Post-colonoscopy colorectal cancers in a national fecal immunochemical test-based colorectal cancer screening program.

BACKGROUND: Post-colonoscopy colorectal cancers (PCCRCs) decrease the effect of colorectal cancer (CRC) screening programs. To enable PCCRC incidence reduction in the long-term, we classified PCCRCs diagnosed after colonoscopies performed in a fecal immunochemical test (FIT)-based screening program. METHODS: PCCRCs diagnosed after colonoscopies performed between 2014-2016 for a positive FIT in the Dutch CRC screening program were included. PCCRCs were categorized according to the World Endoscopy Organization consensus statement into (a) interval PCCRC (diagnosed before the recommended surveillance); (b) non-interval type A (diagnosed at the recommended surveillance interval); (c) non-interval type B (diagnosed after the recommended surveillance interval); or (d) non-interval type C (diagnosed after the intended recommended surveillance interval, with surveillance not implemented owing to co-morbidity). The most probable etiology was determined by root-cause analysis. Tumor stage distributions were compared between categories. RESULTS: 116362 colonoscopies were performed after a positive FIT with 9978 screen-detected CRCs. During follow-up, 432 PCCRCs were diagnosed. The 3-year PCCRC rate was 2.7%. PCCRCs were categorized as interval (53.5%), non-interval type A (14.6%), non-interval type B (30.6%), and non-interval type C (1.4%). The most common etiology for interval PCCRCs was possible missed lesion with adequate examination (73.6%); they were more often diagnosed at an advanced stage (stage III/IV; 53.2%) compared with non-interval type A (15.9%; P<0.001) and non-interval type B (40.9%; P=0.03) PCCRCs. CONCLUSIONS: The 3-year PCCRC rate was low in this FIT-based CRC screening program. Approximately half of PCCRCs were interval PCCRCs. These were mostly caused by missed lesions and were diagnosed at a more advanced stage. This emphasizes the importance of high quality colonoscopy with optimal polyp detection.

Oncologic outcomes of screen-detected and non-screen-detected T1 colorectal cancers.

BACKGROUND: The incidence of T1 colorectal cancer (CRC) has increased with the implementation of CRC screening programs. It is unknown whether the outcomes and risk models for T1 CRC based on non-screen-detected patients can be extrapolated to screen-detected T1 CRC. This study aimed to compare the stage distribution and oncologic outcomes of T1 CRC patients within and outside the screening program. METHODS: Data from T1 CRC patients diagnosed between 2014 and 2017 were collected from 12 hospitals in the Netherlands. The presence of lymph node metastasis (LNM) at diagnosis was compared between screen-detected and non-screen-detected patients using multivariable logistic regression. Cox proportional hazard regression was used to analyze differences in the time to recurrence (TTR), metastasis-free survival (MFS), cancer-specific survival (CSS), and overall survival. Additionally, the performance of conventional risk factors for LNM was evaluated across the groups. RESULTS: 1803 patients were included (1114 [62%] screen-detected), with median follow-up of 51 months (interquartile range 30). The proportion of LNM did not significantly differ between screen- and non-screen-detected patients (12.6% vs. 8.9%; odds ratio 1.41; 95%CI 0.89-2.23); a prediction model for LNM performed equally in both groups. The 3- and 5-year TTR, MFS, and CSS were similar for patients within and outside the screening program. However, overall survival was significantly longer in screen-detected T1 CRC patients (adjusted hazard ratio 0.51; 95%CI 0.38-0.68). CONCLUSIONS: Screen-detected and non-screen-detected T1 CRCs have similar stage distributions and oncologic outcomes and can therefore be treated equally. However, screen-detected T1 CRC patients exhibit a lower rate of non-CRC-related mortality, resulting in longer overall survival.

Adenoma Detection Rate and Risk for Interval Postcolonoscopy Colorectal Cancer in Fecal Immunochemical Test-Based Screening : A Population-Based Cohort Study.

