Cancer trials
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About clinical trials

What is a clinical trial? And why do they matter…

A clinical trial is a research study that involves people. A study will look at the effect of a medical action on people’s health. While most research begins in the lab, it will only move forward into clinical trials once promising results have been achieved. A cancer clinical trial will be designed to test a new way of treating, diagnosing, preventing or reducing the side effects of cancer.

Clinical trials matter because they help advance cancer treatments, help us detect cancer earlier and allow researchers and doctors to answer specific scientific questions. The cancer treatments that are available today are the result of previous clinical trials. Cancer clinical trials offer people with cancer the opportunity to actively participate in their cancer treatment. Clinical trials also give individuals the opportunity to help others by contributing to cancer research to make future treatments better.

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Types of cancer clinical trials

There are many different types of clinical trials run at the Odette Cancer Centre, including:

  • Cancer treatment trials test new treatments or improvements to existing treatments. These may include:
    • New cancer drugs
    • New radiation or surgical techniques
    • Using an existing treatment in a new way

All treatment trials compare the new treatment or technique with the current best available standard of care. These trials involve individuals with diagnosed cancer. 

  • Cancer prevention trials look to find new ways to prevent or lower the chances of getting cancer. These trials can involve many different individuals, including:
    • Healthy individuals who have not had cancer but are at a high risk of getting cancer
    • People who have previously had cancer and are at a high risk of the cancer returning
  • Cancer screening trials include looking at new techniques to find cancer earlier. By detecting cancers earlier, they are easier to treat and may result in better outcomes for patients. These trials may involve healthy people that are at a high risk of getting cancer.
  • Cancer supportive care trials, also known as quality of life trials, look at ways to improve the quality and comfort of life for individuals with cancer. Treatments may focus on side effects from cancer and cancer treatments, including:
    • Pain
    • Nausea
    • The effects of cancer and cancer treatments on patients and their loved ones
  • Observational studies look for certain outcomes by following a group of patients. Patients will receive care and treatment led by their doctor. The study does not involve a specific intervention or actively affect outcomes. For example, observing a group of patients receiving cancer therapy to see if their physical abilities change.

Phases of cancer clinical trials

Cancer clinical trials are run in a series of steps, known as phases. Each phase is designed to answer a specific scientific question about the treatment or technique being tested. Once the treatment is successful in one phase, it will move onto the next phase for further testing. As a clinical trial participant, you would only be taking part in one phase of the new treatment.

Phase 1

Purpose: to determine how safe a new treatment is which may include identifying a safe dose (how much medication). This may also include determining the best way to give the new treatment (by mouth or in a vein, for example) as well as the effects the treatment may have on the body.
Number of participants: usually less than 30

Phase 2

Purpose: to determine how well the specific treatment works on a certain type of cancer. This will also include ongoing monitoring of the effects the treatment may have on the body.
Number of participants: usually less than 100

Phase 3

Purpose: to compare the new treatment with the current standard of treatment. Trials in this phase will also continue to closely monitor patients for effects the treatment may have on the body as well as the treatment’s effect on the cancer.
Number of participants: 100s to 1000s

Phase 4

Purpose: to look at the long-term safety and effects of the treatment. Trials in this phase take place after the treatment has been approved for market (use in a hospital or clinic setting).
Number of participants: 100s to 1000s

Who can participate in a clinical trial?

Every clinical trial has guidelines about who can participate. These guidelines help to ensure that all trial participants are similar in key ways. This is so researchers can be more certain the trial results are from the treatment and not from other factors. The guidelines for each trial are written in what is known as the trial protocol.

Some common criteria for participating in a clinical trial include:

  • The type or stage of cancer you may have
  • Being in a certain age group
  • Having received (or not received) treatment for your cancer
  • Your overall health, including current or previous medical conditions
  • Certain cancer genetic changes

To find out if you qualify for a clinical trial, please speak with your doctor. Additional tests may be required to ensure that you meet all criteria for participating in a certain trial.

Why do clinical trials use randomization?

In many clinical trials, patients are assigned to different groups that receive different treatments. This is usually done in order to compare the new treatment with the current standard treatment. The process of assigning patients to one group or the other is done by chance through a computer program and is known as randomization. Randomization reduces bias when assigning patients to one group or the other. By reducing bias, study results are not affected by human choice and are more accurate. If your clinical trial is a randomized trial, you will be placed in one of the following groups:
  • The investigational group, which will receive the new treatment being tested
  • The control group, which will receive the current best standard of treatment

If you are participating in a randomized clinical trial, it is important to keep in mind that there are set numbers of participants placed in one group or the other. Your doctor will have no choice or say about which group you are in. In some trials, you and your doctor will both not know which group you have been placed in; these are known as blinded trials.

