About Clinical Trials: Information from the National Cancer Institute

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 clinical 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 the safety of the therapy for the next phase of

  • 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

  • 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

  • Phase IV trials. These include the ongoing study of
    the therapy. They look at long-term safety and effectiveness. They take place
    after the FDA approves the therapy. The therapy is already available for general

What is 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, including the risks and
benefits, of the clinical trial will be shared with you before you agree to be in
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 protocol. 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
be combined and compared.

After you learn about all the
details and you agree to take part in the study, you’ll be asked to sign the consent
form. Signing it means that you understand the risks and benefits of the clinical
plan and agree to take part in the study. Even after signing the form, you may leave
study at any time.

Where are trials conducted?

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

Who can take part 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

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, such as the National Cancer Institute

  • Institutional Review Board
    (IRB) that oversees clinical research in a healthcare organization. The IRB
    includes healthcare providers, consumers, patient advocates, 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
stop the trial early if the main research question is answered sooner than expected
if there are safety concerns.

For information on how to
participate in a clinical trial, talk with your healthcare provider or visit the
National Cancer Institute’s
clinical trial web page.