BACKGROUND: The adenoma detection rate (ADR) is an essential quality indicator for endoscopists performing colonoscopies for colorectal cancer (CRC) screening as it is associated with postcolonoscopy CRCs (PCCRCs). Currently, data on ADRs of endoscopists performing colonoscopies in fecal immunochemical testing (FIT)-based screening, the most common screening method, are scarce. Also, the association between the ADR and PCCRC has not been demonstrated in this setting. OBJECTIVE: To evaluate the association between the ADR and PCCRC risk in colonoscopies done after a positive FIT result. DESIGN: Population-based cohort. SETTING: Dutch, FIT-based, CRC screening program. PARTICIPANTS: Patients undergoing colonoscopy, done by accredited endoscopists, after a positive FIT result. MEASUREMENTS: Quality indicator performance and PCCRC incidence for colonoscopies in FIT-positive screenees were assessed. The PCCRCs were classified as interval, a cancer detected before recommended surveillance, or noninterval. The association between ADR and interval PCCRC was evaluated with a multivariable Cox regression model and PCCRC incidence was determined for different ADRs. RESULTS: 362 endoscopists performed 116 360 colonoscopies with a median ADR of 67%. In total, 209 interval PCCRCs were identified. The ADR was associated with interval PCCRC, with an adjusted hazard ratio of 0.95 (95% CI, 0.92 to 0.97) per 1% increase in ADR. For every 1000 patients undergoing colonoscopy, the expected number of interval PCCRC diagnoses after 5 years was approximately 2 for endoscopists with ADRs of 70%, compared with more than 2.5, almost 3.5, and more than 4.5 for endoscopists with ADRs of 65%, 60%, and 55%, respectively. LIMITATION: The relative short duration of follow-up (median, 52 months) could be considered a limitation. CONCLUSION: The ADR of endoscopists is inversely associated with the risk for interval PCCRC in FIT-positive colonoscopies. Endoscopists performing colonoscopy in FIT-based screening should aim for markedly higher ADRs compared with primary colonoscopy. PRIMARY FUNDING SOURCE: None.

Full-Thickness Scar Resection After R1/Rx Excised T1 Colorectal Cancers as an Alternative to Completion Surgery.

INTRODUCTION: Local full-thickness resections of the scar (FTRS) after local excision of a T1 colorectal cancer (CRC) with uncertain resection margins is proposed as an alternative strategy to completion surgery (CS), provided that no local intramural residual cancer (LIRC) is found. However, a comparison on long-term oncological outcome between both strategies is missing. METHODS: A large cohort of patients with consecutive T1 CRC between 2000 and 2017 was used. Patients were selected if they underwent a macroscopically complete local excision of a T1 CRC but positive or unassessable (R1/Rx) resection margins at histology and without lymphovascular invasion or poor differentiation. Patients treated with CS or FTRS were compared on the presence of CRC recurrence, a 5-year overall survival, disease-free survival, and metastasis-free survival. RESULTS: Of 3,697 patients with a T1 CRC, 434 met the inclusion criteria (mean age 66 years, 61% men). Three hundred thirty-four patients underwent CS, and 100 patients underwent FTRS. The median follow-up period was 64 months. CRC recurrence was seen in 7 patients who underwent CS (2.2%, 95% CI 0.9%-4.6%) and in 8 patients who underwent FTRS (9.0%, 95% CI 3.9%-17.7%). Disease-free survival was lower in FTRS strategy (96.8% vs 89.9%, P = 0.019), but 5 of the 8 FTRS recurrences could be treated with salvage surgery. The metastasis-free survival (CS 96.8% vs FTRS 92.1%, P = 0.10) and overall survival (CS 95.6% vs FTRS 94.4%, P = 0.55) did not differ significantly between both strategies. DISCUSSION: FTRS after local excision of a T1 CRC with R1/Rx resection margins as a sole risk factor, followed by surveillance and salvage surgery in case of CRC recurrence, could be a valid alternative strategy to CS.

Endoscopic full-thickness resection of T1 colorectal cancers: a retrospective analysis from a multicenter Dutch eFTR registry.

BACKGROUND: Complete endoscopic resection and accurate histological evaluation for T1 colorectal cancer (CRC) are critical in determining subsequent treatment. Endoscopic full-thickness resection (eFTR) is a new treatment option for T1 CRC < 2 cm. We aimed to report clinical outcomes and short-term results. METHODS: Consecutive eFTR procedures for T1 CRC, prospectively recorded in our national registry between November 2015 and April 2020, were retrospectively analyzed. Primary outcomes were technical success and R0 resection. Secondary outcomes were histological risk assessment, curative resection, adverse events, and short-term outcomes. RESULTS: We included 330 procedures: 132 primary resections and 198 secondary scar resections after incomplete T1 CRC resection. Overall technical success, R0 resection, and curative resection rates were 87.0 % (95 % confidence interval [CI] 82.7 %-90.3 %), 85.6 % (95 %CI 81.2 %-89.2 %), and 60.3 % (95 %CI 54.7 %-65.7 %). Curative resection rate was 23.7 % (95 %CI 15.9 %-33.6 %) for primary resection of T1 CRC and 60.8 % (95 %CI 50.4 %-70.4 %) after excluding deep submucosal invasion as a risk factor. Risk stratification was possible in 99.3 %. The severe adverse event rate was 2.2 %. Additional oncological surgery was performed in 49/320 (15.3 %), with residual cancer in 11/49 (22.4 %). Endoscopic follow-up was available in 200/242 (82.6 %), with a median of 4 months and residual cancer in 1 (0.5 %) following an incomplete resection. CONCLUSIONS: eFTR is relatively safe and effective for resection of small T1 CRC, both as primary and secondary treatment. eFTR can expand endoscopic treatment options for T1 CRC and could help to reduce surgical overtreatment. Future studies should focus on long-term outcomes.

