Abstract 2925: Distribution of copy number alterations defines clonal populations involved in colorectal cancer evolution

Colorectal cancer progresses in a multi-step manner with adenoma being the most well-known precursor lesion. Malignant polyp, an adenoma that contains a focus of adenocarcinoma, is a suitable model to study the colorectal tumor evolution. Although the mutations that lead adenoma to evolve into carcinoma have been previously described, the copy number changes involved in this malignant transformation have not been fully explored. To understand how these genomic alterations contribute to carcinogenesis, we used sequential fluorescence in situ hybridization using probes for the oncogenes EGFR, MYC, CDX2, and ZNF217 and the tumor suppressor genes SMAD7 and APC in order to analyze the copy number changes in 23 cases of malignant polyps and 10 cases of low grade dysplasia (LGD) adenomas based on single cell analyses. We found the levels of genomic heterogeneity increased from LGD adenomas to malignant polyps, with the adenoma component having a lower degree of chromosomal instability than the adenocarcinoma component. Despite the intercellular heterogeneity, we observed different patterns of evolution. The gain of ZNF217 was the earliest event as it was found to be in some cases of the LGD adenoma, and was also important in the neoplastic transformation of malignant polyps. Other notable genomic imbalances we observed during the malignant transformation were the gain of CDX2 and the loss of SMAD7. Interestingly, in a significant proportion of cases we observed the gain of all loci analyzed to be the decisive step in the transition from adenoma to carcinoma, suggesting a whole genome duplication event. Lastly, in half of the malignant polyps studied the main clone in the carcinoma component was already present in the adjacent adenoma component, although in some cases at a low frequency only detected by single cell analysis. Our data suggest that copy number changes are early events in colorectal carcinogenesis that can determine the evolution from adenoma to carcinoma.

Citation Format: Isabel Quintanilla, Elena Asensio, Maria Pellisé, Antoni Castells, Miriam Cuatrecasas, Jordi Camps. Distribution of copy number alterations defines clonal populations involved in colorectal cancer evolution [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 2925. doi:10.1158/1538-7445.AM2017-2925

Quality indicators for esophagogastroduodenoscopy: A comparative study of outcomes after an improvement programme in a tertiary hospital

INTRODUCTION

There is an opportunity for improvement in the recording and measuring of quality indicators. However, no previous experiences exist in our field in terms of their compliance in esophagogastroduodenoscopy (EGD).

OBJECTIVE

To analyse compliance with EGD quality criteria and evaluate improvement after conducting a training programme.

PATIENTS AND METHODS

Comparative study of 2 cohorts: one retrospective (control group) and one prospective (intervention group), before and after a training programme consisting of an information session and the report writing improvement programme. The quality indicators proposed by the American Society for Gastrointestinal Endoscopy and the American College of Gastroenterology were used.

RESULTS

A total of 1,200 EGDs were included in a sequential manner (600 in each group). Following the training programme, a significant improvement was observed in the following indicators: documented indication (93 vs. 99.8%; P<0.01), documented full examinations (94.7 vs. 97.3%; P<0.01), correct performance (63.7 vs. 87.9%; P<0.01), appropriate biopsies according to protocols (57.9 vs. 83.8%; P<0.01), photo-documentation of described lesions (84.1 vs. 94.9%; P<0.01), photo-documentation per segment (52.9 vs. 70.5%; P<0.01) and correct overall assessment (56,9 vs. 90.5%; P<0.01). Biopsies for coeliac disease, documented indication, full examination and correct performance, if it went ahead, exceeded the recommended standard.

CONCLUSION

A very simple training programme improves EGD quality indicators, with the majority reaching the standards recommended by the American Society for Gastrointestinal Endoscopy and the American College of Gastroenterology.

Rationale and design of the European Polyp Surveillance (EPoS) trials

BACKGROUND

Current guidelines recommend surveillance colonoscopies after polyp removal depending on the number and characteristics of polyps, but there is a lack of evidence supporting the recommendations. This report outlines the rationale and design of two randomized trials and one observational study investigating evidence-based surveillance strategies following polyp removal. Study design and endpoints: The EPoS studies started to recruit patients in April 2015. EPoS study I randomizes 13 746 patients with low-risk adenomas (1 - 2 tubular adenomas size < 10 mm, low-grade dysplasia) to surveillance after 5 and 10 years, or 10 years only. EPoS study II randomizes 13 704 patients with high-risk adenomas (3 - 10 adenomas or adenoma ≥ 10 mm in diameter, or adenoma with high-grade dysplasia, or > 25 % villous features) to surveillance after 3, 5, and 10 years, or 5 and 10 years only. EPoS study III offers surveillance after 5 and 10 years to patients with serrated polyps ≥ 10 mm in diameter at any location, or serrated polyps ≥ 5 mm in diameter proximal to the splenic flexure. All polyps are removed before patients enter the trials. The primary end point is colorectal cancer incidence after 10 years. We assume a colorectal cancer risk of 1 % for patients in EPoS I, and 2 % for patients in EPoS II. Using a noninferiority hypothesis with an equivalence interval of 0.5 % for EPoS I and 0.7 % for EPoS II, the trials are 90 % powered to uncover differences larger than the equivalence intervals. For EPoS III, no power analyses have been performed.

CONCLUSIONS

The present trials aim to develop evidence-based strategies for polyp surveillance, thereby maximizing effectiveness and minimizing resources.

TRIAL REGISTRATION

ClinicalTrials.gov (NCT02319928).

Genetic Variants Associated with Colorectal Adenoma Susceptibility

Background

Common low-penetrance genetic variants have been consistently associated with colorectal cancer risk.

Aim

To determine if these genetic variants are associated also with adenoma susceptibility and may improve selection of patients with increased risk for advanced adenomas and/or multiplicity (≥ 3 adenomas).

Methods

We selected 1,326 patients with increased risk for advanced adenomas and/or multiplicity and 1,252 controls with normal colonoscopy from population-based colorectal cancer screening programs. We conducted a case-control association study analyzing 30 colorectal cancer susceptibility variants in order to investigate the contribution of these variants to the development of subsequent advanced neoplasia and/or multiplicity.

Results

We found that 14 of the analyzed genetic variants showed a statistically significant association with advanced adenomas and/or multiplicity: the probability of developing these lesions increased with the number of risk alleles reaching a 2.3-fold risk increment in individuals with ≥ 17 risk alleles.

Conclusions

Nearly half of the genetic variants associated with colorectal cancer risk are also related to advanced adenoma and/or multiplicity predisposition. Assessing the number of risk alleles in individuals within colorectal cancer screening programs may help to identify better a subgroup with increased risk for advanced neoplasia and/or multiplicity in the general population.

Endoscopist characteristics that influence the quality of colonoscopy

BACKGROUND AND STUDY AIM

Several factors have been shown to be related to colonoscopy quality; however, little is known about the effects of endoscopist factors. This study analyzed the influence of endoscopist-related characteristics on quality indicators for colonoscopy.

PATIENTS AND METHODS

The study included 48 endoscopists who each performed at least 20 colonoscopies in the colonoscopy arm of a randomized controlled trial comparing fecal immunochemical test vs. colonoscopy in colorectal cancer screening. These endoscopists performed a total of 3838 procedures in the trial. The following were calculated for each endoscopist: adenoma detection rate (ADR), advanced ADR, proximal ADR, distal ADR, and adenoma per colonoscopy rate (APCR). The characteristics of endoscopists were assessed with regard to colonoscopy quality using multivariate regression analysis. Endoscopist characteristics included age, sex, exclusive endoscopy practice, years as a physician, years as a specialist, specialty, total (life-long) number of colonoscopies performed, annual colonoscopy volume, number of hours/week dedicated to endoscopy and number of educational activities in the previous year.

RESULTS

Factors associated with ADR were age of the endoscopist (odds ratio [OR] 1.11, 95 % confidence interval [CI] 1.01 - 1.21; P = 0.01) and life-long number of colonoscopies (OR 1.06, 95 %CI 1.01 - 1.11; P = 0.01). Only exclusive dedication to endoscopy practice was found to be independently related to proximal ADR (OR 1.71, 95 %CI 1.15 - 2.74; P = 0.001). Life-long number of colonoscopies was independently related to detection of distal adenomas (OR 1.07, 95 %CI 1.01 - 1.13; P = 0.01). None of the analyzed endoscopist characteristics was associated with advanced ADR or APCR.

CONCLUSIONS

This study found that the experience of the endoscopist and exclusive dedication to endoscopy practice, but not annual colonoscopy volume, were associated with better colonoscopy quality.

The influence of clips on scars after EMR: clip artifact

BACKGROUND AND AIMS

Laterally spreading lesions ≥20 mm are conventionally removed by EMR. Endoscopic clips are increasingly used to mitigate the risk of delayed bleeding. Clips may alter the endoscopic appearance of the scar after EMR, interfering with the assessment of adenoma recurrence. We aimed to evaluate this.

METHODS

Prospective, single-center data from the Australian Colonic Endoscopic resection study (January 2011-May 2015) were analyzed. Patients undergoing EMR of laterally spreading lesions with endoscopic clips used at the EMR defect were eligible. Data included patient and lesion characteristics and procedural, clinical, and histologic outcomes.

RESULTS

Clips were used in 111 of 885 lesions (12.5%). A total of 62 of 111 clipped lesions had standardized, high-definition, white light, and narrow-band images of the scars after EMR at first surveillance colonoscopy, and the patients were enrolled. Analysis of the images showed 4 situations: a bland scar (N = 27), residual adenoma (N = 6), mucosal elevation with normal pit pattern (N = 14), or granulation tissue related to the presence of residual clips (N = 15). The latter 2 entities were termed post-EMR scar clip artifact (ESCA). Overall, 29 of 62 previously clipped EMR sites (46.8%) had ESCA at a median follow-up of 5.2 months. Twenty scars had residual clips, and 15 of 20 (75.0%) showed ESCA (P = .002). Lesions clipped for prophylaxis of bleeding were more likely to show ESCA than those clipped for deep mural injury or intraprocedural bleeding (65.5% vs 41.7%; P = .006). ESCA was associated with female sex (P = .010) and greater age (P = .011).

CONCLUSIONS

ESCA is characterized by a nodular elevation of the mucosa with a normal pit pattern and can occur with or without residual clips. Prophylactic clip closure and the presence of residual clips are associated with ESCA. (

CLINICAL TRIAL REGISTRATION NUMBER

NCT01368289.).

Rate of detection of advanced neoplasms in proximal colon by simulated sigmoidoscopy vs fecal immunochemical tests

BACKGROUND & AIMS

We compared the ability of biennial fecal immunochemical testing (FIT) and one-time sigmoidoscopy to detect colon side-specific advanced neoplasms in a population-based, multicenter, nationwide, randomized controlled trial.

METHODS

We identified asymptomatic men and women, 50-69 years old, through community health registries and randomly assigned them to groups that received a single colonoscopy examination or biennial FIT. Sigmoidoscopy yield was simulated from results obtained from the colonoscopy group, according to the criteria proposed in the UK Flexible Sigmoidoscopy Trial for colonoscopy referral. Patients who underwent FIT and were found to have ≥75 ng hemoglobin/mL were referred for colonoscopy. Data were analyzed from 5059 subjects in the colonoscopy group and 10,507 in the FIT group. The main outcome was rate of detection of any advanced neoplasm proximal to the splenic flexure.

RESULTS

Advanced neoplasms were detected in 317 subjects (6.3%) in the sigmoidoscopy simulation group compared with 288 (2.7%) in the FIT group (odds ratio for sigmoidoscopy, 2.29; 95% confidence interval, 1.93-2.70; P = .0001). Sigmoidoscopy also detected advanced distal neoplasia in a higher percentage of patients than FIT (odds ratio, 2.61; 95% confidence interval, 2.20-3.10; P = .0001). The methods did not differ significantly in identifying patients with advanced proximal neoplasms (odds ratio, 1.17; 95% confidence interval, 0.78-1.76; P = .44). This was probably due to the lower performance of both strategies in detecting patients with proximal lesions (sigmoidoscopy detected these in 19.1% of patients and FIT in 14.9% of patients) vs distal ones (sigmoidoscopy detected these in 86.8% of patients and FIT in 33.5% of patients). Sigmoidoscopy, but not FIT, detected proximal lesions in lower percentages of women (especially those 50-59 years old) than men.

CONCLUSIONS

Sigmoidoscopy and FIT have similar limitations in detecting advanced proximal neoplasms, which depend on patients' characteristics; sigmoidoscopy underperforms for women 50-59 years old. Screening strategies should be designed on the basis of target population to increase effectiveness and cost-effectiveness. ClinicalTrials.gov number: NCT00906997.

Advanced imaging for detection and differentiation of colorectal neoplasia: European Society of Gastrointestinal Endoscopy (ESGE) Guideline

MAIN RECOMMENDATIONS

1 ESGE suggests the routine use of high definition white-light endoscopy systems for detecting colorectal neoplasia in average risk populations (weak recommendation, moderate quality evidence). 2 ESGE recommends the routine use of high definition systems and pancolonic conventional or virtual (narrow band imaging [NBI], i-SCAN) chromoendoscopy in patients with known or suspected Lynch syndrome (strong recommendation, low quality evidence). 2b ESGE recommends the routine use of high definition systems and pancolonic conventional or virtual (NBI) chromoendoscopy in patients with known or suspected serrated polyposis syndrome (strong recommendation, low quality evidence). 3 ESGE recommends the routine use of 0.1 % methylene blue or 0.1 % - 0.5 % indigo carmine pancolonic chromoendoscopy with targeted biopsies for neoplasia surveillance in patients with long-standing colitis. In appropriately trained hands, in the situation of quiescent disease activity and adequate bowel preparation, nontargeted, four-quadrant biopsies can be abandoned (strong recommendation, high quality evidence). 4 ESGE suggests that virtual chromoendoscopy (NBI, FICE, i-SCAN) and conventional chromoendoscopy can be used, under strictly controlled conditions, for real-time optical diagnosis of diminutive (≤ 5 mm) colorectal polyps to replace histopathological diagnosis. The optical diagnosis has to be reported using validated scales, must be adequately photodocumented, and can be performed only by experienced endoscopists who are adequately trained and audited (weak recommendation, high quality evidence). 5 ESGE suggests the use of conventional or virtual (NBI) magnified chromoendoscopy to predict the risk of invasive cancer and deep submucosal invasion in lesions such as those with a depressed component (0-IIc according to the Paris classification) or nongranular or mixed-type laterally spreading tumors (weak recommendation, moderate quality evidence).

CONCLUSION

Advanced imaging techniques will need to be applied in specific patient groups in routine clinical practice and to be taught in endoscopic training programs.

Multiple sporadic colorectal cancers display a unique methylation phenotype

Epigenetics are thought to play a major role in the carcinogenesis of multiple sporadic colorectal cancers (CRC). Previous studies have suggested concordant DNA hypermethylation between tumor pairs. However, only a few methylation markers have been analyzed. This study was aimed at describing the epigenetic signature of multiple CRC using a genome-scale DNA methylation profiling. We analyzed 12 patients with synchronous CRC and 29 age-, sex-, and tumor location-paired patients with solitary tumors from the EPICOLON II cohort. DNA methylation profiling was performed using the Illumina Infinium HM27 DNA methylation assay. The most significant results were validated by Methylight. Tumors samples were also analyzed for the CpG Island Methylator Phenotype (CIMP); KRAS and BRAF mutations and mismatch repair deficiency status. Functional annotation clustering was performed. We identified 102 CpG sites that showed significant DNA hypermethylation in multiple tumors with respect to the solitary counterparts (difference in β value ≥0.1). Methylight assays validated the results for 4 selected genes (p = 0.0002). Eight out of 12(66.6%) multiple tumors were classified as CIMP-high, as compared to 5 out of 29(17.2%) solitary tumors (p = 0.004). Interestingly, 76 out of the 102 (74.5%) hypermethylated CpG sites found in multiple tumors were also seen in CIMP-high tumors. Functional analysis of hypermethylated genes found in multiple tumors showed enrichment of genes involved in different tumorigenic functions. In conclusion, multiple CRC are associated with a distinct methylation phenotype, with a close association between tumor multiplicity and CIMP-high. Our results may be important to unravel the underlying mechanism of tumor multiplicity.

