Post-colonoscopy Colorectal Cancer Research Articles

Beyond the scope: diverticular disease and post-colonoscopy colorectal cancer.

Beyond the scope: diverticular disease and post-colonoscopy colorectal cancer.

Postcolonoscopy colorectal cancer: Prevalence, categorization and root-cause analysis based on the World Endoscopic Organization system

AimsThe World Endoscopy Organization (WEO) recommends that endoscopy units implement a process to identify postcolonoscopy colorectal cancer (PCCRC). The aims of this study were to assess the 3-year PCCRC rate and to perform root-cause analyses and categorization in accordance with the WEO recommendations. Patients and methodsCases of colorectal cancers (CRCs) in a tertiary care center were retrospectively included from January 2018 to December 2019. The 3-year and 4-year PCCRC rates were calculated. A root-cause analysis and categorization of PCCRCs (interval and type A, B, C noninterval PCCRCs) were performed. The level of agreement between two expert endoscopists was assessed. ResultsA total of 530 cases of CRC were included. A total of 33 were deemed PCCRCs (age 75.8±9.5 years; 51.5% women). The 3-year and 4-year PCCRC rates were 3.4% and 4.7%, respectively. The level of agreement between the two endoscopists was acceptable either for the root-cause analysis (k=0.958) or for the categorization (k=0.76).The most plausible explanations of the PCCRCs were 8 “likely new PCCRCs”, 1 (4%) “detected, not resected”, 3 (12%) “detected, incomplete resection”, 8 (32%) “missed lesion, inadequate examination”, and 13 (52%) “missed lesion, adequate examination”. Most PCCRCs were deemed noninterval Type C PCCRCs (N=17, 51.5%). ConclusionWEO recommendations for root-cause analysis and categorization are useful to detect areas for improvement. Most PCCRCs were avoidable and were likely due to missed lesions during an otherwise adequate examination.

Measuring post-colonoscopy colorectal cancers: Variations in methodology to address indicator timeliness and use in high-risk populations

Measuring post-colonoscopy colorectal cancers: Variations in methodology to address indicator timeliness and use in high-risk populations

Type 2 diabetes mellitus and post-colonoscopy colorectal cancer: clinical and molecular characteristics and survival.

Studies suggest that patients with type two diabetes mellitus (T2D) may be at increased risk of post-colonoscopy colorectal cancer (PCCRC). We investigated clinical and molecular characteristics and survival of T2D patients with PCCRC to elucidate how T2D-related PCCRC may arise. We identified T2D patients with colorectal cancer (CRC) from 1995 to 2015 and computed prevalence ratios (PRs) comparing clinical and molecular characteristics of CRC in T2D patients with PCCRC vs. in T2D patients with colonoscopy-detected CRC (dCRC). We also followed T2D patients from the diagnosis of PCCRC/dCRC until death, emigration, or study end and compared mortality using Cox-proportional hazards regression models adjusted for sex, age, year of CRC diagnosis, and CRC stage. Compared with dCRC, PCCRC was associated with a higher prevalence of proximal CRCs (54% vs. 40%; PR: 1.43, 95% confidence interval [CI] 1.27-1.62) in T2D patients. We found no difference between PCCRC vs. dCRC for CRC stage, histology, and mismatch repair status. The proportion of CRCs that could be categorized as PCCRC decreased over time. Within one year after CRC, 63% of PCCRC vs. 78% of dCRC patients were alive (hazard ratio [HR] 1.85 [95% CI 1.47-2.31]). Within five years after CRC, 44% of PCCRC vs. 54% of dCRC patients were still alive (HR 1.44 [95% CI 1.11-1.87]). The increased prevalence of proximally located PCCRCs and the poorer survival may suggest overlooked colorectal lesions as a predominant explanation for T2D-related PCCRC, although altered tumor progression cannot be ruled out.

Risk of a post-colonoscopy colorectal cancer in patients with diverticular disease: a population-based cohort study.