Computer-based patient education is non-inferior to nurse counselling prior to colonoscopy: a multicenter randomized controlled trial.

BACKGROUND: Optimal patient education prior to colonoscopy improves adherence to instructions for bowel preparation and leads to cleaner colons. We developed computer-based education (CBE) supported by video and 3 D animations. We hypothesized that CBE could replace nurse counselling without loss of bowel preparation quality during colonoscopy. METHODS: We conducted a prospective, multicenter, endoscopist-blinded, non-inferiority randomized controlled trial. The primary outcome was adequate bowel preparation, evaluated using the Boston Bowel Preparation Scale (BBPS). Secondary outcome measures were: sickness absence for outpatient clinic visits; patient anxiety/satisfaction scores; and information recall. We included patients in four endoscopy units (rural, urban, and tertiary). RESULTS: We screened 1035 eligible patients and randomized 845. After evaluation, 684 were included in the intention-to-treat (ITT) group. Subsequently, 497 patients were included in the per-protocol analysis, 217 in the nurse counselling and 280 in the CBE group. Baseline characteristics were similarly distributed among the groups. On per-protocol analysis, adequate bowel cleansing was achieved in 93.2 % (261/280) of CBE patients, which was non-inferior to nurse-counselled patients (94.0 %; 204/217), with a difference of -0.8 % (95 % confidence interval [CI] -5.1 % to 3.5 %). Non-inferiority was confirmed in the ITT population. Sickness absence was significantly more frequent in nurse-counselled patients (28.0 % vs. 4.8 %). In CBE patients, 21.5 % needed additional information, with 3.0 % needing an extra outpatient visit. CONCLUSION: CBE is non-inferior to nurse counselling in terms of bowel preparation during colonoscopy, with lower patient sickness leave. CBE may serve as an efficient educational tool to inform patients before colonoscopy in routine clinical practice.

Periprocedural adverse events after endoscopic resection of T1 colorectal carcinomas.

BACKGROUND AND AIMS: In contrast to the adverse event (AE) risk of endoscopic resection (ER) of adenomas, the intra- and postprocedural AE risks of ER of T1 colorectal cancer (CRC) are scarcely reported in the literature. It is unclear whether ER of early CRCs, which grow into the submucosal layer and sometimes show incomplete lifting, is associated with an increased AE risk. We aimed to identify the AE rate after ER of T1 CRCs and to identify the risk factors associated with these AEs. METHODS: Medical records of patients with T1 CRCs diagnosed between 2000 and 2014 in 15 hospitals in the Netherlands were reviewed. Patients who underwent primary ER were selected. The primary outcome was the occurrence of endoscopy-related AEs. The secondary outcome was the identification of risk factors. Multivariate logistic regression was performed. RESULTS: Endoscopic AEs occurred in 59 of 1069 (5.5%) patients, among which 37.3% were classified as mild, 59.3% as moderate, and 3.4% as severe. AEs were postprocedural bleeding (n = 40, 3.7%), perforation (n = 13, 1.2%), and postpolypectomy electrocoagulation syndrome (n = 6, 0.6%). No fatal AEs were observed. Independent predictors for AEs were age >70 years (odds ratio, 2.11; 95% confidence interval, 1.12-3.96) and tumor size >20 mm (odds ratio, 2.22; 95% confidence interval, 1.05-4.69). CONCLUSIONS: In this large multicenter retrospective cohort study, AE rates of ER of T1 CRC (5.5%) are comparable with reported AE rates for adenomas. Larger tumor size and age >70 years are independent predictors for AEs. This study suggests that endoscopic treatment of T1 CRCs is not associated with an increased periprocedural AE risk.

Endoscopic full-thickness resection (eFTR) of colorectal lesions: results from the Dutch colorectal eFTR registry.

