Cost-effectiveness analysis of colorectal cancer screening with stool DNA testing in intermediate-incidence countries

Abstract

Background: The aim of this study is to compare the cost-effectiveness of screening with stool DNA testing with that of screening with other tools (annual fecal occult blood testing, flexible sigmoidoscopy every 5 years, and colonoscopy every 10 years) or not screening at all.

Methods: We developed a Markov model to evaluate the above screening strategies in the general population 50 to 75 years of age in Taiwan. Sensitivity analyses were performed to assess the influence of various parameters on the cost-effectiveness of screening. A third-party payer perspective was adopted and the cost of dollar 13,000 per life-year saved (which is roughly the per capita GNP of Taiwan in 2003) was chosen as the ceiling ratio for assessing whether the program is cost-effective.

Results: Stool DNA testing every three, five, and ten years can reduce colorectal cancer mortality by 22%, 15%, and 9%, respectively. The associated incremental costs were dollar 9,794, dollar 9,335, and dollar 7,717, per life-year saved when compared with no screening. Stool DNA testing strategies were the least cost-effective with the cost per stool DNA test, referral rate with diagnostic colonoscopy, prevalence of large adenoma, and discount rate being the most influential parameters.

Conclusion: In countries with a low or intermediate incidence of colorectal cancer, stool DNA testing is less cost-effective than the other currently recommended strategies for population-based screening, particularly targeting at asymptomatic subjects.

Figure 1

Markov process for disease natural history and prognosis of colorectal cancer (CRC).* * The ovals represent Markov states; the solid arrows represent the direct transition between states, and the dotted arrows represent the transition toward competing cause of death. Abbreviations: Small adenoma, adenoma smaller than 1 cm in size; large adenoma, adenoma larger than 1 cm in size; early CRC, Dukes' stage A and B colorectal cancer, late CRC, Dukes' stage C and D colorectal cancer; OCD, other cause of death.

Figure 2

Structure of decision tree model.* * At the beginning of the first Markov cycle, all the probabilities of being in clinical early CRC, clinical late CRC, surveillance for small adenoma, surveillance for large adenoma, screen-detected early CRC, screen-detected late CRC, CRC death, complication death, and other death are zero. Ovals are the chance nodes governed by the probability related to compliance rate, sensitivity, specificity, and referral rate.: Markov cycle. Abbreviations: CRC, colorectal cancer; DNA₃, stool DNA testing every 3 years; DNA₅, stool DNA testing every 5 years; DNA₁₀, stool DNA testing every 10 years; FOBT₁, fecal occult blood testing every year; SIGM₅, sigmoidoscopy every 5 years; COLO₁₀, colonoscopy every 10 years; Small adenoma, adenoma smaller than 1 cm in size; large adenoma, adenoma larger than 1 cm in size; early CRC, Dukes' stage A and B colorectal cancer; late CRC, Dukes' stage C and D colorectal cancer.

Figure 3

Comparison of observed and predicted cumulative colorectal cancer incidence.

Figure 4

Cost-effectiveness of CRC screening under different scenarios. Abbreviations: CRC, colorectal cancer; DNA₃, DNA₅, and DNA₁₀, stool DNA testing every 3, 5, and 10 years, respectively; -W, under the worst case scenario (the same with the base-case estimates) in which the sensitivity of stool DNA testing for small adenoma, large adenoma, and colorectal cancer, and the specificity are 8%, 15%, 52%, and 94% based on Imperiale et al study [10]; -M, under the moderate case scenario in which the corresponding estimates are 8%, 18%, 85%, and 94% based on meta-analysis [10-13, 16]; -B, under the best case scenario in which the corresponding estimates are 8%, 82%, 91%, and 93% based on Ahlquist et al study [10]; FOBT₁, fecal occult blood testing every year; SIGM₅, sigmoidoscopy every 5 years; COLO₁₀, colonoscopy every 10 years.

Figure 5

Sensitivity analysis regarding compliance to screening tool (0.1, 0.2, 0.4, 0.6, 0.8, and 1.0). Abbreviations: DNA₃, stool DNA testing every 3 years; DNA₅, stool DNA testing every 5 years; DNA₁₀, stool DNA testing every 10 years; FOBT₁, fecal occult blood testing every year; SIGM₅, sigmoidoscopy every 5 years; COLO₁₀, colonoscopy every 10 years.