The Add-Aspirin trial is for people who have had, or have started treatment for, cancer of the breast, stomach, oesophagus (food pipe), prostate or bowel (see who can take part? for more)  

We are aiming to find out whether taking aspirin daily for 5 years after treatment for an early stage cancer (cancer that has not spread widely), stops or delays the cancer coming back. This study will compare groups of people who take aspirin and those who take placebo (what is a placebo?) tablets.

There have already been some studies testing the beneficial effect of aspirin on heart disease. In these studies aspirin appeared to reduce the number of people who developed cancer and, if people did develop cancer, it appeared to be less likely to spread. Researchers therefore believe that aspirin may stop cancer coming back in people who have had treatment for an early stage cancer. But, importantly, since previous studies were not specifically designed to answer this question, there is not any reliable evidence yet.

A clinical trial is the best way to test this. It will look at both the benefits and the side-effects of taking aspirin in a large group of people who have had cancer. The study will look at two different doses of aspirin. This is because we don't yet know how much aspirin may be needed to have an effect, if any, against cancer.

This trial is randomised (see what are randomised controlled trials? for more). This means that people taking part are put into the treatment groups at random by a computer. Neither the participant nor their doctor will know or be able to decide whether the participant is taking aspirin or a placebo.

For more information on the trial treatment please click here.

Who can take part?

Individuals will only be able to take part in the study if the hospital where they are being treated is participating in the trial. If you are an individual who is interested in taking part in Add-Aspirin, please talk to your doctor, who will be able to consider whether you are suitable for the trial.    

Individuals can take part in the Add-Aspirin study if they have had (or are currently having) treatment for an early stage cancer of the breast, bowel, stomach, oesophagus or prostate. Individuals who have taken part in other trials and satisfy the eligibility criteria might also be eligible: please click here for an updated list of other approved trials.   

Individuals cannot take part in the study if they regularly take aspirin, non-steroidal anti-inflammatory drugs (NSAIDs, e.g. ibuprofen), anti-coagulants (e.g. warfarin) or are at risk of developing side effects from aspirin (e.g. a stomach ulcer).  For a full list of eligibility criteria please click here.            

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What is a placebo?

A placebo is a “dummy” tablet. It looks like an aspirin tablet but it doesn’t contain any medicine.
We are using a placebo in this study so that we can make as clear an assessment as possible about the effects of aspirin. To make sure the results are as reliable as possible, neither the participants, nor the doctors, will know or be able to choose who is taking aspirin and who is taking a placebo.    

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What are randomised control trials

Randomised controlled trials (RCTs) are a type of clinical trial. RCTs aim to make a fair comparison between a new treatment and the existing treatment, or between two (or more) existing treatments, to see which one works best.      

A controlled trial compares two or more groups of people: one or more experimental group(s) who receive a new treatment, and a control group, who receive the current standard treatment (which might be the best existing treatment, no treatment or a placebo. Information from the follow-up of the control group allows the researchers to see whether the new treatment(s) they are testing are any more or less effective than the existing treatment.

The decision about which treatment each participant in a randomised controlled trial receives is made at random – based on chance, rather than decided by the doctor or participant. This process is called randomisation.    

Randomisation ensures that the two (or more) groups of people in a trial are as similar as possible, except for the treatment they receive. This is important because it means that researchers can be sure that any differences in outcomes between the groups are only due to the treatment received.    

Randomisation is the best way of ensuring that the way the participants in each group are selected does not bias, or affect, the results of the trial. For example, if a doctor chose which treatment a patient should receive as part of a trial, she or he might give the new treatment to sicker patients, or to younger patients. This would make the results of a trial unreliable, as it could exaggerate or hide the effects of the treatment.    

Randomised controlled trials are the most reliable way to compare treatments. Click here for more information on the treatments in the Add-Aspirin trial.      

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The trial is being jointly funded by Cancer Research UK (grant number C471 /A15015, www.cancerresearchuk.org), the National Institute for Health Research Health Technology Assessment Programme (project number 12/01/38, www.nihr.ac.uk) and the MRC Clinical Trials Unit at UCL.
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