Vienna, Austria: Aspirin improves survival in patients with tumours situated throughout the gastrointestinal (GI) tract, results from a large study in The Netherlands show. This is the first time that survival data from patients with tumours in different GI locations have been analysed at the same time; previously, only one type of cancer, usually colorectal, was studied. The results of the study, involving nearly 14,000 patients, may lead to new insights regarding the use of aspirin in GI cancer say the researchers. Presenting the results to the 2015 European Cancer Congress [1], the trial co-ordinator Martine Frouws, MD, from Leiden University Medical Centre, Leiden, The Netherlands, will describe how her team analysed data from 13,715 patients who had been diagnosed with a GI cancer between 1998 and 2011. By linking the data to drug dispensing information from PHARMO, the Institute for Drug Outcomes Research based in Utrecht, the team was able to show an association between aspirin use after a cancer diagnosis and overall survival (OS); they found there was a significant increase in OS among patients who did take aspirin compared to those who did not.

In total, 30.5% of patients used aspirin pre-diagnosis, 8.3% were solely post-diagnosis users, and 61.1% had not taken aspirin at all. The commonest sites for tumours were colon (42.8% of patients), rectum (25.4%), and oesophagus (10.2%). Median follow-up time for all patients was 48.6 months, with 28% of patients surviving for at least five years. Patients using aspirin after their diagnosis had a chance of survival twice as high than that of those who did not use it in the same circumstances. The beneficial effect of aspirin use on survival was seen in patients with GI tumours after adjusting for potential confounding factors such as sex, age, stage of cancer, surgery, radiotherapy, chemotherapy and other medical conditions or disorders. [2]

"In most observational studies an 'intention to treat' method (once an aspirin user, always an aspirin user) is used for analysing aspirin's effect. In this study we analysed each separate prescription per patient, and therefore we were able to achieve a more exact estimate of the effect of aspirin on cancer survival. Now we would like to analyse tumour material from these patients to try and discover which ones would benefit from aspirin treatment. Through studying the characteristics of tumours in patients where aspirin was beneficial, we should be able to identify patients who could profit from such treatment in the future," Dr Frouws will say.