Amir Qaseem, MD, PhD, MHA; Thomas D. Denberg, MD, PhD; Robert H. Hopkins, MD; Linda L. Humphrey, MD, MPH; Joel Levine, MD; Donna E. Sweet, MD; Paul Shekelle, MD, PhD; for the Clinical Guidelines Committee of the American College of Physicians*
* This paper, written by Amir Qaseem, MD, PhD, MHA; Thomas D. Denberg, MD, PhD; Robert H. Hopkins Jr., MD; Linda L. Humphrey, MD, MPH; Joel Levine, MD; Donna E. Sweet, MD; and Paul Shekelle, MD, PhD, was developed for the Clinical Guidelines Committee of the American College of Physicians: Paul Shekelle, MD, PhD (Chair); Roger Chou, MD; Paul Dallas, MD; Thomas D. Denberg, MD, PhD; Nick Fitterman, MD; Mary Ann Forciea, MD; Robert H. Hopkins Jr., MD; Linda L. Humphrey, MD, MPH; Tanveer P. Mir, MD; Holger J. Schünemann, MD, PhD; Donna E. Sweet, MD; and David S. Weinberg, MD, MSc. Approved by the ACP Board of Regents on 19 November 2011.
Note: Clinical guidance statements are “guides” only and may not apply to all patients and all clinical situations. Thus, they are not intended to override clinicians' judgment. All ACP clinical guidance statements are considered automatically withdrawn or invalid 5 years after publication, or once an update has been issued.
Disclaimer: The authors of this article are responsible for its contents, including any clinical or treatment recommendations.
Financial Support: Financial support for the development of this guidance statement comes exclusively from the ACP operating budget.
Potential Conflicts of Interest: Any financial and nonfinancial conflicts of interest of the group members were declared, discussed, and resolved. A record of conflicts of interest is kept for each Clinical Guidelines Committee meeting and conference call and can be viewed at www.acponline.org/clinical_information/guidelines/guidelines/conflicts_cgc.htm. Drs. Denberg, Hopkins, and Humphrey: Support for travel to meetings for the study or other purposes: ACP. Dr. Hopkins: Board membership: National Foundation for Infectious Diseases; Consultancy: Qualchoice of Arkansas, MedStudy Corporation; Payment for lectures including service on speakers bureaus: VEMCO MedEd Corp. Dr. Shekelle: Consultancy: ECRI; Employment: VA; Grants/grants pending (money to institution): AHRQ, VA, CMS, NINR-NIH, DHHS; Royalties: UpToDate. Disclosures can also be viewed at www.acponline.org/authors/icmje/ConflictOfInterestForms.do?msNum=M11-3122.
Requests for Single Reprints: Amir Qaseem, MD, PhD, MHA, American College of Physicians, 190. N Independence Mall West, Philadelphia, PA 19106; e-mail, email@example.com.
Current Author Addresses: Dr. Qaseem: 190 N. Independence Mall West, Philadelphia, PA 19106.
Dr. Denberg: 275 Grove Street, Auburndale, MA 02466.
Dr. Hopkins: 4301 West Markham Street, Little Rock, AR 72205.
Dr. Humphrey: 3710 SW U.S. Veterans Hospital Road, Portland, OR 97201.
Dr. Levine: Academic Office Building 1, PO Box 6511, 12631 East 17th Avenue, Room 7614, Aurora, CO 80045.
Dr. Sweet: 1010 N. Kansas, Wichita, KS 67214.
Dr. Shekelle: 11301 Wilshire Boulevard, Los Angeles, CA 90073.
Author Contributions: Conception and design: A. Qaseem, R.H. Hopkins, D.E. Sweet, P. Shekelle.
Analysis and interpretation of the data: A. Qaseem, R.H. Hopkins, L.L. Humphrey, J. Levine, D.E. Sweet.
Drafting of the article: A. Qaseem, T.D. Denberg, R.H. Hopkins, D.L. Sweet.
Critical revision for important intellectual content: A. Qaseem, T.D. Denberg, R.H. Hopkins, L.L. Humphrey, D.E. Sweet, P. Shekelle.
Final approval of the article: A. Qaseem, T.D. Denberg, R.H. Hopkins, L.L. Humphrey, J. Levine, D.E. Sweet, P. Shekelle.
Provision of study materials or patients: A. Qaseem.
Statistical expertise: A. Qaseem, D.E. Sweet.
Administrative, technical, or logistic support: A. Qaseem.
Collection and assembly of data: A. Qaseem.
Qaseem A., Denberg T., Hopkins R., Humphrey L., Levine J., Sweet D., Shekelle P., ; Screening for Colorectal Cancer: A Guidance Statement From the American College of Physicians. Ann Intern Med. 2012;156:378-386. doi: 10.7326/0003-4819-156-5-201203060-00010
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Published: Ann Intern Med. 2012;156(5):378-386.
This article has been corrected. The original version (PDF) is appended to this article as a supplement.