BACKGROUND: Endoscopic full-thickness resection (eFTR) is a minimally invasive resection technique that allows definite diagnosis and treatment for complex colorectal lesions ≤ 30 mm unsuitable for conventional endoscopic resection. This study reports clinical outcomes from the Dutch colorectal eFTR registry. METHODS: Consecutive patients undergoing eFTR in 20 hospitals were prospectively included. The primary outcome was technical success, defined as macroscopic complete en bloc resection. Secondary outcomes were: clinical success, defined as tumor-free resection margins (R0 resection); full-thickness resection rate; and adverse events. RESULTS : Between July 2015 and October 2018, 367 procedures were included. Indications were difficult polyps (non-lifting sign and/or difficult location; n = 133), primary resection of suspected T1 colorectal cancer (CRC; n = 71), re-resection after incomplete resection of T1 CRC (n = 150), and subepithelial tumors (n = 13). Technical success was achieved in 308 procedures (83.9 %). In 21 procedures (5.7 %), eFTR was not performed because the lesion could not be reached or retracted into the cap. In the remaining 346 procedures, R0 resection was achieved in 285 (82.4 %) and full-thickness resection in 288 (83.2 %). The median diameter of resected specimens was 23 mm. Overall adverse event rate was 9.3 % (n = 34/367): 10 patients (2.7 %) required emergency surgery for five delayed and two immediate perforations and three cases of appendicitis. CONCLUSION : eFTR is an effective and relatively safe en bloc resection technique for complex colorectal lesions with the potential to avoid surgery. Further studies assessing the role of eFTR in early CRC treatment with long-term outcomes are needed.

Pedunculated Morphology of T1 Colorectal Tumors Associates With Reduced Risk of Adverse Outcome.

BACKGROUND & AIMS: Risk stratification for adverse events, such as metastasis to lymph nodes, is based only on histologic features of tumors. We aimed to compare adverse outcomes of pedunculated vs nonpedunculated T1 colorectal cancers (CRC). METHODS: We performed a retrospective study of 1656 patients diagnosed with T1CRC from 2000 through 2014 at 14 hospitals in The Netherlands. The median follow-up time of patients was 42.5 months (interquartile range, 18.5-77.5 mo). We evaluated the association between tumor morphology and the primary composite end point, adverse outcome, adjusted for clinical variables, histologic variables, resection margins, and treatment approach. Adverse outcome was defined as metastasis to lymph nodes, distant metastases, local recurrence, or residual tissue. Secondary end points were tumor metastasis, recurrence, and incomplete resection. RESULTS: Adverse outcome occurred in 67 of 723 patients (9.3%) with pedunculated T1CRCs vs 155 of 933 patients (16.6%) with nonpedunculated T1CRCs. Pedunculated morphology was independently associated with decreased risk of adverse outcome (adjusted odds ratio [OR], 0.59; 95% CI, 0.42-0.83; P = .003). Metastasis, incomplete resection, and recurrence were observed in 5.8%, 4.6%, and 3.9% of pedunculated T1CRCs vs 10.6%, 8.0%, and 6.6% of nonpedunculated T1CRCs, respectively. Pedunculated morphology was independently associated with a reduced risk of metastasis (adjusted OR, 0.62; 95% CI, 0.41-0.94; P = .03), incomplete resection (adjusted OR, 0.57; 95% CI, 0.36-0.91; P = .02), and recurrence (adjusted hazard ratio, 0.52; 95% CI, 0.32-0.85; P = .009). Metastasis, incomplete resection, and recurrence did not differ significantly between low-risk pedunculated vs nonpedunculated T1CRCs (0.8% vs 2.9%, P = .38; 1.5% vs 0%, P = .99; 1.5% vs 0%; P = .99). However, incomplete resection and recurrence were significantly lower for high-risk pedunculated vs nonpedunculated T1CRCs (6.5% vs 12.5%; P = .007; 4.4% vs 8.6%; P = .03). CONCLUSIONS: In a retrospective study of patients with T1CRC, we found pedunculated morphology to be associated independently with a decreased risk of adverse outcome in a T1CRC population at high risk of adverse outcome. Incorporating morphologic features of tumors in risk assessment could help predict outcomes of patients with T1CRC and help identify the best candidates for surgery.

Electronic nose can discriminate colorectal carcinoma and advanced adenomas by fecal volatile biomarker analysis: proof of principle study.

