[Cost and cost-effectiveness of the colorectal cancer screening program for key populations in Zhejiang Province, 2020-2022].

Objective: To comprehensively evaluate the cost and cost-effectiveness of the colorectal cancer screening program for key populations in Zhejiang Province from 2020 to 2022, and provide reference for optimizing colorectal cancer screening strategies. Methods: Based on the colorectal cancer screening program for key populations in Zhejiang Province from 2020 to 2022, parameters such as initial screening positivity rates, colonoscopy compliance rates, and detection rates for colorectal-related lesions among residents aged 50-74 were obtained. Questionnaire surveys assessed program costs and direct medical costs associated with colorectal cancer-related lesions. From a health system perspective, the cost-effectiveness ratio was calculated using the Early Detection Cost Index (EDCI) and the cost per detected case, followed by sensitivity analysis. Results: A total of 5 881 364 screenings were completed from 2020 to 2022. The initial screening positive rate (positive for either questionnaire or fecal immunochemical testing ) was 16.83%, with a colonoscopy compliance rates of 33.96% (n=336 150). Detection rates for non-advanced adenomas, advanced adenomas, and colorectal cancer were 24.83% (n=83 453), 11.91% (n=40 033), and 1.01% (n=3 397), respectively. Initial screening positivity rates and detection rates increased with age, while colonoscopy compliance rates decreased with age. Cost analysis showed a total project investment of 378 730 457 yuan, with initial screening costing 146 633 103 yuan (38.72%) and diagnostic colonoscopy 232 097 354 yuan (61.28%). The average cost per initial screening and diagnostic colonoscopy was 24.93 and 690.46 yuan, respectively. Direct medical costs for non-advanced adenomas, advanced adenomas, and colorectal cancer at stages Ⅰ, Ⅱ, Ⅲ, and Ⅳ were 4 921, 8 380, 42 547, 62 156, 66 720, and 72 334 yuan, respectively. Cost-effectiveness analysis indicated that screening needed to detect one case of colorectal cancer required 1 731 people and cost 111 490 yuan; the cost per detected advanced adenoma was 9 460 yuan, and the EDCI was 0.09. Costs decreased with increasing age per detected colorectal lesion. Sensitivity analysis showed that increasing colonoscopy compliance could reduce the cost-effectiveness ratio. Conclusions: The colorectal cancer screening program for key populations in Zhejiang Province demonstrates cost-effectiveness. Improving colonoscopy compliance can enhance overall screening effectiveness and economic benefits.