Colorectal cancer is the second leading cause of cancer-related deaths for men and women in the United States. The American College of Physicians (ACP) developed this guidance statement for clinicians by assessing the current guidelines developed by other organizations on screening for colorectal cancer. When multiple guidelines are available on a topic or when existing guidelines conflict, ACP believes that it is more valuable to provide clinicians with a rigorous review of the available guidelines rather than develop a new guideline on the same topic.
The authors searched the National Guideline Clearinghouse to identify guidelines developed in the United States. Four guidelines met the inclusion criteria: a joint guideline developed by the American Cancer Society, the U.S. Multi-Society Task Force on Colorectal Cancer, and the American College of Radiology and individual guidelines developed by the Institute for Clinical Systems Improvement, the U.S. Preventive Services Task Force, and the American College of Radiology.
ACP recommends that clinicians perform individualized assessment of risk for colorectal cancer in all adults.
ACP recommends that clinicians screen for colorectal cancer in average-risk adults starting at the age of 50 years and in high-risk adults starting at the age of 40 years or 10 years younger than the age at which the youngest affected relative was diagnosed with colorectal cancer.
ACP recommends using a stool-based test, flexible sigmoidoscopy, or optical colonoscopy as a screening test in patients who are at average risk. ACP recommends using optical colonoscopy as a screening test in patients who are at high risk. Clinicians should select the test based on the benefits and harms of the screening test, availability of the screening test, and patient preferences.
ACP recommends that clinicians stop screening for colorectal cancer in adults over the age of 75 years or in adults with a life expectancy of less than 10 years.
Colorectal cancer is the second leading cause of cancer-related deaths among both men and women in the United States (1). The incidence of colorectal cancer was 102 900 people in 2010, and prevalence was 1 110 077 people in 2008, including 542 127 men and 567 950 women (2, 3). Americans have a 5% lifetime risk for colorectal cancer (2), and approximately 51 370 Americans die of the disease each year (3). However, the incidence of colorectal cancer has been declining in the United States by 2% to 3% per year over the past 15 years (4). Colorectal cancer is rare before age 40 years in both men and women, with 90% of cases occurring after age 50 years (2).
The usual pathogenesis of colorectal cancer is an adenomatous polyp that slowly increases in size, followed by dysplasia and finally cancer. Screening for colorectal cancer is valuable because early detection and removal of premalignant adenomas or localized cancer can prevent cancer or cancer-related deaths. Good evidence shows that screening reduces mortality from colorectal cancer (5). Several methods are currently available for colorectal cancer screening. They fall under 2 categories: stool-based tests, including guaiac-based fecal occult blood test (gFOBT), immunochemical-based fecal occult blood test (iFOBT), and stool DNA panel (sDNA); and endoscopic and radiologic tests, including flexible sigmoidoscopy, optical colonoscopy, double-contrast barium enema (DCBE), and computed tomography colonography (CTC) (virtual colonoscopy). Of these screening methods, only gFOBT and flexible sigmoidoscopy have been evaluated in randomized, controlled trials that showed that they are associated with decreased colorectal cancer–related mortality.
The purpose of this guidance statement is to critically review available guidelines to help internists and other clinicians in making decisions about screening for colorectal cancer. The target patient population for this guideline is all men and women. This statement is derived from an evaluation of current guidelines in the United States on screening for colorectal cancer.
The Clinical Guidelines Committee of the American College of Physicians (ACP) developed this guidance statement for clinicians, according to methods published previously (6), by assessing current guidelines from other organizations on screening for colorectal cancer. When multiple guidelines are available on a topic or when existing guidelines conflict, ACP believes that providing clinicians with a rigorous review of the available guidelines is more useful than developing a new guideline on the same topic.
We searched the National Guideline Clearinghouse (NGC) to identify all discrete guidelines on screening for colorectal cancer developed in the United States. After reviewing the titles and abstracts of each identified document, we excluded articles that simply restated guidelines from other organizations. The NGC included 4 U.S. guidelines on screening for colorectal cancer: the joint guideline developed by the American Cancer Society (ACS), the U.S. Multi-Society Task Force on Colorectal Cancer (USMSTF), and the American College of Radiology (ACR) (7) and individual guidelines developed by the Institute for Clinical Systems Improvement (ICSI) (8), the U.S. Preventive Services Task Force (USPSTF) (9), and the ACR (10). The 7 co-authors reviewed these guidelines independently by using the Appraisal of Guidelines for Research and Evaluation II (AGREE II) appraisal instrument (11), which asks 23 questions in 6 domains: scope and purpose, stakeholder involvement, rigor of development, clarity and presentation, applicability, and editorial independence. We selected 1 guideline to calibrate our scores on the 6 domains of the AGREE II instrument, scored each guideline independently, and then compared the scores. Although total quantitative scores varied somewhat, the qualitative assessment of guideline quality was consistent among the 7 reviewers; indeed, the overall rankings of the quality of the guidelines were similar (Table 1).
