Effect of an E-learning resource on endoscopists' proximal serrated polyp detection rate: a randomized controlled trial.

BACKGROUND: Recent studies demonstrated that a higher proximal serrated polyp detection rate (PSPDR) among endoscopists is associated with a lower risk of post-colonoscopy colorectal cancer (PCCRC) incidence and death for their patients. Our objective was to evaluate the effect of an e-learning resource on PSPDR. METHODS: We performed a multicenter randomized controlled trial within the Dutch fecal immunochemical test-based colorectal cancer screening program. Endoscopists were randomized using block randomization per center to either receive a 60-minute e-learning resource on serrated polyp detection or not. PSPDR was calculated based on all colonoscopies performed during a 27-month pre-intervention and a 17-month post-intervention period. The primary end point was difference in PSPDR between intervention and control arms (intention to treat) using mixed effect logistic regression modeling, with time (pre-intervention/post-intervention) and interaction between time and arm (intervention/control) as fixed effects, and endoscopists as random effects. RESULTS: 116 endoscopists (57 intervention, 59 controls) were included, and performed 27494 and 33888 colonoscopies, respectively. Median PSPDR pre-intervention was 13.6% (95%CI 13.0-14.1) in the intervention arm and 13.8% (95%CI 13.3-14.3) in controls. Post-intervention PSPDR was significantly higher over time in the intervention arm than in controls (17.1% vs. 15.4%, P=0.01). CONCLUSION: In an era of increased awareness and increasing PSPDRs, endoscopists who undertook a one-time e-learning course significantly accelerated the increase in PSPDR compared with endoscopists who did not undertake the e-learning. Widespread implementation might reduce PCCRC incidence.

Polyps and Colorectal Cancer in Serrated Polyposis Syndrome: Contribution of the Classical Adenoma-Carcinoma and Serrated Neoplasia Pathways.

INTRODUCTION: Patients with serrated polyposis syndrome (SPS) have an increased risk to develop colorectal cancer (CRC). Due to an abundance of serrated polyps, these CRCs are assumed to arise mainly through the serrated neoplasia pathway rather than through the classical adenoma-carcinoma pathway. We aimed to evaluate the pathogenetic routes of CRCs in patients with SPS. METHODS: We collected endoscopy and pathology data on CRCs and polyps of patients with SPS under treatment in our center. Our primary end point was the proportion of BRAFV600E mutated CRCs, indicating serrated pathway CRCs (sCRCs). CRCs lacking BRAFV600E most likely inferred a classical adenoma-carcinoma origin (aCRCs). We assessed patient, polyp, and CRC characteristics and stratified for BRAFV600E mutation status. RESULTS: Thirty-five patients with SPS harbored a total of 43 CRCs. Twenty-one CRCs (48.8%) carried a BRAFV600E mutation, 10 of which lacked MLH1 staining and 17 (81%) were located in the proximal colon. Twenty-two CRCs (51.1%) did not carry a BRAFV600E mutation and were MLH1 proficient. Of these 22 putatively aCRCs, 17 (77.3%) were located distally and one-third (36.4%) harbored a pathogenic KRAS or NRAS mutation. In patients with BRAFwt -CRCs, a higher ratio of the median number of conventional adenomas versus serrated polyps was found (4 vs 13) than patients with BRAFV600E -CRCs (1 vs 14). DISCUSSION: Our study indicates that in patients with SPS, the ratio of sCRCs:aCRCs on average is 50:50. This elevated sCRC:aCRC ratio in patients with SPS, when compared with non-SPS patients, correlates well with the differences in the ratios of the numbers of sessile serrated lesions and conventional adenomas in patients with SPS and non-SPS patients, respectively.

Appendiceal lesions in serrated polyposis patients are easily overlooked but only seldomly lead to colorectal cancer.

