A guide to prostate cancer clinical trials
This page is for men affected by prostate cancer who would like to know more about clinical trials. It describes the different types of trial and what taking part in one involves. It also tells you where you can find details of trials currently taking place and other sources of support. The information on this page comes from our Tool Kit fact sheet on clinical trials. To order your own tailored copy of the Tool Kit, visit our publications page. You can also download and print a PDF version of this fact sheet.
- What is a clinical trial?
- What are the main aims of a clinical trial?
- What are the different types of trial?
- What are the different phases of a trial?
- What does randomisation mean?
- What is a placebo?
- Should I take part in a clinical trial?
- What does taking part in a trial involve?
- What are my rights when taking part in a clinical trial?
- Who pays for clinical trials?
- Why does it take so long to get the results from trials?
- How do I find out about trials for the treatment of prostate cancer?
- Questions to ask your doctor
What is a clinical trial?
A clinical trial is a medical research study involving people, who are always volunteers. Trials are done in all areas of medicine, not just cancer. They may involve testing new drugs and combinations of drugs, as well as new technology and procedures.
Clinical trials play a very important role in helping to search for new and more effective treatments as well as better ways of diagnosing, screening or preventing a disease. Clinical trials are the best way to find out whether or not a new treatment is better than the current standard treatment. They can also find out if existing drugs work better in new combinations. Some clinical trials find out more about the psychological and social effects of illness and treatment.
What are the main aims of a clinical trial?
Clinical trials aim to answer specific questions about a treatment or procedure. Researchers want to find out if the treatment they are testing:
- Is safe
- Has side effects
- Works better than existing standard treatment
- Will improve the standard of care for people with illness.
What are the different types of trial?
There are many different types of trial, some of which are more common than others. The following paragraphs describe the main types of trial used in cancer care.
Prevention trials
These use drugs, diet, vitamins or other supplements that doctors believe may help to lower your risk of developing a certain type of cancer. People who take part in prevention trials are often at a higher risk of developing cancer.
Screening trials
Screening trials look at ways of finding a cancer early before symptoms start. Detecting a cancer early means treatment is more likely to be successful. Before you can effectively screen for a cancer you must have an accurate test to diagnose the illness.
Treatment trials
These are the most common type of clinical trial. They look at the best way of treating specific health problems including prostate cancer. These trials test many different types of treatment such as new drugs, new ways of giving treatment or new combinations of treatments. For example, a trial may test whether or not combining hormone therapy with chemotherapy is the best way to treat prostate cancer that has spread to other parts of the body.
Pilot studies
These are small studies designed to test an idea or treatment before doing a larger study. They are sometimes called feasibility studies. If they are successful the research team will go on to do larger studies.
Quality of life studies
These studies look at how an illness or its treatment affects you and your daily life. Many of the large scale treatment trials include a quality of life study. Their aim is to improve the comfort and quality of life for people with cancer. In the case of prostate cancer for example, these studies often look at ways to control the side effects of cancer and its treatment such as incontinence and erectile problems.
What do the different phases of trial mean?
There are four phases of clinical trial. Doctors call these Phases 1, 2, 3 and 4. You may also see this written with Roman numerals - Phase I, II, III and IV.
Phase 1 trials
This is the earliest stage of testing a new drug or treatment that may be effective against cancer. The main aim of this phase is to find a safe dose and find out about side effects. Phase 1 trials involve a small number of people (often 20 to 30) with different types of cancer. The participants are usually in the advanced stages of cancer and have tried all other treatments available to them. Some may benefit from being on the trial, but some will not. Phase 1 trials are important to find possible future treatments for others with cancer.
Some Phase 1 trials are called dose escalations studies. In these, doctors begin by giving the first few patients a very small dose of the drug. If this does not cause too many unmanageable side effects, they will then slowly increase the dose for each subsequent group of patients in the trial, monitoring the side effects on each person. They do this by taking regular blood tests and looking at how the body is coping with and getting rid of the drug. They will also monitor whether or not the drug is helping to shrink the cancer or slow its growth.
Phase 2 trials
This next phase of a trial usually involves around 50 to 100 people. Only about 70 per cent of drugs tested in phase 1 trials make it to this next phase1.
In Phase 2 trials, researchers are still looking at doses and side effects, but they are also looking to see if the treatment is working well enough to take it to a Phase 3 trial. Results at this phase allow researchers to decide whether a treatment is as good as or better than, the current standard treatment and which types of cancer it is most effective at treating.
