Cost-effectiveness of fecal immunochemical testing for colorectal cancer in Mexico City: A microsimulation modeling study

Objectives: Given steady increases in age-standardized colorectal cancer incidence, health authorities in Mexico could consider implementing a colorectal cancer screening program. To inform program design, we evaluated the cost-effectiveness of fecal immunochemical testing (FIT) among a hypothetical cohort of 45-year-old residents of Mexico City. We adapted a validated US microsimulation model of colorectal cancer to reflect epidemiological outcomes in Mexico City. Methods: Using the adapted model, we estimated the lifetime health outcomes and costs associated with no screening and with FIT strategies that varied by the start age, end age, screening interval, and hemoglobin threshold for colonoscopy referral. We obtained costs from published reports and formularies. We calculated incremental cost-effectiveness ratios and identified the cost-effective FIT strategy as the strategy with the highest ratio below the willingness-to-pay threshold of 381,000 MXN per quality-adjusted life-year (QALY) gained (i.e., three times Mexico's per-capita Gross Domestic Product). Results: Compared with no screening, the effectiveness of FIT screening ranged from 23 to 49 QALYs gained per 1000 45-year-olds. Biennial FIT from age 50 to 70 with the most lenient threshold for colonoscopy referral (10 μg of hemoglobin/g of feces) was the cost-effective strategy. The starting age of screening was sensitive to assumptions about the cost of unreturned test kits, outreach costs, and colorectal cancer risk. Conclusions: Screening for colorectal cancer with FIT may be cost-effective in Mexico City. Additional studies are needed to assess whether the colonoscopy capacity is sufficient to support a lenient referral threshold.