BACKGROUND: Serrated polyposis syndrome (SPS) is the most prevalent colonic polyposis syndrome and is associated with an increased colorectal cancer risk. A recent study in resected appendices of SPS patients reported that 6/23 (26.1 %) of identified serrated polyps had histological dysplasia. We evaluated the prevalence and clinical relevance of appendiceal lesions in a large SPS cohort. METHODS: Prospective data from 2007 to 2020 for a cohort of 199 SPS patients were analyzed. Data were retrieved from endoscopy and pathology reports. Patients who underwent (pre)clearance colonoscopies, surveillance colonoscopies, or colorectal surgery including the appendix were separately evaluated for the presence of appendiceal lesions. The primary outcome was the prevalence of adenocarcinomas and serrated polyps/adenomas with advanced histology in the surgery group. RESULTS: 171 patients were included, of whom 110 received endoscopic surveillance and 34 underwent surgery. Appendiceal lesion prevalence in the surgery group was 14 /34 (41.2 %, 95 %CI 24.7 %-59.3 %); none were advanced on histology. Detection rates in the (pre)clearance group were 1 /171 (0.6 %, 95 %CI 0.01 %-3.2 %) for advanced and 3 /171 (1.8 %, 95 %CI 0.04 %-5.0 %) for nonadvanced appendiceal lesions, all of which were sessile serrated lesions. During 522 patient-years of surveillance, no advanced appendiceal lesions were detected at endoscopy, and in 1 /110 patients (0.9 %, 95 %CI 0.02 %-5.0 %) was a nonadvanced lesion detected. CONCLUSION: Appendiceal lesions are common in SPS patients. The discrepancy between the endoscopic detection rate of appendiceal lesions and the reported prevalence in surgically resected appendices suggests a substantial miss-rate of appendiceal lesions during colonoscopy. Advanced appendiceal lesions are however rare and no appendiceal adenocarcinomas occurred, implying limited clinical relevance of these lesions.

Serrated polyp detection and risk of interval post-colonoscopy colorectal cancer: a population-based study.

BACKGROUND: Adenoma detection rate (ADR) is a well-established quality indicator for colonoscopy and is inversely associated with the incidence of interval post-colonoscopy colorectal cancer. However, interval post-colonoscopy colorectal cancers frequently develop from serrated polyps, which are not included in the ADR. Therefore, the proximal serrated polyp detection rate (PSPDR) has been proposed as a quality indicator, but its association with interval post-colonoscopy colorectal cancer has not been studied. We aimed to evaluate this potential association based on data collected in the Dutch colorectal cancer screening programme. METHODS: In this population-based study, using colonoscopy data from the Dutch faecal immunochemical test-based colorectal cancer screening programme and cancer data from the Netherlands Cancer Registry, we evaluated the association between endoscopists' individual PSPDR and their patients' risk of interval post-colonoscopy colorectal cancer with a shared frailty Cox proportional-hazard regression analysis. Participants in the screening programme who were eligible for inclusion were aged 55-76 years, had a positive faecal immunochemical test (cutoff 15 µg Hb/g faeces at start and changed mid-2014 to 47 µg Hb/g faeces), were asymptomatic, and underwent a colonoscopy between Jan 1, 2014, and Dec 31, 2020. The PSPDR was defined as the proportion of colonoscopies in which at least one serrated polyp proximal to the descending colon was detected, confirmed by histopathology. The ADR was defined as the proportion of all colonoscopies in which at least one conventional adenoma was detected, confirmed by histopathology. Detection rates were determined for each endoscopist individually. We additionally evaluated the risk of interval post-colonoscopy colorectal cancer for endoscopists with a PSPDR and ADR above the median versus endoscopists with either one or both parameters below the median. This study is registered with the Netherlands Trial Registry, NL8350. FINDINGS: During the study period, 329 104 colonoscopies were done, of which 277 555, done by 441 endoscopists, were included in the PSPDR calculations. The median PSPDR was 11·9% (IQR 8·3-15·8) and median ADR was 66·3% (61·4-69·9). The correlation between the PSDPR and ADR was moderate (r=0·59; p<0·0001). During a median follow-up of 33 months (IQR 21-42), 305 interval post-colonoscopy colorectal cancers were detected. For each percentage point increase in PSPDR, the adjusted interval post-colonoscopy colorectal cancer hazard was 7% lower (hazard ratio [HR] 0·93, 95% CI 0·90-0·95; p<0·0001). Compared with endoscopists with a PSPDR greater than 11·9% and ADR greater than 66·3%, the HR of interval post-colonoscopy colorectal cancer for endoscopists with a low PSPDR and high ADR was 1·79 (95% CI 1·22-2·63), for endoscopists with a high PSPDR and low ADR was 1·97 (1·19-3·24), and for endoscopists with a low PSPDR and low ADR was 2·55 (1·89-3·45). INTERPRETATION: The PSPDR of an endoscopist is inversely associated with the incidence of interval post-colonoscopy colorectal cancer. Implementation of PSPDR monitoring, in addition to ADR monitoring, could optimise colorectal cancer prevention. FUNDING: None.

