SCREENING FOR COLORECTAL CANCER
Guidelines
1.
American
Gastroenterological Association (AGA). Colorectal cancer screening: clinical guidelines and rationale.
Gastroenterology 1997 Oct;113(4):1423-4 [220 references].
2.
U.S. Preventive Services
Task Force (USPSTF). Screening for colorectal cancer. In: Guide to clinical
preventive services. 2nd ed. Baltimore (MD): Williams & Wilkins, 1996. p.
89-103 [113 references].
3.
American Cancer Society
(ACS). American Cancer Society guidelines on screening and surveillance
for the early detection of adenomatous polyps and cancer-update 2001. In:
American Cancer Society guidelines for the early detection of cancer. CA Cancer
J Clin 2001 Jan-Feb;51(1):44-54 [181 references].
4.
Institute for Clinical
Systems Improvement (ICSI). Colorectal cancer screening. Bloomington (MN): Institute for
Clinical Systems Improvement (ICSI); 2000 Jan. 24 p. [49 references].
5.
Canadian Task Force on
Preventive Health Care (CTFPHC). Preventive Health Care, 2001 Update: colorectal Cancer Screening.
CMAJ 2001; 165(1):206-7 [97 references].
INTRODUCTION:
A
direct comparison of AGA, USPSTF, ACS, ICSI, and CTFPHC recommendations for
screening asymptomatic individuals and individuals at increased risk for
colorectal cancer is provided in the following tables. In formulating their
recommendations, ACS and CTFPHC review the conclusions drawn by AGA and USPSTF.
ICSI considers the guideline released by USPSTF. Following the content
comparison, areas of agreement and differences among the guidelines are discussed.
In general, the timing of the guideline with respect to available data is an
important factor to consider when evaluating areas of differences among
guidelines. The rationale behind differences in practice recommendations that
cannot be attributed to differences in the evidence base is also discussed.
The
evidence supporting the major recommendations is also identified, with the
definitions of the rating schemes used by USPSTF, ICSI and CTFPHC included in
the last row of the table.
Abbreviations
used in the text and tables follow:
·
ACS, American Cancer
Society
·
AGA, American
Gastroenterological Association
·
CRC, colorectal cancer
·
CTFPHC, Canadian Task
Force on Preventive Health Care
·
DCBE, double contrast
barium enema
·
DRE, digital rectal
examination
·
FOBT, fecal occult blood
testing
·
HNPCC, hereditary
nonpolyposis colorectal cancer
·
ICSI, Institute for
Clinical Systems Improvement
·
TCE, total colon
examination
·
USPSTF, United States
Preventive Services Task Force
|
|
OBJECTIVE
AND SCOPE |
|
AGA |
|
|
USPSTF |
|
|
ACS |
|
|
ICSI |
|
|
CTFPHC |
|
|
|
INTENDED
USERS |
|
AGA |
Primary care
clinicians and specialists |
|
USPSTF |
Primary care
clinicians |
|
ACS |
Primary care
clinicians and specialists |
|
ICSI |
Primary care
clinicians |
|
CTFPHC |
Primary care
clinicians and specialists |
|
|
INTERVENTIONS
AND PRACTICES CONSIDERED |
|
AGA |
Screening
options:
Recommendations for high risk populations
(i.e., counseling for genetic testing) |
|
USPSTF |
Screening
options:
High-risk patients are outside the scope of
this guideline |
|
ACS |
Screening
options:
Recommendations for high risk populations
(i.e., counseling for genetic testing) |
|
ICSI |
Screening
options:
High-risk patients are outside the scope of
this guideline |
|
CTFPHC |
Screening
options:
Screening with digital rectal examination and
double contrast barium enema were not considered because of the lack of
direct evidence |
|
COMPARISON OF RECOMMENDATIONS FOR SCREENING FOR
COLORECTAL CANCER: |
|
|
|
Fecal
occult blood testing (FOBT) |
|
AGA |
|
|
USPSTF |
