as travel.
- Asking questions about the trial, risks, rights, costs, and daily life helps you make an informed choice.
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The full explanation.
The simple version
If you are thinking about joining a clinical trial, it helps to ask questions and to understand the possible risks and benefits. Every clinical trial is different, which means the risks and benefits can differ from one trial to another. Learning what to expect can help you decide what is right for you.
In short: asking good questions helps you make an informed choice.
Questions worth asking
Before joining a trial, you may want to ask your doctor and the research team about several areas.
About the trial
- What is the purpose of the trial?
- Why do the researchers believe the treatment being studied may be better than the one used now — and why may it not be better?
- How long will I be in the trial, and how many visits will I need to make?
- What kinds of tests and treatments are involved?
- How will the doctor know if the treatment is working, and how will I be told the results?
- Who will be in charge of my care, and who can I speak with about questions?
About risks and benefits
- What are the possible side effects or risks of the new treatment?
- What are the possible benefits?
- How do the risks and benefits compare to standard treatment?
About your rights
- How will my health information be kept private?
- If I decide to leave the trial, what other options will I have?
About costs
- Which costs do I have to pay, and what will my insurance cover?
- Who can help with questions from my insurance company?
About daily life
- How could the trial affect my daily life, and how often would I come to the clinic?
- Will I need to stay in the hospital? How far will I need to travel? Will I have check-ups after the trial?
Possible benefits
Some of the benefits of joining a treatment clinical trial may include:
- The trial may help researchers learn more about cancer and help people in the future.
- You might have access to a treatment under study that may not be available to people outside the trial.
- The research team will watch you closely, adding an extra layer of care.
- Though not common, if the treatment being studied is more effective than standard treatment, you may be among the first to benefit.
Possible risks
Some common risks include:
- The study treatment may not be better than, or even as good as, standard treatment.
- Study treatments may have serious side effects that are worse than those of standard treatment.
- You may need to make more visits to the doctor and have more tests than with standard treatment.
- You may have extra expenses related to these visits, such as travel, housing, and childcare.
In short: a trial can offer new options and close care, but the study treatment is not guaranteed to be better.
Your healthcare team can help you weigh these points for your own situation.
Watch instead
Animated lessons are in production. Here’s the planned video slate for this topic — each one will be based on the same NCI-sourced explanation you’re reading.
Joining a Clinical Trial: the quick overview
A one-breath explanation you can watch before an appointment.
Coming soonJoining a Clinical Trial, explained simply
The core ideas with friendly animation and plain language.
Coming soonUnderstanding joining a clinical trial — full lesson
A deeper walkthrough covering the key takeaways and common questions.
Coming soonVideo transcript▾
A full, readable transcript will appear here when the video is published — so the lesson is accessible whether you prefer to watch, listen, or read. For now, the article above is the complete text version.
Suggested animation storyboard▾
- 1Open on a calm title card: "Joining a Clinical Trial" with the Cancer Explained mark.
- 2Narrator reads the 30-second summary while a soft animated diagram builds on screen: "If you are thinking about joining a cancer clinical trial, it helps to understand the possible risks and benefits and to ask questions first. Trials may offer access to a treatment under study and close monitoring, but the study treatment may not be better than standard care and could have serious side effects. Asking questions helps you decide what is right for you."
- 3Scene 2: illustrate the idea — "Every clinical trial is different, so its risks and benefits can differ too."
- 4Scene 3: illustrate the idea — "Possible benefits include access to a treatment under study and close monitoring by the research team."
- 5Scene 4: illustrate the idea — "Possible risks include that the study treatment may not be better than standard treatment and may have serious side effects."
- 6Close on a reminder card: this is educational only; talk with your healthcare team, and a link to the NCI source.
Words to know
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Quick knowledge check
According to this article, why can the risks and benefits differ from one clinical trial to another?
Frequently asked questions
▸What questions should I ask before joining a clinical trial?
It helps to ask about the trial's purpose, why the treatment being studied may or may not be better than current treatment, how long the trial lasts, how many visits are needed, what tests and treatments are involved, and how you will learn the results. You can also ask about risks and benefits, your rights and privacy, costs, and how the trial could affect your daily life.
▸What are the possible benefits of joining a clinical trial?
Possible benefits include helping researchers learn more about cancer and helping people in the future, gaining access to a treatment under study that may not be available otherwise, being watched closely by the research team as an extra layer of care, and — though not common — possibly being among the first to benefit if the new treatment works better than standard treatment.
▸What are the possible risks of joining a clinical trial?
Possible risks include that the study treatment may not be better than, or even as good as, standard treatment; that it may have serious side effects that are worse than standard treatment; that you may need more doctor visits and tests; and that you may have extra expenses such as travel, housing, and childcare.
▸Will a clinical trial affect my daily life?
It might. You can ask how often you would need to come to the hospital or clinic, whether you would need to stay in the hospital and for how long, how far you would need to travel, and whether you would have check-ups after the trial. These questions can help you understand what taking part would involve.
▸What if I decide to leave a clinical trial?
You can ask what other options you would have if you decide to leave the trial. It is a good idea to ask this, along with how your health information will be kept private, before you join.
▸Who pays for a clinical trial?
Costs vary, so it helps to ask which costs you would have to pay, what your health insurance would cover, who can help answer questions from your insurance company, and who you can talk with about costs and payments.
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Questions to ask your healthcare team
Consider bringing these questions to your next appointment.
- What is the purpose of this trial, and how long would I be in it?
- What are the possible side effects, risks, and benefits of the new treatment?
- How do the risks and benefits compare to standard treatment?
- Which costs would I pay, and what would my insurance cover?
- How could this trial affect my daily life, travel, and time?
- If I decide to leave the trial, what other options would I have?
- How will my health information be kept private?
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