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Background & Aims We compared the accuracy of a qualitative fecal immunochemical test (FIT) in identifying patients with proximal vs distal advanced neoplasia and evaluated whether analysis of 2 specimens performed better than analysis of 1 specimen. Distal advanced neoplasia was defined as colorectal cancer (CRC), any colorectal adenoma ≥10 mm in diameter, high-grade dysplasia, or a lesion with villous or tubulovillous histologic characteristics in a location distal to the splenic flexure, including the descending colon, the rectosigmoid, and the rectum. Methods We collected data from 5343 subjects (50−70 years old) who received 2 FITs (Hemosure; cutoff value, 10 μg hemoglobin/g feces) before colonoscopy in an invitational CRC screening program in Hong Kong from 2008 through 2012. We calculated the FIT’s sensitivity, specificity, positive predictive value (PPV), and negative predictive value in detecting colorectal neoplasia. Results Of the participants, 13.6%, 12.2%, and 6.0% had distal, proximal, and synchronous distal or proximal neoplasia, respectively. Advanced neoplasia was detected in 291 subjects (5.4%); 22 (0.4%) had CRC. FIT detected distal advanced adenoma with 39.7% sensitivity (95% confidence interval [CI], 32.0%−48.0%) vs proximal advanced adenoma with 25.0% sensitivity (95% CI, 17.3%−34.6%; P = .014), distal advanced neoplasia with 40.0% sensitivity (95% CI, 32.5%−47.9%) vs proximal advanced neoplasia with 27.9% sensitivity (95% CI, 20.0%−37.4%; P = .039), and any distal adenoma ≥10 mm, irrespective of other lesion characteristics, with 39.5% sensitivity (95% CI, 31.0%−48.7%) vs proximal adenoma with 25.3% sensitivity (95% CI, 16.5%−36.6%; P = .038). The specificity of FIT in detecting CRC was similar between the proximal and distal colon. FIT detected distal lesions with higher PPV than proximal lesions. One FIT detected advanced neoplasia with 31.8% sensitivity (95% CI, 25.9%−38.4%) and 92.4% specificity (95% CI, 91.6%−93.2%), whereas 2 FITs detected advanced neoplasia with 34.1% sensitivity (95% CI, 28.0%−40.8%; P = .617) and 91.9% specificity (95% CI, 91.0%−92.7%; P = .327). FIT detected distal advanced neoplasia with greater sensitivity and higher PPV than proximal advanced neoplasia. Conclusions In an analysis of data from subjects who underwent CRC screening in Hong Kong, FIT detected distal advanced neoplasia with higher sensitivity than proximal advanced neoplasia. Analysis of 1 vs 2 specimens by FIT identified advanced neoplasia with similar test characteristics. [ABSTRACT FROM AUTHOR]

Flexible sigmoidoscopy (FS) and colonoscopy are two commonly used screening tools for colorectal cancer (CRC), and FS mainly detects distal lesions. Colonoscopy resource is limited, yet there is no definite evidence on when flexible sigmoidoscopy is suitable as a screening alternative. This study evaluated the optimal cut-off score from a validated risk stratification system which best predicts proximal advanced neoplasia (PAN) by comparing the sensitivity, specificity and relative risk of PAN according to various cut-off scores. 5819 asymptomatic subjects aged between 50 and 70 years (average age 57.7 years, standard deviation (SD) 4.9) received colonoscopy between 2008 and 2014 in Hong Kong. Their prevalence of PAN was evaluated according to a prediction tool for colorectal neoplasia based on age, gender, smoking status, family history of CRC, body mass index (BMI) and diabetes (ranging from 0 to 6). One binary logistic regression model was performed with PAN as the outcome variable and the risk score as the variable tested for association. In multivariate regression analysis, risk score ⩾3 was associated with significantly higher risk of PAN (3.4–9.1%; AOR = 3.18–8.09, p < 0.001) when compared with those scoring 0. Risk scores 0–2 were associated with either insignificant or lower risks of PAN compared to the overall risk. Applying FS for screening those who scored 0–2 and colonoscopy for those who scored ⩾3 led to a very small proportion of PAN being missed (1.60%), whilst maintaining a high level of specificity (81.9%). Clinicians may use this scoring system to inform subjects and facilitate their choice between colonoscopy and FS. [ABSTRACT FROM AUTHOR]