Monofunctiona-lity is so last century. These days, everything's
about multitasking. We want our phones to take pictures,
our cameras to play music, and our MP3 players to do everything
but the dishes.
Medical researchers, too, have
caught the co-opting bug, dusting off one-trick-pony
drugs to find out what else they can do.
Hopes are high that statins will
be the next to diversify — into the cancer prevention
business. A study published in the May 26 issue of the
New England Journal of Medicine (NEJM) suggests
that the celebrated cholesterol-lowering agents may
significantly reduce the risk of colorectal cancer.
This observational study, a collaboration
between US and Israeli researchers, drew on data from
the Molecular Epidemiology of Colorectal Cancer study
of patients who received a diagnosis of colorectal cancer
in northern Israel between 1998 and 2004.
Researchers interviewed 1,953 of
the patients with colorectal cancer and 2,015 healthy
controls matched by age, sex, clinic and ethnic group
about their statin use. Twelve percent of controls and
6% of patients reported taking statins for at least
five years. Analysis showed that five year statin use
was associated with a 47% relative reduction in the
risk of colorectal cancer, after adjustment for other
known risk factors, including family history, diet and
fitness level.
DON'T
RUSH TO PRESCRIBE
Despite this exciting claim, the study authors themselves
are calling for caution. Senior study author Dr Stephen
Gruber, of the Division of Molecular Medicine and Genetics
at the University of Michigan, advises physicians to
think twice before prescribing statins to well-informed
patients who may request them for cancer prevention.
"As a clinician, I would...be attentive to the possibility
of inherited cancer syndromes with a family history
of colorectal cancer," he says in an interview from
Ann Arbor. "But statins are not something I would prescribe
for cancer prevention, even in high risk settings. There's
just not enough evidence yet."
This dearth of evidence has some
physicians exercising a healthy scepticism. Writing
in Journal Watch, Dr Allan S Brett notes that
"the analysis might not have accounted for every potential
confounder, and not all previous observational studies
have demonstrated this association."
There are also real risks that
could outweigh potential preventative benefits. In March
the US Food and Drug Administration ordered that a warning
be added to the statin rosuvastatin's label, alerting
physicians and patients to the possibility that it may
cause serious muscle problems and kidney damage, especially
among Asians. Other statin dangers include liver toxicity,
rhabdomyolysis, immune suppression and weakness.
On the other hand, since the alternative
is an invasive, uncomfortable and embarrassing screening
test like colonoscopy or sigmoidoscopy — which
have low patient compliance — some wonder if the
risks might be worth it, particularly for high risk
patients. According to the Canadian Cancer Society,
in 2005, an estimated 19,600 Canadians will be diagnosed
with colorectal cancer and 8,400 will die of it. Those
startling stats rank colorectal cancer as Canada's number
two cancer killer.
NEJM May 26, 2005;352(21):2184-92
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