Table 1. Mean Guideline Scores and Scaled Domain Scores Across Domains of the AGREE II Instrument
Of note, the American College of Gastroenterology (ACG) published a 2008 update to its colorectal cancer screening guideline (12), but this guideline is not currently included in the NGC database. Because many clinicians involved in decision making about colorectal cancer screening consult the ACG guidelines, we chose to summarize this guideline despite its absence from the NGC. However, we did not formally evaluate it by using the AGREE II instrument because our predefined methods were to rate guidelines available in the NGC. In addition, the ACG was a contributor to the joint ACS/USMSTF/ACR guideline.
ACS/USMSTF/ACR recommends screening average-risk adults starting at age 50 years.
ACS/USMSTF/ACR recommends that individuals should have an opportunity to make an informed decision when choosing one the following screening tests: flexible sigmoidoscopy every 5 years, colonoscopy every 10 years, double-contrast barium enema every 5 years, CT colonography every 5 years, annual gFOBT with high test sensitivity for cancer or annual fecal immunochemical testing with high test sensitivity for cancer, and/or fecal sDNA with high test sensitivity for cancer at an unspecified interval.
ACS/USMSTF/ACR recommends that tests that are designed to detect both early cancer and adenomatous polyps should be encouraged if resources are available and patients are willing to undergo an invasive test.
The stated purpose of the ACS/USMSTF/ACR guideline is to assess the data and comparative evidence for various screening tests for colorectal cancer and to assess when to screen adults who are at average risk for colorectal cancer. The guideline divides screening methods into tests that can detect adenomatous polyps and cancer and can therefore be considered preventive (flexible sigmoidoscopy, colonoscopy, DCBE, and CTC) and tests that primarily detect cancer (gFOBT, fecal immunochemical test [FIT], and sDNA). The ACS/USMSTF/ACR encourages using, when possible, the structural methods that are considered preventive techniques. The guideline presents a very clear rationale for the starting age of screening and acknowledges that none of the currently available screening tests is perfect for detecting cancer or adenomas. The guideline acknowledges the limitations of evidence related to sensitivity and specificity of various screening tests and relies on the judgment of the expert panel that developed the guideline. It presents information on the advantages, cost-effectiveness, limitations, and risks of each test. The strengths of this guideline include a collaborative effort; a good discussion on the benefits, harms, and limitations of various screening tests; and a discussion of the issues related to shared and informed decision making with patients. Limitations include that it did not use a systematic literature review of evidence and, in many situations, used expert opinion. In addition, the evidence that was presented did not include evaluation of the quality.
ICSI recommends routine colorectal cancer screening for all average-risk patients 50 years of age and older— age 45 and older for African Americans or American Indians. Patients with average risk for colorectal cancer are defined by: 50 years or older, or if African American or American Indian, 45 years or older with no personal history of polyps, colorectal cancer, or inflammatory bowel disease; no family history of colorectal cancer in: one first-degree relative diagnosed before age 60, or two first-degree relatives diagnosed at any age; and no family history of adenomatous polyps in one first-degree relative diagnosed before age 60.
ICSI recommends the following methods for colorectal cancer screening of average-risk patients based on joint decision making by patient and provider: stool testing: gFOBT annually or FIT annually; 60-cm flexible sigmoidoscopy every five years with or without stool test for occult blood annually; CT colonography every five years; or colonoscopy every 10 years.
ICSI considers the following for patients at increased risk of colorectal cancer and recommends different screening for these patients:
One first-degree relative with either colorectal cancer or adenomatous polyps diagnosed before age 60 years or two or more first-degree relatives diagnosed at any age: colonoscopy every five years beginning at age 40 or 10 years before the age of the youngest case in the immediate family.
Inflammatory bowel disease (chronic ulcerative colitis and Crohn's disease): colonoscopy every one to two years starting eight years after the onset of pancolitis or 12 to 15 years after the onset of left-sided colitis.
Genetic diagnosis of familial adenomatous polyposis (FAP) or suspected FAP without genetic testing evidence: annual flexible sigmoidoscopy beginning at age 10 to 12 years, along with genetic counseling.
Genetic or clinical diagnosis of hereditary nonpolyposis colorectal cancer (HNPCC): colonoscopy every one to two years beginning at age 20 to 25 years or 10 years before the age of the youngest case in the immediate family.
The purpose of the ICSI guideline is to address the appropriate screening method for patients at average and increased risk for colorectal cancer. The guideline provides clear recommendations, discusses the benefits and harms of various tests, and presents various implementation strategies. However, the details regarding the development process are not very clear in the guideline or in the available information on the ICSI Web site. Although the evidence is graded, the scoring system does not adequately differentiate between the high-quality and low-quality randomized, controlled trials. The guideline does not provide an upper age limit to stop screening but recognizes that comorbid conditions may influence the decision.
USPSTF recommends screening for colorectal cancer using fecal occult blood testing, sigmoidoscopy, or colonoscopy in adults, beginning at age 50 years and continuing until age 75 years. The risks and benefits of these screening methods vary.
USPSTF recommends against routine screening for colorectal cancer in adults 76 to 85 years of age. There may be considerations that support colorectal cancer screening in an individual patient.
USPSTF recommends against screening for colorectal cancer in adults older than age 85 years.
USPSTF concludes that the evidence is insufficient to assess the benefits and harms of CT colonography and fecal DNA testing as screening modalities for colorectal cancer.