|
|
ACS |
|
|
ICSI |
|
|
CTFPHC |
|
|
|
Flexible
sigmoidoscopy |
|
AGA |
An acceptable
screening option is to offer sigmoidoscopy every five years. This option is supported by strong evidence of
effectiveness. A five year interval is chosen because of strong (randomized
trial) evidence that colonoscopy is equally effective at 1- or 1- and 3- year
intervals, weaker (case control) evidence that sigmoidoscopy is effective at
up to 10-year intervals, and the observation that few polyps arise and
progress to advanced cancer in a 5 year period. |
|
USPSTF |
Sigmoidoscopy is
considered an effective screening technique; however, there is insufficient
evidence to recommend a periodicity for sigmoidoscopy screening. (I-2, II-3) |
|
ACS |
Flexible sigmoidoscopy
performed every 5 years is an acceptable screening option. This recommendation is supported by
case-control studies of clinical effectiveness. The five year interval is
chosen because of a range of factors that may affect the overall sensitivity
of flexible sigmoidoscopy:
|
|
ICSI |
An acceptable
screening option is 60 cm flexible sigmoidoscopy every 5 years. (Evidence
supporting the screening recommendations is of classes: C, R, B, D) |
|
CTFPHC |
There is evidence from
case control studies, to recommend that flexible sigmoidoscopy be included in
the periodic health examination of patients over age 50 [B, II-2, III]. |
|
|
Combined
fecal occult blood testing and flexible sigmoidoscopy |
|
AGA |
The individual
components of this strategy are supported by strong evidence but the added
value of combining the two, while theoretically present, is not well
established by research evidence. Indirect evidence, including the panel’s
decision analysis on the clinical consequences of CRC, supports this
recommendation. |
|
USPSTF |
There is insufficient
evidence to determine whether this combination of tests produces greater
benefits than either test alone. |
|
ACS |
FOBT every year plus
flexible sigmoidoscopy every 5 years is an acceptable screening option. Because combining flexible sigmoidoscopy with
FOBT can increase the benefits of either test alone, the ACS regards annual
FOBT accompanied by flexible sigmoidoscopy every five years as a better
choice than either FOBT or flexible sigmoidoscopy alone. |
|
ICSI |
An acceptable
screening option is a combination of both 60 cm flex sigmoidoscopy every 5
years and FOBT annually. (Evidence supporting the screening recommendations is
of classes: C, R, B, D) |
|
CTFPHC |
There is insufficient
evidence to make recommendations about whether only 1 or both of FOBT and
sigmoidoscopy should be performed [C, I]. |
|
|
Digital
rectal examination (DRE) |
|
AGA |
DRE by itself has not
been shown to be an effective way of screening for CRC. However, it is part of other screening
examinations for CRC (sigmoidoscopy, colonoscopy, and barium enema) and may
be included in a comprehensive program of preventive health care for other
reasons. |
|
USPSTF |
DRE is of limited
value as a screening test for CRC. There is insufficient evidence to
recommend for or against routine screening with DRE. Recommendations against using this test may be
made on other grounds (e.g., availability of alternate tests of proven
effectiveness, inaccuracy of DRE). (C, III) |
|
ACS |
Although DRE is a
useful method for identifying masses in the anal canal or lower rectum, it
has very poor sensitivity for detecting colorectal cancer due to limited
reach. While DRE is often included as part of a routine physical examination,
it is not recommended as a stand-alone screening test for colorectal cancer.