The long-term outcomes and natural disease course of serrated polyposis syndrome: over 10 years of prospective follow-up in a specialized center.

BACKGROUND AND AIMS: Serrated polyposis syndrome (SPS) is the most prevalent colonic polyposis syndrome known and is associated with a high risk of colorectal cancer (CRC) if left untreated. Treatment consists of clearance of the initial polyp burden, followed by lifelong stringent endoscopic surveillance. However, the long-term safety and efficacy of surveillance and the natural disease course after initial clearance have not been described in detail. METHODS: We analyzed a single-center cohort of patients with SPS with over 10 years of prospective follow-up. Outcome measures were (1) CRC incidence, (2) postcolonoscopy adverse event rates, and (3) trends in polyp recurrence during endoscopic surveillance. RESULTS: The cohort included 142 patients who underwent a median of 6 colonoscopies with a median of 47 months of prospective follow-up after initial polyp clearance. During surveillance (every 1-2 years), 1 case of CRC occurred (5-year CRC incidence, 1.0%; 95% confidence interval, 0%-2.9%). During 447 surveillance colonoscopies with 1308 polypectomies, 1 episode of postpolypectomy bleeding, 1 postpolypectomy syndrome, and no perforations occurred (adverse event rate, 0.45% per colonoscopy). During up to 9 rounds of surveillance, no upward or downward trend in polyp recurrence was observed. CONCLUSIONS: In this prospective cohort with over 10 years of follow-up, endoscopic surveillance was effective and safe, with a low risk of CRC and colonoscopy-related adverse events. Furthermore, we show that the disease course of SPS is such that the polyp burden remains more or less equal during long-term surveillance, which advocates lifelong adherence to (personalized) surveillance guidelines and discourages de-intensifying surveillance intervals after multiple rounds of surveillance.

Substantial and sustained improvement of serrated polyp detection after a simple educational intervention: results from a prospective controlled trial.

OBJECTIVE: Serrated polyps (SPs) are an important cause of postcolonoscopy colorectal cancers (PCCRCs), which is likely the result of suboptimal SP detection during colonoscopy. We assessed the long-term effect of a simple educational intervention focusing on optimising SP detection. DESIGN: An educational intervention, consisting of two 45 min training sessions (held 3 years apart) on serrated polyp detection, was given to endoscopists from 9 Dutch hospitals. Hundred randomly selected and untrained endoscopists from other hospitals were selected as control group. Our primary outcome measure was the proximal SP detection rate (PSPDR) in trained versus untrained endoscopists who participated in our faecal immunochemical test (FIT)-based population screening programme. RESULTS: Seventeen trained and 100 untrained endoscopists were included, who performed 11 305 and 51 039 colonoscopies, respectively. At baseline, PSPDR was equal between the groups (9.3% vs 9.3%). After training, the PSPDR of trained endoscopists gradually increased to 15.6% in 2018. This was significantly higher than the PSPDR of untrained endoscopists, which remained stable around 10% (p=0.018). All below-average (ie, PSPDR ≤6%) endoscopists at baseline improved their PSPDR after training session 1, as did 57% of endoscopists with average PSPDR (6%-12%) at baseline. The second training session further improved the PSPDR in 44% of endoscopists with average PSPDR after the first training. CONCLUSION: A simple educational intervention was associated with substantial long-term improvement of PSPDR in a prospective controlled trial within FIT-based population screening. Widespread implementation of such interventions might be an easy way to improve SP detection, which may ultimately result in fewer PCCRCs. TRIAL REGISTRATION NUMBER: NCT03902899.