In the course and prognosis of colorectal cancer (CRC), early detection and treatment are essential factors. Fecal immunochemical tests (FITs) are currently the most commonly used non-invasive screening tests for CRC and premalignant (advanced) adenomas, however, with restricted sensitivity. We hypothesized that fecal volatile organic compounds (VOCs) may serve as a diagnostic biomarker of CRC and adenomas. In this proof of concept study, we aimed to assess disease-specific VOC smellprints in fecal gas to distinguish patients with CRC and advanced adenomas from healthy controls. Fecal samples of patients who were scheduled to undergo an elective colonoscopy were collected. An electronic nose (Cyranose 320) was used to measure VOC patterns in fecal gas from patients with histopathologically proven CRC, with advanced adenomas and from controls (no abnormalities seen at colonoscopy). Receiver operator characteristic curves and corresponding sensitivity and specificity for detection of CRC and advanced adenomas were calculated. A total of 157 stool samples (40 patients with CRC, 60 patients with advanced adenomas, and 57 healthy controls) were analyzed by electronic nose. Fecal VOC profiles of patients with CRC differed significantly from controls (area under curve ± 95%CI, p-value, sensitivity, specificity; 0.92 ± 0.03, <0.001, 85%, 87%). Also VOC profiles of patients with advanced adenomas could be discriminated from controls (0.79 ± 0.04, <0.001, 62%, 86%). The results of this proof of concept study suggest that fecal gas analysis by an electronic nose seems to hold promise as a novel screening tool for the (early) detection of advanced neoplasia and CRC.

Prospective cross-sectional study on faecal immunochemical tests: sex specific cut-off values to obtain equal sensitivity for colorectal cancer?

BACKGROUND: Faecal immunochemical tests (FITs) are commonly used in colorectal cancer (CRC) screening. Diagnostic accuracy of FIT differs between males and females. This so far unexplained difference could result in a dissimilarity in screening outcome between both sexes. The aim of this study is to compare sensitivity and specificity of a FIT between males and females, and study potential explanatory variables. METHODS: In this cross-sectional study, data were prospectively collected. 3,022 subjects performed a FIT prior to complete colonoscopy. Sensitivity, specificity, and ROC curves were compared for both sexes. Potential explanatory variables of the relation between sensitivity and sex were explored. RESULTS: At all cut-off values, FIT sensitivity for CRC was higher (range 13-23%) and specificity was lower (range 2-4%) in males compared to females. At 75 ng/ml, sensitivity for CRC was 93% in males compared to 71% in females (p = 0.03), and specificity was 90% in males compared to 93% in females (p = <0.05). For advanced adenomas, males had a slightly higher sensitivity and lower specificity (not significant). At 75 ng/ml, sensitivity for advanced adenomas was 33% in males compared to 29% in females (p = 0.46), and specificity was 93% in males compared to 95% in females (p = 0.22). ROC curves were similar for both sexes, and equal combinations of sensitivity and specificity could be achieved by adjusting the cut-off values. For CRC, the difference in sensitivity could not be explained by age or location of the tumour. CONCLUSIONS: FIT has a higher sensitivity and a lower specificity for CRC in males than in females. Equal test characteristics can be achieved by allowing separate cut-off values for both sexes. Location and age do not explain the observed differences in sensitivity.

Anticipating implementation of colorectal cancer screening in The Netherlands: a nation wide survey on endoscopic supply and demand.

BACKGROUND: Colorectal cancer (CRC) screening requires sufficient endoscopic resources. The present study aims to determine the Dutch endoscopic production and manpower for 2009, evaluate trends since 2004, determine additional workload which would be caused by implementation of a CRC screening program, and inventory colonoscopy rates performed in other European countries. METHODS: All Dutch endoscopy units (N = 101) were surveyed for manpower and the numbers of endoscopy procedures performed in 2009. Based on calculations in the report issued by the Dutch Health Council, future additional workload caused by faecal immunochemical test (FIT) screening was estimated. The number of colonoscopies performed in Europe was evaluated by a literature search and an email-inquiry. RESULTS: Compared to 2004, there was a 24% increase in total endoscopies (N = 505,226 in 2009), and a 64% increase in colonoscopies (N = 191,339 in 2009) in The Netherlands. The number of endoscopists had increased by 4.6% (N = 583 in 2009). Five years after stepwise implementation of FIT-based CRC screening, endoscopic capacity needs to be increased an additional 15%. A lack of published data on the number of endoscopies performed in Europe was found. Based on our email-inquiry, the number of colonoscopies per 100,000 inhabitants ranged from 126 to 3,031 in 15 European countries. CONCLUSIONS: Over the last years, endoscopic procedures increased markedly in The Netherlands without a corresponding increase in manpower. A FIT-based CRC screening program requires an estimated additional 15% increase in endoscopic procedures. It is very likely that current colonoscopy density varies widely across European countries.

