Multiple rounds of one sample versus two sample faecal immunochemical test-based colorectal cancer screening: a population-based study.

BACKGROUND: Faecal immunochemical test (FIT)-based colorectal cancer screening requires successive rounds for maximum preventive effect. Advanced neoplasia can bleed intermittently and thus might be missed by single faecal sampling. Few studies have been done on two sample FIT (2-FIT) screening over multiple rounds. Therefore, we compared multiple rounds of one sample FIT (1-FIT) with 2-FIT screening with respect to participation, positive predictive value (PPV), diagnostic yield, and interval colorectal cancer. METHODS: In this population-based study, a random selection of asymptomatic individuals aged 50-74 years in the Rotterdam-Rijnmond region, Netherlands, were invited by post for four rounds (every 2 years) of 1-FIT or 2-FIT screening. Key exclusion criteria were a history or colorectal cancer or inflammatory bowel disease, colon imaging in the previous 2 years, and life expectancy of less than 5 years. Per round, invitees received one or two FITs to sample either one or two consecutive bowel movements. OC-Sensor Micro (Eiken Chemical Co., Ltd, Japan) FITs were used by all participants, except the fourth round of screening for the 1-FIT cohort, for which participants used either an OC-Sensor or a FOB-Gold (Sentinel Diagnostics, Milan, Italy). A faecal haemoglobin cutoff concentration of 10 µg/g of faeces in at least one test was used for referral for colonoscopy. FINDINGS: Between 2006 and 2015, of 10 008 invited individuals for the 1-FIT cohort, 9787 were eligible for inclusion, of whom 7310 participated at least once in four successive rounds. Of 3197 invited individuals for the 2-FIT cohort, 3131 were eligible for inclusion, and 2269 participated at least once in four successive rounds. In the 1-FIT screening cohort, 74·7% (7310 of 9787) of invitees participated at least once versus 72·5% (2269 of 3131) of invitees in the 2-FIT cohort (p=0·013). Among participants who participated at least once, the cumulative positivity rate over four rounds was 19·2% (1407 of 7310) for the 1-FIT cohort versus 28·5% (647 of 2269) for the 2-FIT cohort (p<0·0001). The cumulative PPV for advanced neoplasia was 33·0% (432 of 1308 colonoscopies) for the 1-FIT cohort versus 24·2% (147 of 607 colonoscopies) for the 2-FIT cohort (p<0·0001). The cumulative diagnostic yield of advanced neoplasia among invited individuals was 4·4% (432 of 9787) for 1-FIT versus 4·7% (147 of 3131) for 2-FIT screening (p=0·46)). FIT interval colorectal cancers were detected in eight (0·1%) of 7310 participants in the 1-FIT cohort and two (0·1%) of 2269 with 2-FIT screening (p=1·00). INTERPRETATION: Four rounds of 2-FIT screening with a low faecal haemoglobin cutoff level did not result in a significant increase in diagnostic yield or a decrease in interval colorectal cancers compared with 1-FIT, despite higher colonoscopy demand. Therefore, 1-FIT colorectal cancer screening programmes should be preferred. FUNDING: None.

Do Men and Women Need to Be Screened Differently with Fecal Immunochemical Testing? A Cost-Effectiveness Analysis.

Background: Several studies suggest that test characteristics for the fecal immunochemical test (FIT) differ by gender, triggering a debate on whether men and women should be screened differently. We used the microsimulation model MISCAN-Colon to evaluate whether screening stratified by gender is cost-effective.Methods: We estimated gender-specific FIT characteristics based on first-round positivity and detection rates observed in a FIT screening pilot (CORERO-1). Subsequently, we used the model to estimate harms, benefits, and costs of 480 gender-specific FIT screening strategies and compared them with uniform screening.Results: Biennial FIT screening from ages 50 to 75 was less effective in women than men [35.7 vs. 49.0 quality-adjusted life years (QALY) gained, respectively] at higher costs (€42,161 vs. -€5,471, respectively). However, the incremental QALYs gained and costs of annual screening compared with biennial screening were more similar for both genders (8.7 QALYs gained and €26,394 for women vs. 6.7 QALYs gained and €20,863 for men). Considering all evaluated screening strategies, optimal gender-based screening yielded at most 7% more QALYs gained than optimal uniform screening and even resulted in equal costs and QALYs gained from a willingness-to-pay threshold of €1,300.Conclusions: FIT screening is less effective in women, but the incremental cost-effectiveness is similar in men and women. Consequently, screening stratified by gender is not more cost-effective than uniform FIT screening.Impact: Our conclusions support the current policy of uniform FIT screening. Cancer Epidemiol Biomarkers Prev; 26(8); 1328-36. ©2017 AACR.

