The world's first ever large scale trial to investigate whether aspirin can prevent early stage cancer from coming back after treatment, has opened in Ireland.

The trial, called Add-Aspirin, aims to investigate whether taking aspirin daily for five years after undergoing standard cancer treatment, including chemotherapy and surgery, can prevent the disease from returning.

The Irish trial is part of an international trial involving the UK and India. A total of 11,000 people from these three countries will take part.

In Ireland, 300 volunteers who have, or previously had, cancer of the breast, oesophagus, stomach, colon, rectum or prostate will join the trial. Their cancer must be early stage cancer which has not spread.

The Irish leg of the trial is being coordinated by Cancer Trials Ireland, with funding coming from the Health Research Board and the Irish Cancer Society.

Aspirin is already used as a painkiller, and to prevent and treat heart attacks and stroke. However, studies which looked at the effect of aspirin on heart disease found that fewer people taking the drug went on to develop cancer. Furthermore, among those who did develop cancer, it appeared to be less likely to spread.

However, as these studies were not specifically designed to investigate the impact of aspirin on cancer, there is not enough scientific data to support its use to prevent the disease. This is why a large clinical trial is warranted.

The trial aims to produce this scientific evidence, looking at both potential benefits and side-effects among people who have had early stage cancer.

The trial's chief investigator for Ireland is Dr Gregory Leonard, a consultant in medical oncology at Galway University Hospital. He noted that while aspirin has been used as a painkiller in Ireland for over 100 years, and more recently to prevent heart attacks and stroke, evidence about the drug's potential as an anti-cancer agent has been growing.

"This is the first trial ever to investigate if aspirin could stop or prevent the return of cancer among such a significantly large group of patients with early stage cancer. At a time when we are used to new cancer treatments being relatively costly, the possibility of repurposing an inexpensive, generic drug that is available worldwide to stop or slow cancer is potentially groundbreaking," he said.

He insisted that the results of this trial could have ‘a huge impact on the global cancer burden, particularly given the increasing cancer incidence in lower resource countries'.

Participants will be recruited over a three-to-six-year period and they will be expected to self-administer tablets on a daily basis for at least five years. They will then be followed up for a further 10 years after treatment.

The trial will have three groups. One group will receive a placebo, while the other two will receive different doses of aspirin, as it is not known how much aspirin may be needed to have an effect. This will be done randomly, and neither the participants or the researchers will know who is receiving what.

Anyone interested in taking part in this trial should speak to their oncologist, who will be able to determine if they are a suitable participant.

For more information on cancer trials taking place in Ireland, see cancertrials.ie