The purpose of the USPSTF guideline is to update its 2002 guideline and present the evidence on the benefits and harms of screening technologies as well as a decision analytic model to compare the expected health outcomes and resource requirements of available screening methods. The strengths of this guideline include the use of rigorous methods, evaluation of evidence through a systematic literature review, and linkages between the evidence and recommendations. Recommendations have a very clear age specification for the purpose of screening. The USPSTF guideline is the only guideline we reviewed that does not recommend CTC as an option for colorectal cancer screening. It does not discuss specific patient populations, such as high-risk populations, or differences based on race, such as African American. In addition, the guideline did not discuss implementation-related issues, such as information on shared decision making with the patient.
ACR recommends CT colonography every 5 years after a negative CTC screen or X-ray colon barium enema double-contrast every 5 years after negative screen for average risk patients (age >50 years) and those with moderate risk (personal history of adenoma or carcinoma or first-degree family history of cancer or adenoma).
ACR recommends CT colonography or X-ray colon barium enema double-contrast for average risk patients following positive fecal occult blood test and for patients with average, moderate or high risk after incomplete colonoscopy.
ACR recommends colonoscopy for high risk patients with ulcerative colitis or Crohn's colitis and those with HNPCC.
The ACR guideline evaluates the evidence on whom and how to screen for colorectal cancer and focuses only on imaging tests. The guideline has a narrow focus and presents only information on radiologic tests. No information on the starting age for high-risk individuals, the upper age limit to stop screening, and whether this guideline supersedes the joint ACS/USMSTF/ACR guideline recommendations was included. The guideline is not based on a systematic literature review, does not account for harms, and demonstrates no clear linkage between the presented evidence and the recommendations. The guideline also does not include any information about conflicts of interests.
The ACG published an update to its colorectal cancer screening guideline in 2009. It recommends screening beginning at age 50 years in average-risk adults, age 45 years for African Americans, and age 40 years (or 10 years younger than the age at diagnosis of the youngest affected relative) in adults with a first-degree relative with colorectal cancer or advanced adenoma (an adenoma ≥1 cm in size, high-grade dysplasia, or villous elements) diagnosed at less than 60 years of age or 2 first-degree relatives with colorectal cancer or advanced adenoma.
The ACG recommends colonoscopy as the preferred colorectal cancer prevention test every 10 years in average-risk and 5 years in high-risk adults. In the event that colonoscopy is unavailable or if patients prefer an alternative test, they should be presented with the following options: colorectal cancer prevention tests (flexible sigmoidoscopy every 5 to 10 years, CTC every 5 years) or cancer detection test (FIT).
The purpose of the ACG guideline is to address the appropriate screening method for patients at average risk and increased risk for colorectal cancer. The guideline provides clear recommendations but lacks a discussion on the benefits and harms of various tests. In addition, the details regarding the development process or systematic literature review are not clearly presented. The evidence is not presented sufficiently in the tables to adequately differentiate between the high-quality and low-quality randomized, controlled trials.
The success of any screening program, especially colorectal cancer screening, depends on the appropriate testing and follow-up of patients with abnormal screening results as well as following up with patients for repeated testing at designated intervals. Colorectal cancer is a common disease with high incidence, prevalence, and mortality. Although the effectiveness of screening in reducing mortality is supported by the available evidence, only 60.8% of adults aged 50 years or older get screened in the United States (13). All of the guidelines evaluated in this guidance statement recommend screening average-risk adults starting between 40 and 50 years of age depending on ethnicity. The choice of screening method, however, varies among the guidelines we evaluated. The joint ACS/USMSTF/ACR guideline and the ICSI guideline encourage a shared decision-making approach with the patient when selecting a screening method. The USPSTF and ACR guidelines present the evidence on various screening tests but do not make any specific recommendations on selecting the appropriate screening test. For screening interval, the joint ACS/USMSTF/ACR guideline, the ICSI guideline, and the ACR guideline make specific recommendations, whereas the USPSTF guideline does not offer any recommendation.
On the basis of the review of the available guidelines, ACP concludes:
Guidance Statement 1: ACP recommends that clinicians perform individualized assessment of risk for colorectal cancer in all adults.
Clinicians should perform individualized assessment of colorectal cancer risk in all adults to help in deciding when to begin screening. Risks for colorectal cancer include age, race, and family history (for example, diagnosis of colorectal cancer, hereditary nonpolyposis, or familial adenomatous polyposis). Diagnosis of colorectal cancer in a first-degree relative, especially before age 50 years, increases the probability of colorectal cancer in all adults; a thorough family history, including the age of diagnosis of colorectal cancer for primary and secondary relatives, is important for assessing this risk. African Americans have the highest incidence of colorectal cancer compared with other races.
Guidance Statement 2: ACP recommends that clinicians screen for colorectal cancer in average-risk adults starting at the age of 50 years and in high-risk adults starting at the age of 40 years or 10 years younger than the age at which the youngest affected relative was diagnosed with colorectal cancer.