Post-colonoscopy colorectal cancers (PCCRCs) may account for up to 30% of all colorectal cancers (CRCs) diagnosed in patients with diverticular disease; however, absolute and relative risks of PCCRC among these patients undergoing colonoscopy remain unknown. We performed a cohort study (1995-2015) including patients with and without diverticular disease who underwent colonoscopy. We calculated 7-36-month cumulative incidence proportions (CIPs) of PCCRC. We used Cox proportional hazards regression models to compute hazard ratios (HRs) of PCCRC, comparing patients with and without diverticular disease, as a measure of relative risk. We calculated 3-year PCCRC rates, as per World Endoscopy Organization recommendations, to estimate the proportion of CRC patients with and without diverticular disease who were considered to have PCCRC. We stratified all analyses by PCCRC location. We observed 373 PCCRCs among 56 642 patients with diverticular disease and 1536 PCCRCs among 306 800 patients without diverticular disease. The PCCRC CIP after first-time colonoscopy was 0.45% (95%CI 0.40%-0.51%) for patients with and 0.36% (95%CI 0.34%-0.38%) for patients without diverticular disease. Comparing patients with and without diverticular disease undergoing first-time colonoscopy, the adjusted HR was 0.84 (95%CI 0.73-0.97) for PCCRC and 1.23 (95%CI 1.01-1.50) for proximal PCCRCs. The 3-year PCCRC rate was 19.0% (22.3% for proximal PCCRCs) for patients with and 6.5% for patients without diverticular disease. Although the absolute risk was low, the relative risk of proximal PCCRCs may be elevated in patients with diverticular disease undergoing colonoscopy compared with patients without the disease.

Proportions and characteristics of interval cancer in annual fecal immunochemical test screening and postcolonoscopy colorectal cancer: Results from a Japanese multicenter prospective study using questionnaires, the C-DETECT study.

There are several types of colorectal cancer (CRC) according to the detection methods and intervals, including interval CRC (iCRC) and postcolonoscopy CRC (PCCRC). We aimed to examine their proportions and characteristics. We conducted a multicenter prospective study using questionnaires in Japan ("C-DETECT study"), in which differences in CRC characteristics according to detection methods and intervals were examined from consecutive adult patients. Because the annual fecal immunochemical test (FIT) was used in population-based screening, the annual FIT-iCRC was assessed. In total, 1241 CRC patients (1064 with invasive CRC) were included. Annual FIT-iCRC (a), 3-year PCCRC (b), and CRC detected within 1 year after a positive FIT with noncompliance to colonoscopy (c) accounted for 4.5%, 7.0%, and 3.9% of all CRCs, respectively, and for 3.9%, 5.4%, and 4.3% of invasive CRCs, respectively. The comparison among these (a, b, c) and other CRCs (d) demonstrated differences in the proportions of ≥T2 invasion ([a] 58.9%, [b] 44.8%, [c] 87.5%, [d] 73.0%), metastasis ([a] 33.9%, [b] 21.8%, [c] 54.2%, [d] 43.9%), right-sided CRC ([a] 42.9%, [b] 40.2%, [c] 18.8%, [d] 28.6%), and female sex ([a] 53.6%, [b] 49.4%, [c] 27.1%, [d] 41.6%). In metastatic CRC, (a) and (b) showed a higher proportions of BRAF mutations ([a] [b] 12.0%, [c] [d] 3.1%). Annual FIT-iCRC and 3-year PCCRC existed in nonnegligible proportions. They were characterized by higher proportions of right-sided tumors, female sex, and BRAF mutations. These findings suggest that annual FIT-iCRC and 3-year PCCRC may have biological features different from those of other CRCs.

Big data approach in the field of gastric and colorectal cancer research.