Hemorrhoids detected at colonoscopy: an infrequent cause of false-positive fecal immunochemical test results.

BACKGROUND: Colorectal cancer screening by fecal immunochemical tests (FITs) is hampered by frequent false-positive (FP) results and thereby the risk of complications and strain on colonoscopy capacity. Hemorrhoids might be a plausible cause of FP results. OBJECTIVE: To determine the contribution of hemorrhoids to the frequency of FP FIT results. DESIGN: Retrospective analysis from prospective cohort study. SETTING: Five large teaching hospitals, including 1 academic hospital. PATIENTS: All subjects scheduled for elective colonoscopy. INTERVENTIONS: FIT before bowel preparation. MAIN OUTCOME MEASUREMENTS: Frequency of FP FIT results in subjects with hemorrhoids as the only relevant abnormality compared with FP FIT results in subjects with no relevant abnormalities. Logistic regression analysis to determine colonic abnormalities influencing FP results. RESULTS: In 2855 patients, 434 had positive FIT results: 213 had advanced neoplasia and 221 had FP results. In 9 individuals (4.1%; 95% CI, 1.4-6.8) with an FP FIT result, hemorrhoids were the only abnormality. In univariate unadjusted analysis, subjects with hemorrhoids as the only abnormality did not have more positive results (9/134; 6.7%) compared with subjects without any abnormalities (43/886; 4.9%; P = .396). Logistic regression identified hemorrhoids, nonadvanced polyps, and a group of miscellaneous abnormalities, all significantly influencing false positivity. Of 1000 subjects with hemorrhoids, 67 would have FP results, of whom 18 would have FP results because of hemorrhoids only. LIMITATIONS: Potential underreporting of hemorrhoids; high-risk individuals. CONCLUSIONS: Hemorrhoids in individuals participating in colorectal cancer screening will probably not lead to a substantial number of false-positive test results.

Faecal immunochemical test accuracy in patients referred for surveillance colonoscopy: a multi-centre cohort study.

BACKGROUND: Given the increasing burden on colonoscopy capacity, it has been suggested that faecal immunochemical test (FIT) results could guide surveillance colonoscopy intervals. Against this background, we have evaluated the test accuracy of single and double FIT sampling to detect colorectal cancer (CRC) and/or advanced adenomas in an asymptomatic colonoscopy-controlled high-risk population. METHODS: Cohort study of asymptomatic high-risk patients (personal history of adenomas/CRC or family history of CRC), who provided one or two FITs before elective colonoscopy. Test accuracy of FIT for detection of CRC and advanced adenomas was determined (cut-off level 50 ng/ml). RESULTS: 1,041 patients provided a FIT (516 personal history of adenomas, 172 personal history of CRC and 353 family history of CRC). Five CRCs (0.5%) and 101 advanced adenomas (9.7%) were detected by colonoscopy. Single FIT sampling resulted in a sensitivity, specificity, PPV and NPV for CRC of 80%, 89%, 3% and 99.9%, respectively, and for advanced adenoma of 28%, 91%, 24% and 92%, respectively. Double FIT sampling did not result in a significantly higher sensitivity for advanced neoplasia. Simulation of multiple screening rounds indicated that sensitivity of FIT for advanced adenoma could reach 81% after 5 screening rounds. CONCLUSIONS: In once-only FIT sampling before surveillance colonoscopy, 70% of advanced neoplasia were missed. A simulation approach indicates that multiple screening rounds may be more promising in detecting advanced neoplasia and could potentially alleviate endoscopic burden.

Impact of ≥ 0.1-mm free resection margins on local intramural residual cancer after local excision of T1 colorectal cancer.

