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Screening for colorectal cancer: Strategies in patients at average risk

Chyke Doubeni, MD, FRCS, MPH
Section Editors
J Thomas Lamont, MD
Joann G Elmore, MD, MPH
Deputy Editor
H Nancy Sokol, MD


Colorectal cancer (CRC) is a common and lethal disease. Screening provides benefit because removal of premalignant adenomas can prevent CRC and removal of localized cancer may prevent CRC-related death. CRC is infrequent before age 40; the incidence rises progressively thereafter to 3.7/1000 per year by age 80 (figure 1). The lifetime incidence for patients at average risk in the United States is 4.5 percent [1,2], with 90 percent of cases occurring after age 50.

Worldwide, CRC is the second most commonly diagnosed cancer in women and third most common in men, accounting for over 690,000 deaths in 2012 [3]. In the United States, CRC is the second leading cause of cancer death and accounts for approximately 8.4 percent of cancer deaths overall [4]. Approximately one in three people who develop CRC die of this disease.

Both the incidence of and mortality rates from CRC have been declining in the United States [5-7], with death rates from CRC declining on average 2.7 percent each year between 2004 and 2013 [1]. One microsimulation model, MISCAN-Colon, suggests that screening may account for 53 percent of the observed reduction in CRC mortality [8]. A study of temporal trends in CRC incidence and screening rates in the United States reported that approximately 250,000 to 500,000 CRC cases may have been prevented from 1987 to 2010, along with a shift from late- to early-stage disease [7]. Removal of adenomatous polyps during sigmoidoscopy or colonoscopy most likely prevented progression to CRC, although there may be other contributing factors. (See "Colorectal cancer: Epidemiology, risk factors, and protective factors".)

Screening rates for CRC, although rising in the United States over the past few years, are generally below national targets [9]. In 2012 in the United States, 65.1 percent of adults between ages 50 and 75 years were up-to-date with CRC screening and 27.7 percent had never been screened [10]. Colonoscopy was the most commonly used screening test (nearly 62 percent). Screening rates rose between 2002 and 2010 from 52.3 to 65.4 percent [5] and appear stable subsequently. Screening rates are higher in adults who are insured, better educated, non-Hispanic, or have a usual source of medical care [11]. Approximately one-half of the cases of CRC diagnosed in the United States between 2004 and 2006 were late-stage, particularly in older adults and in black men and women [12].

This topic addresses the rationale and modalities recommended for CRC screening in patients who are at average risk for the disease. Screening recommendations for patients at increased risk, as well as surveillance for CRC in patients with colon polyps, are addressed separately (see "Screening for colorectal cancer in patients with a family history of colorectal cancer" and "Familial adenomatous polyposis: Screening and management of patients and families" and "Approach to the patient with colonic polyps" and "Lynch syndrome (hereditary nonpolyposis colorectal cancer): Screening and management", section on 'Cancer screening' and "Juvenile polyposis syndrome", section on 'Cancer screening'). Additionally, characteristics of specific tests used for screening for colorectal cancer are discussed separately. (See "Tests for screening for colorectal cancer: Stool tests, radiologic imaging and endoscopy".)


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  1. SEER Stat Fact Sheet; colon and rectum. National Cancer Institute http://seer.cancer.gov/statfacts/html/colorect.html (Accessed on June 28, 2016).
  2. SEER Stat Fact Sheet; colon and rectum. National Cancer Institute. Available at: http://seer.cancer.gov/statfacts/html/colorect.html (Accessed on October 10, 2011).
  3. Centers for Disease Control and Prevention Global Cancer Statistics http://www.cdc.gov/cancer/international/statistics.htm (Accessed on July 21, 2016).
  4. Siegel RL, Miller KD, Jemal A. Cancer statistics, 2015. CA Cancer J Clin 2015; 65:5.
  5. Centers for Disease Control and Prevention (CDC). Vital signs: Colorectal cancer screening, incidence, and mortality--United States, 2002-2010. MMWR Morb Mortal Wkly Rep 2011; 60:884.