Big data is characterized by three attributes: volume, variety,, and velocity. In healthcare setting, big data refers to vast dataset that is electronically stored and managed in an automated manner and has the potential to enhance human health and healthcare system. In this review, gastric cancer (GC) and postcolonoscopy colorectal cancer (PCCRC) will be used to illustrate application of big data approach in the field of gastrointestinal cancer research. Helicobacter pylori (HP) eradication only reduces GC risk by 46% due to preexisting precancerous lesions. Apart from endoscopy surveillance, identifying medications that modify GC risk is another strategy. Population-based cohort studies showed that long-term use of proton pump inhibitors (PPIs) associated with higher GC risk after HP eradication, while aspirin and statins associated with lower risk. While diabetes mellitus conferred 73% higher GC risk, metformin use associated with 51% lower risk, effect of which was independent of glycemic control. Nonetheless, nonsteroidal anti-inflammatory drugs (NA-NSAIDs) are not associated with lower GC risk. CRC can still occur after initial colonoscopy in which no cancer was detected (i.e. PCCRC). Between 2005 and 2013, the rate of interval-type PCCRC-3y (defined as CRC diagnosed between 6 and 36months of index colonoscopy which was negative for CRC) was 7.9% in Hong Kong, with >80% being distal cancers and higher cancer-specific mortality compared with detected CRC. Certain clinical and endoscopy-related factors were associated with PCCRC-3 risk. Medications shown to have chemopreventive effects on PCCRC include statins, NA-NSAIDs, and angiotensin-converting enzyme inhibitors/angiotensin receptor blockers.

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

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. 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. 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. 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.

Clinicopathological features of post-colonoscopy colorectal cancer in patients with Japanese Lynch syndrome: A multicentric retrospective observational study.

79 Background: Due to the high incidence of heterochronic and concurrent colorectal cancer in Lynch syndrome (LS), colonoscopic surveillance is recommended in Japan every 1-2 years. Even with regular colonoscopic surveillance, post-colonoscopy colorectal cancer (PCCRC) often occurs in the intervals between surveillance, but there are currently no reports of the details of PCCRC in LS in Japan. Methods: Of 1756 colonoscopies performed between 2009 and 2018 in 316 patients with a diagnosis of LS confirmed by genetic testing who were enrolled in a nationwide, Japanese, multicentric study conducted by the Committee of Hereditary Colorectal Cancer of the Japanese Society for Cancer and Rectum, 1203 colonoscopies in 256 patients were assessed to determine the clinicopathological characteristics of PCCRC, after including cases of first-time surveillance, previously untreated lesions, and inadequate pretreatment. Then, the incidence of PCCRC was compared between patients with a median surveillance colonoscopy interval &lt; 12 months (group A) and &gt; 12 months (group B). Results: There were 49 cases of PCCRC with a total of 84 lesions. The number of lesions per tumor depth was 66, one, five, seven, four, and one for pTis, pT1, pT1a, pT1b, pT2, and pT3, respectively. Two (2.4%), 20 (23.8%), 21 (25%), four (4.8%), 18 (21.4%), and 19 (22.6%) lesions were localized in the cecum, ascending colon, transverse colon, descending colon, sigmoid colon, and rectum, respectively. In pTis-pT1b, the macroscopic type was 0-IIa in 33 lesions (41.8%), 0-IIc in four lesions (5.1%), 0-IIa+IIc in five lesions (6.3%), 0-IIb in one lesion (1.3%), 0-Is in 15 lesions (19%), 0-Ip in one lesion (1.3%), 0-Isp in 16 lesions (20.3%), and unknown in four lesions. In pT1b-pT3, seven lesions (63.6%) were smaller than 20 mm. In terms of the median interval between surveillance colonoscopies, 130 patients had a median interval &lt; 12 months (group A), and 126 patients had a median interval &gt; 12 months (group B). In groups A and B, PCCRC, metachronous cases, simultaneous cases, and depths than pT1b were observed in 29 (22%) and 20 (16%) cases (p=0.21); 14 (11%) and two (1.6%) cases (p=0.006); six (4.6%) and one (0.8%) case (p=0.22), and six (4.6%) and four (3.2%) cases (p=1), respectively. Conclusions: In PCCRC in Lynch syndrome, invasive carcinomas &lt; 2 cm should be noted. In addition, a surveillance interval of 12 months may be insufficient in patients with LS. Thus, further investigation is warranted.

