About Clinical Trials

Aprobado por la Junta Editorial de Cancer.Net, 08/2017

A clinical trial is a research study that involves volunteers. These types of studies help doctors find better treatments and ways to prevent cancer and other diseases.

Why are clinical trials done?

Clinical trials are the main way that doctors find better treatments for diseases such as cancer. They also help doctors answer other questions, such as how to prevent disease or manage symptoms and side effects.

In the United States, the Food and Drug Administration (FDA) requires all new drugs and other treatments to be tested in clinical trials. This must happen before the FDA approves any new treatment for everyone to use.

There are many clinical trials at a given time because doctors always need new information and ways of caring for people with cancer. If you or a loved one has cancer, joining a clinical trial may be an option. You might do this because you want to try a new drug or treatment. Or, you might do it because it helps doctors develop better treatments for the future.

What are the different types of clinical trials?

Clinical trials are used in 4 different ways.

Clinical trials to find new treatments. Clinical trials to find treatments might study:

  • A new drug or drug combination

  • A new way of doing surgery or giving radiation therapy

  • A new way to combine treatments or give them in a different way

Doctors want to know if a new drug or treatment works as well or better than the treatment they already use, called the “standard of care.” They also want to learn about the side effects and make sure that the side effects are not too severe.

Clinical trials for side effects and symptoms. Doctors are always looking for ways to make people with cancer feel better. They find these ways by doing clinical trials for side effects and symptoms. For example, some types of chemotherapy can make you vomit (throw up). Through clinical trials, researchers looked for drugs to prevent nausea and vomiting from chemotherapy. This research has helped them develop better drugs to reduce these side effects. Now, people who get chemotherapy do not usually get as sick as in the past.

Clinical trials for long-term side effects. Today, doctors cure more than half of all cancers. But cancer treatment can affect people’s health for years after the cancer is cured. Side effects that happen a long time after treatment are called late effects. For example, some cancer treatments can cause heart problems later in life. Doctors learn how to better prevent and manage long-term side effects for their patients through clinical trials.

Clinical trials to prevent and look for cancer. Doctors also use clinical trials to look for new ways to prevent cancer and find it early. Treatments often work better at earlier stages of the cancer. Some questions they study in these clinical trials are:

  • How can we keep people from getting this type of cancer?

  • Is this cancer inherited (passed on from parent to child)?

  • Can we prevent an inherited cancer from developing? Can we find it earlier or warn people they could get it?

  • Can this cancer be prevented by eating or avoiding certain foods or medicines?

  • Does it help to change your habits, such as getting more sleep or exercise?

How do clinical trials work?

All clinical trials follow a set of rules. Doctors call these rules the “protocol.” Every clinical trial has its own protocol, but the protocol must always include certain things. These are:

  • Who can be in the clinical trial, and who cannot

  • When and how much medicine is given

  • When medical tests and procedures are done

  • How long the clinical trial lasts

  • How doctors will compare the different treatments in the clinical trial

How do doctors decide if I can be in a clinical trial?

Doctors decide who can be in a clinical trial by looking for people with certain things in common. You may hear this called the “eligibility criteria.” This allows them to accurately compare the clinical trial treatments. Similarities they look for include:

  • Age

  • The type of cancer or cancer stage

  • Medical history (other health problems or conditions, now or in the past)

  • How your health is now

  • Any treatments you already had

They also decide if it is safe for people to be in the clinical trial. Some ways they decide include:

  • Medical history

  • Your health now

  • If the clinical trial treatment is safe for you

You should not feel bad if your doctor says you cannot join a specific clinical trial. The doctor and clinical trial research team want to keep patients safe and also make sure the clinical trial treatment is right for you.   

How does clinical trial staff keep me safe?

The clinical trial doctor and staff check your health regularly during the clinical trial. Clinical trial staff also include nurses, research staff, and other health care professionals.

Before you start a clinical trial, the research team answers any questions you have. They review all the clinical trial information with you and help you join the clinical trial, if you understand the information and still want to.

During the clinical trial, the research staff will monitor your health and tell you about the medical tests and procedures you will need to get done.

After the clinical trial ends, the staff may check on you for several weeks, months, or even longer. They will want to know if the treatment causes any problems. They might also want to know how long the treatment works.

What should I do if I am in a clinical trial?

You should:

  • Follow all the instructions from the research team

  • Ask questions if something isn’t clear to you

  • Tell the research team if you have a new health problem (It might be a side effect of the clinical trial treatment, or it might not.)

  • Tell the research team if you are worried about anything

It is important to share information about your health with the research team during and after treatment. They are interested in all the details of your health during the clinical trial. They want to keep you safe.

Will I know what treatment I get?

That depends on the clinical trial. In some studies, the research team knows what treatment patients are receiving but the patients do not. In other studies, no one knows what treatment people in the clinical trial get, including the research team. Sometimes everyone knows, including the patients.

What are the phases of clinical trials?

Phases are the stages a clinical trial must go through. The main phases are phase I, phase II, and phase III, written in Roman numerals. All clinical trials must start with phase I. The different phases give doctors different information about the treatment being studied.

Clinical trial phases are different from cancer stages. Cancer stages describe how much cancer there is and how far it has spread. Clinical trial phases describe different things doctors are studying about a new drug or treatment.

A person does not go through each phase of a clinical trial. You can join or leave a clinical trial at any phase.

Learn more about phases of clinical trials.

Can a clinical trial help my cancer?

It might. Clinical trials offer a lot of hope for many people with cancer.

If you or a loved one has cancer, your doctor might ask if you want to be in a clinical trial. If you decide to participate, you will get the same level of care you would with cancer treatment outside of a clinical trial. There is also a chance the clinical trial treatment will help you.

Clinical trials may include hundreds or even thousands of people. That means it can take a long time to get results.

There are more children in clinical trials than adults. More than 60% of children with cancer join a clinical trial, and 75% survive for a long time after cancer. Fewer than 5% of adults join a cancer clinical trial and about 50% of adults survive a long time after cancer.

Learn more with free videos

PRE-ACT, Preparatory Education About Clinical TrialsYou can watch a free series of educational videos on Cancer.Net. The series is called Preparatory Education About Clinical Trials, or PRE-ACT.

To get a personalized selection of videos, you can answer questions about your own information and preferences. Or you can watch the entire series. You need to create an account to get personalized videos. If you have an account, you can also start and stop watching at any time.

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