Taking aspirin may have a protective effect against a number of cancers, a new study has suggested.

Kanal24 reports that a trial involving more than 600,000 people found that long-term aspirin use appeared to reduce a person's risk of a number of digestive cancers as well as leukaemia, lung and prostate cancer.

It did not seem to have a protective effect for breast, bladder or kidney cancers.

The study saw researchers compare cancer incidence among non-aspirin users and people who had been prescribed the drug for at least six months.

Researchers found that long-term use of aspirin carried a "significant reduction" in the incidence of major gastrointestinal cancers.

They also assessed cancers outside of the digestive system and found significant reductions in leukaemia, lung and prostate cancers among aspirin users.

Long-term aspirin users were 14% less likely to have developed prostate cancer, 24% less likely to have leukaemia and had a 35% reduced incidence of lung cancer.

"The findings demonstrate that the long-term use of aspirin can reduce the risk of developing many major cancers," said lead researcher Professor Kelvin Tsoi from the Chinese University of Hong Kong.