Attendance and diagnostic yield of repeated two-sample faecal immunochemical test screening for colorectal cancer.

OBJECTIVE: Limited data exist on attendance and additional yield of 2-sample faecal immunochemical testing (FIT) screening during multiple rounds. We therefore conducted a population-based colorectal cancer screening trial comparing attendance and yield of repeated 1-sample and 2-sample FIT screenings. DESIGN: Two randomly selected groups of average-risk subjects aged 50-74 years were invited for two rounds of either 1-sample (n=5007) or 2-sample (n=3197) FIT (OC-sensor Micro) screening. The test was considered positive if at least one sample was positive (cut-off 50 ng/mL; 10 µg haemoglobin/g). RESULTS: The cumulative attendance rate was similar for repeated 1-sample and 2-sample FIT screenings (1-sample FIT: 68.1%; 2-sample FIT: 67.1%, p=0.368). The positivity rate in the second round was lower for 1-sample FIT (6.2%, 95% CI 5.4% to 7.2%) than for 2-sample FIT (8.4%, 95% CI 7.1% to 9.8%, p=0.007), whereas the detection rate of advanced neoplasia (AN, 1-sample FIT: 1.9%, 95% CI 1.2% to 2.2%; 2-sample FIT: 1.7%, 95% CI 1.2% to 2.5%, p=0.861) and the positive predictive value (1-sample FIT: 32%, 95% CI 24% to 40%; 2-sample FIT: 21%, 95% CI 15% to 29%, p=0.075) did not differ. After two rounds of screening, the cumulative diagnostic yield of AN for 1-sample FIT was 29.3 per 1000 invitees, compared with 34.0 for 2-sample FIT (p=0.241). CONCLUSIONS: Using 2-sample FIT instead of 1-sample FIT does not result in a higher detection rate of AN in the second round of repeated FIT screening. Furthermore, both strategies lead to a similar yield of AN over two rounds. These findings imply that 1-sample FIT screening is preferred over 2-sample FIT screening.

Second-Look Colonoscopies and the Impact on Capacity in FIT-Based Colorectal Cancer Screening.

OBJECTIVES: Fecal immunochemical testing (FIT) and colonoscopy are tandem procedures in colorectal cancer (CRC) screening. A positive FIT predicts advanced neoplasia (AN) that requires endoscopic detection and removal. En bloc or piecemeal resection of AN is associated with a significant rate of residual or recurrent neoplasia. Second-look colonoscopies are indicated to assess completeness of removal of AN. These colonoscopies can make a substantial demand on colonoscopy capacity and health-care system. This study is the first to evaluate the demand and risk factors for second-look colonoscopy in FIT CRC screening. METHODS: All colonoscopies after a positive FIT, in subjects aged 50-74 years approached for 3 rounds of FIT screening, were prospectively registered. Second-look colonoscopies were defined as any colonoscopy within 1 year following a colonoscopy after positive FIT. RESULTS: Out of 1,215 FIT-positive screenees undergoing colonoscopy, 105 (8.6%) patients underwent a second-look colonoscopy, of whom 30 (2.5%) underwent more than one colonoscopy (range 2-9), leading to a total of 149 (12.3%) additional colonoscopies. Main reasons for second-look colonoscopies were assessment of complete AN removal (41.9%) and need for additional polypectomy (34.3%). Risk factors were advanced adenomas and poor bowel preparation (P<0.001). High fecal hemoglobin concentration was the only predictor of a second-look colonoscopy before index colonoscopy (P<0.001). CONCLUSIONS: Second-look colonoscopies have substantial impact on colonoscopy resources, increasing the demand with 12%. The main reasons for these second-look colonoscopies were previous incomplete polypectomy and control of completeness of removal of neoplastic lesions. A high fecal hemoglobin concentration as measured by FIT can help to identify patients at risk of a second-look colonoscopy.