Post-colonoscopy colorectal cancer: A population-based cohort study of fecal occult blood test-positive colonoscopies

BackgroundData on post-colonoscopy colorectal cancers (PCCRCs) after fecal occult blood test (FOBT)-positive colonoscopies is scarce (guaiac-based (gFOBT) or fecal immunochemical test (FIT)). AimsEvaluate the prevalence and characteristics of PCCRCs in the French gFOBT CRC screening program. MethodsRetrospective population-based cohort study of all gFOBT-positive colonoscopies performed among individuals aged 50–74 between 2003 and 2014 within the CRC screening program organized in the Haut-Rhin (Alsace, France). The main outcome was PCCRC-3y rate. Adenoma detection rates (ADRs) calculated on gFOBT-positive colonoscopies were compared to those calculated on FIT-positive colonoscopies performed by the same gastroenterologists. ResultsOverall, 9106 gFOBT-positive colonoscopies performed by 36 gastroenterologists were included. Sixteen PCCRC-3y and 31 PCCRC-5y were diagnosed (68.8 % and 58.1 % were true interval PCCRCs respectively). The unadjusted PCCRC-3y rate was 2.4 % [95 % confidence interval (CI) 1.4 %-3.9 %]. The risk for PCCRC-5y was significantly higher when the gastroenterologist's ADR was <35 % compared to ≥35 % (HR 2.17 [95 %CI 1.19–3.93]). The mean absolute difference for ADR between gFOBT- and FIT-positive colonoscopies was 16.3 % in favor of FIT-positive colonoscopies. ConclusionPCCRC-3y prevalence was low, estimated at 2.4 %. We suggest that the minimum standard for ADR in gFOBT- and FIT-positive colonoscopies should be set at 35 % and 50 % to 55 % respectively, in the French screening program.

Incidence, characteristics, and predictive factors of post-colonoscopy colorectal cancer.

Post-colonoscopy colorectal cancer (PCCRC) is colorectal cancer (CRC) diagnosed after a colonoscopy in which no cancer is found. As PCCRC has become an important quality indicator, we determined its rates, characteristics, and index colonoscopy-related predictive factors. We carried out a multicenter, observational, retrospective study between 2015 and 2018. Rates were calculated for PCCRC developing up to 10years after colonoscopy. PCCRC was categorized according to the most plausible explanation using World Endoscopy Organization methodology. Our PCCRC population was compared to a control cohort without CRC matched 1:4 by sex, age, index colonoscopy date, indication, endoscopist, and hospital. One hundred seven PCCRC and 2508 detected CRC were diagnosed among 101,524 colonoscopy (0.1%), leading to rates of 0.4%, 2.2%, 3.1%, and 4.1% at 1, 3, 5, and 10years, respectively. PCCRC was in right (42.4%), left (41.4%), and transverse (16.4%) colon with 31.5% at stage I, 24.7% stage II, 32.6% stage III, and 11.2% stage IV. Twenty point three percent were classified as incomplete resection, 5.4% as unresected lesions, 48.6% as missed lesions with adequate colonoscopy, and 25.7% as missed lesions with inadequate colonoscopy. The median time from colonoscopy to PCCRC was 42months. Previous inadequate preparation (OR 3.05, 95%CI 1.73-5.36) and piecemeal polypectomy (OR 19.89, 95%CI 8.67-45.61) were independently associated with PCCRC. In our population, 4.1% of CRC cases were PCCRC. Most of these lesions were in right colon and attributable to lesions not visualized despite adequate bowel cleansing. Previous inadequate cleansing and piecemeal polypectomy were associated with PCCRC.

Genome-wide polygenic risk scores for colorectal cancer have implications for risk-based screening.

Hereditary factors, including single genetic variants and family history, can be used for targeting colorectal cancer (CRC) screening, but limited data exist on the impact of polygenic risk scores (PRS) on risk-based CRC screening. Using longitudinal health and genomics data on 453,733 Finnish individuals including 8801 CRC cases, we estimated the impact of a genome-wide CRC PRS on CRC screening initiation age through population-calibrated incidence estimation over the life course in men and women. Compared to the cumulative incidence of CRC at age 60 in Finland (the current age for starting screening in Finland), a comparable cumulative incidence was reached 5 and 11 years earlier in persons with high PRS (80-99% and >99%, respectively), while those with a low PRS (< 20%) reached comparable incidence 7 years later. The PRS was associated with increased risk of post-colonoscopy CRC after negative colonoscopy (hazard ratio 1.76 per PRS SD, 95% CI 1.54-2.01). Moreover, the PRS predicted colorectal adenoma incidence and improved incident CRC risk prediction over non-genetic risk factors. Our findings demonstrate that a CRC PRS can be used for risk stratification of CRC, with further research needed to optimally integrate the PRS into risk-based screening.

