Colonoscopy Becomes Less Effective at Finding Polyps
as the Day Progresses
Fewer polyps were found in colon cancer screening
hour by hour as the day progressed in a new UCLA study
What is colonoscopy? See below.
Nov. 3, 2009 Senior citizens who must endure the
stress of having a colonoscopy certainly want the procedure to be
successful. There is new evidence that the effectiveness of a screening
colonoscopy depends on the time of day it is performed.
Early-morning colonoscopies yielded more polyps per
patient than later screenings, and fewer polyps were found hour by hour
as the day progressed in a new UCLA study.
The findings, published in the November issue of
the journal Clinical Gastroenterology and Hepatology, point to
the need for more research in this area to possibly improve outcomes for
colonoscopy procedures.
While the current study was done at a single
institution, the clinical setup is much the same in other practice
settings, the researchers said.
"Our research was conducted at an
academic-affiliated facility that far exceeds published quality
benchmarks for colonoscopy outcomes," said study author Dr. Brennan M.R.
Spiegel, director of the UCLA/Veterans Affairs Center for Outcomes
Research and Education.
"So, if this is occurring at such a high-performing
academic center, it is probably happening at other facilities across the
country."
Spiegel noted that although this is a new area of
research, other studies have reached similar conclusions, including
recent research from the Cleveland Clinic published in the July issue of
the American Journal of Gastroenterology.
What is colonoscopy?
Colonoscopy
is a procedure used to see inside the colon and rectum.
Colonoscopy can detect inflamed tissue, ulcers, and abnormal
growths. The procedure is used to look for early signs of
colorectal cancer and can help doctors diagnose unexplained
changes in bowel habits, abdominal pain, bleeding from the anus,
and weight loss.
More information at National Digestive Diseases Information
Clearing House
A colonoscopy is the only test that allows the
identification and removal of polyps from the entire colon. Studies have
shown that polyp removal has been associated with a 60- to 90-percent
reduction in colorectal cancer, which is the second leading cause of
death in the United States.
"Successful colonoscopy procedures depend on a
number of key patient, provider and procedural factors - and time of day
may also be important as well," said Spiegel, who is an assistant
professor of digestive diseases at the David Geffen School of Medicine
at UCLA and the VA Greater Los Angeles Healthcare System.
During the study, researchers tracked 477 patients
receiving colonoscopies over the course of one year at a single VA
hospital. Researchers found that early-morning cases, started at 8:30
a.m. or earlier, yielded 27 percent more polyps - 0.19 more overall
polyps and 0.17 more premalignant polyps - per patient than later cases.
The amount of polyps discovered decreased hour by
hour as the day progressed. This translates into less than a quarter of
a polyp per patient, so the risk for individual patients is very low.
"Although individual patient risk is very low,
multiplying this effect by thousands of patients across the United
States could mean we're missing lots of polyps, some of which might turn
into cancer one day," Spiegel said. "More research needs to be done at a
wide range of centers to pinpoint why there's a decrease in the number
of polyps found later in the day and to identify ways we might improve
outcomes."
Spiegel added that colonoscopy remains a highly
effective means of screening for colon cancer whatever the time of day
and warned against patients insisting on being the first case of the
day.
"The impact of appointment time for any individual
patient is very, very small," he said. "Patients should feel confident
that colonoscopy is helpful regardless of time of day and should be more
focused on the quality and experience of their doctor rather than the
time of their appointment."
The study authors noted that these findings were
independent, after accounting for a number of demographic and clinical
factors, including age, gender and history of polyps or cancer, as well
as the skill level of the physician.
Researchers added that colonoscopies performed in
the morning may have better results partly due to improved bowel
preparation the night before, but that this didn't completely explain
the overall study results.
Spiegel said that fatigue may play a role, as it
does in other professions with prolonged and repetitive activities, like
trucking, surgery and aviation.
"We may find that setting a cap on the duration of
endoscopic work shifts or other types of adjustments may be helpful," he
said.
The study was funded by a Veterans Affairs Health
Services Research and Development grant and a Career Development
Transition Award.
Other researchers in this study included Michael Y.
Chan, of the division of digestive diseases at the David Geffen School
of Medicine at UCLA, and Hartley Cohen, of the department of
gastroenterology at the VA Greater Los Angeles Healthcare System.
Keep up with the latest news for senior citizens, baby
boomers
Colonoscopy
is a procedure used to see inside the colon and rectum.
Colonoscopy can detect inflamed tissue, ulcers, and abnormal
growths. The procedure is used to look for early signs of
colorectal cancer and can help doctors diagnose unexplained
changes in bowel habits, abdominal pain, bleeding from the anus,
and weight loss.