Impact of Fecal Hb Levels on Advanced Neoplasia Detection and the Diagnostic Miss Rate For Colorectal Cancer Screening in High-Risk vs. Average-Risk Subjects: a Multi-Center Study

Abstract

Objectives:The Asia-Pacific Colorectal Screening (APCS) scoring system was developed to identify high-risk subjects for advanced neoplasia. However, the appropriate fecal immunochemical test (FIT) cutoff for high-risk population may be different from that of average-risk population. We aimed to evaluate the FIT performance at different cutoffs in high-risk subjects undergoing colorectal cancer (CRC) screening.Methods:We prospectively enrolled asymptomatic subjects aged 50–75 years. Using the APCS score, subjects were stratified into either the average-risk or high-risk groups. All subjects were tested with one-time quantitative FIT and underwent colonoscopy. We compared the FIT performance for advanced neoplasia between two groups using different cutoffs (5 (FIT5), 10 (FIT10), 20 (FIT20), 30 (FIT30), and 40 (FIT40) μg Hb/g feces).Results:Overall, 1,713 subjects were recruited, and 1,222 (71.3%) and 491 (28.7%) were classified as average-risk and high-risk, respectively. Advanced neoplasia was detected in 90 (7.4%) of the average-risk subjects and 65 (13.2%) of the high-risk subjects. In the high-risk group, by decreasing the cutoff from FIT40 to FIT5, the sensitivity increased by 33.8 percentage points with decreased specificity by 11 percentage points. In the average-risk group, the sensitivity increased by 20 percentage points with decreased specificity by 9.6 percentage points. At the lowest cutoff (FIT5), the number of needed colonoscopies to find one advanced neoplasia was 2.8 and 6.1 for the high-risk and average-risk groups, respectively.Conclusions:Using an appropriate FIT cutoff for CRC screening in high-risk subjects could improve CRC screening performance and reduce the unnecessary colonoscopies. To maintain high sensitivity and specificity for advanced neoplasia, the optimal cutoff FIT in the high-risk subjects should be lower than that in the average-risk subjects.

Overweight as an Additional Risk Factor for Colorectal Neoplasia in Lean Population

“…APCS scoring system is helpful to predict individual harboring CRN in Asian population. In this study, the result is concordant with our earlier reports showing an approximately 1.5-fold higher prevalence of colorectal adenoma in the high-risk subjects as compared to that of in the average-risk subjects (Aniwan et al, 2015;Aniwan et al, 2017). The development of APCS scoring system included several important variables including age, sex, smoking, family history of CRC, alcohol and diabetes.…”

“…We hypothesized that subject with high-risk and overweight would have the highest prevalence of CRN. In Thailand, the prevalence of CRN was 27% (Aniwan et al, 2015) and the prevalence of the high-risk was 29% (Aniwan et al, 2017). Assuming the detection rate of CRN in subject with average-risk and normal body weight was 20% and that of subject with high-risk and overweight was 50%.…”

“…The Asia-Pacific Colorectal Screening (APSC) score has been developed across 11 countries in Asia and Pacific region (Yeoh et al, 2011). It has been validated in Asian and Western population (Aniwan et al, 2015;Corte et al, 2016;Aniwan et al, 2017;Quach et al, 2018). The score that composed of 4 traditional CRC risk factors; age, sex, family history of CRC and smoking, ranges from score 0 to 7.…”

Current Status of Colorectal Cancer and Its Public Health Burden in Thailand

“…At the cutoff values of 25 ng/mL and 150 ng/mL, patients in the high-risk group yielded significantly higher sensitivities than those in the average-risk group (cutoffs at 25 ng/mL = 52.3% vs. 34.4%, p = 0.03; cutoff at 150 ng/mL = 32.3% vs. 17.8%; p= 0.04). 24 At this cutoff, high-risk patients still yielded comparable specificity for advanced neoplasia (92%) and high negative predictive values to reject the risk of colon cancers (100%). 24 At a cut-off of 25 ng/mL, the number of needed colonoscopies to find one advanced neoplasia for the highrisk and average-risk groups was 2.8 and 6.1, respectively.…”

“…23 To answer this question, another multi-center prospective study evaluated the diagnostic performance of the FIT at different cutoffs in high-risk subjects, as defined by the APCS scoring system, compared to average-risk subjects. 24 A total of 1,713 patients were recruited for the study. A total of 1,222 (71.3%) subjects were classified as average-risk and 491 (28.7%) subjects were high-risk.…”