A Bradford cancer specialist has backed warnings over internet sites offering 'alternative' cures for the disease.

Professor John Double, head of Bradford University's Cancer Research Unit, supported a warning by researchers who have investigated 13 sites about alternative or complementary medicine and cancer.

The scientists at Exeter University's Department of Complementary Medicine found five sites which were potentially harmful and two which could be "dangerous".

They said cancer patients were discouraged from using conventional therapies and were not told that alternative therapies were ineffective.

Their findings have been published in the British Journal of Cancer.

Researcher Katja Schmidt said one site downgraded conventional cancer treatments with statements like "women with breast cancer are likely to die faster with chemotherapy than without" and "of approximately half a million people who die of cancer each year only about two to three per cent actually gain benefit from chemotherapy." Professor Double said he thought people should be warned about these sites.

"The problem is that cancer patients are pretty wound up - they will try anything and some of these claims that are made are pretty well unfounded. People need to seek specialist advice."

Professor Edzard Ernst, who led the research, said when people were diagnosed with cancer they were in shock and looked for answers.

"Patients are overloaded with information and it is very difficult for them to assess the credibility of information they find on random websites."

The Cancer Research UK website was praised as a useful source of information.

Cancer Research UK is backing the Telegraph & Argus Bradford Can... Cancer Res-earch Appeal to raise £1million for cancer research in the city.