Clinical trials fact sheet
This factsheet provides a brief overview of clinical trials
A clinical trial is a research study that tests new and better ways of improving health in people. It is the final stage of a long and careful process that often starts many years earlier in the laboratory.
Clinical trials are the link between scientific discoveries made in the laboratory and making new treatments available for people with cancer.
Clinical trials may be carried out to:
This factsheet provides a brief overview of clinical trials
Get a better understanding of why clinical trials are important.
This booklet contains detailed information about clinical trials.
Treatment trials test new treatments and are the most common kind of trial. New treatments can include:
Prevention trials test new approaches – such as medicines, vitamins, minerals, a new diet, exercise or other approaches that may lower the risk of developing cancer.
These trials look for the best way to prevent cancer in people who have never had it, or for those who may be at high risk of developing cancer.
A screening trial tests the best way to find cancer in early stages before symptoms appear. Examples include cervical HPV testing, mammograms, x-rays and blood tests.
Clinical trials are the best way to improve the treatment and care of people who have cancer. They give us essential information about the effects of different treatments – information that doctors, and patients cannot find in any other way. They can show us whether new treatments are more effective or have fewer side effects.
The results of clinical trials today will improve treatment for people who develop cancer in the future. A new treatment can only become standard treatment if it is proven to be safe and effective in a clinical trial.
Many of the most effective treatments used today are the result of clinical trials done in the past 30 years. Clinical trials also identify risks and side effects, which must be weighed up against the possible benefits of the new treatment.
People being treated as part of a clinical trial can often see better results than people treated outside of a clinical trial. This is most likely because people who take part in trials:
The new treatment does not always mean it will be better than the standard treatment, which is the reason for testing this in the trial.
It normally takes several years before the results of a trial are known.
Researchers follow up what happens to people in the trial, calculate and interpret results, and prepare reports.
To work out whether accepted cancer treatment should change, all trials looking at the same question have to be compared to reach an overall conclusion. The results are usually first presented at a meeting of the researchers involved in the trial. The results are then presented to a meeting of cancer researchers not involved in the trial where there is more scrutiny and debate.
A report is prepared and submitted to a medical journal. The report is peer-reviewed. This means that independent experts in the field provide criticisms, questions, and suggestions. If the researchers can answer these satisfactorily, the medical journal publishes the report.
When a study is published in a medical journal, it allows many doctors to consider the study, to debate the issues and consider whether they should change the way they treat cancer.
When the treatment is proven to be better, based on the available medical evidence, clear recommendations can be made about the treatment, such as who should have it, in what dose and for how long.
Each clinical trial aims to answer specific questions that will help find new and better ways of helping people affected by cancer. Three questions must be answered before a new treatment can be used widely:
A separate and different clinical trial is needed to answer each of these questions – known as a phase I, II or III clinical trial – because they need to be done in this order.
Phase 1 trials are the first clinical studies that involve people. They are conducted after the treatment has been tested for safety and efficacy in laboratory tests and in animals.
These trials test:
Usually, a Phase 1 trial involves 15-30 people, because only a small number of people are needed to find a safe dose.
At first, a few people are given a certain dose and watched carefully for side effects.
If side effects are not a major problem, a few more people are treated at a higher dose. The dose is gradually increased to find the best dose that can be given safely.
These trials carry the greatest uncertainty because there is little experience with the treatment. Generally, they are only suitable for people who have already had all the known effective treatments for their cancer.
Most people in phase 1 trials have incurable cancer. Some people take part in the hope that the treatment may extend their life or improve their quality of life. But often people go on a phase 1 trial because they want to fight their cancer and to help others.
Some people who participate in phase 1 trials sometimes benefit from having the new treatment, but major improvements in their condition are uncommon.
If a phase 1 trial shows the new treatment is safe, the treatment will go on to phase 2 testing.
A Phase 2 clinical trial continues to test the safety of the treatment.
Usually, it will involve less than 100 people who have the same kind of cancer and are given the same treatment.
Throughout the study, researchers monitor the people taking part (participants). They watch for side effects and measure the effects of the treatment on their cancer, often using scans and blood tests.
Generally, Phase 2 trials are suitable for people who have already had treatments known to be effective for their kind of cancer. The chance of benefiting from treatment in a phase 2 trial depends on the type and stage of the cancer, and on the person’s response to previous treatment.
If the treatment continues to be safe and seems effective in a significant number of people, it goes on to phase 3 testing.
Phase 3 clinical trials compare the new treatment with the current standard treatment, to work out which is best.
Phase 3 trials test new drugs, combinations of drugs, types of surgery, ways of giving radiation therapy and other new approaches.
People are assigned at random to receive the best standard treatment or to have the new treatment.
A Phase 3 trial usually involves between hundreds and thousands of people with the same kind of problem. They are usually done at many different clinics and cancer centres around the country or even around the world.
Participants are given the treatment and are watched carefully for side effects, and for effects on their disease, length of life and quality of life. At the end of the study, these effects are compared – to work out which treatment is best and by how much.
Researchers studying cancer treatments follow strict guidelines.
First, they must write a plan of the clinical trial. This is called a protocol. Before the trial can begin, the protocol must be reviewed and approved by the ethics committee at each place the trial will be done.
Everyone doing the trial must follow the protocol, which describes:
The protocol also describes how the trial may need to be modified if new information becomes available.
In a randomised controlled trial, some people receive the new treatment while others receive the standard treatment.
The people having the new treatment are known as the trial group and the people having the standard treatment are known as the control group.
A computer randomly assigns people to each group. All treatments tested in a randomised trial are considered likely to be at least as good as the best standard treatment, and possibly better.
