This Article
Right arrow Full Text (PDF)
Right arrow Submit a response
Right arrow Alert me when this article is cited
Right arrow Alert me when eLetters are posted
Right arrow Alert me if a correction is posted
Right arrow Citation Map
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Winawer, S. J.
Right arrow Articles by Zauber, A.
Right arrow Search for Related Content
PubMed
Right arrow Articles by Winawer, S. J.
Right arrow Articles by Zauber, A.
Related Collections
Right arrow Screening tests
Right arrow Gastroenterological Cancer
Right arrow Other evidence-based medicine
CMAJ • September 5, 2000; 163 (5)
© 2000 Canadian Medical Association or its licensors

Commentary
Commentaire

Controversy

Rebuttal

Sidney J. Winawer and Ann Zauber

Dr. Winawer is with the Gastroenterology and Nutrition Service, Department of Medicine, and Dr. Zauber is with the Department of Epidemiology and Biostatistics, Memorial Sloan-Kettering Cancer Center, New York, NY.

Correspondence to: Dr. Sidney J. Winawer, Gastroenterology and Nutrition Service, Department of Medicine, Memorial Sloan-Kettering Cancer Center, 1275 York Ave., New York NY 10021; fax 212 639-2766; winawers{at}mskcc.org

Kenneth Marshall uses misleading data, unfounded assumptions and exaggerations to support his bias against screening.1 Calculating the number of people needed to be screened to save one life is misleading when it is used as the only measure of screening benefit. A more complete assessment of screening benefit is years of useful life gained. Using a computer simulation model of the clinical consequence of screening, we can estimate that 12 325 life-years would be saved per 100 000 people screened with fecal occult blood testing annually.2 Death is inevitable, but premature death can be prevented. Death from colorectal cancer constitutes about 3% of the total mortality; therefore, the effect of colorectal cancer screening on total mortality cannot be demonstrated with the comparatively small sample size of clinical trials.

To say that screening distorts the communal value system is unfounded. What is preferable — a family focused on wellness, or family devastated by a lethal disease? Colorectal cancer screening is as cost-effective as mammography. There is also a cost of failure to screen, failure to detect early curable cancer, failure to prevent morbidity, and failure to find and remove screen-detected adenomatous polyps with the resultant decrease in incidence of colorectal cancer. These polyps are found by screening, not by random chance.2 With rising medical costs and decreasing screening costs, screening is actually becoming cost-saving.2,3,4,5

Marshall exaggerates possible screening harms. Psychological and medical harms have been studied and have not been demonstrated.6,7 False reassurance with a program of annual fecal occult blood testing is uncommon; sensitivity for cancer with this approach is over 90%.8 Screening has been shown to have a net benefit in reducing colorectal cancer mortality.2 Marshall's statement of a 7% mortality following surgical resection of polyps is inflated. Resection is rarely needed today, but in those rare instances when it is required it has demonstrated an excellent risk-benefit ratio.7

Dr. Marshall raises the specter of colonoscopy complication rates, which have fallen considerably and are now 1 to 2 per 1000 cases.2 Complications from diagnostic colonoscopy are rare; almost all result from polypectomy, which is performed to prevent cancer. No cardiopulmonary deaths occurred after the 13 000 colonoscopies in the Minnesota trial.9 Only 2 cases of hepatitis C transmission have been reported,10 both of which involved improper disinfection of the instrument. The introduction of colonoscopy, its demonstrated safety after 30 years of experience, and standards for training, clinical application and disinfection of equipment now make screening feasible.11

An estimated 2250 people in Ontario will die of colorectal cancer this year.5 Their families should not have to bear the loss. We now have screening techniques with acceptable sensitivity and specificity, accurate diagnostic methods and definitive treatment with colonoscopic polypectomy and cancer surgery. We can intervene and make a difference in their lives. Losing even one life prematurely is a tragedy.12

Footnotes

Drs. Winawer and Zauber respond to Dr. Marshall:

This article has been peer reviewed.