  6. Jemal A, Simard EP, Dorell C, et al. Annual Report to the Nation on the Status of Cancer, 1975-2009, featuring the burden and trends in human papillomavirus(HPV)-associated cancers and HPV vaccination coverage levels. J Natl Cancer Inst 2013; 105:175.
  7. Yang DX, Gross CP, Soulos PR, Yu JB. Estimating the magnitude of colorectal cancers prevented during the era of screening: 1976 to 2009. Cancer 2014; 120:2893.
  8. Edwards BK, Ward E, Kohler BA, et al. Annual report to the nation on the status of cancer, 1975-2006, featuring colorectal cancer trends and impact of interventions (risk factors, screening, and treatment) to reduce future rates. Cancer 2010; 116:544.
  9. Centers for Disease Control and Prevention (CDC). Use of colorectal cancer tests--United States, 2002, 2004, and 2006. MMWR Morb Mortal Wkly Rep 2008; 57:253.
  10. Centers for Disease Control and Prevention (CDC). Vital signs: colorectal cancer screening test use--United States, 2012. MMWR Morb Mortal Wkly Rep 2013; 62:881.
  11. Meissner HI, Breen N, Klabunde CN, Vernon SW. Patterns of colorectal cancer screening uptake among men and women in the United States. Cancer Epidemiol Biomarkers Prev 2006; 15:389.
  12. Henley SJ, King JB, German RR, et al. Surveillance of screening-detected cancers (colon and rectum, breast, and cervix) - United States, 2004-2006. MMWR Surveill Summ 2010; 59:1.
  13. Fearon ER, Vogelstein B. A genetic model for colorectal tumorigenesis. Cell 1990; 61:759.
  14. Winawer SJ, Fletcher RH, Miller L, et al. Colorectal cancer screening: clinical guidelines and rationale. Gastroenterology 1997; 112:594.
  15. Soetikno RM, Kaltenbach T, Rouse RV, et al. Prevalence of nonpolypoid (flat and depressed) colorectal neoplasms in asymptomatic and symptomatic adults. JAMA 2008; 299:1027.
  16. Rembacken BJ, Fujii T, Cairns A, et al. Flat and depressed colonic neoplasms: a prospective study of 1000 colonoscopies in the UK. Lancet 2000; 355:1211.
  17. Saitoh Y, Waxman I, West AB, et al. Prevalence and distinctive biologic features of flat colorectal adenomas in a North American population. Gastroenterology 2001; 120:1657.
  18. Ferlitsch M, Reinhart K, Pramhas S, et al. Sex-specific prevalence of adenomas, advanced adenomas, and colorectal cancer in individuals undergoing screening colonoscopy. JAMA 2011; 306:1352.
  19. Corley DA, Jensen CD, Marks AR, et al. Adenoma detection rate and risk of colorectal cancer and death. N Engl J Med 2014; 370:1298.
  20. Hawkins NJ, Ward RL. Sporadic colorectal cancers with microsatellite instability and their possible origin in hyperplastic polyps and serrated adenomas. J Natl Cancer Inst 2001; 93:1307.
  21. Burt R, Jass JR. Hyperplastic polyposis. In: WHO International Classification of Tumors, Hamilton and Aaltonen (Ed), IARC Press, 2000. p.135.
  22. Winawer SJ, Zauber AG, Fletcher RH, et al. Guidelines for colonoscopy surveillance after polypectomy: a consensus update by the US Multi-Society Task Force on Colorectal Cancer and the American Cancer Society. CA Cancer J Clin 2006; 56:143.
  23. Laiyemo AO, Murphy G, Albert PS, et al. Postpolypectomy colonoscopy surveillance guidelines: predictive accuracy for advanced adenoma at 4 years. Ann Intern Med 2008; 148:419.
  24. Flood DM, Weiss NS, Cook LS, et al. Colorectal cancer incidence in Asian migrants to the United States and their descendants. Cancer Causes Control 2000; 11:403.