Background and study aims A free resection margin (FRM) > 1 mm after local excision of a T1 colorectal cancer (CRC) is known to be associated with a low risk of local intramural residual cancer (LIRC). The risk is unclear, however, for FRMs between 0.1 to 1 mm. This study evaluated the risk of LIRC after local excision of T1 CRC with FRMs between 0.1 and 1 mm in the absence of lymphovascular invasion (LVI), poor differentiation and high-grade tumor budding (Bd2-3). Patients and methods Data from all consecutive patients with local excision of T1 CRC between 2014 and 2017 were collected from 11 hospitals. Patients with a FRM ≥ 0.1 mm without LVI and poor differentiation were included. The main outcome was risk of LIRC (composite of residual cancer in the local excision scar in adjuvant resection specimens or local recurrence during follow-up). Tumor budding was also assessed for cases with a FRM between 0.1 and 1mm. Results A total of 171 patients with a FRM between 0.1 and 1 mm and 351 patients with a FRM > 1 mm were included. LIRC occurred in five patients (2.9 %; 95 % confidence interval [CI] 1.0-6.7 %) and two patients (0.6 %; 95 % CI 0.1-2.1 %), respectively. Assessment of tumor budding showed Bd2-3 in 80 % of cases with LIRC and in 16 % of control cases. Accordingly, in patients with a FRM between 0.1 and 1 mm without Bd2-3, LIRC was detected in one patient (0.8%; 95 % CI 0.1-4.4 %). Conclusions In this study, risks of LIRC were comparable for FRMs between 0.1 and 1 mm and > 1 mm in the absence of other histological risk factors.

Double sampling of a faecal immunochemical test is not superior to single sampling for detection of colorectal neoplasia: a colonoscopy controlled prospective cohort study.

BACKGROUND: A single sampled faecal immunochemical test (FIT) has moderate sensitivity for colorectal cancer and advanced adenomas. Repeated FIT sampling could improve test sensitivity. The aim of the present study is to determine whether any of three different strategies of double FIT sampling has a better combination of sensitivity and specificity than single FIT sampling. METHODS: Test performance of single FIT sampling in subjects scheduled for colonoscopy was compared to double FIT sampling intra-individually. Test positivity of double FIT sampling was evaluated in three different ways: 1) "one of two FITs+" when at least one out of two measurements exceeded the cut-off value, 2) "two of two FITs+" when both measurements exceeded the cut-off value, 3) "mean of two FITs+" when the geometric mean of two FITs exceeded the cut-off value. Receiver operator curves were calculated and sensitivity of single and the three strategies of double FIT sampling were compared at a fixed level of specificity. RESULTS: In 124 of 1096 subjects, screen relevant neoplasia (SRN) were found (i.e. early stage CRC or advanced adenomas). At any cut-off, "two of two FITs+" resulted in the lowest and "one of two FITs+" in the highest sensitivity for SRN (range 35-44% and 42%-54% respectively). ROC's of double FIT sampling were similar to single FIT sampling. At specificities of 85/90/95%, sensitivity of any double FIT sampling strategy did not differ significantly from single FIT (p-values 0.07-1). CONCLUSION: At any cut off, "one of two FITs+" is the most sensitive double FIT sampling strategy. However, at a given specificity level, sensitivity of any double FIT sampling strategy for SRN is comparable to single FIT sampling at a different cut-off value. None of the double FIT strategies has a superior combination of sensitivity and specificity over single FIT.

Clip placement to prevent delayed bleeding after colonic endoscopic mucosal resection (CLIPPER): study protocol for a randomized controlled trial.

BACKGROUND: Endoscopic mucosal resection (EMR) for large colorectal polyps is in most cases the preferred treatment to prevent progression to colorectal carcinoma. The most common complication after EMR is delayed bleeding, occurring in 7% overall and in approximately 10% of polyps ≥ 2 cm in the proximal colon. Previous research has suggested that prophylactic clipping of the mucosal defect after EMR may reduce the incidence of delayed bleeding in polyps with a high bleeding risk. METHODS: The CLIPPER trial is a multicenter, parallel-group, single blinded, randomized controlled superiority study. A total of 356 patients undergoing EMR for large (≥ 2 cm) non-pedunculated polyps in the proximal colon will be included and randomized to the clip group or the control group. Prophylactic clipping will be performed in the intervention group to close the resection defect after the EMR with a distance of < 1 cm between the clips. Primary outcome is delayed bleeding within 30 days after EMR. Secondary outcomes are recurrent or residual polyps and clip artifacts during surveillance colonoscopy after 6 months, as well as cost-effectiveness of prophylactic clipping and severity of delayed bleeding. DISCUSSION: The CLIPPER trial is a pragmatic study performed in the Netherlands and is powered to determine the real-time efficacy and cost-effectiveness of prophylactic clipping after EMR of proximal colon polyps ≥ 2 cm in the Netherlands. This study will also generate new data on the achievability of complete closure and the effects of clip placement on scar surveillance after EMR, in order to further promote the debate on the role of prophylactic clipping in everyday clinical practice. TRIAL REGISTRATION: ClinicalTrials.gov NCT03309683 . Registered on 13 October 2017. Start recruitment: 05 March 2018. Planned completion of recruitment: 31 August 2021.