Randomisation means your treatment will be selected at random (like drawing a card from a pack), which is usually done by a computer. This is done so each group has a similar mix of people – to ensure the people getting each treatment can be compared without bias.
Neither you nor your doctor can choose which treatment you will receive.
If you are involved in a trial of a new drug, you and your doctor might not be told which treatment group you are in. This is known as blinding. It is used to eliminate bias from a trial.
If people know they are taking the new treatment, they might expect it to work and report positive reactions because they want to believe they are getting better. This can make the trial results look better than they really are.
Blinding is done by giving some patients the placebo and some the standard treatment by making the treatments look identical, for example the same injection or tablet.
Sometimes blinding involves placebo (non-treatment) tablets or injections that look the same as the experimental treatment but don’t contain the active ingredient, however placebos are rarely used in cancer treatment trials.
In double blind trials, neither you nor your doctor knows which treatment you are getting. You must be told if the trial you are considering is blinded or if some people will receive a placebo.
Many medical treatments have side effects.
The risks of side effects in clinical trials are more uncertain because less is known about the new treatments being tested. This is one of the important reasons for clinical trials – to identify risks and side effects, which must be weighed up against the possible benefits of the new treatment.
In a trial, a person may experience none, some or all of the side effects, which may be mild, moderate or severe. There is also the risk of a previously unknown side effect occurring.
Some clinical trials try to find treatments that are as effective as existing treatments but have fewer side effects. Other trials test treatments for reducing side effects, for example, drugs to reduce nausea caused by chemotherapy.
Cancer is a life-threatening illness that causes its own symptoms. The unavoidable risks of the cancer need to be weighed against the risks and benefits of any treatments.
Talk to your doctor about the risks and side effects of being in a clinical trial.
You should be given comprehensive information to read and discuss before deciding whether to take part in a clinical trial.
The medical profession formally reviews clinical trials. This is called peer review. It is carried out by an ethics committee and other bodies.
Before a trial can begin in a hospital, the ethics committee must judge it to be safe and ethical before approving it.
The ethics committee makes sure people participating in the trial have their rights and interests protected. They ensure people in the trial are offered the best available treatment, and that no beneficial treatments are denied.
Funding is usually covered by organisations such as Cancer Council and the National Health and Medical Research Council or companies that produce the treatments being tested, like pharmaceutical companies and device manufacturers. Participation is free for Australian residents and citizens.
Taking part in a trial will not cost you more money than not taking part. Some of the tests and treatments involved in a trial are part of standard care. The cost of any extra tests or treatments that are not part of standard care are covered by the trial organisers.
Participation in trials generally means extra work for doctors, nurses, and other medical staff. In many cases, the research group or company running the trial provides funds to help pay for some or all of these extra costs.
Cancer trials take time and money. Research funding is limited and competition for funds is fierce. Fewer than one in four research proposals get funding and many trials are inadequately funded.
Your doctor may suggest that you enter a clinical trial. To carefully assess if a trial is suitable for you should:
If the trial is not suitable, the best treatment currently available will be offered.
If you are considering a trial, you should be given a participant information sheet, or fact sheet about the trial. This should explain everything you need to know about the trial and treatment.
Your doctor should help you understand the trial, without trying to persuade you either way. In turn, you should be open and honest in telling your doctor about your health and information needs.
You should only agree to participate in a trial when you are satisfied and understand all you need to know about it and have considered how it will impact on your life.
Before entering a trial, you must be informed of exactly what is involved in the study, including effects you might expect. This is all part of informed decision making.
Always remember that the choice to join a trial is yours and you can withdraw at any time. Withdrawal will not affect your future care, and you will be returned to receiving the standard treatment for your type of cancer.
Each study has its own guidelines for who can participate. Generally, participants are alike in key ways such as the type and stage of cancer, age, gender and other factors. Eligibility criteria are outlined in a trial protocol. Your doctor can tell you if you might be eligible for a trial.
It’s important to keep in mind that not all trials are run in every centre or hospital. You may have to travel to a different location to participate.
Check that your doctor has given you the following information:
Download a printable version of this checklist with space to write down your answers.
If you participate in a clinical trial, you will be watched closely, and detailed records will be kept. You may receive more examinations and tests than are usually given.
Although these tests can be inconvenient, they provide extra information about your progress and the effects of treatment.
You may also be asked to answer questions about how you are feeling – the quality-of-life questionnaires. These additional tests and observations can have their own risks, benefits and inconveniences.
You can withdraw at any time.
During the trial, if it is clear that a treatment is not in your best interest – for example, if it is not working or if you have severe side effects – you or your doctor can stop the treatment at any time.
Withdrawal will not affect your future care, and you will return to receiving the standard treatment for your type of cancer.
Cancer Council WA provides a number of cancer support services. Cancer Council WA’s 13 11 20 Information and Support Service is a one-stop-shop for anyone with questions about cancer, including prevention, diagnosis, treatment and support. Please also visit the patients, families and friends section to learn more about these services.
If you would like to take part in a clinical trial but have not been asked, you can talk to your doctor, who may be involved in a suitable trial or know of one being done elsewhere. If not, they may be able to help you find one.
Trials aren’t run in every treatment centre, so you might have to travel to a different location.
If you hear or read in the media about a clinical trial for your type of cancer, you should ask your doctor for more information. Keep in mind that the trial may be for people with other kinds of cancer and may not be running in your State or country.
The following websites are appropriate for assessing trial availability:
If you decide to take part in a clinical trial, you will be asked to sign an informed consent form. The informed consent form will outline:
It is required by law, essential and a standard part of every clinical trial. A copy of this form will be given to you for your records.
Clinical Trials and Research Booklet
Videos on clinical trials from the National Cancer Institute: