Mutational signature profiling classifies subtypes of clinically different mismatch-repair-deficient tumours with a differential immunogenic response potential.

BACKGROUND: Mismatch repair (MMR) deficiency is the hallmark of tumours from Lynch syndrome (LS), sporadic MLH1 hypermethylated and Lynch-like syndrome (LLS), but there is a lack of understanding of the variability in their mutational profiles based on clinical phenotypes. The aim of this study was to perform a molecular characterisation to identify novel features that can impact tumour behaviour and clinical management. METHODS: We tested 105 MMR-deficient colorectal cancer tumours (25 LS, 35 LLS and 45 sporadic) for global exome microsatellite instability, cancer mutational signatures, mutational spectrum and neoepitope load. RESULTS: Fifty-three percent of tumours showed high contribution of MMR-deficient mutational signatures, high level of global exome microsatellite instability, loss of MLH1/PMS2 protein expression and included sporadic tumours. Thirty-one percent of tumours showed weaker features of MMR deficiency, 62% lost MSH2/MSH6 expression and included 60% of LS and 44% of LLS tumours. Remarkably, 9% of all tumours lacked global exome microsatellite instability. Lastly, HLA-B07:02 could be triggering the neoantigen presentation in tumours that show the strongest contribution of MMR-deficient tumours. CONCLUSIONS: Next-generation sequencing approaches allow for a granular molecular characterisation of MMR-deficient tumours, which can be essential to properly diagnose and treat patients with these tumours in the setting of personalised medicine.

Quality of Colonoscopy Is Associated With Adenoma Detection and Postcolonoscopy Colorectal Cancer Prevention in Lynch Syndrome.

BACKGROUND & AIMS: Colonoscopy reduces colorectal cancer (CRC) incidence and mortality in Lynch syndrome (LS) carriers. However, a high incidence of postcolonoscopy CRC (PCCRC) has been reported. Colonoscopy is highly dependent on endoscopist skill and is subject to quality variability. We aimed to evaluate the impact of key colonoscopy quality indicators on adenoma detection and prevention of PCCRC in LS. METHODS: We conducted a multicenter study focused on LS carriers without previous CRC undergoing colonoscopy surveillance (n = 893). Incident colorectal neoplasia during surveillance and quality indicators of all colonoscopies were analyzed. We performed an emulated target trial comparing the results from the first and second surveillance colonoscopies to assess the effect of colonoscopy quality indicators on adenoma detection and PCCRC incidence. Risk analyses were conducted using a multivariable logistic regression model. RESULTS: The 10-year cumulative incidence of adenoma and PCCRC was 60.6% (95% CI, 55.5%-65.2%) and 7.9% (95% CI, 5.2%-10.6%), respectively. Adequate bowel preparation (odds ratio [OR], 2.07; 95% CI, 1.06-4.3), complete colonoscopies (20% vs 0%; P = .01), and pan-chromoendoscopy use (OR, 2.14; 95% CI, 1.15-3.95) were associated with significant improvement in adenoma detection. PCCRC risk was significantly lower when colonoscopies were performed during a time interval of less than every 3 years (OR, 0.35; 95% CI, 0.14-0.97). We observed a consistent but not significant reduction in PCCRC risk for a previous complete examination (OR, 0.16; 95% CI, 0.03-1.28), adequate bowel preparation (OR, 0.64; 95% CI, 0.17-3.24), or previous use of high-definition colonoscopy (OR, 0.37; 95% CI, 0.02-2.33). CONCLUSIONS: Complete colonoscopies with adequate bowel preparation and chromoendoscopy use are associated with improved adenoma detection, while surveillance intervals of less than 3 years are associated with a reduction of PCCRC incidence. In LS, high-quality colonoscopy surveillance is of utmost importance for CRC prevention.

Clinical and Pathological Characterization of Lynch-Like Syndrome.

BACKGROUND & AIMS: Lynch syndrome is characterized by DNA mismatch repair (MMR) deficiency. Some patients with suspected Lynch syndrome have DNA MMR deficiencies but no detectable mutations in genes that encode MMR proteins-this is called Lynch-like syndrome (LLS). There is no consensus on management of patients with LLS. We collected data from a large series of patients with LLS to identify clinical and pathology features. METHODS: We collected data from a nationwide-registry of patients with colorectal cancer (CRC) in Spain. We identified patients whose colorectal tumors had loss of MSH2, MSH6, PMS2, or MLH1 (based on immunohistochemistry), without the mutation encoding V600E in BRAF (detected by real-time PCR), and/or no methylation at MLH1 (determined by methylation-specific multiplex ligation-dependent probe amplification), and no pathogenic mutations in MMR genes, BRAF, or EPCAM (determined by DNA sequencing). These patients were considered to have LLS. We collected data on demographic, clinical, and pathology features and family history of neoplasms. The χ2 test was used to analyze the association between qualitative variables, followed by the Fisher exact test and the Student t test or the Mann-Whitney test for quantitative variables. RESULTS: We identified 160 patients with LLS; their mean age at diagnosis of CRC was 55 years and 66 patients were female (41%). The Amsterdam I and II criteria for Lynch syndrome were fulfilled by 11% of cases and the revised Bethesda guideline criteria by 65% of cases. Of the patients with LLS, 24% were identified in universal screening. There were no proportional differences in sex, indication for colonoscopy, immunohistochemistry, pathology findings, or personal history of CRC or other Lynch syndrome-related tumors between patients who met the Amsterdam and/or Bethesda criteria for Lynch syndrome and patients identified in universal screening for Lynch syndrome, without a family history of CRC. CONCLUSIONS: Patients with LLS have homogeneous clinical, demographic, and pathology characteristics, regardless of family history of CRC.

Cuff-assisted versus cap-assisted colonoscopy for adenoma detection: results of a randomized study.

BACKGROUND: The adenoma detection rate (ADR) is the most important marker of colonoscopy quality. Devices to improve adenoma detection have been developed, such as the Endocuff and transparent cap. The aim of the current study was to examine whether there was a difference in ADR between Endocuff-assisted (EAC) and cap-assisted colonoscopy (CAC). METHODS: A randomized prospective trial was conducted. Eligible patients included adults ≥ 18 years referred because of symptoms, surveillance, or colonoscopies as part of the Bowel Cancer Screening Programme (BCSP). The primary outcome measure was ADR. Secondary outcomes included mean number of adenomas, mean number of polyps, polyp detection rate, cecal intubation rate, and time to cecal intubation. Procedural measures, device removal rate, and adverse events were also recorded. RESULTS: A total of 711 patients (51.1 % men; median age 63 years) were included, of whom 357 patients were randomized to EAC and 354 patients to CAC. In the intention-to-treat analysis, the ADR was similar in both groups: EAC 50.4 % (95 % confidence interval [CI] 45.1 - 55.7) vs. CAC 50.6 % (95 %CI 45.2 - 55.9). Similar results were obtained in the per-protocol analysis: EAC 51.6 % (95 %CI 46.2 - 57) vs. CAC 51.4 % (95 %CI 46 - 56.8). There were no differences between the two devices in ADR according to the mean number of adenomas and polyps per procedure, polyp detection rate, cecal intubation rate, and time to cecal intubation. Device removal rate and adverse events were also similar. CONCLUSION: In this randomized study, no differences in ADR were found between Endocuff- and cap-assisted colonoscopy.

Accuracy for optical diagnosis of colorectal polyps in clinical practice.

BACKGROUND: Optical diagnostic involves predicting polyp histopathology from its endoscopic characteristics. It is only recommended for diminutive polyps ( < or = 5 mm) and for predictions made with high confidence. OBJECTIVES: To evaluate the accuracy of optical imaging in clinical practice and to assess if optical diagnosis is useful for predicting future colonoscopy surveillance intervals without waiting for histopathological analysis. METHODS: consecutive > 18 years patients were enrolled in this prospective study. Colonoscopies were performed by five expert endoscopists who previously participated in an ex-vivo training. Colonoscopes CF-H180AL and CF-Q180AL were used together with Exera II (Olympus Medical System, Tokyo, Japan) processors. Each polyp was characterized in real time using white light and Narrow Band Imaging. Accuracy of optical diagnosis (S, E, NPV, PPV) and correlation between surveillance interval based on optical diagnosis and histopathological analysis were calculated. RESULTS: 311 colon polyps < 10 mm (216 diminutive) in 195 patients were analyzed. Accuracy of optical diagnostics for predictions made with high confidence: Diminutive polyps(sensitivity 0.59, specificity 0.92, NPV 0.48); polyps < 10 mm (sensitivity 0.73, specificity 0.88, NPV 0.50). An optical diagnosis based surveillance recommendation was given to 90 patients. Concordance with histopathology based recommendation was 92.2% according to the European guideline and 93.3% according to the ESGE guideline. CONCLUSIONS: Optical diagnostics can be used to predict future surveillance intervals immediately after colonoscopy. However, in this study, based on clinical practice, the accuracy of optical imaging is below the recommended standards.

Factors related to the effectiveness of variable stiffness colonoscope: results of a multivariate analysis.

BACKGROUND: Various studies and two meta-analysis have shown that a variable stiffness colonoscope improves cecal intubation rate. However, there are few studies on how this colonoscope should be used. OBJECTIVE: The aim of this study was to identify factors related to the advancement of the colonoscope when the variable stiffness function is activated. METHODS: Prospective study enrolling consecutive patients referred for colonoscopy. The variable stiffness colonoscope (Olympus CF-H180DI/L®) was used. We performed univariate and multivariate analyses of factors associated with the success of the variable stiffness function. RESULTS: After the data inclusion period, 260 patients were analyzed. The variable stiffness function was used most in the proximal colon segments (ascending and transverse colon 85%; descending/sigmoid colon 15.2%). The body mass index was lower in patients in whom the endoscope advanced after activating the variable stiffness than those in which it could not be advanced (25.9 + or - 4.8 vs. 28.3 + or - 5.4 kg/m2, p = 0.009). The endoscope advanced less frequently when the stiffness function was activated in the ascending colon versus activation in other segments of the colon (25% vs. 64.5% ascending colon vs. other segments; p < 0.05). In the multivariate analysis, only the colon segment in which the variable stiffness was activated was an independent predictor of advancement of the colonoscope. CONCLUSIONS: The variable stiffness function is effective, allowing the colonoscope advancement especially when applied in the transverse colon, descending colon and sigmoid. However, when used in the ascending colon it has a lower effectiveness.

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

BACKGROUND: Post-colonoscopy colorectal cancer (PCCRC) is colorectal cancer (CRC) diagnosed after a colonoscopy in which no cancer is found. OBJECTIVE: As PCCRC has become an important quality indicator, we determined its rates, characteristics, and index colonoscopy-related predictive factors. METHODS: We carried out a multicenter, observational, retrospective study between 2015 and 2018. Rates were calculated for PCCRC developing up to 10 years 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. RESULTS: 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 10 years, 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 42 months. 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. CONCLUSIONS: 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.

Risk of Cancer in Family Members of Patients with Lynch-Like Syndrome.

Lynch syndrome (LS) is a common cause of hereditary colorectal cancer (CRC). Some CRC patients develop mismatch repair deficiency without germline pathogenic mutation, known as Lynch-like syndrome (LLS). We compared the risk of CRC in first-degree relatives (FDRs) in LLS and LS patients. LLS was diagnosed when tumors showed immunohistochemical loss of MSH2, MSH6, and PMS2; or loss of MLH1 with BRAF wild type; and/or no MLH1 methylation and absence of pathogenic mutation in these genes. CRC and other LS-related neoplasms were followed in patients diagnosed with LS and LLS and among their FDRs. Standardized incidence ratios (SIRs) were calculated for CRC and other neoplasms associated with LS among FDRs of LS and LLS patients. In total, 205 LS (1205 FDRs) and 131 LLS families (698 FDRs) had complete pedigrees. FDRs of patients with LLS had a high incidence of CRC (SIR, 2.08; 95% confidence interval (CI), 1.56-2.71), which was significantly lower than that in FDRs of patients with LS (SIR, 4.25; 95% CI, 3.67-4.90; p < 0.001). The risk of developing other neoplasms associated with LS also increased among FDR of LLS patients (SIR, 2.04; 95% CI, 1.44-2.80) but was lower than that among FDR of patients with LS (SIR, 5.01, 95% CI, 4.26-5.84; p < 0.001). FDRs with LLS have an increased risk of developing CRC as well as LS-related neoplasms, although this risk is lower than that of families with LS. Thus, their management should take into account this increased risk.

The Colonoscopy Satisfaction and Safety Questionnaire (CSSQP) for Colorectal Cancer Screening: A Development and Validation Study.

Colonoscopy services working in colorectal cancer screening programs must perform periodic controls to improve the quality based on patients' experiences. However, there are no validated instruments in this setting that include the two core dimensions for optimal care: satisfaction and safety. The aim of this study was to design and validate a specific questionnaire for patients undergoing screening colonoscopy after a positive fecal occult blood test, the Colonoscopy Satisfaction and Safety Questionnaire based on patients' experience (CSSQP). The design included a review of available evidence and used focus groups to identify the relevant dimensions to produce the instrument (content validity). Face validity was analyzed involving 15 patients. Reliability and construct and empirical validity were calculated. Validation involved patients from the colorectal cancer screening program at two referral hospitals in Spain. The CSSQP version 1 consisted of 15 items. The principal components analysis of the satisfaction items isolated three factors with saturation of elements above 0.52 and with high internal consistency and split-half readability: Information, Care, and Service and Facilities features. The analysis of the safety items isolated two factors with element saturations above 0.58: Information Gaps and Safety Incidents. The CSSQP is a new valid and reliable tool for measuring patient' experiences, including satisfaction and safety perception, after a colorectal cancer screening colonoscopy.

Gastrointestinal Hemorrhage Secondary to Duodenal Cystic Dystrophy in Heterotopic Pancreas.

Cystic dystrophy of the duodenal wall (CDDW) is a complication of heterotopic pancreatic tissue located in the wall of the gastrointestinal tract, characterized by the presence of multiple small cysts, usually found in the wall of the second part of the duodenum. Gastrointestinal hemorrhage due to CDDW is a rare complication. We report the case of a 50-year-old man who was admitted to our hospital for persistent vomiting. The imaging tests confirmed the diagnosis of CDDW. During his stay in hospital, the patient had a gastrointestinal hemorrhage secondary to this disorder, which made it necessary to perform a Roux-en-Y gastrojejunostomy (Billroth III).

Does the use of a variable stiffness colonoscope offer advantages during colonoscopy under deep sedation? Results of a randomized trial.

INTRODUCTION: Variable stiffness colonoscope may be useful in performing colonoscopies in nonsedated patients or under endoscopist-controlled sedation. The objective of this study is to evaluate whether this instrument facilitates colonoscopy in patients under deep sedation monitored by an anaesthesiologist. METHODS: Prospective and randomized study enroling consecutive patients referred for colonoscopy under deep sedation monitored by an anaesthesiologist. In group I, a variable stiffness colonoscope was used, whereas in group II, a standard colonoscope was used. The main variable was the need to change the position of the patient during the endoscopy. RESULTS: Fifty-six patients were included in group I (variable stiffness colonoscope) and 54 in group II (standard colonoscope). The caecum was reached in 92.9% of patients in group I and in 90.7% of group II (P=0.7). The time required to reach the caecum was significantly less in group I (6.14±3.5 vs. 7.7±3.8; P=0.035). The variable stiffness colonoscope was effective in 66.7% of cases. Changing the position of the patient was necessary in 12.5% of cases in group I compared with 33.3% of cases in group II (P=0.01). CONCLUSION: The variable stiffness colonoscope avoids the need to change the patient's position and reduces caecal intubation time in patients undergoing colonoscopy under deep sedation controlled by an anaesthesiologist.