Phase 3 trials
Phase 3 trials compare the best existing (standard) treatment with the treatment being tested. Researchers are now trying to find out if the new treatment is better than what is already used. For example, they may test a new type of surgery with the standard approach, or compare a completely new drug with the existing standard one. The trial may also use a different dose of a standard treatment to find out which dose is most effective. Participants are randomly assigned, usually by a computer, to either the standard treatment or the new one. This is called randomisation. There is more information on randomisation further on in this page.
This phase of a trial usually involves many more people than Phase 1 and 2. There may be thousands of people involved from different hospitals in one country or in many different countries. Because the outcomes of new treatments or approaches may arise from other possibly unknown causes, large numbers of participants enables the researchers to draw more confident conclusions about the results they uncover.
Phase 4 trials
Phase 4 trials are done after the new treatment has been given a licence2. The researchers know the new treatment works and is safe to use but other questions may still need to be answered such as:
- Does the treatment have any long term side effects?
- Does the treatment have any rare side effects that did not show up in the earlier phase trials?
- Will those people who took the treatment live longer than those who did not?
It can take many more years to find answers to these questions.
What does randomisation mean?
Most Phase 3 trials are randomised. This means that the people taking part in the trial are put into one of the two or more groups in order to avoid bias. The researchers do not have any say in who goes in which group. It is usually decided by a computer1. This helps make sure that there are similar patients in each group, and that any differences in results are due to the treatment and not differences in age, gender or stage of cancer, for example.
Where there are two groups, one group is randomly selected to take the new treatment or drug. The other group is given the current standard treatment or drug. This group is known as the control group.
What is a placebo?
If there is no known standard treatment then a Phase 3 trial may compare a new treatment with no treatment at all. This is known as a dummy treatment or placebo. The group assigned to having no treatment would take the placebo.
The placebo may be a pill, injection or ointment that has most of the characteristics of the real medication but it contains none of the active ingredients and it will not be of any medical value to the person taking it. Using a placebo is quite rare in cancer clinical trials because most people with cancer will need some kind of treatment. It would be unethical to withhold a treatment in favour of a dummy pill and it is more common to give a placebo with a standard treatment3. Medical teams must advise participants in advance if the trial involves a placebo.
Should I take part in a clinical trial?
This can be a very difficult question to answer and only you can decide. Not everyone is able to take part in a trial. Each trial will be looking for men who fit a very specific set of criteria. For example, your PSA level may need to be within a certain range, or your cancer may need to be at a particular stage. Other factors may also be taken into account such as how fit you are and if the trial is taking place in a centre you can easily get to. The databases listed at the end of this fact sheet include the criteria for current trials. Your doctor can also give you more information about your suitability for any trial.
Before making any decisions, it is important to find out as much as you can about a trial including its potential advantages and disadvantages. Each trial is different but generally taking part in a trial means that you may:
- Help to improve future cancer treatments for others.
- Access newer and perhaps more effective treatments otherwise unavailable outside the trial.
- Have more regular check-ups and tests than usual. Some people find this very reassuring.
If you take part in clinical trials you may also have a better health outcome than people with a similar stage and type of cancer who do not participate2. This is because taking part in the trial you will be:
- Very closely monitored.
- Receive care provided by some of the best health professionals in the field of cancer research.
- Receive on-going care once the trial is over. A recurrence may, therefore, be picked up sooner.
- Feel that you are taking a more active role in your treatment and recovery. This often helps people feel more in control and able to cope with their situation.
As with all treatments, there are also risks involved with taking part in a trial. These include:
- Possible inconvenience of more frequent testing. Some people find this makes them more anxious about their cancer.
- You may have unexpected side effects from the treatment especially if it is an early phase trial (Phase 1 or 2).
- If the trial is randomised you will not get a choice about which treatment you have. You may not even know which treatment you are getting. This is called a blind trial.
- As with most treatments, there is the risk that the new treatment may not help you, even if it helps others.
You have to decide whether the risks outweigh the benefits. It is important to have a realistic view of what going on a specific trial means for you. Some questions to ask your doctor are listed further on in this page. The answers may help you make a decision about whether or not taking part in a particular clinical trial is right for you.
What does taking part in a trial involve?
If you decide to take part in a trial, the research team will give you the full details of what it will involve. All trials have guidelines for who can and cannot take part. Doctors call these eligibility criteria. This is to make sure that trials compare similar groups of people and that they are safe. There will be differences between trials and some involve a lot more paperwork, tests and trips to the hospital than others.
All trials will involve signing a consent form to say that you understand what taking part means and that you agree to take part in the trial. No one can enter a trial without signing this form4. The medical team will give you information about the trial and will have time to answer questions before you agree to sign the consent form. The important factors to consider when deciding whether to sign this form include:
- Do you feel comfortable with the frequency and types of tests (blood tests, scans etc) that need to be done during the course of the trial?