The evidence in the reviewed guidelines shows that colorectal cancer screening helps to identify undiagnosed premalignant lesions and reduces mortality with the provision of timely treatment. The benefit of reduced mortality outweighs the harms of screening for colorectal cancer in average-risk adults starting at age 50 years and high-risk adults starting at age 40 years or 10 years younger than the age at which the youngest affected relative was diagnosed.
Guidance Statement 3: ACP recommends using a stool-based test, flexible sigmoidoscopy, or optical colonoscopy as a screening test in patients who are at average risk. ACP recommends using optical colonoscopy as a screening test in patients who are at high risk. Clinicians should select the test based on the benefits and harms of the screening test, availability of the screening test, and patient preferences.
Shared decision making is important when selecting a screening test because the currently available colorectal cancer screening tests are believed to be similarly efficacious. Clinicians should discuss the benefits, harms, effectiveness, safety, and costs of the options available to screen for colorectal cancer. The sensitivity, specificity, costs, benefits, harms, and screening intervals for the tests are described in Table 2. The test quality also varies on the basis of the skill of the person performing the test (for example, ensuring correct stool preparation or having an experienced professional perform a colonoscopy), and stool-based test quality can also depend on the samples collected by the patient. Harms of endoscopic and radiologic screening tests include perforation and major bleeding with endoscopic tests and exposure to radiation with radiologic tests. Although few studies have evaluated the harms of stool-based tests, the probability of major harms is probably very small. The choice of test may also need to be made on the basis of the local availability of screening methods. For example, accessibility to endoscopic tests varies by region in the United States.
Table 2. Screening Tests for Colorectal Cancer
The screening interval for average-risk adults older than 50 years is 10 years for colonoscopy; 5 years for flexible sigmoidoscopy, DCBE, and CTC; annually for gFOBT and iFOBT; and uncertain for sDNA.
Although optical colonoscopy is generally regarded as the gold standard, it has limitations, including a false-negative rate of 10% to 20% (7, 14, 15). Also, evidence is not clear on the optimal frequency of screening using colonoscopy, but in average-risk patients, 10 years is usually regarded as a safe interval. Colonoscopy should be used as a follow-up for positive test results regardless of the noncolonoscopic screening test used. In patients who are at high risk because of family history, the ACG recommends screening every 5 years (7).
Computed tomography colonography is an option for screening in average-risk patients older than 50 years and is supported by some guidelines (7, 8, 10). However, the USPSTF found that the evidence is insufficient to assess the benefits and harms of CTC.
Guidance Statement 4: ACP recommends that clinicians stop screening for colorectal cancer in adults over the age of 75 years or in adults with a life expectancy of less than 10 years.
The harms of screening for colorectal cancer seem to outweigh the benefits in most adults older than 75 years or in adults who have a life expectancy of less than 10 years. Therefore, clinicians should not screen adults older than 75 years or those with substantial comorbid conditions (for example, diabetes, cardiopulmonary diseases, and stroke) with a life expectancy of less than 10 years.
Figure 1 summarizes the guidance statements and clinical considerations for colorectal cancer screening.
The American College of Physicians Guidance Statement on screening for colorectal cancer.
The goal of this best practice advice from the Clinical Guidelines Committee is to discuss the appropriate screening for colorectal cancer and to highlight how clinicians can contribute to delivering high-value, cost-conscious health care. Currently, no evidence shows that screening more frequently than recommended improves patient outcomes or reduces cancer-related deaths. On the other hand, screening more frequently than recommended can contribute substantially to avoidable health care costs. The benefit of screening is reduced mortality and possibly reduced incidence, whereas the harms include perforation and major bleeding with endoscopic tests and exposure to radiation with radiologic tests. A recent study suggests that colonoscopy is overused in elderly patients, including repeated screening at less than 10-year intervals and routine screening of patients older than 80 years (16). Overuse of colonoscopy in younger age groups is also a concern. Although the evidence is not clear to determine the optimal frequency of screening with colonoscopy, 10 years is usually regarded as a safe interval. Also, the repeated screening interval after normal results is 5 years for flexible sigmoidoscopy and DCBE, annually for gFOBT and iFOBT, and uncertain for sDNA. Screening should be reserved for average-risk adults starting at age 50 years and for high-risk adults starting at age 40 years or younger depending on their risk profile (Figure 2). Clinicians should not screen adults older than 75years or those with substantial comorbid conditions (for example, diabetes, cardiopulmonary diseases, and stroke) and a life expectancy of less than 10 years.
The American College of Physicians Best Practice Advice on screening for colorectal cancer.
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Video News Release - ACP Releases Colorectal Cancer Screening Guidance Statement
CharlesMaltz, Associate Professor of Clinical Medicine
Weill Cornell Medical College
March 10, 2012
Adenomas, Dysplasia, and Colorectal Cancer
The authors describe the evolution of colorectal cancer "as an adenomatous polyp that slowly increases in size, followed by dysplasia and finally cancer." However, an adenoma does not become dysplastic, but is already dysplastic. An adenoma of the colon is by definition a visible mass of dysplastic cells in the colon. The cells are determined to be dysplastic by cellular atypia as well as architectural abnormalities. These abnormalities reflect underlying genetic abnormalities in the cells. As long as the abnormal cells are above the muscularis mucosa, one is dealing with an adenoma. If additional genetic mutations develop these cells may penetrate the muscularis mucosa and then cancer is present. Colonoscopy is believed to prevent colon cancer by allowing the identification and removal of these dysplastic lesions (adenomas) before they can penetrate the muscularis mucosa and thus becomes cancer with the potential to metastasize.
