The growth of the internet has given cancer sufferers the chance
to access information about their complaint easily and in the
comfort of their own homes, but it has also given the market in
complementary medicines an extra boost.
Many products can be bought on-line without a prescription, but
most of these products have not been tested properly or may have
unseen effects when combined with conventional cancer
treatments.
In a survey of 32 cancer web sites, Professor Ernst and research
fellow Katja Schmidt, both of the Peninsula Medical School,
Universities of Exeter & Plymouth, found that the quality of
web sites differed extensively, to such an extent that the public
should be advised.
Speaking to reporters on Monday, Professor Ernst warned, "if it
sounds too good to be true, it probably is."
The report, published in the Annals of Oncology, rated three web
sites as high risk, overtly encouraging patients to reject
conventional treatment in favour of complementary medicine, while
16% included content that would discourage conventional care.
"A significant proportion of the web sites are a risk to cancer
patients," Ernst told reporters. "There is no good evidence that
any complementary treatment can prevent cancer."
In total, the web sites advertised 118 different complementary
or alternative treatments for curing cancer, most of which are not
supported by scientific evidence, according to the report.
This included adverts for shark cartilage, laetrile (which
contains a toxin found in the kernels of apricots and peaches), the
Gerson's diet and mistletoe.
The report recommends a public awareness programme, highlighting
the large number of sites that contain misleading information on
cancer treatments, and a "seal of approval", which could be given
to web sites deemed safe and reliable.