Occurrence of Colorectal Cancer After a Negative Colonoscopy in Patients With Inflammatory Bowel Disease: A Systematic Review and Meta-analysis.

Despite the application of colorectal cancer (CRC) surveillance guidelines, the detection of early neoplastic lesions might be difficult in patients with inflammatory bowel disease (IBD). To explore the risk of post-colonoscopy CRC (PCCRC) in patients with IBD we performed a systematic review and meta-analysis. A systematic literature search was performed (PROSPERO; no. CRD42023453049). We included studies reporting the 3-year PCCRC (PCCRC-3y) prevalence, according to World Endoscopy Organization (WEO)-endorsed definition, in IBD and non-IBD patients. As primary outcome we evaluated the PCCRC-3y prevalence, according to WEO definitions, in IBD- and non-IBD patients and calculated the odds ratio (OR). The secondary outcome was to assess risk factors for PCCRC development in IBD patients. Three retrospective observational cohort studies were included. The pooled PCCRC-3y rate in patients with IBD was 30.8% [95% confidence interval (CI)=24.4-37.5%] and in non-IBD patients was 6.8% (95%CI=6.2-7.4%). The PCCRC-3y occurrence in IBD patients was significantly higher than that in non-IBD patients (OR=6.04; 95%CI=4.04-9.4; I2=95%), but a high heterogeneity among studies was noted. Furthermore, patients with ulcerative colitis (UC) had a significantly higher prevalence of PCCRC than patients with Crohn's Disease (CD): 30.9% (95%CI=27.8-34.2%) vs. 22.3% (95%CI=18-27%), respectively (OR=1.6, 95%CI=1.2-2.2; I2=0%). One-third of CRC in IBD patients were PCCRC, and these numbers were significantly higher when compared with those in non-IBD patients. Furthermore, the prevalence of PCCRC in patients with UC was higher compared to those with CD. However, prospective studies are required to better characterize risk factors for PCCRC development in patients with IBD.

The role of endoscopist adenoma detection rate in in sex differences in colonoscopy findings: cross-sectional analysis of the SCREESCO randomized controlled trial

Background Fewer adenomas are detected at colonoscopy in women compared to men and failure to detect adenomas and sessile serrated polyps is associated with an increased risk of post-colonoscopy colorectal cancer. The aim of this study was to investigate whether this was in part due to the greater difficulty of conducting colonoscopy in women, with the difference being more apparent in colonoscopies conducted by less skilled endoscopists. Material and methods Cross-sectional exploratory analysis of data on 16,551 individuals undergoing a primary colonoscopy (PCOL group) or colonoscopy after positive faecal immunochemical test (FIT group) within the randomized controlled trial SCREESCO. Endoscopist adenoma detection rate (ADR; low or high) was determined based on each endoscopist’s colonoscopies performed in SCREESCO. In each study group, the relationship between the sex difference in colonoscopy outcome and endoscopist ADR was assessed using multiplicative interaction tests. Results Endoscopists performed equally many colonoscopies in men and women (median 52% men). There were no signs of effect modification of the risk ratio of any finding (men vs women) by endoscopist ADR in the PCOL group (p = 0.33) or the FIT group (p = 0.30). The proportion of incomplete index colonoscopies was lower in men than in women in both groups and there was no effect modification by endoscopist ADR in either the PCOL group (p = 0.41) or the FIT group (p = 0.96). Conclusions This study provides no evidence that endoscopist skill measured by ADR underlies the sex difference in adenoma detection at colonoscopy. This study has trial number NCT02078804 and is registered with ClinicalTrials.gov.