  25. Winawer SJ, Zauber AG, Ho MN, et al. Prevention of colorectal cancer by colonoscopic polypectomy. The National Polyp Study Workgroup. N Engl J Med 1993; 329:1977.
  26. Troisi RJ, Freedman AN, Devesa SS. Incidence of colorectal carcinoma in the U.S.: an update of trends by gender, race, age, subsite, and stage, 1975-1994. Cancer 1999; 85:1670.
  27. Jessup JM, McGinnis LS, Steele GD Jr, et al. The National Cancer Data Base. Report on colon cancer. Cancer 1996; 78:918.
  28. Cheng L, Eng C, Nieman LZ, et al. Trends in colorectal cancer incidence by anatomic site and disease stage in the United States from 1976 to 2005. Am J Clin Oncol 2011; 34:573.
  29. Thörn M, Bergström R, Kressner U, et al. Trends in colorectal cancer incidence in Sweden 1959-93 by gender, localization, time period, and birth cohort. Cancer Causes Control 1998; 9:145.
  30. Stewart RJ, Stewart AW, Turnbull PR, Isbister WH. Sex differences in subsite incidence of large-bowel cancer. Dis Colon Rectum 1983; 26:658.
  31. Mamazza J, Gordon PH. The changing distribution of large intestinal cancer. Dis Colon Rectum 1982; 25:558.
  32. Vukasin AP, Ballantyne GH, Flannery JT, et al. Increasing incidence of cecal and sigmoid carcinoma. Data from the Connecticut Tumor Registry. Cancer 1990; 66:2442.
  33. Schub R, Steinheber FU. Rightward shift of colon cancer. A feature of the aging gut. J Clin Gastroenterol 1986; 8:630.
  34. Brenner H, Hoffmeister M, Arndt V, et al. Protection from right- and left-sided colorectal neoplasms after colonoscopy: population-based study. J Natl Cancer Inst 2010; 102:89.
  35. Brenner H, Chang-Claude J, Seiler CM, et al. Protection from colorectal cancer after colonoscopy: a population-based, case-control study. Ann Intern Med 2011; 154:22.
  36. Petersen GM. Genetic epidemiology of colorectal cancer. Eur J Cancer 1995; 31A:1047.
  37. Fuchs CS, Giovannucci EL, Colditz GA, et al. A prospective study of family history and the risk of colorectal cancer. N Engl J Med 1994; 331:1669.
  38. Lin JS, Piper M, Perdue LA et al. Screening for colorectal cancer: A systematic review for the US Preventive Services Task Force: Evidence synthesis no. 135. AHRQ publication 14-05203-EF-1, Agency for Healthcare Research and Quality, Rockville, MD, 2016.
  39. Burt RW, Bishop DT, Lynch HT, et al. Risk and surveillance of individuals with heritable factors for colorectal cancer. WHO Collaborating Centre for the Prevention of Colorectal Cancer. Bull World Health Organ 1990; 68:655.
  40. Johns LE, Houlston RS. A systematic review and meta-analysis of familial colorectal cancer risk. Am J Gastroenterol 2001; 96:2992.
  41. Schoen RE, Razzak A, Yu KJ, et al. Incidence and mortality of colorectal cancer in individuals with a family history of colorectal cancer. Gastroenterology 2015; 149:1438.
  42. Samadder NJ, Smith KR, Hanson H, et al. Increased Risk of Colorectal Cancer Among Family Members of All Ages, Regardless of Age of Index Case at Diagnosis. Clin Gastroenterol Hepatol 2015; 13:2305.
  43. Winawer SJ, Zauber AG, Gerdes H, et al. Risk of colorectal cancer in the families of patients with adenomatous polyps. National Polyp Study Workgroup. N Engl J Med 1996; 334:82.
  44. Cottet V, Pariente A, Nalet B, et al. Colonoscopic screening of first-degree relatives of patients with large adenomas: increased risk of colorectal tumors. Gastroenterology 2007; 133:1086.
  45. Jemal A, Siegel R, Xu J, Ward E. Cancer statistics, 2010. CA Cancer J Clin 2010; 60:277.
  46. Lieberman DA, Holub JL, Moravec MD, et al. Prevalence of colon polyps detected by colonoscopy screening in asymptomatic black and white patients. JAMA 2008; 300:1417.
