Correspondence
Screening for Colorectal Cancer
N Engl J Med 2010; 362:84-85January 7, 2010
- Article
To the Editor:
In his Clinical Practice article, Lieberman (Sept. 17 issue)1 recommends colonoscopy for colorectal-cancer screening, but he gives little attention to immunochemical fecal occult-blood tests. The overall performance of screening programs using colonoscopy (the detection of advanced neoplasias in 5 to 10 patients per 100 colonoscopies) should be balanced by their limitations, such as low participation rates and variation in performance according to the endoscopist, and by their risk (3 to 5 serious adverse events per 1000 colonoscopies). A similar risk of an adverse event is associated with colonoscopies after a positive fecal occult-blood test, but advanced neoplasias are detected in 30 to 50 patients per 100 colonoscopies.1-4 The performance of immunochemical fecal occult-blood testing appears to be worse when it is grouped with guaiac fecal occult-blood testing, as done by Lieberman. Immunochemical fecal occult-blood testing can be more sensitive and more specific than guaiac fecal occult-blood testing.2,5
More data are needed to determine the best test or tests and strategies for analysis, but we believe that immunochemical fecal occult-blood tests will probably have growing importance in the future.
Lydia Guittet, M.D.
Caen University Hospital, Caen, France
guittet-l@chu-caen.fr Guy Launoy, M.D., Ph.D.
INSERM Unité ERI3, Caen, FranceNo potential conflict of interest relevant to this letter was reported.
5 References1
Lieberman DA . Screening for colorectal cancer. N Engl J Med 2009;361:1179-1187
Full Text | Web of Science | Medline2
Guittet L ,Bouvier V ,Mariotte N , et al. Performance of immunochemical faecal occult blood test in colorectal cancer screening in average-risk population according to positivity threshold and number of samples. Int J Cancer 2009;125:1127-1133
CrossRef | Web of Science | Medline3
Imperiale TF ,Glowinski EA ,Juliar BE ,Azzouz F ,Ransohoff DF . Variation in polyp detection rates at screening colonoscopy. Gastrointest Endosc 2009;69:1288-1295
CrossRef | Web of Science | Medline4
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 2009 August 10 (Epub ahead of print).
5
Hol L ,Wilschut JA ,van Ballegooijen M , et al. Screening for colorectal cancer: random comparison of guaiac and immunochemical faecal occult testing at different cut-off levels. Br J Cancer 2009;100:1103-1110
CrossRef | Web of Science | Medline
To the Editor:
Although perforation and bleeding are the two major potential serious adverse events associated with colonoscopy, it should also be acknowledged that other serious adverse events may occur during the preparation phase in screening programs that involve colonoscopy. These events are associated with the use of the oral bowel-cleansing preparations initiated before colonoscopy.
These preparations are usually safe and have an acceptable side-effect profile, but in the United Kingdom, the National Patient Safety Agency issued a rapid-response report in February 2009 alerting health care providers to the potential risk of harm associated with the use of oral bowel-cleansing preparations.1 These risks include renal failure as a result of phosphate nephropathy,2 complications of hypo-volemia, and electrolyte imbalances including hypokalemia, hyponatremia,3 and hypermagnesemia. Patients and their physicians need to be aware of these risks.
Faiyaz Mohammed, M.B., B.S.
Chorley Hospital, Chorley, United Kingdom
faiyaz@doctors.org. uk No potential conflict of interest relevant to this letter was reported.
3 References1
Reducing risk of harm from oral bowel cleansing solutions. London: National Patient Safety Agency, 2009. (Accessed December 15, 2009, at http://www.npsa.nhs.uk/nrls/alerts-and-directives/rapidrr/reducing-risk-of-harm-from-oral-bowel-cleansing-solutions.)
2
Markowitz GS ,Stokes MB ,Radakrishnan J ,D'Agati VD . Acute phosphate nephropathy following oral sodium phosphate bowel purgative: an unrecognized cause of chronic renal failure. J Am Soc Nephrol 2005;16:3389-3396
CrossRef | Web of Science | Medline3
Frizelle FA ,Colls BM . Hyponatremia and seizures after bowel preparation: report of three cases. Dis Colon Rectum 2005;48:393-396
CrossRef | Web of Science | Medline
Author/Editor Response
The case vignette of an average-risk 76-year-old woman highlighted some of the uncertainties associated with colorectal-cancer screening. Each of the screening tests that are currently available has advantages and limitations. Guittet and Launoy note the promising data showing that fecal immunochemical tests may be more sensitive and specific for detection of early cancer than guaiac-based stool tests, and they indicate the potential advantages of a quantitative test. However, these tests may have limited potential for cancer prevention if they do not identify most patients with advanced adenomas.1,2 Recent guidelines have prioritized screening tests that are more likely to achieve both early cancer detection and cancer prevention.3
Structural examinations of the colon, such as colonoscopy, are much more likely to detect ad-vanced adenomas, but they are subject to the performance of the examiner and risk. Most studies of complications of colonoscopy have focused on gastrointestinal events such as bleeding and perforation, and they underestimate the true rate of adverse events. Other adverse events include complications related to bowel preparation, which was discussed in the letter by Mohammed. However, cardiovascular events are more common, and they may result in hospitalization within 30 days after colonoscopy.4 Few studies have measured the effect of these events in colorectal-cancer screening programs. Ultimately, the performance of all such programs depends on quality and patient adherence, which should be measured routinely.
David A. Lieberman, M.D.
Oregon Health and Science University, Portland, OR
lieberma@ohsu.edu Since publication of his article, the author reports no further potential conflict of interest.
4 References1
Allison JE ,Sakoda LC ,Levin TR , et al. Screening for colorectal neoplasms with new fecal occult bood tests: update on performance characteristics. J Natl Cancer Inst 2007;99:1462-1470
CrossRef | Web of Science | Medline2
Hundt S ,Haug U ,Brenner H . Comparative evaluation of immunochemical fecal occult blood tests for colorectal adenoma detection. Ann Intern Med 2009;150:162-169
Web of Science | Medline3
Levin B ,Lieberman DA ,McFarland B , et al. Screening and surveillance for early detection of colorectal cancer and adenomatous polyps, 2008: a joint guideline from the American Cancer Society, the US Multi-Society Task Force on Colorectal Cancer, and the American College of Radiology. Gastroenterology 2008;134:1570-1595
CrossRef | Web of Science | Medline4
Warren JL ,Klabunde CN ,Mariotto AB , et al. Adverse events after outpatient colonoscopy in the Medicare population. Ann Intern Med 2009;150:849-857
Web of Science | Medline
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1
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