The impact of cumulative colorectal cancer screening delays: A simulation study

Objective Annual fecal immunochemical tests can reduce colorectal cancer incidence and mortality. However, screening is a multi-step process and most patients do not perfectly adhere to guideline-recommended screening schedules. Our objective was to compare the reduction in colorectal cancer incidence and life-years gained based on US guideline-concordant fecal immunochemical test screening to scenarios with a range of delays. Method The Colorectal Cancer Simulated Population model for Incidence and Natural history (CRC-SPIN) microsimulation model was used to estimate the effect of systematic departures from fecal immunochemical test screening guidelines on lifetime screening benefit. Results The combined effect of consistent modest delays in screening initiation (1 year), repeated fecal immunochemical test screening (3 months), and receipt of follow-up or surveillance colonoscopy (3 months) resulted in up to 1.3 additional colorectal cancer cases per 10,000, 0.4 additional late-stage colorectal cancer cases per 10,000 and 154.7 fewer life-years gained per 10,000. A 5-year delay in screening initiation had a larger impact on screening effectiveness than consistent small delays in repeated fecal immunochemical test screening or receipt of follow-up colonoscopy after an abnormal fecal immunochemical test. The combined effect of consistent large delays in screening initiation (5 years), repeated fecal immunochemical test screening (6 months), and receipt of follow-up or surveillance colonoscopy (6 months) resulted in up to 3.7 additional colorectal cancer cases per 10,000, 1.5 additional late-stage colorectal cancer cases per 10,000 and 612.3 fewer life-years gained per 10,000. Conclusions Systematic delays across the screening process can result in meaningful reductions in colorectal cancer screening effectiveness, especially for longer delays. Screening delays could drive differences in colorectal cancer incidence across patient groups with differential access to screening.

Adherence to fecal immunochemical test screening among adults at average risk for colorectal cancer

Purpose This study examined adherence to screening for fecal immunochemical test (FIT). Methods Adults (≥ 50–75) with a FIT between 1/1/2014 and 6/30/2019 in MarketScan administrative claims were selected (index = earliest FIT). Patients were followed for 10 years pre- and 3 years post-index. Patients at increased risk for CRC or with prior screening were excluded. Year over year adherence was measured post-index. Results Of 10,253 patients, the proportion adherent to repeat testing at year 2 was 23.4% and 10.6% at year 3. Of 76.6% not adherent in year 2, 5.4% were adherent in year 3. Conclusion Results suggest adherence to FIT tests is poor, minimizing potential benefits. Future studies are needed to consider alternative test options and whether more choice will improve long-term adherence.

Management of large polyps in a colorectal cancer screening program with fecal immunochemical test: a community- and population-based observational study

Background and study aims The aim of this study was to analyze presentation, management, and outcomes of large polyps (LPs; ≥ 20 mm) detected in a colorectal cancer (CRC) screening program using a quantitative fecal immunochemical test (FIT). Patients and methods This was a retrospective community- and population-based observational study of all LPs detected in patients aged 50 to 74 years between 2015 and 2019 during FIT-positive colonoscopies within the screening program organized in Alsace (France). Results Among 13,633 FIT-positive colonoscopies, 1256 LPs (8.5 % malignant and 51.8 % nonpedunculated) were detected by 102 community gastroenterologists in 1164 patients (one in 12 colonoscopies). The sensitivity of optical diagnosis of malignancy was 54 % for nonpedunculated and 27 % for pedunculated T1 CRCs. The endoscopic resection rate was 82.7 % (95 % confidence interval [CI] 80.3–84.9) for benign LPs (70.2 % [95 % CI 66.4–74.1]) nonpedunculated, 95.2 % [95 % CI 93.4–97.1] pedunculated), varying from 0 to 100 % depending on the endoscopist. It was correlated with cecal intubation (Pearson r = 0.49, P < 0.01) and adenoma detection rates (r = 0.25, P = 0.01). Most endoscopists did not refer patients to more experienced endoscopists, and as a result, 60 % to 90 % of 183 surgeries for benign LPs were unwarranted. Endoscopic resection was curative for 4.3 % (95 % CI 0.9–12.0) of nonpedunculated and 37.8 % (95 % CI 22.5–55.2) of pedunculated T1 CRCs. Overall, 22 endoscopic submucosal dissections had to be performed to avoid one surgery. Conclusions Compared with current recommendations, there is tremendous room for improvement in community endoscopy practices in the diagnosis and management of LPs. Detection and polypectomy competencies are correlated and highly variable among endoscopists. Endoscopic resection is curative for 83 % of benign LPs and 16 % of T1 CRCs.

