screening colonoscopy in very elderly may be limited
Newswise — 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 a study in the May 24/31 issue of JAMA.
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 possibly 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.
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
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 much lower in the 2 elderly groups. T
he 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.
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.”
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
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 Health’s 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.
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
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.
suggest that screening colonoscopies do not need to be performed at
intervals shorter than 10 years,” the authors conclude.