However, DRE should be performed prior to insertion of a sigmoidoscope or
colonoscope. |
|
ICSI |
DRE is a simple
examination to perform with potential to discover a small percentage of colon
cancers within reach of the examining finger. Palpation of any mass or polyp
should lead to further investigation. Separate health care encounters for the sole
purpose of doing a DRE are not suggested. A DRE might be performed as part of
a visit for either health evaluation or illness-related concerns. |
|
CTFPHC |
Screening with digital
rectal examination was not considered because of the lack of direct evidence. |
|
|
Barium
enema |
|
AGA |
An acceptable
screening option is double contrast barium enema (DCBE) every 5-10 years. This option is not supported by direct
evidence (from randomized trial, nonrandomized trial, or case-control
studies) that DCBE reduces mortality from CRC; but it is supported by the
panel’s decision analysis on the clinical consequence of CRC. |
|
USPSTF |
There is insufficient
evidence to recommend for or against routine screening with barium enema. Recommendations against using this test for
screening average-risk persons may be made on other grounds (e.g.,
availability of alternate tests of proven effectiveness). (C, III) |
|
ACS |
Examining the entire
colorectum, either by colonoscopy every 10 years or by DCBE every 5 years is
an acceptable screening option. The choice of colonoscopy or DCBE for
screening can be made on an individual basis, depending on factors such as
personal preference, cost, feasibility, tolerance of potential complications,
and the local availability of trained clinicians able to offer a high-quality
examination. For those who elect either colonoscopy or DCBE for screening,
there is no need for annual FOBT. |
|
ICSI |
Acceptable screening
option: perform total colon examination by flexible sigmoidoscopy combined
with fluoroscopic barium enema or DCBE every 5 years. (Evidence supporting
the screening recommendations is of classes: C, R, B, D) |
|
CTFPHC |
Screening with double
contrast barium enema was not considered because of the lack of direct
evidence. |
|
|
Colonoscopy |
|
AGA |
An acceptable screening
option is colonoscopy every 10 years. This option is not supported by direct
evidence (from randomized trial, nonrandomized trial, or case-control
studies) that colonoscopy reduces mortality from CRC; but it is supported by
other evidence and the panel’s decision analysis on the clinical consequence
of CRC. |
|
USPSTF |
There is insufficient
evidence to recommend for or against routine screening with colonoscopy. Recommendations against using this test for
screening average-risk persons may be made on other grounds (e.g.,
availability of alternate tests of proven effectiveness, costs and risks of
colonoscopy). (C, III) |
|
ACS |
Examining the entire
colorectum, either by colonoscopy every 10 years or by DCBE every five years
is an acceptable screening option. The choice of colonoscopy or DCBE for
screening can be made on an individual basis, depending on factors such as
personal preference, cost, feasibility, tolerance of potential complications,
and the local availability of trained clinicians able to offer a high-quality
examination. For those who elect either colonoscopy or DCBE for screening,
there is no need for annual FOBT. |
|
ICSI |
An acceptable
screening option is total colon examination, by colonoscopy every 5-10 years
(Evidence supporting the screening recommendations is of classes: C, R, B, D) |
|
CTFPHC |
There is insufficient
evidence to include or exclude colonoscopy as an initial screen in the
periodic health examination [C, II-3]. Although colonoscopy is the best method for
detecting adenomas and carcinomas, it may not be feasible to screen
asymptomatic patients because of patient compliance and the expertise and
equipment required and the potential costs. On the other hand, if colonoscopy
were an effective screening strategy when performed at less frequent
intervals, these issues might be of less concern. |
|
COMPARISON OF RECOMMENDATIONS FOR SCREENING FOR
COLORECTAL CANCER: |
|
|
|
People
with family history of colorectal cancer |
|
AGA |
People with a close
relative (sibling, parent or child) who has had colorectal cancer or an
adenomatous polyp should be offered the same options as average-risk people
but beginning at age 40 years. If the close relative was diagnosed with
colorectal cancer before the age of 55 years or with an adenomatous polyp
before age 60, special efforts should be made to assure that screening takes
place. |
|
USPSTF |
The increased risk of
developing cancer at younger ages may justify beginning screening before age
50 (no specific age stated) in
persons with a single first-degree relative with colon cancer, especially
when affected relative developed CRC at younger ages. |
|
ACS |
People with a family
history of either colorectal cancer or colorectal adenomas that occurred in a
first-degree relative before age 60, or in multiple first-degree relatives of
any age (if not a hereditary syndrome), should have a colonoscopy* at age 40,
or 10 years before the youngest case in the immediate family. Examination
should be repeated every 5-10 years. Colorectal cancer in relatives more
distant than first-degree does not increase risk substantially above the
average risk group. *Note:
If a colonoscopy is not available, not feasible, or not desired by the
patient, a DCBE, or flexible sigmoidoscopy followed by a DCBE can be used. |
|
ICSI |
Patients at increased
