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Senior Health & Medicine
Colonoscopy Very Effective But Maybe Used Too Often
Little value for those over 80; Second
test not needed for 10 years
May 23, 2006 Two studies reported in today's
Journal of the American Medical Association suggest that colonoscopy may
be used too often. One of the studies says in does little for those over
80, and the second says those who pass a colonoscopy test probably do
not need another for ten years.
Benefits of Screening Colonoscopy In Very
Elderly May Be Limited
Even though the prevalence of colon tumors
increases with age, screening colonoscopy in patients over 80 years of
age results in smaller gains in life expectancy, compared to younger
patients, according to this study.
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Virtual Colonoscopy Makes Progress Detecting Polyps,
Studies Say
Studies find broad value and ease of CTC for
average risk patients
May 23, 2006 - With more than 100,000 people in the
U.S. diagnosed each year with colon cancer, doctors are working to
improve screening techniques through more accurate technologies and more
comfortable procedures. In research presented today at Digestive Disease
Week 2006 (DDW), studies suggest that virtual screenings may be just as
effective as standard colonoscopy at detecting colon polyps in
average-risk individuals.
Read more...
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on
Health & Medicine |
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Current guidelines recommend colorectal cancer (CRC)
screening for all patients 50 years or older, but do not specify an age
limit above which screening is not recommended.
The number of screening colonoscopies in elderly
U.S. patients has increased dramatically since Medicare coverage was
approved in 2001, according to background information in the article.
However, some clinicians may have concerns with
regard to screening extremely elderly patients, especially when an
invasive procedure such as colonoscopy is used. Colonoscopy in very
elderly patients is associated with lower procedural completion rates
and higher complication rates.
In addition, very elderly patients have shorter
life expectancies, potentially limiting the benefits of screening
procedures. Decisions concerning undergoing a colonoscopy are being
based on limited data regarding its impact on life expectancy.
Otto S. Lin, M.D., M.Sc., of Virginia Mason Medical
Center, Seattle, and colleagues conducted a study to estimate the
average extension in life expectancy in very elderly vs. younger
patients undergoing screening colonoscopy. The study included 1,244
asymptomatic individuals in 3 age groups (50 to 54 years, n = 1,034; 75
to 79 years, n = 149; and 80 years and older, n = 63) who underwent
screening colonoscopy.
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Editorial: Screening For Colorectal Cancer By
Colonoscopy Adding To The Evidence |
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In an accompanying editorial, Timothy R. Church,
Ph.D., of the University of Minnesota School of Public Health,
Minneapolis, comments on the studies in this weeks JAMA on colorectal
cancer screening.
The authors of these two studies address two
important questions. Because the population average age is steadily
increasing and decisions about screening elderly patients have been made
inconsistently and with little reference to data, the attempt to bring a
careful analysis to bear is crucial. As colonoscopy becomes more widely
used as the primary screening method, it is important to reevaluate the
performance of the recommended 10-year screening interval, not only for
its effect on clinical outcomes but also on the cost-effectiveness of
the screening effort. These 2 analyses are solid attempts to address
these unanswered questions. Efforts to get at better answers will no
doubt continue.
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The researchers found that the prevalence of colon
neoplasia increased with age. Participants aged 80 years or older had a
significantly higher prevalence of advanced neoplasia than the 50- to
54-year-old group (14 percent vs. 3.2 percent).
Baseline average life expectancy was lower in the 2
older age groups vs. the 50- to 54-year-old group. Because of this,
despite the higher prevalence of advanced neoplasia in elderly patients,
the average extension of life expectancy was lower in the 2 elderly
groups.
The group aged 80 years or older had a average
extension of life expectancy of only 0.13 years, compared with 0.85
years for the 50- to 54-year-old group, a 6.5-fold difference. The
number of colonoscopies per life-year saved was much lower for the 50-
to 54-year-old group than for the 2 older groups (1.18 vs. 5.77 and
7.95, respectively).
The results reported here show that even though
the prevalence of colonic neoplasia increases with age, screening
colonoscopy in very elderly patients results in only 15 percent of the
expected gain in life expectancy achieved in younger patients, the
authors write.
These data suggest that the benefit of screening
colonoscopy in very elderly patients may be smaller than what is
commonly believed. This should help individual patients and clinicians
decide whether screening colonoscopy should be performed and help avoid
its use in patients who are unlikely to benefit substantively.
Study Provides Evidence Supporting Recommended
10 Year Interval For Colonoscopies For Most Patients
Patients with a negative colonoscopy examination
have a reduced risk of developing colorectal cancer for more than 10
years, compared to the general population, according to a study in the
May 24/31 issue of JAMA.
Colorectal cancer is the third most commonly
diagnosed cancer and the second leading cause of cancer deaths in North
America. Screening for CRC and its precursor lesions has become an
increasingly prevalent practice. Colonoscopy has been recommended as the
preferred initial screening test by several medical organizations and is
being widely performed in the United States for screening among
average-risk individuals.
Colonoscopy allows for removal of most precancerous
polyps at the time of detection. A screening interval of 10 years after
a normal colonoscopy has been adopted based on the estimate of the time
it takes for an adenomatous (benign tumor) polyp to transform into
carcinoma. However, the duration over which the risk of CRC remains
decreased following the performance of a normal colonoscopy has been
unknown.
Harminder Singh, M.D., of the University of
Manitoba, Canada, and colleagues analyzed data from individuals who
underwent a colonoscopic evaluation that did not result in the diagnosis
of colorectal neoplasia to determine the magnitude and duration of their
lowered risk of developing CRC.
The patients (n = 35,975), who had been evaluated
between April 1989 and December 2003, were identified using Manitoba
Healths physician billing claims database. Standardized incidence
ratios (SIRs) were calculated to compare colorectal cancer incidence in
this group with colorectal cancer incidence in the provincial
population. The patients were followed up from the time of the
colonoscopy until diagnosis of colorectal cancer, death, moving from
Manitoba, or end of the study period on December 31, 2003.
The researchers found that a negative colonoscopy
was associated with SIRs of 0.69 (31 percent lower incidence of CRC
compared to general population) at 6 months, 0.66 (34 percent lower
incidence) at 1 year, 0.59 (41 percent lower incidence) at 2 years, 0.55
(45 percent lower incidence) at 5 years, and 0.28 (72 percent lower
incidence) at 10 years. The proportion of colorectal cancer located in
the right side of the colon was significantly higher in the colonoscopy
group than the rate in the Manitoba population (47 percent vs. 28
percent).
This study demonstrates that following a negative
result from a colonoscopy performed in the usual clinical practice, the
risk of developing CRC is at most 60 percent to 70 percent of the risk
of developing CRC in the general population and the duration of the
interval of decreased CRC risk persists for more than 10 years.
Furthermore, if an individual undergoes a single
negative colonoscopy, excepting any follow-up endoscopies at which CRC
is diagnosed, the risk of developing CRC is even lower and the duration
of the interval of decreased risk again exceeds the 10-year interval
currently recommended between screening colonoscopies.
Our findings suggest that screening colonoscopies
do not need to be performed at intervals shorter than 10 years, the
authors conclude.
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