  47. Schroy PC 3rd, Coe A, Chen CA, et al. Prevalence of advanced colorectal neoplasia in white and black patients undergoing screening colonoscopy in a safety-net hospital. Ann Intern Med 2013; 159:13.
  48. Laiyemo AO, Doubeni C, Pinsky PF, et al. Race and colorectal cancer disparities: health-care utilization vs different cancer susceptibilities. J Natl Cancer Inst 2010; 102:538.
  49. Regula J, Rupinski M, Kraszewska E, et al. Colonoscopy in colorectal-cancer screening for detection of advanced neoplasia. N Engl J Med 2006; 355:1863.
  50. Rundle AG, Lebwohl B, Vogel R, et al. Colonoscopic screening in average-risk individuals ages 40 to 49 vs 50 to 59 years. Gastroenterology 2008; 134:1311.
  51. Brenner H, Hoffmeister M, Stegmaier C, et al. Risk of progression of advanced adenomas to colorectal cancer by age and sex: estimates based on 840,149 screening colonoscopies. Gut 2007; 56:1585.
  52. Hoffmeister M, Schmitz S, Karmrodt E, et al. Male sex and smoking have a larger impact on the prevalence of colorectal neoplasia than family history of colorectal cancer. Clin Gastroenterol Hepatol 2010; 8:870.
  53. Brenner H, Altenhofen L, Hoffmeister M. Sex, age, and birth cohort effects in colorectal neoplasms: a cohort analysis. Ann Intern Med 2010; 152:697.
  54. Nguyen SP, Bent S, Chen YH, Terdiman JP. Gender as a risk factor for advanced neoplasia and colorectal cancer: a systematic review and meta-analysis. Clin Gastroenterol Hepatol 2009; 7:676.
  55. Schoenfeld P, Cash B, Flood A, et al. Colonoscopic screening of average-risk women for colorectal neoplasia. N Engl J Med 2005; 352:2061.
  56. Tomeo CA, Colditz GA, Willett WC, et al. Harvard Report on Cancer Prevention. Volume 3: prevention of colon cancer in the United States. Cancer Causes Control 1999; 10:167.
  57. Chan AT, Giovannucci EL. Primary prevention of colorectal cancer. Gastroenterology 2010; 138:2029.
  58. Botteri E, Iodice S, Bagnardi V, et al. Smoking and colorectal cancer: a meta-analysis. JAMA 2008; 300:2765.
  59. www.cancer.gov/colorectalcancerrisk (Accessed on October 10, 2011).
  60. Freedman AN, Slattery ML, Ballard-Barbash R, et al. Colorectal cancer risk prediction tool for white men and women without known susceptibility. J Clin Oncol 2009; 27:686.
  61. Winawer S, Fletcher R, Rex D, et al. Colorectal cancer screening and surveillance: clinical guidelines and rationale-Update based on new evidence. Gastroenterology 2003; 124:544.
  62. Ziogas A, Horick NK, Kinney AY, et al. Clinically relevant changes in family history of cancer over time. JAMA 2011; 306:172.
  63. Doubeni CA, Corley DA, Zauber AG. Colorectal Cancer Health Disparities and the Role of US Law and Health Policy. Gastroenterology 2016; 150:1052.
  64. Lin JS, Piper MA, Perdue LA, et al. Screening for Colorectal Cancer: Updated Evidence Report and Systematic Review for the US Preventive Services Task Force. JAMA 2016; 315:2576.
  65. US Preventive Services Task Force, Bibbins-Domingo K, Grossman DC, et al. Screening for Colorectal Cancer: US Preventive Services Task Force Recommendation Statement. JAMA 2016; 315:2564.
  66. US Food and Drug Administration, April 12, 2016 http://www.accessdata.fda.gov/cdrh_docs/pdf13/P130001a.pdf.
  67. Mandel JS, Church TR, Ederer F, Bond JH. Colorectal cancer mortality: effectiveness of biennial screening for fecal occult blood. J Natl Cancer Inst 1999; 91:434.
