Some Internet websites promoting "alternative" cures for cancer can seriously harm patients who follow their advice, scientists in Britain warned today.
Researchers from Exeter University’s Department of Complementary Medicine looked at 13 sites covering alternative or complementary medicine.
The survey, published in today’s British Journal of Cancer, found the site discouraged patients from using conventional cancer therapies.
They were also not informed about alternative remedies that had been shown to be ineffective.
Professor Edzard Ernst who headed the research into the subject said: "Cancer patients get confused in the maze of claims and counter-claims and often turn to the Internet for information which can give advice that has led to real harm and even death in some cases."
The study defined five sites as potentially harmful to patients who followed their advice.
Two sites, www.alternativemedicine.com and www.heall.com, were described as "dangerous" to cancer patients.
The site www.alternativemedicine.com contains statements such as "women with breast cancer are likely to die faster with chemotherapy than without".
It also states that "of approximately half a million people who die of cancer each year only about two to three per cent actually gain benefit from chemotherapy".
Researcher Katja Schmidt said: "The site lists treatments such as herbal remedies and shark cartilage as offering 'promise as cancer treatment'.
"With a statement like that a patient might abandon orthodox cancer treatment on the basis of the arguments on this website," she warned.
She pointed out the site also offered products for sale and is supported by advertising.
The researchers criticised www.heall.com for not providing research details for the therapies it promotes and for not advising a patient to also seek conventional advice.
The site claims that botanicals such as goldenseal, pokeroot, wild indigo, thuja, figwort, red clover, Essiac and astragalus are being used to treat and or cure cancer.
"But there is no evidence that any of these herbal medicines cure cancer," said Ms Schmidt.
Professor Ernst said when people are diagnosed with cancer they are often in shock and have a sense of crisis.
"They read pages of information on websites and read that shark cartilage promises a cure for cancer.
"Patients are overloaded with information and it is very difficult for them to assess the credibility of information they find on random websites."
He said statements on the web that do not promise a cure but simply offer a chance to improve the quality of a cancer patient’s life were an entirely different matter.
"If a person feels better after massage or reflexology or aromatherapy that is a good thing - as long as the patient is aware that this is not a cure," he said.
Paul Nurse, chief executive of Cancer Research UK, whose website was praised by the Exeter team, said: "There is a confusing amount of information about cancer treatment and so-called 'alternative' cancer cures available on the Internet.
"Many of these have no clinical or scientific basis and so it is vitally important that patients seek advice from their doctors before embarking on any alternative therapy."