Nov 6 (Reuters) – For people who have had a negative
colonoscopy, less-invasive screening options may work just fine
for follow-up cancer tests, according to a U.S. study.
The findings, which appeared in the Annals of Internal
Medicine and are based on a mathematical model, showed that life
expectancy varied by only a few days between people who
continued getting colonoscopies every ten years and those who
chose annual fecal blood tests and other less-invasive
alternatives.
“No one screening test is right for everyone,” said lead
researcher Amy Knudsen, from the Institute for Technology
Assessment at Massachusetts General Hospital in Boston, in an
email to Reuters Health.
“The best test for you depends on your risk, your
preferences, and which screening approach you are willing and
able to adhere to, since no screening is effective unless it is
done.”
Knudsen’s team fed colon cancer screening and survival data
into a National Cancer Institute (NCI) model, starting with
hypothetical study participants who had a negative colonoscopy
at age 50.
The researchers found that with no further screening, 31 out
of every 1,000 people would be diagnosed with colon cancer
during their lives and 12 would die from it. For people who had
colonoscopies every ten years, that would fall to eight colon
cancer diagnoses and two deaths per 11,000 people.
With annual fecal tests starting at age 60, Knudsen and her
colleagues calculated that 11 to 13 out of every 1,000 people
would get colon cancer, and three or four would die.
With the last screening method, known as computed
tomographic colonography, or CTC, nine people would be diagnosed
with cancer and three would die if the tests were done every
five years. Like colonoscopies, CTC requires bowel preparation,
but otherwise is not as invasive.
The less-invasive screening methods would each cause about
half as many complications as colonoscopy, affecting one percent
of patients versus two percents. Those complications include
bleeding and colon perforations.
“All of these methods will work if your ultimate goal is to
reduce deaths from colon cancer,” wrote gastroenterologist David
Weinberg from Fox Chase Cancer Center in Philadelphia, in an
editorial accompanying the study.
He said that one of the advantages of a colonoscopy is that
it finds pre-cancerous polyps that can be removed before they
turn into cancer. Fecal blood tests typically catch very early
cancers, so more patients screened that way will have cancer and
need treatment, although they’ll have a good prognosis.
Colonoscopy is also more expensive, sometimes 50 times more
expensive than a fecal test and twice that of a CTC.
“If everybody gets a colonoscopy, you will have many fewer
people who ever develop colon cancer, but you’re going to pay a
lot more money to get that,” Weinberg told Reuters Health.
The United States Preventive Services Task Force, a
government-backed panel, recommends screening for colon cancer
using colonoscopy, sigmoidoscopy or fecal occult blood testing
between ages 50 and 75.
SOURCE: http://bitly.com/MnBiCA
(Reporting from New York by Genevra Pittman at Reuters Health;
editing by Elaine Lies)
