Clinical trial benefits, risks and costs

Clinical trials are carefully designed to have as few risks and as many benefits as possible for everyone who takes part. But each clinical trial offers its own possible benefits and risks – and it’s important to talk about them with the clinical trial team.

Clinical trials must be approved by a research ethics board of the hospital or clinic where the trial takes place. Health Canada reviews the clinical trial protocol. A protocol is a written description of the trial. Health Canada also reviews the scientific evidence behind the new treatment (if the trial is testing a drug or device that has been approved by Health Canada for some people but not for the people who would be enrolled in this trial). These groups make sure that the trial is legal, ethical and well designed, and that it does not involve unnecessary risks to the people in the trial. Health Canada’s review also makes sure that drugs and devices meet acceptable standards.

While the trial is going on, trial leaders (called the trial committee), the research ethics boards of participating centres and hospitals, Health Canada, and an independent data and safety monitoring committee (in larger trials only) watch over the safety of patients and make sure that the research is done according to the clinical trial protocol. These groups regularly review trial conduct and may change or stop a trial if they are concerned. If you are a participant in a trial, you will be told about any changes or new risks seen in a trial. A trial may be stopped early if deemed unsafe or if results of a new treatment are extremely good.

The possible benefits of being in a clinical trial include:

  • You will be given the best standard cancer treatment available, even if you aren’t given the new treatment. You will also be followed closely during and after the clinical trial.
  • If the new drug being studied in a clinical trial works effectively to treat or prevent cancer, you may be one of the first people to benefit from the treatment.
  • Taking part in a clinical trial is a chance to help others and improve the treatment of cancer.

The possible risks of being in a clinical trial include:

  • New drugs or treatments under study are not always better than, or as good as, the standard ones.
  • There may be unexpected side effects that may be worse than those caused by standard drugs or treatments.
  • A new treatment may not work for everyone in the trial (just as a standard treatment may not work for everyone).
  • If you are in the control group, you may not benefit as much if the new treatment is more effective at treating cancer. (The people in a control group do not get the treatment being studied.)
  • Being in a clinical trial may take extra time or be inconvenient. You may have more tests or take extra medicines.


In most cancer treatment trials in Canada, your provincial health insurance plan or the group sponsoring the study will cover the cost of care, medicine and testing. But it’s a good idea to ask the clinical trial team about possible extra costs or expenses and whether these are covered. These might include the cost of getting to the treatment centre or medicine to treat side effects of treatment, such as anti-nausea drugs.

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 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.

We do our best to make sure that the information we provide is accurate and reliable but cannot guarantee that it is error-free or complete.

The Canadian Cancer Society is not responsible for the quality of the information or services provided by other organizations and mentioned on, nor do we endorse any service, product, treatment or therapy.

1-888-939-3333 | | © 2024 Canadian Cancer Society