risk of developing colorectal cancer require colonoscopic surveillance at a 3
to 5 year interval, and are outside the scope of this guideline. |
|
CTFPHC |
Patients who have only
one or two first-degree relatives with colorectal cancer should be screened
in the same way as average risk individuals. There is insufficient evidence
to recommend colonoscopy for individuals who have a family history of
colorectal polyps or cancer but do not fit the criteria for hereditary
non-polyposis colon cancer [C, III]. While there is evidence that there is an
increased prevalence of neoplasms in these individuals, there is insufficient
information to recommend more intense screening than that of individuals at
average risk. Further delineation of the risk for individuals with multiple
affected family members and family members with early age of diagnosis of
colorectal cancer is necessary. |
|
|
People
with a family history of familial adenomatous polyposis |
|
AGA |
Genetic counseling and
consider genetic testing to see if they are gene carriers. Gene carriers or indeterminate
cases should be offered flexible sigmoidoscopy every 12 months beginning at
puberty to see if they are expressing the gene. If polyposis is present, they
should begin to consider when they should have colectomy. |
|
USPSTF |
Refer to specialist
for regular endoscopic screening, diagnosis and management. |
|
ACS |
Individuals with a
family history of familial adenomatous polyposis are at high risk and should
undergo early surveillance with endoscopy, and counseling to consider genetic
testing beginning at puberty. If the genetic test is positive, colectomy is
indicated; These patients are best referred to a center with experience in
the management of familial adenomatous polyposis. |
|
ICSI |
Patients at increased
risk of developing colorectal cancer require colonoscopic surveillance at a 3
to 5 year interval, and are outside the scope of this guideline. |
|
CTFPHC |
The Task Force
recommends genetic testing of individuals at risk for familial adenomatous polyposis
if the genetic mutation has been identified in the family and if genetic
testing is available [B, II-3]. If the individual carries the mutation, then
he or she should be screened with flexible sigmoidoscopy beginning at puberty
[B, II-3]. Individuals from families where the gene mutation has been
identified but are negative themselves, require screening similar to the
average risk population. For at risk individuals where the mutation has not
been identified in the family or where genetic testing is not available,
screening with annual or biannual flexible sigmoidoscopy should be undertaken
beginning at puberty. In all instances, genetic counseling should be
performed prior to genetic testing. |
|
|
People
with a family history of hereditary nonpolyposis colorectal cancer (HNPCC) |
|
AGA |
Genetic counseling and
consider genetic testing for HNPCC. Offer an examination of the entire colon
every 1-2 years starting between the ages of 20 and 30 years and every year
after age 40 years. |
|
USPSTF |
Refer to specialist
for regular endoscopic screening, diagnosis and management. |
|
ACS |
Individuals with a
family history of HNPCC should undergo colonoscopy and counseling to consider
genetic testing beginning at age 21. If the genetic test is positive or if
patient has not had genetic testing, colonoscopy is recommended every 1-2
years until age 40 years, then annually. These patients are best referred to
a center with experience in the management of HNPCC. |
|
ICSI |
Patients at increased
risk of developing colorectal cancer require colonoscopic surveillance at a 3
to 5 year interval, and are outside the scope of this guideline. |
|
CTFPHC |
Patients in kindreds
with the cancer family syndrome (HNPCC) have a high risk of colorectal cancer
and a high incidence of right-sided colon cancer. Thus, colonoscopy rather
than sigmoidoscopy is recommended for screening such patients. Based on Level
III evidence, the Task Force recommends screening with colonoscopy in
individuals from hereditary non-polyposis colon cancer kindreds [B, II-3].
Although higher levels of evidence are usually required to give a B
recommendation, the Task Force realizes that it is unlikely that more rigorous
studies could be performed in this cohort of patients given the high risk of
cancer and relative infrequency of hereditary non-polyposis colon cancer. The
ages when screening should begin and the frequency at which colonoscopy
should be performed are unclear. |
|
|
People
with a history of adenomatous polyps |
|
AGA |
Patients in whom large
(>1-cm diameter) or multiple adenomatous polyps are found and removed at
colonoscopy should have an examination of the colon 3 years after the initial
examination. The interval for subsequent examinations depends on the type of
polyps that were detected. If the first follow-up is normal or only a single,
small, tubular adenoma is found, the next examination can be in 5 years. In
special circumstances (e.g., polyps with invasive cancer, large sessile
adenomas, or numerous adenomas), a shorter interval may be necessary,
according to the judgment of the clinician and the wishes of the patient. |
|
USPSTF |
Refer to specialist
for regular endoscopic screening, diagnosis and management. |
|
ACS |
People who have been
diagnosed as having adenomatous polyps should have a colonoscopy to remove
all polyps from the colorectum, after which a colonoscopic exam should be
repeated at an interval to be determined on the basis of the size,
multiplicity, and histologic appearance of the adenoma(s).
