The cost-effectiveness of screening for colorectal cancer.
BACKGROUND
Published decision analyses show that screening for colorectal cancer is cost-effective. However, because of the number of tests available, the optimal screening strategy in Canada is unknown. We estimated the incremental cost-effectiveness of 10 strategies for colorectal cancer screening, as well as no screening, incorporating quality of life, noncompliance and data on the costs and benefits of chemotherapy.


METHODS
We used a probabilistic Markov model to estimate the costs and quality-adjusted life expectancy of 50-year-old average-risk Canadians without screening and with screening by each test. We populated the model with data from the published literature. We calculated costs from the perspective of a third-party payer, with inflation to 2007 Canadian dollars.


RESULTS
Of the 10 strategies considered, we focused on three tests currently being used for population screening in some Canadian provinces: low-sensitivity guaiac fecal occult blood test, performed annually; fecal immunochemical test, performed annually; and colonoscopy, performed every 10 years. These strategies reduced the incidence of colorectal cancer by 44%, 65% and 81%, and mortality by 55%, 74% and 83%, respectively, compared with no screening. These strategies generated incremental cost-effectiveness ratios of $9159, $611 and $6133 per quality-adjusted life year, respectively. The findings were robust to probabilistic sensitivity analysis. Colonoscopy every 10 years yielded the greatest net health benefit.


CONCLUSIONS
Screening for colorectal cancer is cost-effective over conventional levels of willingness to pay. Annual high-sensitivity fecal occult blood testing, such as a fecal immunochemical test, or colonoscopy every 10 years offer the best value for the money in Canada.
Telford
Jennifer J
JJ
University of British Columbia, Vancouver, BC, Canada. jtelford@telus.net
Levy
Adrian R
AR
Sambrook
Jennifer C
JC
Zou
Denise
D
Enns
Robert A
RA
D002170:Canada; D003113:Colonoscopy / Q000191:economics; D015179:Colorectal Neoplasms / Q000188:drug therapy / Q000191:economics / Q000517:prevention & control*; D003362:Cost-Benefit Analysis; D003365:Costs and Cost Analysis; D006801:Humans; D008017:Life Expectancy; D008390:Markov Chains; D008403:Mass Screening / Q000191:economics* / Q000379:methods / Q000592:standards; D009780:Occult Blood; D011788:Quality of Life; D012680:Sensitivity and Specificity; D013997:Time Factors