## Introduction

### Statistical Analyses

In this study, detection of colorectal lesions was regarded as a measure of effectiveness and it is superior to detect more lesions when the different strategies were evaluated. The numerator for the ICER was the difference in direct costs between the two screening methods and the denominator was the difference in the number of colorectal lesions detected. The time window to include any screening cost is from the starting point of the screening when the practitioners delivered services to the end point of screening when the CRC was found or when the test was negative. Since the individuals receiving FIT vs. colonoscopy had different risks for colorectal neoplasia, the Asia Pacific Colorectal Screening (APCS) scoring system based on age, gender, family history and smoking31 was used to stratify the subjects into the lower risk (scores for average risk: 0–1; moderate risk: 2–3) and higher risk (scores: 4–7) groups. As no subjects had APCS scores falling into the range of average risk (0–1), we compared the cost-effectiveness between the moderate risk and high risk subjects. The above analyses were repeated again according to these two risk tiers.