Dave Dansereau, 47, puts on
his long-suffering face as he prepares for the colonoscope
to invade his nether regions. Since he had a polyp removed
three years ago, Dave's seen a yearly colonoscopy as a
necessary evil. But how necessary is it really? A survey
of American gastroenterologists' and general surgeons'
screening practices after polypectomy published in the
August issue of the Annals of Internal Medicine
revealed that US doctors are performing it more often
than guidelines demand after polyp removal.
The 40-question survey grilled
a nationally representative group comprising 349 gastroenterologists
and 316 general surgeons about their attitudes on colorectal
cancer screening in general, and surveillance colonoscopy
in particular. It also presented four hypothetical patients
with different types of polyps and asked the physicians
how they would respond to each case.
Both groups tended to perform colonoscopy
more often than the guidelines recommended although,
unsurprisingly, gastroenterologists, whose own professional
associations created the guidelines, stuck to them more
closely. Even when the polyp was of the hyperplastic
type, which has no malignant potential and for which
the guidelines don't recommend any followup surveillance
colonoscopy, 25% of gastroenterologists and no fewer
than 56% of general surgeons would perform the procedure.
Most of these physicians also said they would repeat
it within five years.
In the case of small adenomatous
polyps, which have a moderate risk of recurrence, most
doctors said they would recommend colonoscopy within
three years, and a third of general surgeons said they
would continue periodic colonoscopic investigations
for the rest of the patient's life. Such a level of
surveillance, according to guidelines, is not even appropriate
for the high-risk polyps � large or multiple adenomas
with villus features. In these cases, US guidelines
suggest colonoscopy every three to five years. But faced
with a hypothetical patient who recently had such polyps
removed, almost half of the gastroenterologists and
80% of the general surgeons recommended having the procedure
more often than once every three years.
The authors of the study said the
overuse of colonoscopy is particularly acute in the
case of low-risk and no-risk polyps. "We believe colonoscopy
can be a lifesaving procedure, but it shouldn't be done
more often than necessary," said lead author Dr Pauline
Mysliwiec from the University of California Davis School
of Medicine. "When it's used inappropriately, it strains
healthcare resources and puts patients at unnecessary
risk."
The possibility exists with self-reporting
surveys like this that doctors were overstating their
zeal. In particular, the general surgeons may be a self-selecting
group. While almost all of the gastroenterologists contacted
completed their survey form, only about a third of the
surgeons did.
Canadian doctors were less likely
to breach guidelines on followup after polyp removal,
since they have fewer to breach. The Canadian Task Force
on Preventive Health Care only pronounces on the most
dangerous polyps, adenomas bigger than 2cm in diameter,
in which case endoscopy is recommended within three
to six months. The Canadian Association of Gastroenterology
suggested that "clinical judgement determine the type
of followup for advanced adenomas."
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