*Note:
If a colonoscopy is not available, not feasible, or not desired by the
patient, a DCBE, or flexible sigmoidoscopy followed by a DCBE can be used. |
|
ICSI |
Patients at increased
risk of developing colorectal cancer require colonoscopic surveillance at a 3
to 5 year interval, and are outside the scope of this guideline. |
|
CTFPHC |
People with a history
of adenomatous polyps are beyond the scope of the guideline. |
|
|
People
with a history of colorectal cancer |
|
AGA |
Patients with a colorectal
cancer that has been resected with curative intent (but who did not undergo
complete adequate colonoscopic examination preoperatively) should have a
complete examination of the colon within 1 year after resection. If this or a
complete preoperative examination is normal, subsequent examination should be
offered after 3 years and then, if normal, every 5 years. |
|
USPSTF |
Refer to specialist
for regular endoscopic screening, diagnosis and management. |
|
ACS |
Individuals with a
personal history of curative-intent resection of colorectal cancer are at
increased risk. Colonoscopy* is recommended within 1 year after resection. If
normal, repeat examination in 3 years; if normal then, repeat examination
every 5 years. *Note:
If a colonoscopy is not available, not feasible, or not desired by the
patient, a DCBE, or flexible sigmoidoscopy followed by a DCBE can be used. |
|
ICSI |
Patients at increased
risk of developing colorectal cancer require colonoscopic surveillance at a 3
to 5 year interval, and are outside the scope of this guideline. |
|
CTFPHC |
People with a history
of colorectal cancer are beyond the scope of the guideline. |
|
|
People
with inflammatory bowel disease |
|
AGA |
Surveillance
colonoscopy, looking for dysplasia as a marker of colorectal cancer risk,
should be considered along with the extent and duration of the disease as a
guide to when or if colectomy should be considered. |
|
USPSTF |
Refer to specialist
for regular endoscopic screening, diagnosis and management. |
|
ACS |
Individuals with
inflammatory bowel disease, chronic ulcerative colitis, or Crohn’s disease
are at high risk. Colonoscopies with biopsies for dysplasia are recommended 8
years after the start of pancolitis; 12-15 years after the start of
left-sided colitis. Examination should be repeated every 1-2 years. These
patients are best referred to a center with experience in the surveillance
and management of inflammatory bowel disease. |
|
ICSI |
Patients at increase
risk of developing colorectal cancer require colonoscopic surveillance at a 3
to 5 year interval, and are outside the scope of this guideline. |
|
CTFPHC |
People with inflammatory
bowel disease are beyond the scope of the guideline. |
|
EVIDENCE RATING SCHEMES |
|
|
|
Rating
Scheme |
|
USPSTF |
Levels
of Evidence Well-designed and well-conducted meta-analyses
were also considered, and were graded according to the quality of the studies
on which the analyses were based (e.g., Grade I if the meta-analysis pooled
properly randomized controlled trials). Recommendation Grade |
|
ICSI |
Evidence
Grading System: Classes of Research Reports A. Primary Reports of New Data Collection:
Class B
Class C
Class D
B. Reports that Synthesize or Reflect upon
Collections of Primary Reports
Class R
Class X
|
|
CTFPHC |
Level
of Evidence: Recommendation Grade: |
GUIDELINE CONTENT COMPARISON
The
American Gastroenterological Association (AGA), the U.S. Preventive Services
Task Force (USPSTF), the American Cancer Society (ACS), the Institute for
Clinical Systems Improvement (ICSI), and the Canadian Task Force on Preventive
Health Care (CTFPHC) present recommendations for screening for colorectal
cancer in people at average risk (asymptomatic, age > 50 years, no
other risk factors) and provide explicit reasoning behind their judgments. The
AGA, ACS, and CTFPHC also present screening recommendations for individuals at
increased risk of colorectal cancer. Because the USPSTF and ICSI guidelines are
intended for primary care clinicians and surveillance of high-risk populations
requires referral to a specialist, further recommendations are not offered for
these high-risk groups by the USPSTF and ICSI.
Areas of Agreement
The
AGA, USPSTF, ACS, ICSI, and CTFPHC agree that asymptomatic adults >
50 years, with no other risk factors, should be screened for colorectal cancer,
utilizing one of several acceptable screening tests such as fecal occult blood
testing or flexible sigmoidoscopy. All five groups present two or more
acceptable screening options and do not explicitly recommend one screening test
over another. The ACS suggests that, whenever possible, patients participate in
a shared decision-making process, where information about each of the screening
options, such as accuracy, cost, potential for prevention, discomfort and risk
is discussed. Similarly, the AGA concludes that decisions about which test or
tests to use should take into account the patient’s preferences, the patient’s
age, any existing comorbidity, and local resources and expertise. The USPSTF
also recommends consideration of patient preferences and patient education in
decision making rather than a uniform policy for all patients.