What is a placebo?

A placebo is a pill or injection that is designed to look like the treatment being tested but has no active effect on the body.
In cancer clinical trials a placebo is rarely given to patients on its own. Instead, a placebo may be given alongside standard treatment, for example:
  • The investigational group may be given standard treatment plus the new treatment
  • The control group may be given standard treatment plus a placebo

Placebos are used to help prevent doctors and patients from knowing which group they are placed in for trials that are randomized and blinded. You will be told if a clinical trial uses a placebo before agreeing to participate.

Deciding to take part in a clinical trial

Deciding to take part in a clinical trial is a decision that you, those close to you, your doctor and health-care team make together. Ultimately, it is your personal choice to participate or not. By considering a clinical trial as part of your cancer treatment, you are actively taking part in a decision that affects your life. The following are things to consider when making your decision.

Possible risks and benefits

As with all cancer treatments, clinical trials have both benefits and risks. It is important to discuss possible benefits and risks with your doctor as well as with those close to you. Each patient may face different benefits and risks.

Possible benefits may include:

  • You may be among the first to receive a new treatment that is otherwise not available
  • If the new treatment works and you are receiving it, you may or may not be among the first to benefit
  • You will be closely followed by your doctor and the research team
  • If you are placed in the group that does not receive the new treatment, you will still receive the best standard of treatment available. This may be as good as the new treatment that is being studied
  • You have the chance to help scientists learn more about cancer and cancer treatments that will benefit future patients

Possible risks may include:

  • If you receive the new treatment it may not be better than the current standard of treatment
  • You may experience side effects of the new treatment
  • If you are in the group that receives the standard treatment, you may not do as well as the group that receives the new treatment
  • The new treatment may work for other patients but not for you
  • You may be required to attend additional appointments, take additional medications and have additional tests

Your safety and rights as a patient on a clinical trial

It is important to feel that your health, safety and privacy are protected when you participate in a clinical trial. It is also important to know that you have rights when participating in a clinical trial. Some of these are outlined below.

How you’re protected

To protect participants, clinical trials must follow strict rules and meet high standards. These include approval and ongoing monitoring of the trial by:

  • Research Ethics Boards
  • International Conference on Harmonization Good Clinical Practice Guidelines
  • Sunnybrook Policies and Procedures
  • Regulatory Boards, such as Health Canada and the US Food and Drug Administration when appropriate

Trial protocol

The trial protocol is a written document that acts as the plan for the trial. It includes all of the information required for research staff to carry out the trial. It will include information about:

  • The reason why the trial is being done
  • Who can participate in the trial
  • How many people are required to participate
  • What treatments participants will receive, including doses and how often
  • What medical tests are required and how often
  • How long the trial is expected to run for
  • What information is collected about participants
  • How to manage side effects of the trial treatment
  • How the researchers will measure if the treatment is working

Informed consent

Before deciding to take part in a clinical trial, you will be informed by research staff of the purpose of the trial, the possible risks, possible benefits and what involvement will be required from you. The process of learning this information and making a decision based on it is called informed consent. It is an important step in clinical trials to ensure patient safety. The informed consent is specific to the trial’s protocol. The research staff will go over the document with you to explain the trial in detail, including:

  • The purpose of the trial
  • What treatments will be involved
  • Possible risks, benefits and side effects
  • What tests and procedures may be required
  • What information about you will be collected
  • How your information will be kept confidential
  • Who to contact if you have questions about the trial

You will receive a printed copy of the informed consent form to read, review and sign if you decide to participate. You will also be able to take the form home. The form must be written in terms that you easily understand. The research staff will be there to answer any questions you may have and to ensure that you fully understand all aspects of the trial. You have the right to take your time to understand the trial and to decide if you want to participate.

You also have the right to learn about other treatment options available for your type and stage of cancer and how the trial treatment may compare.


You are able to leave a trial at any time, even after signing the informed consent form. Participating in a clinical trial is voluntary and you have the right to make the decision to withdraw from the trial at any point. If you decide to leave a trial, your doctor will discuss treatment options with you and you will continue to receive the best standard treatment available.

Please ask your healthcare team these questions, along with any others you may have, to help you decide if participating in a clinical trial is right for you.

For further information, please email


Canadian Cancer Society
National Cancer Institute
It Starts With Me - Network of Networks

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