Colon Cancer Testing Should Continue Consistently
Through Age 75, Task Force Says
U.S. Preventative Services Task Force issues new
guidelines on how, when to test for colorectal cancer
Oct. 7, 2008 - New findings from a Decision
Analysis for the U.S. Preventative Services Task Force (USPSTF) suggest
that routine colorectal cancer screenings can be stopped in patients
over the age of 75. The results are based on patients who began
screenings at age 50 and have had consistently negative screenings up to
the age of 75 resulting from annual screening with sensitive Fecal
Occult Blood Test (FOBT), ten yearly colonoscopies, or five yearly
sigmoidoscopies with a mid-interval sensitive FOBT.
Cancer's precursor polyps, known as adenoma, sharply
increase after age 50
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Medicare's coverage of tests for colorectal cancer.
More about colon cancer.
Sept. 3, 2008 – People over age 50, who are still
wrestling with the decision of whether they should have a colonoscopy,
received another wake-up call this week from a study detailing the rapid
increase of polyps – the precursor of virtually all colorectal cancers –
that begin to occur at that age.
Read more...
In July 2002, the last recommendation by the USPSTF
concluded that there was enough evidence to recommend strongly that all
average risk adults 50 years of age and older be offered colorectal
cancer screening.
However, the logistics of screening such as type of
screening test, screening intervals, and age to stop screening were not
evaluated in terms of the balance of benefits and potential harms.
In updating its recommendations for 2008, the
USPSTF requested a decision analysis to project expected outcomes of
various colorectal cancer screening strategies to inform its update of
the recommendations for colorectal cancer screening.
“Screening for colorectal cancer saves lives,”
said Task Force Chair Ned Calonge, M.D., who is also chief medical
officer for the Colorado Department of Public Health and Environment.
“Current rates for colorectal cancer screening are
much lower than other types of cancer screening. We hope patients and
physicians will discuss the potential benefits and harms and choose an
appropriate screening method for them.”
Colorectal cancer is the third most common cancer
and the second leading cause of cancer death in the United States.
The findings are published in the October 7, 2008
online edition of
Annals of Internal Medicine, along with the summary of evidence, and
will appear in the Nov. 4 print edition of the journal.
"To date there has been no age to stop colorectal
cancer screening,” says Ann Graham Zauber, PhD, Associate Attending
Biostatistician in the Department of Epidemiology and Biostatistics at
Memorial Sloan-Kettering Cancer Center, and lead author of the study
evaluating testing methods.
“Our results suggest that there is little gain in
life expectancy in continuing colorectal cancer screening after age 75,
for those who have had repeated negative screening examinations since
the age of 50.”
“People who have had adenomas or colorectal cancer
should continue surveillance after age 75," said Dr. Zauber, who added
that "our findings also suggest that the more sensitive fecal occult
blood tests can provide comparable life years saved to screening
colonoscopy provided high adherence to these screening tests."
"Our objective was to assess life years gained and
colonoscopy requirements for colorectal cancer screening strategies and
identify a set of recommendable screening strategies," she said.
The Task Force recommends against routine
colorectal cancer screening in adults between the ages of 76 and 85,
because the benefits of regular screening were small compared with the
risks. The Task Force also recommends that adults over the age of 85
not be screened at all because the harms of screening may be
significant, and other conditions may be more likely to affect their
health or well-being.
For people of all ages, the Task Force found
insufficient evidence to assess the benefits and harms of computed
tomographic (CT) colonography and fecal DNA testing as screening methods
for the disease.
Further, these Task Force recommendations don’t
apply to people with a personal history of certain types of polyps who
are being monitored regularly for the condition or to those who have a
family history of rare syndromes that increase a person’s chances of
getting colon cancer.
“Although colonoscopy is considered to be the
standard against which other screening tests are compared, the test is
not perfect and may in fact miss some polyps and colorectal cancer,”
according to a news release from the Agency for Healthcare Research and
Quality.
“Because colonoscopy is an invasive procedure, it
has greater risk of complications than any other screening methods.
“Sigmoidoscopy or fecal occult blood testing are
less invasive and have a lower risk of harms. However, patients who
receive positive test results for detection of polyps will require a
follow-up colonoscopy regardless of the screening test used.
“Because the risks and benefits of all tests vary,
patients and clinicians are encouraged to decide together which test is
appropriate.”
The Task Force is the leading independent panel of
experts in prevention and primary care. The Task Force, which is
supported by AHRQ, conducts rigorous, impartial assessments of the
scientific evidence for the effectiveness of a broad range of clinical
preventive services, including screening, counseling and preventive
medications.
Its recommendations are considered the gold
standard for clinical preventive services.
The Task Force based its conclusions on a report
from a research team led by Evelyn Whitlock, M.D., at the Kaiser
Permanente Center for Health Research, which is part of AHRQ’s Oregon
Evidence-based Practice Center.
This is the first time that the USPSTF has
incorporated a decision analysis to inform its recommendations.
Previously the Task Force has used an extensive structured literature
review.
This time, the USPSTF has both the evidence review
of published work and this decision analysis, which considered 145
different strategies (90 single-test strategies, 54 combination-test
strategies, and one no screening-strategy) on age to begin, age to stop,
and intervals of testing for guaiac FOBT (lower and higher sensitivity
test), fecal immunochemical test, and flexible sigmoidoscopy alone and
with a sensitive FOBT.
Dr. Zauber and colleagues translated the best
evidence from randomized trials into structured and comparable outcomes
of life years saved relative to use of colonoscopy resources. This work
represents the transition from evidence-based to evidence-informed
recommendations.
"This excellent decision analysis by Dr. Zauber and
colleagues confirms the validity of colorectal cancer screening in men
and women ages 50 to 75, which will provide the greatest benefit with
saving of resources,” added Dr. Sidney Winawer, the Paul Sherlock Chair
in Medicine in the Gastroenterology and Nutrition Service at Memorial
Sloan-Kettering Cancer Center.
“Unfortunately the majority of Americans in this
age range do not get screened at all, resulting in tragic consequences
for them and their families. There is no reason why 50,000 people should
die of this disease in America each year,"
This research is joint work of Memorial
Sloan-Kettering Cancer Center with Erasmus MC of Rotterdam, the
Netherlands, the University of Minnesota, and Massachusetts General
Hospital as part of the Cancer Intervention and Surveillance Modeling
Network (CISNET) of NCI and is an example of comparative modeling with
independently developed microsimulation models.
This study was funded by grants from the National
Cancer Institute and the Agency for HealthCare Research and Quality.
Previous Task Force recommendations, summaries of
the evidence and related materials are available from the AHRQ
Publications Clearinghouse by calling (800) 358-9295 or sending an
e-mail to
ahrqpubs@ahrq.hhs.gov. Clinical information is also available from
AHRQ’s National Guideline Clearinghouse at
http://www.guideline.gov.
Keep up with the latest news for senior citizens, baby
boomers
Oct. 7, 2008 - New findings from a Decision
Analysis for the U.S. Preventative Services Task Force (USPSTF) suggest
that routine colorectal cancer screenings can be stopped in patients
over the age of 75. The results are based on patients who began
screenings at age 50 and have had consistently negative screenings up to
the age of 75 resulting from annual screening with sensitive Fecal
Occult Blood Test (FOBT), ten yearly colonoscopies, or five yearly
sigmoidoscopies with a mid-interval sensitive FOBT. 
Medicare's coverage of tests for colorectal cancer.