- Can you get to the hospital for the tests and treatment? Many people having cancer treatment find travelling long distances very tiring.
- Do you clearly understand the possible side effects and risks of having the treatment?
What are my rights when taking part in a clinical trial?
You can leave a trial at any stage you want without giving a reason. Leaving a trial does not mean that you cannot have treatment for your cancer, nor does it mean that your medical team will treat you differently. You will still be given the current standard treatment for your stage of cancer.
Like all other medical treatments, the information about you and the clinical trial itself is confidential. Only the medical team and the staff involved in conducting the trial will have access to this information. This remains private unless you give your permission for information to be disclosed. Records of your progress in the trial will be identified by a code number, not your name.
Who pays for clinical trials?
In the UK cancer charities, the government and drug companies all fund cancer clinical trials. The government provides funding to The Medical Research Council (MRC) and the National Health Service (NHS) to conduct trials. If you are participating in a trial and want to know who is funding it, ask your doctor. Organisations outside the UK, such as the European Organisation for Research and Treatment for Cancer (EORTC) or the National Cancer Institute (NCI) in the USA may fund international trials that also take place in the UK.
Why does it take so long to get the results from trials?
Many people are unaware of the costing and lengthy process of developing a new treatment. Developing a new drug can take between 10 and 12 years and usually costs millions of pounds, sometimes as much as £500 million. The clinical trials process itself usually accounts for around 60 per cent of the total cost2.
For example, a new drug must go through various stages of testing. Researchers must first test it in the laboratory, sometimes on non-human subjects. If the drug shows promising results they may then carry out trials with people. Some types of trial may go on for anywhere up to ten years. On average, they tend to last about three to five years. Phase 1 trials are usually much shorter than this1.
Once a trial is over, it takes time to collect and analyse the results. It may take years before the researchers know how well treatments really work. It may take a few more years before the results are published.
Before a trial can go ahead, there is a long process of planning, writing a set of rules (a protocol) and getting approval from various local and independent scientific committees. This process is taken very seriously. A trial will not get approval without a rigorous assessment of:
- Whether or not the trial is necessary.
- How well planned and safe the trial is. Is the protocol clear and does it contain all the necessary information about treatment doses, insurance issues, and so on?
- Whether or not the researchers are qualified to carry out the trial.
- Whether or not ethical considerations have been addressed.
How do I find out about trials going on for prostate cancer?
If you would like to find out about current clinical trials for men with prostate cancer you can:
- Ask your cancer specialist if there are any local or national trials that may be suitable for you
- Call our free and confidential Helpline on 0800 074 8383
- Use the Internet to search the clinical trial database listed below.
Trial databases
CancerHelp UK clinical trials database
If you find a trial that you think might be suitable for you print it off and take it along to show your doctor who may help you decide whether it is likely to be suitable.
Questions to ask your doctor
- Do you know of any trials that I could go on for my type and stage of cancer?
- Can you tell me the possible advantages and risks from taking part in the trial?
- Will I definitely receive the experimental drug or treatment?
- How long does the trial go on for?
- When will the results of the trial be available?
- Will I need to travel to another hospital?
- What extra tests will I need to have if I go on the trial?
- What happens if something goes wrong when I am on the trial? Am I covered by insurance?
- Will my expenses be reimbursed?
- How much time will I need off work?
- Where will the trial results be published?
Reviewed by:
- Richard Gledhill, Prostate Cancer Charity Specialist Nurse, Queen Elizabeth Hospital, Birmingham
- Dr Rhoda Molife, Senior Investigator, Drug Development Unit, Royal Marsden Hospital, Surrey
- Claire Connolly, Clinical Trials Database Manager, CancerHelp UK
- The Prostate Cancer Charity Information Volunteers
- The Prostate Cancer Charity Support & Information Specialist Nurses
Written and edited by:
The Prostate Cancer Charity Information Team
Sources used in the compilation of this page
1 CancerHelp UK. Understanding Clinical Trials. January 2006 [cited January 2009]. Available from: www.cancerhelp.org.uk/help/default.asp?page=51
2 The Association of the British Pharmaceutical Industry. Clinical trials: developing new medicines. Oct 2003 [cited January 2009]. Available from: www.abpi.org.uk//publications/briefings/clinical_brief.pdf (PDF file)
3 Medical Research Council. Your health: clinical trials [cited January 2009]. Available from: www.mrc.ac.uk/Achievementsimpact/Clinicaltrials/index.htm
4 Souhami R, Tobias J. Cancer and its management. 5th ed. Oxford: Blackwell; 2005.