Endoscopist adenomas-per-colonoscopy detection rates and risk for postcolonoscopy colorectal cancer: data from the New Hampshire Colonoscopy Registry

Adenomas per colonoscopy (APC) may be a better measure of colonoscopy quality than adenoma detection rate (ADR) because it credits endoscopists for each detected adenoma. There are few data examining the association between APC and postcolonoscopy colorectal cancer (PCCRC) incidence. We used data from the New Hampshire Colonoscopy Registry to examine APC and PCCRC risk. We included New Hampshire Colonoscopy Registry patients with an index examination and at least 1 follow-up event, either a colonoscopy or a colorectal cancer (CRC) diagnosis. Our outcome was PCCRC defined as any CRC diagnosed≥6 months after an index examination. The exposure variable was endoscopist-specific APC quintiles of .25, .40, .50, and .70. Cox regression was used to model the hazard of PCCRC on APC, controlled for age, sex, year of index examination, index findings, bowel preparation, and having more than 1 surveillance examination. In 32,535 patients, a lower hazard for PCCRC (n= 178) was observed for higher APCs as compared to APCs of<.25 (reference): .25 to<.40: hazard ratio (HR), .35; 95% confidence interval (CI), .22-.56; .40 to<.50: HR, .31; 95% CI, .20-.49; .50 to<.70: HR, .20; 95% CI, .11-.36; and≥.70: HR, .19; 95% CI, .09-.37. When examining endoscopists with an ADR of at least 25%, an APC of<.50 was associated with a significantly higher hazard than an APC of≥.50 (HR, 1.65; 95% CI, 1.06-2.56). A large proportion of endoscopists-one-fifth (32 of 152; 21.1%)-had an ADR of≥25% but an APC of<.50. Our novel data demonstrating lower PCCRC risk in examinations performed by endoscopists with higher APCs suggest that APC could be a useful quality measure. Quality improvement programs may identify important deficiencies in endoscopist detection performance by measuring APC for endoscopists with an ADR of≥25%.

Cancer Biology or Ineffective Surveillance? A multicentre retrospective analysis of colitis-associated post-colonoscopy colorectal cancers.

Inflammatory bowel disease (IBD) is associated with high rates of post-colonoscopy colorectal cancer (PCCRC), but further in-depth qualitative analyses are required to determine whether they result from inadequate surveillance or aggressive IBD cancer evolution. All IBD patients who had a colorectal cancer (CRC) diagnosed between January 2015 to July 2019 and a recent (<4 years) surveillance colonoscopy at one of four English hospital trusts underwent root cause analyses as recommended by the World Endoscopy Organisation to identify plausible PCCRC causative factors. 61% (n=22/36) of the included IBD CRCs were PCCRCs. They developed in patients with high cancer risk factors (77.8%; n=28/36) requiring annual surveillance, yet 57.1% (n=20/35) had inappropriately delayed surveillance. Most PCCRCs developed in situations where (i) an endoscopically unresectable lesion was detected (40.9%; n=9/22), (ii) there was a deviation from the planned management pathway (40.9%; n=9/22) e.g. service, clinician or patient-related delays in acting on a detected lesion, or (iii) lesions were potentially missed as they were typically located within areas of active inflammation or post-inflammatory change (36.4%; n=8/22). IBD PCCRC prevention will require more proactive strategies to reduce endoscopic inflammatory burden, improve lesion optical characterisation, adherence to recommended surveillance intervals and patient acceptance of prophylactic colectomy. However, the significant proportion appearing to originate from non-adenomatous-looking mucosa which fail to yield neoplasia on biopsy yet display aggressive cancer evolution highlight the limitations of current surveillance. Emerging molecular biomarkers may play a role in enhancing cancer risk stratification in future clinical practice.

Post-colonoscopy interval colorectal cancer: the dread of every endoscopist

Post-colonoscopy interval colorectal cancer: the dread of every endoscopist

Post-colonoscopy rectal cancer in Swedish patients with Crohn's disease 2001-2015: a population-based case review study.