David L.Keller, Internal Medicine Physician
Providence Medical Group
March 15, 2012
Comments on the Clinical Guideline on Colorectal Cancer Screening
1) Qaseem A, et. al. Screening for colorectal cancer, Ann Intern Med. 2012;156:378-386
2) Neri E, et al. CT colonography versus double-contrast barium enema for screening of colorectal cancer: comparison of radiation burden. Abdom Imaging. 2010 Oct;35(5):596-601
3) Johnson CD, et al. Comparison of the relative sensitivity of CT colonography and double-contrast barium enema for screen detection of colorectal polyps. Clin Gastroenterol Hepatol. 2004 Apr;2(4):314-21.
4)http://www.uspreventiveservicestaskforce.org/uspstf08/colocancer/colors.htm accessed on 3/14/12.
Steven PArmbruster, Gastroenterology Department, Fouad Moawad
Walter Reed National Military Medical Center
March 22, 2012
Colorectal Cancer Screening in African Americans
To the Editor:
We read with great interest the recent article by Qaseem et al. (1) regarding a guidance statement for the screening of colorectal cancer (CRC). We agree that African Americans denote a higher risk population for the development of CRC, and should be screened earlier compared to other ethnicities as endorsed by the American College of Gastroenterology (ACG), the only society to date recommending early screening for African Americans (2). However, we are not in support of the statement that CRC screening should begin at age 40 in African Americans, as recommended in the guidance statement by Qaseem et al.
In 2009, the ACG published their consensus statement recommending CRC screening for African Americans starting at age 45 for several reasons. African Americans have the highest incidence of CRC of any racial group, and survival from CRC in African Americans is lower than other ethnicities (3). Further, African Americans may present with CRC at a median age 6 years younger than Caucasians (4) and are more likely to have a polyp greater than 9mm in size compared to age-matched Caucasians (5). Specifically, colonoscopy has been recommended as the preferred CRC screening modality in African Americans given their higher rate of proximal colon cancers compared to other races (6). However, despite the increased risks of CRC in African Americans, the current recommendation to screen at age 45 is based on only grade2 C evidence (weak evidence), and there is no evidence that screening this patient population with colonoscopy at age 40 is cost-effective, practical, or beneficial.
While it is clear that CRC is the 2nd leading cause of cancer death in the U.S. and colonoscopy reduces the mortality associated with CRC (7), resource constraints will probably not allow additional colonoscopy screening for the approximately 50% of the population who currently does not undergo CRC screening (8). Further, given the cost associated with colonoscopy screening, it is crucial that primary care providers refer the appropriate patient for screening, particularly when a colonoscopy may not be reimbursed by insurance companies in a 40 year old patient without alarm or high risk features. Thus, given these constraints of available resources, that on average African Americans appear to present with CRC younger than Caucasians, and the lack of evidence to support CRC screening at age 40, we would continue to recommend routine colon cancer screening in African Americans at age 45 years in the absence of alarm symptoms.
LCDR Steven P. Armbruster, MD MAJ Fouad J. Moawad, MD Walter Reed National Military Medical Center Bethesda, MD 20889
1. Qaseem A, Denberg T, Hopkins R, et al. Screening for Colorectal Cancer: A Guidance Statement From the American College of Physicians. Ann Intern Med 2012;156;378-386.
2. Rex D, Johnson D, Anderson J, et al. American College of Gastroenterology Guidelines for Colorectal Screening 2008. Am J Gastroenterol 2009;104:739-750.
3. Agrawal S, Bhupinderjit A, Bhutani M, et al. Colorectal Cancer in African Americans. Am J Gastroenterol 2005;100:515-523.
4. Karami S, Young HA, Henson DE. Earlier age at diagnosis: another dimension in cancer disparity? Cancer Detect Prev 2007;31:29-34.
5. Lieberman D, Holub J, Moravec M, et al. Prevalence of Colon Polyps Detected by Colonoscopy Screening in Asymptomatic Black and White Patients. JAMA 2008;300:1417-1422.
6. Rex D, Khan A, Shah P, et al. Screening colonoscopy in asymptomatic average-risk African Americans. Gastrointest Endosc 2000;51:524-7.
7. Zauber A, Winawer S, O'Brien M, et al. Colonoscopy Polypectomy and Long-Term Prevention of Colorectal -Cancer Deaths. N Engl J Med 2012;366:687-696.
