London (PTI): You can't avoid breast cancer. But you can definitely reduce the risk of developing it by taking a regular dose of aspirin or ibuprofen whose active ingredient has been an accepted pain remedy for years.

Researchers in Britain have carried out a study and found that aspirin can cut breast cancer risk by almost 20 per cent in women who pop the pill daily and it could also be used to treat those already having the disease.

"Not only it cuts, but aspirin could also be used to treat those who already have breast cancer by helping hormone treatments to work to their maximum effectiveness," said lead researcher Professor Ian Fentiman of Guy's and St Thomas' NHS Foundation Trust.

According to the researchers, similar nonsteroidal anti-inflammatory drugs (NSAIDs) and over-the-counter drugs such as ibuprofen, could also offer protection against breast cancer in women.

The researchers came to the conclusion after analysing 21 studies over a period of 27 years, involving 37,000 women -- the results of which have been published in the latest edition of the 'International Journal of Clinical Practice'.

However, according to the study, aspirin would be unlikely to offer protection for approximately one in 20 women estimated to carry a gene that has been linked to hereditary breast cancer.

Moreover, the researchers are unsure what quantities of the NSAIDs should be taken or for how long. They warn that women should not start taking NSAIDs to gain extra protection against cancer until the long-term side effects are known.

"More research is needed into potentially negative effects of the drugs, which can include internal bleeding and stomach ulcers," 'The Daily Telegraph' quoted Prof Fentiman as saying.

Cancer research charities have welcomed the research but echoed the warning over side effects.

Dr Kat Arney from Cancer Research UK said: "Drugs like aspirin are often touted as 'wonder-drugs' and we have seen repeatedly from studies like this that there can be a range of positive effects.

"But, as with any drug there can be significant side effects from long term or heavy use -- such as stomach ulcers -- so we certainly wouldn't recommend that people take large doses without medical advice."