Quality Improvement of Sample Collection Increases the Diagnostic Accuracy of Quantitative Fecal Immunochemical Test in Colorectal Cancer Screening: A Pilot Study

Objective: The diagnostic efficiency of the quantitative fecal immunochemical test (qFIT) has large variations in colorectal cancer (CRC) screening. We aimed to explore whether the practical sample collection operant training could improve the diagnostic accuracy of the qFIT in CRC screening.Methods: Moderate-/high-risk individuals aged 50–75 years old were invited to participate in a prospective observational study between July 2020 and March 2021. Participants took a qFIT sample without fecal sample collection operant training in advance and then completed another qFIT sample after the operant training. The primary outcome was the sensitivity and specificity of the qFITs for CRC and advanced colorectal neoplasia (ACRN). The secondary outcome was the difference in the area under the curves (AUCs) and the concentrations of the fecal hemoglobin (Hb) between the qFIT without and after the operant training.Results: Out of 913 patients, 81 (8.9%) patients had ACRN, including 25 (2.7%) patients with CRC. For CRC, the sensitivities of the qFIT without and after the operant training at 10 μg/g were 80.4 and 100.0%, respectively, and the specificities were 90.1 and 88.4%, respectively. For ACRN, the sensitivities were 49.4 and 69.1% and the specificities were 91.7 and 91.3%, respectively. The AUC of the qFIT after the operant training was significantly higher than that without the operant training for CRC (p = 0.027) and ACRN (p = 0.001). After the operant training, the concentration of the fecal Hb was significantly higher than that without the operant training (p = 0.009) for ACRN, but there was no significant difference for CRC (p = 0.367).Conclusion: Practical sample collection operant training improves the diagnostic accuracy of the qFIT, which increases the detection of the low concentrations of fecal Hb. Improving the quality of the sample collection could contribute to the diagnostic efficiency of the qFIT in CRC screening.

Prevalence of adenomatous polyposis in a fecal immunochemical test-based colorectal cancer screening program and risk of advanced neoplasia during follow-up

Background and study aims: current guidelines recommend genetic counseling and intensive colonoscopy surveillance for patients with ≥10 colorectal adenomas based on scarce data. We investigated the prevalence of this condition in a FIT (fecal immunochemical test)-based colorectal (CRC) screening program and the incidence of metachronous lesions during follow-up. Patients and methods: we retrospectively included all FIT-positive participants with ≥10 adenomas at index colonoscopy between 2010 and 2018. Surveillance colonoscopies (SVC) were collected until 2019. Patients with inherited syndromes, serrated polyposis syndrome, total colectomy or lacking surveillance data, were excluded. Cumulative incidence of CRC and advanced neoplasia (AN) were analyzed by Kaplan-Meyer analysis. Risk factors of metachronous AN were investigated by multivariable logistic-regression analysis. Results: 215/9,582 (2.2%) participants had ≥10 adenomas. Germline genetic testing was performed in 92% of patients with ≥20 adenomas identifying 2 (3.3%) inherited syndromes. 3-year cumulative incidence of CRC and AN was 1%, and 16%, respectively. In 39 (24.2%) patients no polyps were found at first SVC. The presence of advanced adenoma was independently associated with a higher risk of AN at first SVC (OR: 3.91, 95% confident interval : 1.12-13.62; p=0.03). Beyond the first SVC, the risk of metachronous AN was lower. Conclusions: the prevalence of ≥10 adenomas in a FIT-based CRC screening program is 2.2% and a small proportion of inherited syndromes are detected even amongst those with ≥ 20 adenomas. Low rate of post-colonoscopy CRC is observed and the risk of AN beyond the first SVC tends to progressively decrease throughout successive follow-up.