This page tells you what you need to know about clinical trials.
What are clinical trials?
Clinical trials are medical research studies. They recruit people at risk of a condition, or who have already been diagnosed or treated.
A clinical trial finds evidence for a new treatment or test before it can be used routinely in medical practice. In the past, doctors only had their own experience to rely on when deciding how best to treat someone. They still use their experience of course. But they now have access to knowledge gained from the experience of large numbers of people, which has been compared objectively in clinical trials.
Different types of trials
There are many different types of trials, from looking at risks and causes of a condition to ways of diagnosing and treating it. For example, trials may compare a new test or treatment with an existing one, looking at:
- how well each works
- the side effects
- how the body copes with them
- how each affects the patients’ quality of life
Phases of clinical trials
There are several steps in clinical trials testing new treatments. These are called phases. Generally, the later the phase, the more people are involved.
The earliest trials (phase 0) may test a new drug to see if it’s safe. These usually recruit around 20 people at most. Phase 1 and 2 trials look at side effects, how the body is affected and gather early information about how well a treatment works.
Phase 3 trials can involve thousands of patients and are often international. They compare a new treatment with the current standard treatment, to see which works better. They do this by putting participants in groups randomly.
Some phase 2 and all phase 3 trials are randomised. This means those taking part are allocated a treatment group at random by a computer. The doctors don’t choose the group you’re in and neither do you.
The researchers do this to make sure the trial results are as reliable as possible. Using a computer to put people into groups means there is less risk of the results being skewed. That could happen if those in one group were sicker than those in the other, for example.
The computer can be programmed to make sure certain factors are the same for both groups – such as the age range, gender, or stage of cancer. Then the researchers know that any difference in results between the groups is down to the treatments patients had.
It’s important to understand that you won’t be able to choose to have a particular treatment when you take part in a randomised trial. It’s a ‘blind’ trial, you won’t know whether you’re having the new treatment or the standard one and neither will your doctor. This also helps to reduce any bias. The trial won’t be ‘unblinded’ until it’s finished. That may not be until some years after you took part.
What you need to know
When you are thinking of joining a clinical trial, you’ll be given a patient information sheet. This should tell you a number of things about the trial in plain English, including:
- why the trial is being done
- who can enter and how many people are taking part
- what being in the trial involves – including the different treatment groups and tests you may have
- whether the trial is randomised and what this means for you
- about the insurance that covers the trial
- how and when the results will be available
Do ask questions about anything that isn’t included in the information sheet that you’d like to know. This may be about claiming expenses and what happens with your medical care when the trial finishes.
If you have private medical insurance, you will need to let them know that you are going to take part in a clinical trial.
The most important thing to understand is that joining a trial is voluntary. You can withdraw at any point. You don’t have to give a reason.
Why do people join clinical trials?
People often want to join a clinical trial because it’ll give them access to a new treatment that isn’t otherwise available. Do remember that if a trial is randomised, there is no guarantee that you will be in the new treatment group. And while the researchers hope that the new treatment will be better than the existing treatment, they don’t know that for sure. That’s why the trial is being done.
Often, people choose to take part in a trial because they want to help improve treatments for others with the same type of cancer. They may feel that they’re giving something back, so some good will come out of their cancer experience. That’s true – all trials help to further medical knowledge whether the new treatments are an improvement or not.
There are advantages and disadvantages to taking part in a trial. But people tend to view these differently. You may feel that extra tests and check-ups are a bonus. Others may see that as a drawback because they mean more travelling to the hospital or because tests and check-ups make them anxious. So it’s a very personal decision and you need to give yourself time to think about it.
Don’t feel you have to join as soon as you’re asked. It’s fine to take the information away and decide later.
Finding a trial
If you’re interested in joining a trial, the first thing to do is speak to your specialist. They will have a good idea of the research that’s going on into your type of cancer. They will certainly know about the major phase 3 trials that are open for recruitment.
If you want to find out about trials yourself, there are some databases you can look at online. When you start to look, do make sure the trial is for your type of primary cancer. Very early phase trials may be open to people with several different cancer types. But later ones – including all phase 3 trials – will be open to people with specific types of cancer. They usually specify the stage of the cancer too (in other words, how far it’s grown). Trials have lists of conditions that you have to meet in order to enter. These are called the eligibility criteria.
Cancer Research UK started the first clinical trials database written for patients about 20 years ago. You can search by cancer type, for the name of a particular drug or trial or by trial phase. All the information provided is written in plain English.
For those with bile duct or gallbladder cancer, the charity AMMF have information about clinical trials on their website.
Content last reviewed: October 2022
Next review date: October 2025