  68. Hardcastle JD, Chamberlain JO, Robinson MH, et al. Randomised controlled trial of faecal-occult-blood screening for colorectal cancer. Lancet 1996; 348:1472.
  69. Jørgensen OD, Kronborg O, Fenger C. A randomised study of screening for colorectal cancer using faecal occult blood testing: results after 13 years and seven biennial screening rounds. Gut 2002; 50:29.
  70. Kronborg O, Fenger C, Olsen J, et al. Randomised study of screening for colorectal cancer with faecal-occult-blood test. Lancet 1996; 348:1467.
  71. Faivre J, Dancourt V, Lejeune C, et al. Reduction in colorectal cancer mortality by fecal occult blood screening in a French controlled study. Gastroenterology 2004; 126:1674.
  72. Shaukat A, Mongin SJ, Geisser MS, et al. Long-term mortality after screening for colorectal cancer. N Engl J Med 2013; 369:1106.
  73. Atkin WS, Edwards R, Kralj-Hans I, et al. Once-only flexible sigmoidoscopy screening in prevention of colorectal cancer: a multicentre randomised controlled trial. Lancet 2010; 375:1624.
  74. Segnan N, Armaroli P, Bonelli L, et al. Once-only sigmoidoscopy in colorectal cancer screening: follow-up findings of the Italian Randomized Controlled Trial--SCORE. J Natl Cancer Inst 2011; 103:1310.
  75. Holme Ø, Løberg M, Kalager M, et al. Effect of flexible sigmoidoscopy screening on colorectal cancer incidence and mortality: a randomized clinical trial. JAMA 2014; 312:606.
  76. Nishihara R, Wu K, Lochhead P, et al. Long-term colorectal-cancer incidence and mortality after lower endoscopy. N Engl J Med 2013; 369:1095.
  77. Collins JF, Lieberman DA, Durbin TE, et al. Accuracy of screening for fecal occult blood on a single stool sample obtained by digital rectal examination: a comparison with recommended sampling practice. Ann Intern Med 2005; 142:81.
  78. Guittet L, Bouvier V, Mariotte N, et al. Comparison of a guaiac based and an immunochemical faecal occult blood test in screening for colorectal cancer in a general average risk population. Gut 2007; 56:210.
  79. Hol L, van Leerdam ME, van Ballegooijen M, et al. Screening for colorectal cancer: randomised trial comparing guaiac-based and immunochemical faecal occult blood testing and flexible sigmoidoscopy. Gut 2010; 59:62.
  80. Quintero E, Castells A, Bujanda L, et al. Colonoscopy versus fecal immunochemical testing in colorectal-cancer screening. N Engl J Med 2012; 366:697.
  81. Imperiale TF, Ransohoff DF, Itzkowitz SH, et al. Multitarget stool DNA testing for colorectal-cancer screening. N Engl J Med 2014; 370:1287.
  82. Baxter NN, Goldwasser MA, Paszat LF, et al. Association of colonoscopy and death from colorectal cancer. Ann Intern Med 2009; 150:1.
  83. Singh H, Nugent Z, Demers AA, et al. The reduction in colorectal cancer mortality after colonoscopy varies by site of the cancer. Gastroenterology 2010; 139:1128.
  84. Holme Ø, Bretthauer M, Fretheim A, et al. Flexible sigmoidoscopy versus faecal occult blood testing for colorectal cancer screening in asymptomatic individuals. Cochrane Database Syst Rev 2013; :CD009259.
  85. Lansdorp-Vogelaar I, Kuntz KM, Knudsen AB, et al. Stool DNA testing to screen for colorectal cancer in the Medicare population: a cost-effectiveness analysis. Ann Intern Med 2010; 153:368.
  86. Zauber AG. Cost-effectiveness of colonoscopy. Gastrointest Endosc Clin N Am 2010; 20:751.
  87. Imperiale TF, Wagner DR, Lin CY, et al. Results of screening colonoscopy among persons 40 to 49 years of age. N Engl J Med 2002; 346:1781.
