The short answer
Clinical trials are research studies that test how well new medical approaches work in people. In cancer research, the main types are treatment trials, prevention trials, screening trials, and supportive or palliative care trials, each answering different research questions.
Clinical trials are research studies that test how well new medical approaches work in people.
Treatment trials are the most common type and involve people who have cancer.
Prevention trials usually involve people at high risk of cancer, or of a new cancer after treatment.
Screening trials test ways to find cancer before it causes symptoms, when it may be easier to treat.
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The full explanation.
A shared starting point
Clinical trials are research studies that test how well new medical approaches work in people. In cancer research, that broad definition covers a lot of ground — from finding cancer earlier to preventing it in the first place to treating it once it's diagnosed to easing the side effects that come with cancer and its treatment. Because the goals differ so much, cancer clinical trials are grouped into a few main types.
Treatment trials
Treatment trials are the most common type of cancer clinical trial. They involve people who already have cancer, and they test new treatments, or new ways of using treatments that already exist. This might mean testing a brand-new drug, a new combination of existing drugs, a new dose or schedule, or a new way of delivering an existing treatment.
Prevention trials
Prevention trials look at ways to prevent cancer from developing in the first place. Participants in these trials usually don't currently have cancer. Instead, they're often people at high risk of developing cancer, or people who've already had cancer and are at high risk of developing a new cancer. Prevention trials might test a medication, a lifestyle change, or another approach aimed at lowering future risk.
Screening trials
Screening trials test ways to find cancer before it causes any symptoms. The idea behind this type of trial is that cancer found earlier, before it's advanced, may be easier to treat. These trials often study new tests or new ways of using existing tests to catch cancer sooner than it might otherwise be found.
Supportive care and palliative care trials
Supportive care trials, sometimes called palliative care trials, focus on improving quality of life for people with cancer. Rather than testing a cancer treatment itself, these trials look at ways to manage the side effects that come from cancer and its treatment — things like pain, fatigue, nausea, or emotional strain. The goal is to help people feel and function better while they're going through cancer care.
Different types, different questions
Each of these four types of trials is built to answer a different research question. A treatment trial asks whether a new approach works better than what's currently used to treat cancer. A prevention trial asks whether something can lower the chance of cancer developing at all. A screening trial asks whether a new method can catch cancer earlier than current approaches. A supportive care trial asks how to make the experience of cancer and its treatment more manageable.
Why the distinction matters to you
Knowing which type of trial you're looking at can help you understand whether it's even relevant to your situation. If you don't currently have cancer but have a strong family history, a prevention trial might be worth discussing with your doctor. If you're newly diagnosed and weighing treatment options, a treatment trial might be the more relevant conversation. And if side effects are your biggest daily challenge, a supportive care trial might be worth exploring even while you continue your current treatment plan.
Talking with your care team about which type of trial fits your circumstances is a good first step before searching for specific studies to consider.
Words to know
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Common questions
▸What are the main types of clinical trials?
The main types are treatment trials, prevention trials, screening trials, and supportive or palliative care trials. Each type is designed to answer a different research question.
▸What is a treatment trial?
A treatment trial is the most common type of cancer clinical trial. It tests new treatments, or new ways of using existing treatments, in people who already have cancer.
▸What is a cancer prevention trial?
A prevention trial looks at ways to prevent cancer. Most participants don't have cancer but are at high risk of developing it, or they've had cancer before and are at high risk of a new cancer.
▸What is a screening trial?
A screening trial tests ways to find cancer before it causes symptoms, when it may be easier to treat.
▸What is a supportive care or palliative care trial?
This type of trial looks at ways to improve quality of life for people with cancer, especially by managing side effects of cancer and its treatment.
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