Pancreatitis-associated protein does not predict disease relapse in inflammatory bowel disease patients

Background

The pancreatitis-associated protein (PAP) is increased in the serum of active inflammatory bowel disease (IBD) patients and its levels seem to be correlated with disease activity. Our aim was to evaluate the usefulness of serum and fecal PAP measurements to predict relapse in patients with inactive IBD.

Materials and Methods

We undertook a 12-month prospective study that included 66 Crohn's disease (CD) and 74 ulcerative colitis (UC) patients. At inclusion, patients were in clinical remission, defined by a Harvey-Bradshaw (HB) Index≤4 (CD) or a partial Mayo Score (MS)<3 (UC), along with a normal serum C reactive protein (CRP) and fecal calprotectin. Patients were followed every 3 months. Blood and stool samples were collected and a clinical evaluation was performed at each visit. Serum PAP and CRP levels as well as fecal concentrations of PAP and calprotectin were assessed.

Results

Active CD patients had an increased mean serum PAP at the diagnosis of the flare (104.1 ng/ml) and 3 months prior to activity (22.68 ng/ml) compared with patients in remission (13.26 ng/ml), p<0.05. No significant change in serum PAP levels in UC and fecal PAP levels in CD and UC were detected during disease activity. In CD, serum PAP was a poor diagnostic predictor of disease activity, with an AUC of 0.69. In patients in remission, fecal PAP was barely detectable in UC compared with CD patients.

Conclusion

Serum PAP is increased only in active CD patients, but this marker does not predict disease activity. Inactive UC patients have marked low levels of PAP in fecal samples compared with CD patients.

LINE-1 hypomethylation is neither present in rectal aberrant crypt foci nor associated with field defect in sporadic colorectal neoplasia

Background

Aberrant crypt foci (ACF) are considered the first identifiable preneoplastic lesion in colorectal cancer (CRC), and have been proposed as a potential biomarker for CRC risk. Global DNA hypomethylation is an early event in colorectal carcinogenesis, and long interspersed nuclear element-1 (LINE-1) methylation status is a well-known surrogate marker for genome-wide DNA methylation levels. Despite the gradual increase in DNA hypomethylation in the adenoma–carcinoma sequence, LINE-1 methylation in ACF has never been studied. Moreover, recent studies have reported a field defect for LINE-1 hypomethylation, suggesting that LINE-1 methylation status in normal mucosa could be used to stratify CRC risk and tailor preventive strategies. Thus, we assessed LINE-1 status by pyrosequencing in rectal ACF and paired normal colorectal mucosa from individuals with sporadic colon cancer (CC) (n = 35) or adenoma (n = 42), and from healthy controls (n = 70).

Findings

Compared with normal mucosa, LINE-1 in ACF were hypermethylated across all groups (P < 0.0001). Furthermore, LINE-1 methylation status in normal colorectal mucosa was independent of the presence of adenoma or CC (P = 0.1072), and did not differ depending on the distance to the adenoma or CC. Interestingly, when we compared the LINE-1 methylation status in normal mucosa from different segments of the colorectum, we found higher hypomethylation in the rectum compared with the descending colon (P < 0.0001).

Conclusions

Overall, our results suggest that global hypomethylation is not present in rectal ACF and argues against the existence of LINE-1 methylation field defect in sporadic colon cancer.

Electronic supplementary material

The online version of this article (doi:10.1186/1868-7083-6-24) contains supplementary material, which is available to authorized users.