References

  1. Marshall KG. Population-based fecal occult blood screening for colon cancer: Will the benefits outweigh the harm? CMAJ 2000;163(5):545-6.[Free Full Text]
  2. Winawer SJ, Fletcher RH, Miller L, Godlee F, Stolar MH, Mulrow CD, et al. Colorectal cancer screening: clinical guidelines and rationale. Gastroenterology 1997;112:594-642.[Medline]
  3. Wagner JL, Tunis S, Brown M, Ching A, Almeida R. The cost-effectiveness of colorectal cancer screening in average-risk adults. In: Young G, Levin B, Rozen A, editors. Prevention and early detection of colorectal cancer. London: WB Saunders; 1996. p. 321-56.
  4. Lieberman DA. Cost-effectiveness model for colon cancer screening. Gastroenterology 1995;109:1781-6.[Medline]
  5. Ontario Expert Panel on Colorectal Cancer Screening. Colorectal cancer in Ontario 1971-1996. Toronto: Cancer Care Ontario; 1999. Available: www.cancercare.on.ca/ocr/colorectal (accessed 2000 Aug 3).
  6. Thiis-Evensen E, Wihelmsen I, Hoff GS, Blomhoff S, Sauar J. The psychological effect of attending a screening program for colorectal polyps. Scand J Gastroenterol 1999;34:103-9.[Medline]
  7. Robinson MHE, Hardcastle JD, Moss SM, Amar SS, Chamberlain JO, Armitage NCM, et al. The risks of screening: data from the Notingham randomised controlled trial of faecal occult blood screening for colorectal cancer. Gut 1999;45:588-92.[Abstract/Free Full Text]
  8. Church TR, Ederer F, Mandel JS. Fecal occult screening in the Minnesota Study: sensitivity of the screening test. J Natl Cancer Inst 1997;89:1440-8.[Abstract/Free Full Text]
  9. Mandel JS, Bond JH, Bradley M, Snover DC, Church TR, Williams S, et al. Sensitivity, specificity, and positive predictivity of the Hemoccult test in screening for colorectal cancers: The University of Minnesota's Colon Cancer Control Study. Gastroenterology 1989;97:597-600.[Medline]
  10. Bronowicki JP, Venard V, Botté C, Monhoven N, Gastin I, Chone L, et al. Patient-to-patient transmission of hepatitis C virus during colonoscopy. N Engl J Med 1997;337:237-40.[Free Full Text]
  11. American Society for Gastrointestinal Endoscopy Technology Assessment. Transmission of infection by gastrointestinal endoscopy. Manchester (MA): The Society; 1993.
  12. Winawer SJ, Taylor N. Healing lessons. New York: Routledge; 1998.



This article has been cited by other articles:


Home page
 CMAJHome page
G. Brock and V. Gurekas
Screening for colorectal cancer
Can. Med. Assoc. J., April 1, 2001; 164(7): 966 - 966.
[Full Text]

Home page
 CMAJHome page
P. Koduri
Screening for colorectal cancer
Can. Med. Assoc. J., April 1, 2001; 164(7): 967 - 967.
[Full Text]

Home page
 CMAJHome page
C. J. Wright
Screening for colorectal cancer
Can. Med. Assoc. J., April 1, 2001; 164(7): 965 - 965.
[Full Text]

This Article
Right arrow Full Text (PDF)
Right arrow Submit a response
Right arrow Alert me when this article is cited
Right arrow Alert me when eLetters are posted
Right arrow Alert me if a correction is posted
Right arrow Citation Map
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Winawer, S. J.
Right arrow Articles by Zauber, A.
Right arrow Search for Related Content
PubMed
Right arrow Articles by Winawer, S. J.
Right arrow Articles by Zauber, A.
Related Collections
Right arrow Screening tests
Right arrow Gastroenterological Cancer
Right arrow Other evidence-based medicine