OHSU Knight Cancer Institute

Understanding Cancer Clinical Trials

The OHSU Knight Cancer Institute takes part in hundreds of clinical trials. Expanding scientific knowledge is a key mission of OHSU, Oregon’s only academic health center. The following information is adapted from the Clinical Trials pages of the National Cancer Institute.

What are clinical trials?

Clinical trials are research studies with human subjects that test ways to prevent, detect, diagnose or treat medical conditions. They play a crucial role in medical breakthroughs by showing which methods safely work.

Clinical trials generally follow years of lab research. Scientists test only the most promising medications and methods on people.

Benefits and risks of clinical trials

Possible benefits of taking part in a clinical trial:

  • Clinical trials offer early access to new and possibly better treatments.
  • You help advance scientific understanding.
  • You may help improve patient care.

Possible risks of taking part:

  • A treatment might cause side effects or carry unknown risks.
  • A new treatment might not work as well as a standard treatment.
  • You may need extra doctor visits and tests.
  • The treatment might not work for you.
  • Insurance may not cover all costs.

How clinical trials work

How clinical trials are organized

A “principal investigator,” usually a doctor, leads the trial. The doctor designs a “protocol” that outlines:

  • The trial’s goal
  • Who can join or “enroll” (the “eligibility criteria”)
  • How many people are needed
  • Any drugs or treatments that will be given, how and how often
  • Any tests that will be done and how often
  • Information that will be collected from the people who take part

Enrolling in a clinical trial

Trials often have precise criteria — age, type of cancer, health status and other factors — for those who take part. It can be important to test medications or treatments on similar people to make sure other factors aren’t playing a role.

Phases of clinical trials

Cancer trials typically span three phases. A trial advances to the next phase only if it’s successful. Learn more from the National Cancer Institute and from the American Cancer Society.

  • Phase 1: These are done to find a safe dose, to find the best way to give a treatment (by mouth or shot, for example) or to see how a treatment affects the body or fights cancer. Phase 1 trials may include 15 to 30 people.
  • Phase 2: These are done to see if a new treatment has an effect on a particular cancer. They may include fewer than 100 people.
  • Phase 3: This phase compares the new treatment with the standard treatment (placebos are seldom used in cancer trials). It may involve 100 to thousands of people.

Clinical trial safety

Informed consent: Before you agree to join, the research team must explain the trial’s purpose, procedures, risks and benefits. They will also explain your rights, including the right to stop at any time. 

Oversight: Experts review a trial’s protocols before it starts. Members of institutional review boards, or IRBs, evaluate and monitor trials for safety. Trials also may have a data and safety monitoring board, or DSMB. IRBs and DSMBs can stop trials early if needed. The federal Office for Human Research Protections and the U.S. Food and Drug Administration also play important oversight roles. 

Learn more about clinical trial safety, including rules for children. 

Who pays

Research costs: The trial’s sponsor, such as a drug company, typically pays for the cost of medication, lab tests and imaging.

Patient care costs: A patient’s health insurance usually covers costs such as:

  • Doctor visits
  • Hospital stays
  • Standard treatments
  • Lab tests and imaging not done for the trial 

Learn more about who pays for clinical trials.

Questions to ask about a clinical trial

Talk with your care team about whether a clinical trial is right for you. You might take a friend or family member for support and to help ask questions and write answers. Consider recording the conversation.

Here are questions you might ask. Find more on the National Cancer Institute and American Cancer Society websites.

  • Does this trial make sense for my type of cancer?
  • What are the potential benefits and risks?
  • What are the potential benefits and risks of my other options?
  • What is the purpose of the trial?
  • Why do researchers think the new treatment may be better?
  • How long will I be in the trial?
  • What kinds of tests and treatments are involved?
  • Will they hurt? If so, for how long?
  • What are possible side effects?
  • How could the tests and treatments affect my daily life?
  • How will the doctor know if the treatment is working?
  • Who will be in charge of my care?
  • Who will I contact if I have problems or concerns?
  • What happens if I decide to leave the trial?
  • Will I have to pay for any of the tests or treatments?
  • Will the trial require extra time?

Learn more

Cancer clinical trials

Clinical trials allow patients to try a new test or treatment.