Frequently Asked Clinical Trials Questions

What is a Clinical Trial?

Before a new intervention (e.g.: a medication or a treatment plan) can be integrated into clinical practice, researchers have to make sure that it is safe and useful. Testing consists of four stages. Stage III of testing is usually a Clinical Trial. This is a large study involving thousands of patients with the disease. Clinical Trials may compare the new intervention (Drug X) to:

  • Drug X versus placebo
  • Drug X versus Drug Y
  • Drug X versus Standard Drug

Patients must fit a set of parameters called the “eligibility criteria” to consider participating in a Clinical Trial. In cancer trials, these criteria often describe a certain location and stage of the disease. If someone is eligible and agrees to join the trial, they are randomly assigned to a treatment group. This is very important, because it means that not everyone receives the same treatment. A lot of the time, patients (and potentially even their doctor) will not be told which treatment they are receiving. This is called “blinding” and it is done to minimize bias and make sure the results of the experiment are accurate.

Successful Clinical Trials are a the best form of evidence to determine appropriate treatments. They are the Gold Standard in science! The results of a Clinical Trial can help researchers determine if a new treatment is better, worse or the same at achieving a particular goal compared to the control drug or placebo.

Participating in Clinical Trials can potentially give patients access to treatment with new or otherwise unavailable medications or treatment routines. It is also an excellent way to contribute to research, so that the medical community can continue to develop better ways to help gastric cancer patients.

Clinical Trial Story:

DISCLAIMER: the following story is fictionalized and meant to explain the general process of enrolling in an oncology clinical trial; it in no way represents a specific patient experience.


Carrie is an advanced gastric cancer patient who has has been diagnosed with a T3 tumor in the distal region of her stomach. She is not eligible for gastrectomy surgery. Carrie has been treated with chemotherapy for the past several months since her diagnosis. However, she does not seem to notice any relief of her symptoms and would like the chance at another treatment. Carrie’s son tells her that it might be possible to enrol in a Clinical Trial, which represents the final stage of quality-testing for a new medicine or treatment plan before it becomes prescribed by doctors. Carrie learns that the treatments being tested in a Clinical Trial have already passed through many stages of intense testing to make sure they are safe. She agrees with her son that this could be a good option for her.

Learning more:

The purpose of a Clinical Trial is to find out if a new treatment is truly better than the standard options which are currently being used to treat patients. So, they often follow a randomized design. This means that patients are randomly assigned to one of the comparable treatment groups. Only one group will actually receive the new treatment, and usually patients are not told which medicine they are taking (which is known as “blinding”). After learning this information, Carrie is still interested in participating in a Clinical Trial even though she knows she is not guaranteed to receive the new chemotherapy.  

Carrie speaks with her doctor about Clinical Trials happening nearby. She learns that a hospital in her city is currently recruiting patients for a trial which compares the old chemotherapy Carrie is currently using, to a new routine. Thankfully, her characteristics (age, cancer diagnosis, previous treatment, etc.) fit the trial eligibility criteria. Carrie is able to get in contact with the local Trial Coordinator using a referral form from her doctor.

This individual gives Carrie more information about the trial and guides her through the consent process. The Trial Coordinator sits down with Carrie and explains what the Trial is trying to accomplish, the commitment and timeline required from participants, as well as potential side effects of the treatment. Carrie correctly understands that she is not obligated to participate, and that she should only say “yes” after thinking about her choices. Also, Carrie knows that if she does decide to participate, she can withdraw consent (drop out of the trial) at any time. Feeling a little overwhelmed, Carrie takes the information she was given home to discuss with her family. She also goes to see her Family Doctor to ask for his advice and takes some time to think it over. Eventually, Carrie decides that she does want to participate in the Trial, and gives the Coordinator a call back.

The Consent Process:

The process of “obtaining informed consent” in Clinical Trials is extremely important! This means: a) the patient fully understands the Trial and their role in it, b) the patient knows about the potential risks and benefits of participating, c) the patient understands that they can choose to stop participating at any time, and d) they give their signature as a participant.

