About Clinical Trials: Information from the National Cancer Institute

What are cancer clinical trials?

Cancer clinical trials are research studies with people. They may be done by government agencies, educational organizations, private not-for-profit groups, or commercial businesses. Trials are used to check how safe new cancer tests or treatments are and how well they work.

What are some types of cancer clinical trials?

According to the National Cancer Institute, there are different types of cancer clinical trials. These include:

  • Prevention trials. These trials are test therapies that might keep cancer from developing in people who have never had cancer. Some of these trials test treatments that might keep a new type of cancer from forming. Others may look at things like activity or diet and cancer risk.

  • Early detection or screening trials. These trials look for new ways to find cancer, especially in its early stages, when it's small and easier to treat.

  • Treatment trials. Such trials test new therapies in people who have cancer. Treatment trials often compare the best treatment available today to new and possibly better treatments. 

  • Quality of life studies. These are done to improve the comfort and quality of life for people who have cancer and their loved ones.

What are the phases of a clinical trial?

Most clinica trials go through an orderly series of steps or phases:

  • Phase 0 trials. These are the earliest steps in testing new treatments in humans. A small number of people are studied. The goal is to learn how the agent is used by the body and how the agent affects the body. This type of trial does not give information on how safe the agent is or how well the agent treats the cancer. These trials help researchers decide if the treatment should move on to Phase I trial. 

  • Phase I trials. These are the first studies to check how a new therapy should be given, how often, and in what dosage. The focus is to find out information about safety of the therapy for the next phase of testing.

  • Phase II trials. These provide beginning information about how well the new therapy works. They also give more information about its safety and benefits. A Phase II study usually focuses on a certain type of cancer.

  • Phase III trials. These compare a promising new therapy, combination of treatments, or procedure with a current standard of treatment. These trials often have large numbers of people. They may be done at healthcare providers' offices, clinics, and cancer centers nationwide, or even worldwide.

  • Phase IV trials. These include the ongoing study that takes place after Food and Drug Administration (FDA) approves the therapy. The therapy is already available for general use.

What is a informed consent?

Informed consent is a process that explains the important facts about a specific clinical trial. The goal is to protect potential people involved in the study. All the details of the clinical trial will be shared with you before you agree to be in it. You will be told things like:

  • What will be studied and how

  • What treatments and medical tests will be used as part of the study

  • What information will be collected

  • Your rights, including your right to leave the study at any time

  • All the treatment options that might be right for you

  • Who is on the research team and their contact information

This information may be found in the clinical trial protcol. This is the action plan or guidelines that must be followed during the course of any study. Several research centers may be involved in the study. Each center uses the same protocols to make sure that information from all centers can be combined and compared.

After discussing all the details with you, you'll be asked to sign the consent form. Signing it means that you understand the clinical trial plan and agree to take part in the study.

Where are trials conducted?

Trials can be done at large cancer centers, university hospitals, local medical centers, or healthcare provider offices. 

Who can participate in a trial?

Each protocol in a trial lists the specific characteristics that participants should have to participate in the study. These characteristics are called eligibility criteria. They may include the type of disease and its stage, as well as the person's age and general health.

These criteria help researchers know for sure that the study results answer the research question. They also identify who will benefit in the future from the approach being studied.

How are trial participants protected?

Several procedures are put in place to protect the safety of the participants. Two groups that watch over the safety are the:

  • Organization that sponsors the study, for example, the National Cancer Institute

  • Institutional Review Board (IRB) that oversees clinical research in a healthcare organization. The IRB includes healthcare providers, consumers, and sometimes members of the clergy. The members of the IRB do not have any personal interest in the results of the study. They make sure that the study is done fairly and that there is a low chance of harm to the participants compared to the possible benefits.

A Data Safety and Monitoring Committee is another special group involved in some clinical trials, especially Phase III trials. This group looks at the ongoing test results, monitors the safety of the participants, and decides whether the study should go on as originally planned. They can stop the trial early if the main research question is answered sooner than expected or there are safety concerns.

For information on how to participate in a clinical trial, please talk with your healthcare provider or visit www.cancer.gov/about-cancer/treatment/clinical-trials.