A UK study has found that although more than half its respondents had cancer symptoms, only two per cent thought cancer might be the cause.

People may be risking their lives by dismissing cancer warning signs as less serious symptoms, a study has found.

More than half of 1700 Londoners taking part in a health survey said they had experienced at least one "red-flag" cancer symptom in the previous three months.

But only two per cent entertained the thought that cancer was a possible cause.

Researchers asked about 17 symptoms, included 10 widely publicised potential cancer warning signs, including an unexplained cough, bleeding, and a persistent change in bowel or bladder habits.

The participants, aged 50 and over, rarely suggested cancer as being a cause of the symptoms.

Instead, they explained them as being signs of age, infection, arthritis, piles or cysts.

Dr Katriina Whitaker, from University College London, who led the study, said: "Most people with potential warning symptoms don't have cancer, but some will and others may have other diseases that would benefit from early attention.

"It's worrying that even the more obvious warning symptoms, such as unexplained lumps or changes to the appearance of a mole, were rarely attributed to cancer, although they are often well recognised in surveys that assess the public's knowledge of the disease."

Dr Whitaker said that even when people thought warning symptoms might be serious, cancer didn't tend to spring to mind.

The findings are published in the online journal Public Library of Science ONE.

AAP.