  88. Rex DK, Johnson DA, Anderson JC, et al. American College of Gastroenterology guidelines for colorectal cancer screening 2009 [corrected]. Am J Gastroenterol 2009; 104:739.
  89. Burt RW, Cannon JA, David DS, et al. Colorectal cancer screening. J Natl Compr Canc Netw 2013; 11:1538.
  90. Wilt TJ, Harris RP, Qaseem A, High Value Care Task Force of the American College of Physicians. Screening for cancer: advice for high-value care from the American College of Physicians. Ann Intern Med 2015; 162:718.
  91. Lansdorp-Vogelaar I, von Karsa L, International Agency for Research on Cancer. European guidelines for quality assurance in colorectal cancer screening and diagnosis. First Edition--Introduction. Endoscopy 2012; 44 Suppl 3:SE15.
  92. Canadian Task Force on Preventive Health Care, Bacchus CM, Dunfield L, et al. Recommendations on screening for colorectal cancer in primary care. CMAJ 2016; 188:340.
  93. Ko CW, Sonnenberg A. Comparing risks and benefits of colorectal cancer screening in elderly patients. Gastroenterology 2005; 129:1163.
  94. Gross CP, McAvay GJ, Krumholz HM, et al. The effect of age and chronic illness on life expectancy after a diagnosis of colorectal cancer: implications for screening. Ann Intern Med 2006; 145:646.
  95. Kistler CE, Kirby KA, Lee D, et al. Long-term outcomes following positive fecal occult blood test results in older adults: benefits and burdens. Arch Intern Med 2011; 171:1344.
  96. Tang V, Boscardin WJ, Stijacic-Cenzer I, et al. Time to benefit for colorectal cancer screening: survival meta-analysis of flexible sigmoidoscopy trials. BMJ 2015.
  97. Lieberman DA, Weiss DG, Bond JH, et al. Use of colonoscopy to screen asymptomatic adults for colorectal cancer. Veterans Affairs Cooperative Study Group 380. N Engl J Med 2000; 343:162.
  98. Warren JL, Klabunde CN, Mariotto AB, et al. Adverse events after outpatient colonoscopy in the Medicare population. Ann Intern Med 2009; 150:849.
  99. van Hees F, Zauber AG, Klabunde CN, et al. The appropriateness of more intensive colonoscopy screening than recommended in Medicare beneficiaries: a modeling study. JAMA Intern Med 2014; 174:1568.
  100. Gross CP, Soulos PR, Ross JS, et al. Assessing the impact of screening colonoscopy on mortality in the medicare population. J Gen Intern Med 2011; 26:1441.
  101. van Hees F, Habbema JD, Meester RG, et al. Should colorectal cancer screening be considered in elderly persons without previous screening? A cost-effectiveness analysis. Ann Intern Med 2014; 160:750.
  102. Walter LC, Lindquist K, Nugent S, et al. Impact of age and comorbidity on colorectal cancer screening among older veterans. Ann Intern Med 2009; 150:465.
  103. Schonberg MA, Breslau ES, Hamel MB, et al. Colon cancer screenng in U.S. adults aged 65 and older according to life expectancy and age. J Am Geriatr Soc 2015; 63:750.
  104. Carlson CM, Kirby KA, Casadei MA, et al. Lack of follow-up after fecal occult blood testing in older adults: inappropriate screening or failure to follow up? Arch Intern Med 2011; 171:249.
  105. Goodwin JS, Singh A, Reddy N, et al. Overuse of screening colonoscopy in the Medicare population. Arch Intern Med 2011; 171:1335.
  106. Raj KP, Taylor TH, Wray C, et al. Risk of second primary colorectal cancer among colorectal cancer cases: a population-based analysis. J Carcinog 2011; 10:6.
  107. Atkin WS, Morson BC, Cuzick J. Long-term risk of colorectal cancer after excision of rectosigmoid adenomas. N Engl J Med 1992; 326:658.
