Researchers are starting the world's largest clinical trials to find out if aspirin can help prevent cancer relapse in the U.K. Although its potency is medically debated, if proven effective, this can be an efficient and cheapest anti-cancer drug.

The study, dubbed as the Add-Aspirin phase III trial, entails 11,000 patients to commit to take a pill per day for five years. Nine thousand of the total will be participated by patients from the UK while the remaining 2000 will be from India, in which the clinical trial will start next year.

Researchers will then analyse the various effects and possible episodes of cancer recurrence in the different groups of patient taking different doses (300 mg and 100 mg) in contrast with those taking placebo tablets. "The trial is especially exciting as cancers that recur are often harder to treat so finding a cheap and effective way to prevent this is potentially game-changing for patients," Dr Fiona Reddington from the Cancer Research UK said.

The long-term trial that could last more than a decade involves about a hundred UK centres and recruit patients who are battling or have had treatment for bowel, esophageal, breast, stomach and prostate cancer.

Several research studies have been made over the effectiveness of aspirin on some types of cancer, although some research is still inconclusive. However, the drug has already been proven effective in preventing strokes and heart attacks.

"There's been some interesting research suggesting that aspirin could delay or stop early stage cancers coming back but there's been no randomised trial to give clear proof," lead investigator Ruth Langley from the University College of London's Medical Research Council Clinical Trials Unit said. "The trial aims to answer this question once and for all," 

However, researchers warn not to self-administer the drug without consulting medical professionals. Such act can have several side effects, which includes bleeding and ulceration of the stomach and brain.