The opposing views expressed by Sidney Winawer and Ann Zauber1 and Kenneth Marshall2 on colorectal cancer screening stem from a common problem in screening programs, namely that “screening for cancer has always been highly controversial, partly because the procedure is for seemingly healthy people, for whom the benefit should be clear cut. Evidence of this benefit is, however, for the group as a whole. At the individual level, prediction of who will benefit and who will suffer more harm than good is impossible. The balance between favourable and unfavourable effects is delicate.”3
Technical details such as annual versus biennial and unhydrated versus hydrated aside, population-based studies have shown that fecal occult blood testing is efficacious.4,5,6 Although there are no published cost-effectiveness studies of colorectal cancer screening in Canada, it is unlikely that Canadian findings would differ from those in other countries, where studies have consistently shown support for testing.7,8,9,10 Most articles suggest that colorectal cancer screening is acceptable to the medical community. But are we, the medical community, the ones who should ultimately decide?
The acceptability of screening to targeted individuals is poorly understood.11 People will probably participate in population-based screening programs because participation is recommended, rather than from a true understanding of the risks and benefits. A 39% reduction in cause-specific colorectal cancer mortality for people who comply with screening guidelines, as quoted by Winawer and Zauber, makes screening a seemingly easy sell. Marshall, however, points out that in the context of the larger picture of overall mortality, colorectal cancer screening has little impact. What information should be presented to the person offered screening?
Before a decision is made about population-based colorectal cancer screening, more should be learned about its acceptability to the target population. An attempt should be made to fully inform a representative sample of this community of the risks and benefits of colorectal cancer screening from both a population and individual perspective and then survey their attitudes. This information can then be used to shape policy. Let the people decide.
Signature
Steven Latosinsky
Division of Surgical Oncology Health Sciences Centre Winnipeg, Man.
References
- 1.Winawer SJ, Zauber AG. Colorectal cancer screening: Now is the time [editorial]. CMAJ 2000;163(5):543-4. [PMC free article] [PubMed]
- 2.Marshall KG. Population-based fecal occult blood screening for colon cancer: Will the benefits outweigh the harm? [editorial]. CMAJ 2000;163(5):545-6. [PMC free article] [PubMed]
- 3.de Haes JC, de Koning HJ, van Oortmarssen GJ, van Agt HM, de Bruyn AE, van Der M. The impact of a breast cancer screening programme on quality-adjusted life-years. Int J Cancer 1991;49:538-44. [DOI] [PubMed]
- 4.Hardcastle JD, Chamberlain JO, Robinson MH, Moss SM, Amar SS, Balfour TW, et al. Randomised controlled trial of faecal-occult-blood screening for colorectal cancer. Lancet 1996; 348:1472-7. [DOI] [PubMed]
- 5.Kronborg O, Fenger C, Olsen J, Jorgensen OD, Sondergaard O. Randomised study of screening for colorectal cancer with faecal-occult-blood test. Lancet 1996;348:1467-71. [DOI] [PubMed]
- 6.Mandel JS, Bond JH, Church TR, Snover DC, Bradley GM, Schuman LM, et al. Reducing mortality from colorectal cancer by screening for fecal occult blood. Minnesota Colon Cancer Control Study. N Engl J Med 1993;328:1365-71. [DOI] [PubMed]
- 7.Schrag D, Weeks J. Costs and cost-effectiveness of colorectal cancer prevention and therapy. Semin Oncol 1999;26:561-8. [PubMed]
- 8.Wagner JL, Herdman RC, Wadhwa S. Cost effectiveness of colorectal cancer screening in the elderly. Ann Intern Med 1991;115:807-17. [DOI] [PubMed]
- 9.Whynes DK, Walker AR, Hardcastle JD. Cost-effective screening strategies for colorectal cancer. J Public Health Med 1992;14:43-9. [PubMed]
- 10.Loeve F, Brown ML, Boer R, van Ballegooijen M, van Oortmarssen GJ, Habbema JD. Endoscopic colorectal cancer screening: a cost-saving analysis. J Natl Cancer Inst 2000;92:557-63. [DOI] [PubMed]
- 11.Towler B, Irwig L, Glasziou P, Kewenter J, Weller D, Silagy C. A systematic review of the effects of screening for colorectal cancer using the faecal occult blood test, hemoccult. BMJ 1998;317:559-65. [DOI] [PMC free article] [PubMed]