Informed consent begins with a conversation between the researcher and the patient. Carrie had talked to the Trial Coordinator and after taking some time to think about her options and get some advice, she decided to give consent! When she calls the Trial Coordinator and lets them know she has decided to participate, she schedules an appointment at her treatment centre for the baseline visit. When she goes and meets with the Trial Coordinator the next time, she signs the consent paperwork and allows researchers to collect some of her information. They record her height, weight and a blood sample. She also fills out a few surveys about her lifestyle, symptoms, gastric cancer diagnosis and past treatment.

After deciding to give consent, Carrie is enrolled in the trial and begins treatment. She attends regular check-up visits at the hospital to allow the researchers to collect data. At these appointments, she typically provides a blood sample, has a CT scan and answers questions about her lifestyle and coping with her cancer. Because this is a Randomized Controlled Trial, Carrie will not find out which chemotherapy routine she is actually receiving. There is no guarantee that by joining the Trial she will receive better treatment than the medication she was taking before.

Although the details of each Clinical Trial are different, Carrie’s story is representative of many cancer patients who may register for a Clinical Trial especially after given a diagnosis of advanced gastric cancer.

What is Informed Consent?

  1. When patients begin the process of enrolling in a clinical trial, it is very important that they understand what the trial is trying to accomplish and what their role as a participant will entail.
  2. According to the Health Care Consent Act of 1996, healthcare providers (including doctors and researchers) need to make reasonable efforts to ensure that patients comprehend the treatment being offered (Government of Ontario). In Clinical Trials, this also means explaining possible adverse effects (side effects) of the treatment.
  3. Informed Consent needs to provide enough information for a “reasonable person” to be able to understand the treatment and make a decision (Government of Ontario). If the patient is incapable of making this choice, then a substitute decision-maker can become involved instead (Government of Ontario)!
  4. Informed Consent begins as a conversation between the researchers and the patient. In many cases, researchers who are recruiting participants for a Clinical Trial will reach out to doctors who can recommend eligible patients.
  5. If the patient is interested, the researchers will explain the Trial and answer any questions. Patients may take some time to think about participating and are usually free to contact the researchers if they do decide to participate.
  6. It is very important to note that this entire process is voluntary! There is no obligation for patients to participate in a Trial at any point (Government of Ontario).
  7. Finally, the patient should know that they can withdraw consent at any time in the Trial process7. This means that if they change their mind and decide to stop participating for any reason, they are allowed to do so!

What do the terms “randomization” and “blinding” mean?

  1. Clinical Trials are a very strong form of evidence. They are the Gold Standard in scientific research! To make sure the results of a clinical trial are valid, the researchers must take precautions to reduce bias as much as possible. Biased research favours one particular result of a study over another one; so, a biased trial would not accurately discover the true pros and cons of a treatment.
  2. Randomization is the technique used in good Clinical Trials to assign patients to a treatment group; it makes sure that each participant has an equal chance of being in any given group. This way, differences between patients in each group are minimized. Often, randomization is done using technology such as a number generator.
  3. For example: if a Clinical Trial enrols 1000 patients to test the effects of Drug A vs. Placebo, every single patient will have a 50% chance of receiving Drug A, and a 50% chance of receiving the placebo. Their assignment will be random.
  4. Blinding means not knowing which treatment group a patient is in. In a single-blind study, patients are not told which treatment they are receiving; this can be done by making sure all of the possible drugs/placebos involved in the Trial look the same, for example.
  5. In a Double-Blind study, both the patient and their healthcare provider do not know which treatment the patient is receiving. Blinding is done to minimize bias and make sure the results of the Trial are valid by ensuring that differences between the patient groups are minimized throughout the length of the trial.
  6. Blinding can be challenging in Clinical Trials comparing surgical techniques – how can a patient not know what surgical procedure they are receiving? This is possible when two similar procedures are being compared. In this case, however, blinding the surgeon (double-blind) is not possible (Karanicolas)!

Works cited

  1. Government of Ontario. Health Care Consent Act, 1996. Available from: [Accessed June 27, 2018].
  2. Karanicolas, P.J. et al. Blinding: who, what, when, why, how? Canadian Journal of Surgery. 2010. 53:5. Available from: PMID: 20858381.