Gender Differences in Fecal Immunochemical Test Performance for Early Detection of Colorectal Neoplasia.

BACKGROUND & AIMS: Fecal immunochemical tests (FITs) are used widely in colorectal cancer screening. Programs use the same fecal hemoglobin threshold for colonoscopy referral for men and women, but it is unclear whether FIT performs equally in both sexes. We therefore assessed FIT performance in men and women. METHODS: A prospective cohort study was performed, in which a total of 10,008 average-risk subjects (age, 50-74 y) were invited for first-round screening and 8316 average-risk subjects (age, 51-74 y) were invited for second-round screening with a single FIT. Subjects with a hemoglobin (Hb) level of 10 µg hemoglobin (Hb)/g (or ≥50 ng/mL) feces or higher were referred for colonoscopy. The test characteristics were assessed by sex for a range of FIT cut-off values. RESULTS: In total, 59.8% of men and 64.6% of women participated in the first round (P < .001). At a cut-off level of 10 µg Hb/g feces, the positivity rate was significantly higher among men (10.7%) compared with women (6.3%; P < .001) in the first round. The detection rate of advanced neoplasia was 4.4% for men and 2.2% for women (P < .001) in the first round. The positive predictive value for advanced neoplasia in the first round was 42% for men and 37% for women (P = .265). A significantly higher false-positive rate in men (6.3%) than in women (4.1%; P < .001) was found. Similar differences in these test characteristics were seen in the second round. CONCLUSIONS: At a cut-off level of 10 µg Hb/g feces the FIT positivity rate was higher in men, reflected by both a higher detection rate and a higher false-positive rate. The use of the same cut-off value in men and women in FIT screening is recommended based on equal test performance in terms of positive predictive value.

Attendance and yield over three rounds of population-based fecal immunochemical test screening.

OBJECTIVES: Fecal immunochemical test (FIT) screening for colorectal cancer (CRC) requires timely successive rounds for an optimal preventive effect. However, data on attendance and trend in yield over multiple rounds of FIT screening are limited. We therefore conducted a consecutive third round of FIT screening in a population-based CRC screening trial. METHODS: Average-risk subjects aged 50-74 years were approached for three rounds of 1-sample FIT (OC-sensor) screening. Subjects with a hemoglobin level ≥50 ng/ml (≥10 µg Hb/g) feces were referred for colonoscopy. Subjects with a positive FIT in previous rounds were not re-invited for FIT screening. RESULTS: In the first round, 7,501 subjects were invited. The participation rate was 62.6% in the first round, 63.2% in the second round, and 68.3% in the third round (P<0.001). In total, 73% (5,241/7,229) of all eligible subjects participated in at least one of three rounds. The positivity rate was significantly higher in the first (8.4%) round compared with the second (6.0%) and third (5.7%) screening rounds (P<0.001). The detection rate of advanced neoplasia (AN) declined from the first round to subsequent rounds (round 1: 3.3%; round 2: 1.9%; and round 3: 1.3%; P<0.001). The positive predictive value for AN was 40.7% in the first screening round, 33.2% in the second screening round, and 24.0% in the third screening round (P<0.001). CONCLUSIONS: Repeated biennial FIT screening is acceptable with increased participation in successive screening rounds, and >70% of all eligible subjects participating at least once over three rounds. The decline in screen-detected AN over three screening rounds is compatible with a decreased prevalence of AN as a result of repeated FIT screening. These findings provide strong evidence for the effectiveness of FIT screening and stress the importance of ongoing research over multiple screening rounds.