What Are the Different Types of Clinical Trials?

Clinical trials are research studies that test how well new medical approaches work in people. In cancer research, that covers a lot of ground. Trials look at finding cancer earlier, preventing it in the first place, treating it once it is found, and easing the side effects of cancer and its treatment. Because those goals differ so much, cancer clinical trials are grouped into a few main types.

Treatment trials are the most common type of cancer clinical trial. They involve people who already have cancer. They test new treatments, or new ways of using treatments that already exist. That might mean a brand-new drug, a new combination of existing drugs, a new dose or schedule, or a new way of delivering a treatment.

Prevention trials look at ways to stop cancer from developing at all. People in these trials usually do not have cancer now. They are often at high risk of developing it, or they have had cancer before and are at high risk of a new one. A prevention trial might test a medication, a lifestyle change, or another approach aimed at lowering future risk.

Screening trials test ways to find cancer before it causes any symptoms. The thinking is that cancer found early, before it is 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 would be found otherwise.

Supportive care trials, sometimes called palliative care trials, focus on quality of life. They do not test a cancer treatment itself. They look at ways to manage what cancer and its treatment bring, such as pain, fatigue, nausea, or emotional strain. The goal is to help people feel and function better while they go through cancer care.

Each of these four types is built to answer a different research question. A treatment trial asks whether a new approach works better than the one used now. 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. A supportive care trial asks how to make cancer and its treatment easier to live with.

Knowing which type of trial you are looking at tells you whether it fits your situation. If you do not have cancer but have a strong family history, a prevention trial may be worth raising with your doctor. If you are newly diagnosed and weighing treatment options, a treatment trial is the more relevant conversation. If side effects are your hardest daily problem, a supportive care trial may be worth exploring while you stay on your current plan.

Talk with your care team about which type of trial fits your circumstances. That is a good first step before you search for specific studies to consider.