The (ir)relevance of the abandoned criterion II for the diagnosis of serrated polyposis syndrome: a retrospective cohort study.

The World Health Organization (WHO) recently updated the diagnostic criteria for serrated polyposis syndrome (SPS). One of the three previous diagnostic criteria (criterion II2010) is now abandoned: ≥ 1 serrated polyp (SP) proximal to the sigmoid in a first-degree relative (FDR) of a patient with SPS. Individuals fulfilling this abandoned criterion now receive the same surveillance recommendations as all FDRs of patients with SPS. We aimed to compare the incidence of advanced neoplasia (AN) in FDRs with vs. without fulfillment of the abandoned criterion II2010. We retrospectively recruited FDRs of patients with SPS who underwent a colonoscopy, and stratified them according to fulfilment of criterion II2010 at baseline. Our primary and secondary outcomes were AN incidence during surveillance and at baseline, respectively. We included 224 FDRs of patients with SPS, of whom 36 (16%) fulfilled criterion II2010 at baseline. One hundred and five underwent surveillance after baseline. Criterion II2010-positive FDRs were at increased risk of AN, both during surveillance (hazard ratio 8.94, 95% CI 2.15-37.1, p = .003) as well as at baseline (adjusted odds-ratio 9.30, 95% CI 3.7-23.3, p < .001). FDRs of patients with SPS that underwent colonoscopy and fulfilled the abandoned criterion II2010 for SPS diagnosis were at increased risk of AN at baseline and during surveillance in this small, retrospective cohort study. Our results should be interpreted with caution but suggest that adherence to surveillance recommendations for all FDRs of patients with SPS is important, especially for those that would have fulfilled the now abandoned criterion II2010.

Impact of differences in adenoma and proximal serrated polyp detection rate on the long-term effectiveness of FIT-based colorectal cancer screening.

BACKGROUND: Both the adenoma detection rate (ADR) and proximal serrated polyp detection rate (PSPDR) vary among endoscopists. It is unclear how these variations influence colorectal cancer (CRC) screening effectiveness. We evaluated the effect of variation in these detection rates on the long-term impact of fecal immunochemical test (FIT) based screening. METHODS: The Adenoma and Serrated pathway to Colorectal CAncer (ASCCA) model was set up to simulate the Dutch national biennial FIT-based CRC screening program between 2014 and 2044. Adherence to FIT and colonoscopy was 73 and 92%. Besides a 'no screening scenario', several screening scenarios varying in ADR and PSPDR were evaluated. Using the available literature on colonoscopy miss rates led to a base-case ADR of 59% and PSPDR of 11%, which were varied with intervals of 3 and 2%. RESULTS: Compared to no screening, FIT-screening in the base-case scenario reduced long-term mortality with 51.8%. At a fixed PSPDR of 11%, an increase in ADR from 44 to 62% would result in a 10.7% difference in mortality reduction. Using a fixed ADR of 59%, changing the PSPDR from 3 to 15% did not substantially influence long-term mortality (51.0 to 52.3%). CONCLUSIONS: An increase in ADR gradually reduces CRC burden in a FIT-based screening program, whereas an increase in PSPDR only minimally influences long-term outcomes at a population-level. The limited effect of the PSPDR can be explained by the limited sensitivity of FIT for serrated polyps (SPs). Other triage modalities aiming to detect relevant SPs should be explored.