8. Roy HK, Bianchi LK. Colorectal Cancer Risk Black, White, or Shades of Gray? JAMA 2008;300:1459-1461.
Ayokunle T.Abegunde, MBBS, MSc, DTM&H
John H. Stroger Jr hospital of Cook County, Chicago, Illinois
March 26, 2012
ACP CRC Guidelines
TO THE EDITOR,
The evidence supporting the effectiveness of early screening of African- Americans at average risk of colorectal cancer (CRC) is scarce. It is surprising that the ACP guideline is recommending CRC screening at 40 years of age in African-Americans (1) when there is no evidence that such a strategy is effective. Gupta et al recently showed that increasing colonoscopy participation by 5% and 10% among African-Americans aged 50 years or older, detected 53% and 57% of CRC respectively, in contrast, early CRC screening of African Americans at 45 years of age detected 52% of CRC (2).
You et al, further demonstrate that young-onset CRC was more prevalent among patients with non-white race/ethnicity who were uninsured or insured by Medicaid (3). The results of these two studies have several implications, which feed into the wider debate on social determinants of health and access to healthcare by the underserved, who are often disproportionately African-American. Firstly, simply implementing race specific early age CRC screening policy for African- Americans is unlikely to increase early CRC detection rates significantly. Secondly, factors leading to reduced colonoscopy participation among AA need to be identified, and appropriately addressed. African -Americans are a diverse group of self- identified Americans with varying amounts of African genetic admixture. Classifying this group as above average risk for CRC presupposes that race, as a proxy of ancestral African genomic identification, predicts CRC disease clusters in the African-American population. If that is the case, biological markers, which make African-Americans more likely to develop CRC earlier should be identifiable, and would lend credence to the argument of those advocating for earlier screening. Furthermore, there should be a corresponding clustering of CRC in ancestral populations in Africa. However, this is not the case, because the available evidence shows that the incidence of CRC in Africa is low (4). Therefore, the observed increased incidence of CRC among African- Americans is more likely related to environmental, lifestyle, and socio-economic factors rather than biological or genetic factors (4). While the medical community eagerly awaits the outcome of ongoing studies on the effectiveness of initiating early CRC screening in African- Americans, strategies to improve access to CRC screening and colonoscopy participation among African-Americans aged 50 years and above should be actively pursued, in addition to timely case detection of symptomatic young adults, and sustained advocacy on healthier lifestyle choices.
Ayokunle T. Abegunde, MBBS, MSc, DTM&H John H. Stroger Jr hospital of Cook County, Chicago, Illinois, 60612
1. Qassem A, Denberg TD et al. Screening for Colorectal Cancer: A guidance statement from the American College of Physicians. Ann Intern Med. 2012 Mar 6;156 (5):378-386.
2. Gupta S, Shah J et al. Strategies for reducing colorectal cancer among blacks. Arch Intern Med 172(2)182-3
3. You YN, Yan X et al. Young-onset colorectal cancer: Is it time to pay attention. Arch Intern
Med .172( 3) 287-8
4. O'Keefe SJ, Chung S et al. Why Do African Americans Get More Colon Cancer than Native Africans ? J Nutr. 2007 Jan;137(1 Suppl):175S-182S
Tazia K.Stagg, preventive medicine physician
James A. Haley Veterans' Hospital
April 2, 2012
Screening for Colorectal Cancer: Guidance Statement 4
The authors' recommendation regarding when to stop screening for colorectal cancer is problematic. In seeking clarification, I was unable to trace the origin of Guidance Statement 4. Did it arise from the "rigorous review of the available guidelines"... or from new evidence not referenced? According to the summaries in the article, only one of the guidelines reviewed--that of the USPSTF--provided guidance related to when to stop screening. However, judging from the fact that the Qaseem et al. used different words to express Guidance Statement 4 (because I don't really know how to interpret it), it seems to depart from the USPSTF's recommendation statement. I believe that for the sake of everyone involved, most importantly patients', the best policy is to acknowledge and present good evidence to defend any such public disagreement. Otherwise, we risk undermining the credibility of the medical/scientific community... and, at least, not accomplishing adherence to the statement with the weaker support.
The statement as it is written is open to interpretation in a significant way because the authors did not specify "...whichever is earlier." If that was the intended message, this should be regarded as a very controversial statement. I intuitively want to instead interpret it in a way that actually means simply, "stop screening for colorectal cancer in patients with a life expectancy of less than 10 years." Since estimating life expectancy, one way or another, introduces uncertainty, and doctors tend to err on the side of being generous with screening tests (when we do remember to offer them), the impact of adherence to this latter interpretation would likely be to increase the upper age limit of screening. Whether this is net-beneficial might depend on how accurately we estimate life expectancy.
Effectively tailoring recommendations is a foundation of excellent preventive service delivery. The idea of basing the decision to stop screening on life expectancy, rather than on chronological age alone, is appealing. (The USPSTF's recommendation leaves room for doing this in their "C" statement and from the premise of what clinical guidelines are: just guidelines.) I don't know how to accurately calculate life expectancy, but if doing so is possible and worthwhile, I'd like to learn. The theory that basing screening on life expectancy is beneficial deserves to be tested. In order to test it, we would need to make it measureable.
Furthermore, I would expect the College to address challenges related to implementation, but the suggestion of a tool for estimating life expectancy, or a discussion of various types of such tools, is conspicuously absent from your Guidance Statement.