Overcoming challenges in IBD management: management of colonic dysplastic lesions

The aim of any screening or surveillance program must be to identify early lesions to enable treatment and prevention before the development of invasive cancer. A surveillance program must be acceptable to patients and practically possible to implement. There is a move away from using random colonic biopsies towards targeted biopsies aimed at abnormal areas identified by newer colonoscopic techniques (narrow band imaging, chromoendoscopy, confocal microendoscopy). However, the attitude towards a patient with a dysplastic lesion is not well established. Bowel cancer screening in the general population relies on identification of adenomatous lesions which can be resected before they transform into carcinoma. The therapeutic approach to such lesions, the patient groups at risk and the intervals of surveillance are reasonably established. In contrast, inflammatory bowel disease (IBD)-colorectal cancer (CRC) poses different challenges: dysplastic lesions do not follow the adenoma-carcinoma sequence, they can be difficult to see (flat lesions), difficult to resect completely, and multifocal. Prophylactic proctocolectomy eliminates the risk of CRC, but this strategy is not acceptable to most patients or physicians. Moreover, IBD patients can harbor dysplastic lesions related to the sporadic CRC pathway, the clinical significance of which differs clearly from colitis-associated dysplastic lesions. Nowadays, therapeutic recommendations for the management of dysplasia in IBD are based on macroscopic pattern and microscopic characteristics. As an example, consensus guidelines state that adenoma-like lesions can be adequately treated by polypectomy unlike non-adenoma-like raised lesions or flat high-grade dysplasia that should undergo colectomy. The present article is aimed to summarize the existing evidence on this thorny matter.

Consensus guidelines for the use of bowel preparation prior to colonic diagnostic procedures: colonoscopy and small bowel video capsule endoscopy

BACKGROUND

Adequate bowel preparation prior to colonic diagnostic procedures is essential to ensure adequate visualisation.

SCOPE

This consensus aims to provide guidance as to the appropriate use of bowel preparation for a range of defined clinical circumstances. A consensus group from across Europe was convened and met to discuss appropriate bowel preparation. The use of polyethylene glycol (PEG), sodium picosulphate and sodium phosphate (NaP), together with other agents, prokinetics and simethicone, in colonoscopy and small bowel video capsule endoscopy were considered. A systematic review of the literature was carried out and additional unpublished data was obtained from the members of the consensus group where required. Recommendations were graded according to the level of evidence.

FINDINGS

PEG-based regimens are recommended first line for both procedures, since their use is supported by good efficacy and safety data. Sodium-picosulphate-based regimens are recommended second line as their cleansing efficacy appears less than PEG-based regimens. NaP is not recommended for bowel cleansing due to the potential for renal damage and other adverse events. However, the use of NaP is acceptable in patients in whom PEG or sodium picosulphate is ineffective or not tolerated. NaP should not be used in patients with chronic kidney disease, pre-existing electrolyte disturbances, congestive heart failure, cirrhosis or a history of hypertension. The timing of the dose, dietary restrictions, use in special patient groups and recording of the quality of bowel preparation are also considered for patients undergoing colonoscopy. During the development of the guidelines the European Society of Gastrointestinal Endoscopy (ESGE) issued guidance on bowel preparation for colonoscopy. The ESGE guidelines and these consensus guidelines share many recommendations; differences between the guidelines are reviewed.

CONCLUSION

The use of bowel preparation should be tailored to the individual patient and their specific clinical circumstances.

Relationship of colonoscopy-detected serrated polyps with synchronous advanced neoplasia in average-risk individuals

BACKGROUND

Serrated cancers account for 10% to 20% of all colorectal cancers (CRC) and more than 30% of interval cancers. The presence of proximal serrated polyps and large (≥10 mm) serrated polyps (LSP) has been correlated with colorectal neoplasia.

OBJECTIVE

To evaluate the prevalence of serrated polyps and their association with synchronous advanced neoplasia in a cohort of average-risk population and to assess the efficacy of one-time colonoscopy and a biennial fecal immunochemical test for reducing CRC-related mortality. This study focused on the sample of 5059 individuals belonging to the colonoscopy arm.

DESIGN

Multicenter, randomized, controlled trial.

SETTING

The ColonPrev study, a population-based, multicenter, nationwide, randomized, controlled trial.

