Clinical research

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Once laboratory researchers have identified a promising way to prevent, treat or manage cancer, their ideas need to be tested in people. This is called clinical research.

Many people associate clinical research with new drugs, but this type of research can be used to test anything that helps prevent, find, predict, treat or manage cancer. That could include testing a phone app to monitor symptoms, an exercise program to help you stay active or a questionnaire to help doctors or nurses monitor potential health issues such as pain.

Researchers use clinical trials to carefully study a promising treatment or tool or a suspected link between cancer and a substance or behaviour. This research happens in phases to make sure that what is being tested is safe and will work well in large groups of people.

The 4 phases of clinical trials

The 4 phases of clinical trials are designed to find out if a new treatment or tool is safe and effective, and how it compares to the current standard of care. In most cases, a new treatment needs to complete the first 3 phases before it can be made widely available.

Phase 1 – Safety: Tests an experimental treatment on a small group of people to check its safety and side effects, and to find the correct dosage. In cancer treatment clinical trials, phase 1 testing usually involves people who are at late stages of the disease.

Phase 2 – Efficacy: Tests a treatment on a larger group to find out if the treatment works in people who have the target disease.

Phase 3 – Comparison: Tests how a new treatment compares to existing options in a group of hundreds or thousands of people.

Phase 4 – Monitoring: Follows a large group of participants over time to gather real world evidence about how a treatment works and monitor for side effects.

Randomized clinical trials

In clinical trials, researchers generally split the people who are taking part into groups. There are 2 groups most of the time, but there can be more.

One group is a control group – the people in this group do not get the treatment being studied but instead receive the current standard of care.

The other group is the experimental group – the people in this group get the treatment being studied.

The safety of everyone in the trial is important and everyone is monitored closely.

In randomized controlled trials, participants are randomly assigned to one of these groups. This process means that personal preferences and behaviours, outside of the study topic, are less likely to affect the results.

Some studies go even further and use a placebo so the people taking part, and sometimes even the researchers, don't know who is in which group. A placebo is a pill or injection that looks like the substance being tested but doesn't actually do anything. Participants in this type of blinded or double-blind trial are told that they might receive a placebo.

Clinical research in diverse populations

Clinical trials are carefully designed to answer a specific question, and every person who joins must meet strict conditions to take part (for example, be diagnosed with a specific type or stage of cancer or be within a certain age range).

However, researchers rely on volunteers to participate in clinical trials. To volunteer, you need to know about a study, be interested in joining, understand the benefits and risks, and have the time and support required to take part. Not everybody who would like to take part can do so. As a result, clinical trial participants are often less diverse than the broader population.

To address this, some clinical research is designed specifically for hard-to-reach and under-served groups such as racial and ethnic minorities, those with financial or literacy challenges and those who experience racism and discrimination within the healthcare system. When clinical trials ensure diversity of age, sex, race, cultural identities and literacy levels, the results are more likely to be an accurate reflection of what would happen in the real world.

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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