Guidance Statement 4 is less practical and more opinion-based than what preceded it; it fails to meet the objectives stated in your Reference 6, and I wonder what motivated it.
AmirQaseem, MD, PhD, MHA, Linda Humphrey, MD, Oregon Health and Science University, 3710 SW US Veterans Hospital Road, Portland, OR 97201, Thomas Denberg, MD, PhD, Harvard Vanguard Medical Associates and Atrius Health, 275 Grove St, Auburndale, MA 02466, Paul Shekelle, MD, PhD, Gr
American College of Physicians, 190 N. Independence Mall W. Philadelphia, PA 19106
April 26, 2012
Race and Upper Age Limit for Colorectal Cancer Screening
We thank Drs. Abegunde, Keller, and Stagg for their comments regarding the American College of Physicians' recent guidance statement on colorectal cancer screening (1).
In response to Dr. Abegunde, we agree that the evidence regarding the benefits of screening African Americans starting at the age of 40 is scarce. ACG recommends initiating screening at age 45 for African Americans, ACS/ACR/ USMSTF recommends beginning at age 40 for high-risk groups (with no mention of race), and the USPSTF does not address high- risk groups in their recommendations. Since this is a guidance statement, we based this recommendation on a review of the existing colorectal cancer screening guidelines, and we felt that it would be more straightforward to have one age to initiate screening for all high-risk groups. Using a different age for each risk group might make it more difficult for clinicians to practically implement the guidance statement and our intent was to simplify the recommendation. We agree that new evidence, such as the emergence of accurate biomarkers, would warrant a change in the recommendation.
We agree with Dr. Keller that the harms of a screening test exist regardless of whether a test is necessary or unnecessary. Since the Best Practice Advice figure focuses on overused testing, we included the word "unnecessary" to further emphasize that the potential harms outweigh the potential benefits. Regarding including double contrast barium enema (DCBE) as a potential screening option, although the USPSTF did not recommend DCBE, both the ACR and ACS/ACR/ USMSTF guidelines included DCBE as a screening option. We believe that the evidence is insufficient to assess the benefits and harms of computed tomography colonography. We agree that it was an oversight on our part not to include radiation exposure as a potential harm for DCBE.
Dr. Keller and Dr. Stagg both brought up the issue of the age to stop screening. We understand that estimating life expectancy can be a difficult task and that there are currently no validated tools available. However, we believe that the evidence does not show that the benefits outweigh the harms of screening for colorectal cancer in the majority of adults over the age of 75. Yet, a study showed that more than 45% of adults aged 75-79 were screened (2). Guidance statements are guides only and may not apply to all patients or clinical situations. The guidance statements do not override physicians' judgment, and if there is a 75 year old with a reasonable life expectancy who desires colorectal cancer screening, this guidance statement does not discourage physicians from screening such an individual.
Authors: Thomas Denberg, MD, PhD Harvard Vanguard Medical Associates and Atrius Health, 275 Grove St, Auburndale, MA 02466
Linda Humphrey, MD Oregon Health and Science University, 3710 SW US Veterans Hospital Road, Portland, OR 97201
Paul Shekelle, MD, PhD Greater Los Angeles VA Health Center/RAND, 1776 Main Street, Santa Monica, CA 90401
Amir Qaseem, MD, PhD, MHA American College of Physicians, 190 N. Independence Mall West, Philadelphia, PA 19106
1. Qaseem A, Denberg TD, Hopkins RH Jr, Humphrey LL, Levine J, Sweet DE, Shekelle P. Screening for colorectal cancer: a guidance statement from the American College of Physicians. Ann Intern Med. 2012. Mar 6;156(5):378-86.
2. Louise C. Walter L, Lindquist K, Nugent S, Schult T, Lee S, Casadei M, Partin M. Impact of Age and Comorbidity on Colorectal Cancer Screening Among Older Veterans. Ann Intern Med. 2009. 150: 465-73.
UT Southwestern Medical Center
May 15, 2012
Re:ACP CRC Guidelines
I agree with the comments by Dr Abegunde raising concern that the ACP colorectal cancer screening guideline goes beyond supporting evidence in recommending earlier screening for African Americans.
High rates of colorectal cancer among African Americans need to be addressed, but, as our prior work suggests, think this is much more likely to be addressed effectively and efficiently by boosting screening among African Americans age 50 and older, rather than recommending screening at an earlier age(1).
Moreover, it seems very unlikely that insurance companies will consistently get behind a race specific recommendation for earlier age of screening for one racial/ethnic group, but not others.
In sum, I am concerned that the ACP guideline issues a guideline for African Americans that is neither evidence based, nor that can be readily implemented.
The ACP should focus efforts on promoting development and implementation of evidence based strategies to reduce colorectal cancer mortality among African Americans.
Samir Gupta, MD, MSCS UT Southwestern Medical Center Dallas, TX
1. Arch Intern Med. 2012 Jan 23;172(2):182-4.
Gastroenterology/Hepatology, Hematology/Oncology, Guidelines, High Value Care, Cancer Screening/Prevention.
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