Markov’s Modeling for Screening Strategies for Colorectal Cancer


Economic decision models are being increasingly used to assess medical interventions. Advances in this fieldare mainly due to enhanced processing capacity of computers, availability of specific software to perform thenecessary tasks, and refined mathematical techniques. We here estimated the incremental cost-effectiveness often strategies for colon cancer screening, as well as no screening, incorporating quality of life, noncomplianceand data on the costs and profit of chemotherapy in Iran. We used a Markov model to measure the costs andquality-adjusted life expectancy of a 50-year-old average-risk Iranian without screening and with screening byeach test. In this paper, we tested the model with data from the Ministry of Health and published literature. Weconsidered costs from the perspective of a health insurance organization, with inflation to 2011, the Iranian Rialbeing converted into US dollars. We focused on three tests for the 10 strategies considered currently being usedfor population screening in some Iranians provinces (Kerman, Golestan Mazandaran, Ardabil, and Tehran):low-sensitivity guaiac fecal occult blood test, performed annually; fecal immunochemical test, performedannually; and colonoscopy, performed every 10 years. These strategies reduced the incidence of colorectalcancer by 39%, 60% and 76%, and mortality by 50%, 69% and 78%, respectively, compared with no screening.These approaches generated ICER (incremental cost-effectiveness ratios) of $9067, $654 and $8700 per QALY(quality-adjusted life year), respectively. Sensitivity analyses were conducted to assess the influence of variousscales on the economic evaluation of screening. The results were sensitive to probabilistic sensitivity analysis.Colonoscopy every ten years yielded the greatest net health value. Screening for colon cancer is economical andcost-effective over conventional levels of WTP8.