  108. Henderson TO, Oeffinger KC, Whitton J, et al. Secondary gastrointestinal cancer in childhood cancer survivors: a cohort study. Ann Intern Med 2012; 156:757.
  109. Nottage K, McFarlane J, Krasin MJ, et al. Secondary colorectal carcinoma after childhood cancer. J Clin Oncol 2012; 30:2552.
  110. http://www.survivorshipguidelines.org/pdf/ColorectalCancer.pdf (Accessed on June 19, 2012).
  111. Singh H, Nugent Z, Demers A, et al. Risk of colorectal cancer after diagnosis of endometrial cancer: a population-based study. J Clin Oncol 2013; 31:2010.
  112. Baxter NN, Tepper JE, Durham SB, et al. Increased risk of rectal cancer after prostate radiation: a population-based study. Gastroenterology 2005; 128:819.
  113. Bini EJ, Park J, Francois F. Use of flexible sigmoidoscopy to screen for colorectal cancer in HIV-infected patients 50 years of age and older. Arch Intern Med 2006; 166:1626.
  114. Fenton JJ, Elmore JG, Buist DS, et al. Longitudinal adherence with fecal occult blood test screening in community practice. Ann Fam Med 2010; 8:397.
  115. Gellad ZF, Stechuchak KM, Fisher DA, et al. Longitudinal adherence to fecal occult blood testing impacts colorectal cancer screening quality. Am J Gastroenterol 2011; 106:1125.
  116. Centers for Disease Control and Prevention (CDC). Cancer screening - United States, 2010. MMWR Morb Mortal Wkly Rep 2012; 61:41.
  117. Ferrante JM, Lee JH, McCarthy EP, et al. Primary care utilization and colorectal cancer incidence and mortality among Medicare beneficiaries: a population-based, case-control study. Ann Intern Med 2013; 159:437.
  118. Singh H, Bernstein CN, Samadder JN, Ahmed R. Screening rates for colorectal cancer in Canada: a cross-sectional study. CMAJ Open 2015; 3:E149.
  119. Centers for Disease Control and Prevention (CDC). Vital signs: colorectal cancer screening among adults aged 50-75 years - United States, 2008. MMWR Morb Mortal Wkly Rep 2010; 59:808.
  120. Pignone MP, Lewis CL. Using quality improvement techniques to increase colon cancer screening. Am J Med 2009; 122:419.
  121. Holden DJ, Jonas DE, Porterfield DS, et al. Systematic review: enhancing the use and quality of colorectal cancer screening. Ann Intern Med 2010; 152:668.
  122. Percac-Lima S, Ashburner JM, Zai AH, et al. Patient Navigation for Comprehensive Cancer Screening in High-Risk Patients Using a Population-Based Health Information Technology System: A Randomized Clinical Trial. JAMA Intern Med 2016; 176:930.
  123. Inadomi JM, Vijan S, Janz NK, et al. Adherence to colorectal cancer screening: a randomized clinical trial of competing strategies. Arch Intern Med 2012; 172:575.
  124. Wardle J, von Wagner C, Kralj-Hans I, et al. Effects of evidence-based strategies to reduce the socioeconomic gradient of uptake in the English NHS Bowel Cancer Screening Programme (ASCEND): four cluster-randomised controlled trials. Lancet 2016; 387:751.
  125. Yabroff KR, Klabunde CN, Yuan G, et al. Are physicians' recommendations for colorectal cancer screening guideline-consistent? J Gen Intern Med 2011; 26:177.
  126. Mysliwiec PA, Brown ML, Klabunde CN, Ransohoff DF. Are physicians doing too much colonoscopy? A national survey of colorectal surveillance after polypectomy. Ann Intern Med 2004; 141:264.
  127. Kruse GR, Khan SM, Zaslavsky AM, et al. Overuse of colonoscopy for colorectal cancer screening and surveillance. J Gen Intern Med 2015; 30:277.
  128. Partin MR, Powell AA, Bangerter A, et al. Levels and variation in overuse of fecal occult blood testing in the Veterans Health Administration. J Gen Intern Med 2012; 27:1618.