Due to
several obstacles in the shared decision-making approach, such as availability
of well trained personnel and the time it takes to explain options to patients,
ACS acknowledges that clinicians may be able to successfully implement only one
or two of the screening modalities, limiting options for patients.
Consequently, ACS notes that of primary importance at this time is that
clinicians recommend at least one of the appropriate screening options for all
of their eligible patients.
The
organizations acknowledge that the option of total colon examination (TCE) by
colonoscopy or barium enema has not been supported by randomized controlled
trials. Consequently, the USPSTF and CTFPHC do not recommend for or against
colonoscopy, and USPSTF does not recommend for or against barium enema in
asymptomatic individuals at average risk of colorectal cancer. CTFPHC did not consider
screening with barium enema because of the lack of direct evidence. The AGA
concluded total colon examination (TCE) by colonoscopy or barium enema were
supported by indirect evidence, including the panel’s decision analysis
conducted to investigate the clinical consequences of screening over time,
despite the absence of direct evidence. ACS also cites compelling indirect
evidence for benefit and efficacy of TCE. Consequently, the AGA, ACS and ICSI
concluded that TCE by colonoscopy or barium enema is an acceptable screening
option.
Areas of Differences
Although
all the organizations share the fundamental recommendation for screening
asymptomatic adults at average risk of colorectal cancer, there are subtle
differences in what they propose as optimal screening measures. A difference
between the ACS and the other groups concerns the recommendations for FOBT and
sigmoidoscopy. Although ACS and the other groups recommend annual FOBT or
flexible sigmoidoscopy every five years as acceptable screening options, ACS
notes that annual FOBT accompanied by flexible sigmoidoscopy (every five years)
is preferable to utilization of either test alone. AGA and ICSI also recommend
the combination of FOBT and flexible sigmoidoscopy as a screening option;
however, ACS is the only organization to advocate the combination strategy as
the preferred approach (over either test alone). USPSTF and CTFPHC concluded
there is insufficient evidence to determine whether this combination of tests
produces greater benefits than either test alone.
Although
all of the groups recommend screening with FOBT, CTFPHC is the only group that
does not specifically recommend annual testing. However, they support screening
in the periodic health examination of asymptomatic patients over age 50 with no
other risk factors.
Screening
recommendations for people with a family history of colorectal cancer vary
among guidelines. AGA, USPSTF, ACS, and ICSI recommend increased surveillance
or earlier screening for these individuals. In contrast, CTFPHC recommends that
people with a family history of colorectal cancer or polyps undergo the same
screening as average risk individuals, stating insufficient evidence to
recommend colonsocopy for these individuals, unless the criteria for hereditary
non-polyposis colon cancer is met. Although CTFPHC acknowledges that there is
evidence of an increased prevalence of neoplasms in these individuals, there is
insufficient information to recommend more intense screening than that of
individuals at average risk.
Although
there is general agreement among AGA, ACS, and CTFPHC regarding the need for
genetic counseling in individuals at risk for familial adenomatous polyposis,
CTFPHC is the only guideline to firmly recommend genetic testing. The Task
Force for the CTFPHC recommends genetic testing of individuals at risk for
familial adenematous polyposis if the genetic mutation has been identified in
the family and if genetic testing is available. This recommendation is based on
fair evidence to support the recommendation that the manoeuvre be specifically
considered in a periodic health examination. USPSTF and ICSI do not comment on
genetic counseling/screening as it is beyond the scope of their guidelines.
Updates in Progress: A third USPSTF was appointed in September 1998 by the Agency for
Health Care Policy and Research (now known as the Agency for Healthcare
Research and Quality [AHRQ]). USPSTF recommendations from the 2nd edition will
be updated on an individual basis and new topics evaluated. Reviews and
recommendations will be released as they are completed. This particular USPSTF
guideline is currently under revision and is scheduled for release in 2002.
Edward E.
Rylander, M.D.
Diplomat American
Board of Family Practice.
Diplomat American
Board of Palliative Medicine.