PATIENTS

A total of 5059 asymptomatic men and women aged 50 to 69 years.

INTERVENTION

Colonoscopy.

MAIN OUTCOME MEASUREMENTS

Prevalence of serrated polyps and their association with synchronous advanced neoplasia.

RESULTS

Advanced neoplasia was detected in 520 individuals (10.3%) (CRC was detected in 27 [0.5%] and advanced adenomas in 493 [9.7%]). Serrated polyps were found in 1054 individuals (20.8%). A total of 329 individuals (6.5%) had proximal serrated polyps, and 90 (1.8%) had LSPs. Proximal serrated polyps or LSPs were associated with male sex (odds ratio [OR] 2.08, 95% confidence interval [CI], 1.76-4.45 and OR 1.65, 95% CI, 1.31-2.07, respectively). Also, LSPs were associated with advanced neoplasia (OR 2.49, 95% CI, 1.47-4.198), regardless of their proximal (OR 4.15, 95% CI, 1.69-10.15) or distal (OR 2.61, 95% CI, 1.48-4.58) locations. When we analyzed subtypes of serrated polyps, proximal hyperplasic polyps were related to advanced neoplasia (OR 1.61, 95% CI, 1.13-2.28), although no correlation with the location of the advanced neoplasia was observed.

LIMITATIONS

Pathology criteria for the diagnosis of serrated polyps were not centrally reviewed. The morphology of the hyperplasic polyps (protruded or flat) was not recorded. Finally, because of the characteristics of a population-based study carried out in average-risk patients, the proportion of patients with CRC was relatively small.

CONCLUSION

LSPs, but not proximal serrated polyps, are associated with the presence of synchronous advanced neoplasia. Further studies are needed to determine the risk of proximal hyperplastic polyps.

Endoscopic features of sessile serrated adenomas: validation by international experts using high-resolution white-light endoscopy and narrow-band imaging

BACKGROUND

Sessile serrated adenomas/polyps (SSAs/Ps) are premalignant lesions susceptible to being easily overlooked by endoscopists. A detailed description of the endoscopic appearance of SSAs/Ps might help endoscopists to recognize these lesions to improve the effectiveness of colonoscopy.

OBJECTIVE

To identify various endoscopic features of SSAs/Ps using high-resolution white-light endoscopy (HR-WLE) and narrow-band imaging (NBI).

DESIGN

Retrospective image evaluation study.

SETTING

Single tertiary referral center.

PATIENTS

Forty-5 patients with serrated polyposis syndrome undergoing surveillance colonoscopies.

INTERVENTION

HR-WLE and NBI images of 150 polyps (50 SSAs/Ps, 50 hyperplastic polyps [HPs], and 50 adenomas) were systematically assessed by 5 experts using various endoscopic descriptors.

MAIN OUTCOME MEASUREMENTS

The prevalence of specific endoscopic features observed in SSAs/Ps versus HPs.

RESULTS

Multivariate analysis demonstrated that indistinct borders (OR, 3.11; 95% CI, 1.57-6.15) and a cloud-like surface (OR, 2.65; 95% CI, 1.21-5.78) were associated with SSA/P histology on HR-WLE. On NBI, a cloud-like surface (OR, 4.91; 95% CI, 2.42-9.97), indistinct borders (OR, 2.38; 95% CI, 1.14-4.96), irregular shape (OR, 3.17; 95% CI, 1.59-6.29), and dark spots inside the crypts (OR, 2.05; 95% CI, 1.02-4.11) were found to be endoscopic predictors of SSA/P histology. The sensitivity, specificity, and accuracy of NBI for differentiating serrated polyps containing either none or all 4 endoscopic SSA/P features were, respectively, 89%, 96%, and 93%.

LIMITATIONS

Retrospective, image evaluation analysis.

CONCLUSIONS

The current study demonstrates that SSAs/Ps possess several specific endoscopic features compared with HPs. Recognition of these characteristics might assist endoscopists in the differentiation of these lesions and could possibly facilitate endoscopic detection of these rather subtle lesions.

