Understanding the clinical trial and informed consent

Before you decide to join a clinical trial, you need to understand the protocol. A protocol is a written description of the trial. It explains why the trial is being done, how it will be conducted and how your safety will be protected.

The protocol will also include information on:

  • who can participate in the trial (eligibility)
  • how many people will take part in the trial
  • what type of treatment will be given and how often
  • what medical tests you will have during the trial and how often
  • how long the trial is expected to last
  • how the researchers will know if a treatment is working
  • what type of information will be collected and how the information will be analyzed

Where clinical trials are held

A clinical trial usually takes place in the same location where standard cancer treatment is given – cancer centres, hospitals, clinics or doctors’ offices. While some trials enrol people at 1 or 2 locations only, a large clinical trial may involve thousands of people at hundreds of locations across the country or around the world.

If you live in a small town or rural area, you may need to travel to a larger city to participate in the trial and take follow-up tests.

The clinical trial team

Clinical trial teams are made up of doctors, nurses, pharmacists, research assistants and other healthcare professionals who are trained in clinical medicine and in proper conduct of clinical trial research. The person in charge of the clinical trial, usually an oncologist, is called a principal investigator.

A clinical research associate or clinical research nurse on the team is there to help support you during treatment. This includes answering your questions, monitoring your health during the trial and helping you understand what will happen during the clinical trial.

Who can be in a trial?

Clinical trials often enrol people who share many of the same characteristics. This is to make sure that the trial results will be scientifically accurate. The rules about who can be in a trial are called eligibility criteria.

The eligibility criteria may include:

  • age and sex
  • the type of cancer
  • the stage of the cancer
  • the results of certain lab tests
  • your overall health and whether you are being treated for other health problems
  • how many and what types of cancer treatments you have received
  • how long it has been since you last had treatment

These criteria also help researchers understand who will benefit most from a new treatment. For example, a new treatment may work for one cancer but not another or it may work best at certain stages of cancer.

Expert review and references

  • American Cancer Society. The basics of clinical trials. 2016.
  • American Cancer Society. Making the decision about clinical trials. 2016.
  • Delacruz A & McCall S . Principles of cancer clinical trials. Yarbro CH, Wujcki D, Holmes Gobel B, (eds.). Cancer Nursing: Principles and Practice. 8th ed. Burlington, MA: Jones and Bartlett Learning; 2018: 9: 227-242.
  • National Cancer Institute. What are clinical trials?. 2016: https://www.cancer.gov/about-cancer/treatment/clinical-trials/what-are-trials.
  • National Cancer Institute. Informed consent. 2016.
  • National Institutes of Health. Are clinical studies for you?. 2017.
  • Simon RM . Design and analysis of clinical trials. DeVita VT Jr, Lawrence TS, Rosenberg SA. Cancer: Principles and Practice of Oncology. 10th ed. Philadelphia: Wolters Kluwer Health/Lippincott Williams & Wilkins; 2015: 36:398-415.

Medical disclaimer

The information that the Canadian Cancer Society provides does not replace your relationship with your doctor. The information is for your general use, so be sure to talk to a qualified healthcare professional before making medical decisions or if you have questions about your health.

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