Clinical trials basics

What clinical trials are, how they work, and what to ask if you are thinking about joining one.

Rosa: Hi, I'm Rosa. Clinical trials help find better ways to treat cancer. Let me explain how they work, so you can decide if one might be right for you.

A clinical trial is a research study that tests a new way to prevent, find, or treat cancer. Almost every cancer treatment used today was first tested in a trial. Trials can be a good choice at any stage, not only as a last option.

Ask about trials when you are first diagnosed and any time your treatment changes. Each trial has rules about who can join, so some doors close once treatment starts. See Find help for ways to search.

Thinking about a trial can bring up many feelings. You may feel hopeful, nervous, or unsure. All of these feelings are normal. You do not have to decide quickly. Take the time you need to learn about the study and talk it over with people you trust.

Trials follow strict rules to protect the people who join. Each study is reviewed before it starts. A team of doctors, nurses, and research staff runs it, and the study is watched closely while it is going on. Your safety and your rights come first.

If you join, you may have extra visits, blood tests, scans, or surveys. The study team will tell you how often and how long. Ask for a copy of the schedule. It can help to bring a family member or friend to visits to listen and take notes.

Keep your own cancer doctor in the loop. They know your health history and can help you decide whether a trial fits your care plan. You do not have to make this choice alone.

Phases in plain words

Phase 1 trials test whether a new treatment is safe and find the right amount. Phase 2 trials check whether it works against a certain cancer. Phase 3 trials compare the new treatment with the current standard treatment.

The placebo myth

Most cancer trials do not give a sugar pill instead of treatment. When a placebo is used, it is usually added on top of standard treatment. You will be told before you join if a placebo is part of the study.

Informed consent

Before you join, the study team explains the goals, tests, possible risks, and possible benefits. You get a written form to read and take home. Ask all your questions before you sign.

You can leave

Joining is always your choice. You can leave a trial at any time, for any reason. Your care team will still take care of you.

Costs

The study often pays for the drug being tested. Most insurance, including Medicare and Medicaid, must cover routine care costs in a trial. Travel and parking may not be covered, so ask whether the trial offers help.

Questions to ask

Write your questions down before your visit. You might ask: Why is this study being done? What will happen to me, and how often? What are the possible side effects? How is this different from my other choices? Who do I call with questions?

Who can help

A nurse navigator or social worker can help you find trials and understand the paperwork. A financial navigator can help with costs, travel, and insurance questions. Your palliative care team can help you manage symptoms and side effects during a trial.

Tell the team how you feel

Report any new symptoms or side effects to the study team, even if they seem small. They need to know so they can help you and keep you safe. Your honest answers also make the study more useful.

When to call your care team

Call right away if you have a fever, trouble breathing, new or worsening pain, or side effects that worry you. Use the phone number the study team gave you. If it feels like an emergency, call 911. You can also call if you are feeling overwhelmed or want to talk about leaving the study.

Last updated: 2026-10-27. Medically reviewed by Veli Bakalov, MD, medical oncologist (October 2026). General education from Step by Step, the patient portal of HemeOncBuddy.