Does delay in diagnosing colorectal cancer in symptomatic patients affect tumor stage and survival? A population-based observational study.

BACKGROUND: Diagnosing colorectal cancer (CRC) at an early stage improves survival. To what extent any delay affects outcome once patients are symptomatic is still unclear.Our objectives were to evaluate the association between diagnostic delay and survival in symptomatic patients with early stage CRC and late stage CRC. METHODS: Prospective population-based observational study evaluating daily clinical practice in Northern Holland. Diagnostic delay was determined through questionnaire-interviews. Dukes' stage was classified into two groups: early stage (Dukes A or B) and late stage (Dukes C or D) cancer. Patients were followed up for 3.5 years after diagnosis. RESULTS: In total, 272 patients were available for analysis. Early stage CRC was present in 136 patients while 136 patients had late stage CRC. The mean total diagnostic delay (SE) was 31 (1.5) weeks in all CRC patients. No significant difference was observed in the mean total diagnostic delay in early versus late stage CRC (p = 0.27).In early stage CRC, no difference in survival was observed between patients with total diagnostic delay shorter and longer than the median (Kaplan-Meier, log-rank p = 0.93).In late stage CRC, patients with a diagnostic delay shorter than the median had a shorter survival than patients with a diagnostic delay longer than the median (log-rank p = 0.01). In the multivariate Cox regression model with survival as dependent variable and median delay, age, open access endoscopy, number and type of symptoms as independent variables, the odd's ratio for survival in patients with long delay (>median) versus short delay (

E-Patient Counseling Trial (E-PACO): Computer Based Education versus Nurse Counseling for Patients to Prepare for Colonoscopy.

Improving patient education focusing on bowel preparation before a colonoscopy leads to cleaner colons. Endoscopy units must obtain informed consent and perform a risk assessment for sedative use prior to a colonoscopy. The current practice in the Netherlands to achieve these goals is nurse counseling in an outpatient setting. This is costly and has disadvantages in terms of uniformity and time consumption for both the patient and the hospital. The hypothesis is that computer-based education with use of video and 3D animations may replace nurse counseling in most cases, without losing quality of bowel cleanliness during colonoscopy. This multicenter, randomized, endoscopist blinded clinical trial evaluates a primary outcome measure (bowel preparation) during colonoscopy. Secondary outcome measures are sickness absence, patient anxiety after instruction and prior to colonoscopy, patient satisfaction and information re-call. The study will be performed in four endoscopy units of different levels (rural, urban, and tertiary). Inclusion criteria are adult age and referral for complete colonoscopy. Exclusion criteria are Dutch illiteracy, audiovisual handicaps or mental disabilities and no (peers with) internet access. This trial aims to establish online computer-based education as tool for patient education prior to a colonoscopy. By choosing a direct comparison with the standard of care (nurse counseling), both endoscopic quality measures and patient related outcome measures can be evaluated.

Evaluation of Cancer-Associated DNA Copy Number Events in Colorectal (Advanced) Adenomas.

About 5% of colorectal adenomas are estimated to progress to colorectal cancer. However, it is important to identify which adenomas actually carry a high risk of progression, because these serve as intermediate endpoints, for example, in screening programs. In clinical practice, adenomas with a size of ≥10 mm, villous component and/or high-grade dysplasia, called advanced adenomas, are considered high risk, although solid evidence for this classification is lacking. Specific DNA copy number changes are associated with adenoma-to-carcinoma progression. We set out to determine the prevalence of cancer-associated events (CAE) in advanced and nonadvanced adenomas. DNA copy number analysis was performed on archival tissues from three independent series of, in total, 297 adenomas (120 nonadvanced and 177 advanced) using multiplex ligation-dependent probe amplification or low-coverage whole-genome DNA sequencing. Alterations in two or more CAEs were considered to mark adenomas as high risk. Two or more CAEs were overall present in 25% (95% CI, 19.0-31.8) of advanced adenomas; 23% (11/48), 36% (12/33), and 23% (22/96) of the advanced adenomas in series 1, 2, and 3, respectively, and 1.7% (1/58) and 4.8% (3/62) of the nonadvanced adenomas, in series 1 and 2, respectively. The majority of advanced adenomas do not show CAEs, indicating that only a subset of these lesions is to be considered high risk. Nonadvanced adenomas have very low prevalence of CAEs, although those with CAEs should be considered high risk as well. Specific DNA copy number alterations may better reflect the true progression risk than the advanced adenoma phenotype. Cancer Prev Res; 11(7); 403-12. ©2018 AACR.