Note: The research on which this study is based has subsequently been found to have been partially fabricated. January 2006.
Smoking is a strong risk factor for mouth cancer
Drugs similar to aspirin reduce the risk of mouth cancer but possibly at a cost to the heart, say researchers.
The Norwegian-led team looked at the cancer protection offered by non-steroidal anti-inflammatory drugs among nearly 1,000 heavy smokers.
Those drugs cut the risk of oral cancer by more than half - the same as
However, they also appeared to double the risk of death due to heart disease, the Lancet journal reports.
Last year, trials raised concerns over the cardiovascular safety of two NSAIDs (non-steroidal anti-inflammatory drugs) and one of them, Vioxx, was taken off the market.
Lead author of the current study, Dr Jon Sudbø from the Norwegian Radium Hospital, said other studies were planned or under way to check whether NSAIDs should be given to people to prevent oral cancer and that these investigators should also check for adverse effects on the heart.
"Researchers of these trials must carefully monitor potential adverse cardiovascular effects in their populations, which are at increased risk of cardiovascular disease as well as oral cancer, and implement other safety measures such as excluding patients with cardiovascular disease or specific risk factors," he said.
His study included 454 heavy smokers with and 454 without oral cancer. Heavy smoking was classified as smoking a pack a day for 15 years or more.
Overall, 293 of the participants had been taking NSAIDs, including aspirin and ibuprofen, for anywhere between a year and more than 26 years.
NSAIDs reduced the risk of oral cancer by 53%.
However, this did not translate into a survival benefit overall because 42 (16%) of those taking NSAIDs died from heart-related complications compared with only 41 (7%) of those not taking these drugs.
Aspirin, taken at a dose that is normally prescribed for people with heart disease, did not appear to increase the risk however.
Belinda Linden of the British Heart Foundation said: "It is promising to find that NSAIDs appear to decrease the risk of oral cancer among heavy smokers with arthritis, but there remains concern about increased risk of heart problems in some people with long-term treatment.
"Stopping smoking and encouraging increased physical activity must be the priority."
Cancer Research UK said larger clinical trials were needed to evaluate the potential drawbacks of using NSAIDs to prevent oral cancer.
Mouth cancer, which can affect the lips, tongue, cheeks and throat, kills 1,700 people in the UK every year. Some 4,300 new cases are diagnosed every year.
People who smoke and drink a lot of alcohol are up to 30 times more likely to develop the disease than those who do neither.
However, stopping smoking cuts the risk of oral cancer by about 50% as well as reducing the risk of heart disease.
The charity is launching a campaign in November to raise awareness of oral cancer and its early signs and symptoms.