Post-colonoscopy colorectal cancer (PCCRC) is a key quality indicator of colonoscopy, and PCCRC rates are high in the IBD population. Rectal cancer, an important risk factor for PCCRC among patients with Crohn's disease (CD), has not previously been examined. Swedish adult patients with CD who underwent a colonoscopy within 36 months before a rectal cancer diagnosis between 2001 and 2015 were identified through the National Patient and Cancer registers. Their medical records were reviewed and a root-cause analysis and a sub-categorization according to the World Endoscopic Organization (WEO) were performed. Of 24 patients with CD and PCCRC in the rectum, 79% were men and the median age was 50 (IQR 45-59) years. The median disease duration was 21.5 (IQR 19-30) years. The cancer was located in the distal 5 cm of the rectum in 63% of the cases. Retroversion in the rectum was reported in only one case. The most common plausible explanation for PCCRC was 'possible missed lesion, prior examination adequate' (63%); when adding retroversion in the rectum, instead 77% of examinations were considered negative but deemed as inadequate. The most common PCCRC sub-category was non-interval type C (54%) and B (37%). Among those with type C, 38% should have been included in surveillance according to present guidelines. Better adherence to surveillance guidelines and more meticulous follow-up is warranted. The importance of performing rectal palpation and retroversion in the rectum is underscored and we suggest that this is included in the WEO algorithm.

Artificial intelligence–assisted real-time monitoring of effective withdrawal time during colonoscopy: a novel quality marker of colonoscopy

Background and aimsThe importance of withdrawal time during colonoscopy cannot be overstated in mitigating the risk of missed lesions and post-colonoscopy colorectal cancer. We evaluated a novel colonoscopy quality metric called the effective withdrawal time (EWT), which is an artificial intelligence (AI) derived quantitative measure of quality withdrawal time and their association with various colonic lesions detection rates, as compared with standard withdrawal time (SWT). MethodsA total of 350 video recordings of colonoscopy withdrawal (from caecum to anus) were assessed by the new AI model. The primary outcome was adenoma detection rate (ADR) according to different quintiles of EWT. Multivariate logistic regression, adjusting for baseline covariates, was used to determine the adjusted odd ratios (OR) for EWT on lesion detection rates, with the lowest quintile as reference. The area under the receiver operating characteristic curve (AUC) of EWT was compared with SWT. ResultsThe crude ADR in different quintiles of EWT, from lowest to highest, was 10.0%, 31.4%, 33.3%, 53.5%, and 85.7%, respectively. The ORs of detecting adenoma and polyp were significantly higher in all top 4th quintiles when compared to the lowest quintile. Each minute increase in EWT was associated with a 49% increase in ADR (aOR, 1.49; 95% CI, 1.36 to 1.65). The AUC of EWT was also significantly higher than SWT on adenoma detection (0.80 [95%CI: 0.75 – 0.84] vs 0.70 [95%CI: 0.64-0.74], p <0.01). ConclusionsThe AI-derived EWT monitoring is a promising novel quality indicator for colonoscopy, which is more associated with ADR than SWT.

Interval post-colonoscopy colorectal cancer following a negative colonoscopy in a fecal immunochemical test-based screening program.

In the Dutch colorectal (CRC) screening program, fecal immunochemical test (FIT)-positive individuals are referred for colonoscopy. If no relevant findings are detected at colonoscopy, individuals are reinvited for FIT screening after 10 years. We aimed to assess CRC risk after a negative colonoscopy in FIT-positive individuals. In this cross-sectional cohort study, data were extracted from the Dutch national screening information system. Participants with a positive FIT followed by a negative colonoscopy between 2014 and 2018 were included. A negative colonoscopy was defined as a colonoscopy during which no more than one nonvillous, nonproximal adenoma < 10 mm or serrated polyp < 10 mm was found. The main outcome was interval post-colonoscopy CRC (iPCCRC) risk. iPCCRC risk was reviewed against the risk of interval CRC after a negative FIT (FIT IC) with a 2-year screening interval. 35 052 FIT-positive participants had a negative colonoscopy and 24 iPCCRCs were diagnosed, resulting in an iPCCRC risk of 6.85 (95 %CI 4.60-10.19) per 10 000 individuals after a median follow-up of 1.4 years. After 2.5 years of follow-up, age-adjusted iPCCRC risk was approximately equal to FIT IC risk at 2 years. Risk of iPCCRC within a FIT-based CRC screening program was low during the first years after colonos-copy but, after 2.5 years, was the same as the risk in FIT-negative individuals at 2 years, when they are reinvited for screening. Colonoscopy quality may therefore require further improvement and FIT screening interval may need to be reduced after negative colonoscopy.