Relevance of GSTM1, GSTT1, and GSTP1 gene polymorphisms to gastric cancer susceptibility and phenotype

Human glutathione S-transferases (GSTs) are phase II metabolizing enzymes that play a key role in protecting against cancer by detoxifying numerous potentially cytotoxic/genotoxic compounds. The genes encoding the human GST isoenzymes GSTM(mu)1, GSTT(theta)1 and GSTP(pi)1 harbour polymorphisms, which have been considered important modifiers of the individual risk for environmentally induced cancers such as gastric cancer (GC). However, results are inconsistent among studies from different geographic areas and ethnic groups. Our goal was to perform a nationwide, case-control study in Spain to evaluate the relevance of several functional GST gene polymorphisms and environmental factors to GC risk and phenotype. DNA from 557 GC patients and 557 sex- and age-matched healthy controls (HC) was typed for two deletions in the GSTM1 and GSTT1 genes and two SNPs in the GSTP1 gene (rs1695 and rs1138272) using polymerase chain reaction-restriction fragment length polymorphism methods. Logistic regression analysis identified Helicobacter pylori infection with CagA strains [odds ratio (OR): 2.36; 95% confidence interval (CI): 1.78-3.15], smoking habit (OR: 2.10; 95% CI: 1.48-2.97) and family history of GC (OR: 3.2; 95% CI: 2.02-5.16) as independent risk factors for GC. No differences in the frequencies of GSTM1 or GSTT1 null genotypes were observed between cases and controls (GSTM1: 50.8% vs. 48%; GSTT1: 21.5% vs. 21%). Moreover, simultaneous carriage of both, the GSTM1 and the GSTT1 null genotypes, was almost identical in both groups (10.7% in GC vs. 10.6% in HC). In addition, no significant differences in GSTP1 Ile105Val (rs1695) and GSTP1 Val114Ala (rs1138272) genotype distribution were observed between GC patients and controls. Subgroup analysis for age, gender, Helicobacter pylori status, smoking habits, family history of GC, anatomic location and histological subtype revealed no significant association between GST variants and GC risk. Our results show that the GST polymorphisms evaluated in this study are not relevant when determining the individual susceptibility to GC or phenotype in a South-European population.

Narrow-band imaging as an alternative to chromoendoscopy for the detection of dysplasia in long-standing inflammatory bowel disease: a prospective, randomized, crossover study

BACKGROUND

Narrow-band imaging (NBI) is a novel technique that may represent an alternative method to chromoendoscopy (CE) for the detection of colitis-associated intraepithelial neoplasia (IN) in patients with long-standing inflammatory bowel disease (IBD).

OBJECTIVE

To compare NBI with CE for the detection of IN.

DESIGN

Prospective, randomized, crossover study.

SETTING

Academic hospital.

PATIENTS

Patients with clinically inactive colonic IBD (≥8 years).

INTERVENTION

Patients underwent both CE and NBI in randomized order. Targeted biopsy specimens from abnormal areas were obtained. Pathological examination was regarded as the reference standard.

MAIN OUTCOME MEASUREMENTS

Number of false-positive and true-positive lesions in patients undergoing CE and NBI were compared as well as the proportion of patients with missed IN lesions.

RESULTS

Eighty patients were screened, of whom 20 were excluded. Mean ± standard deviation withdrawal time for CE was significantly longer than that for NBI (26.87 ± 9.89 minutes vs 15.74 ± 5.62 minutes, P < .01). Thirteen patients had at least 1 IN lesion on 1 of the examinations. In the per-lesion analysis, NBI resulted in a significantly inferior false-positive biopsy rate (P = .001) and a similar true-positive rate. The percentage of missed IN lesions and patients was superior with NBI, albeit without reaching statistical significance.

LIMITATIONS

Lesions were sampled immediately after detection, which precluded the possibility of paired analysis.

CONCLUSIONS

NBI appears to be a less time-consuming and equally effective alternative to CE for the detection of IN. However, given the NBI lesion and patient miss rates, it cannot be recommended as the standard technique.

EUS and magnetic resonance imaging in the staging of rectal cancer: a prospective and comparative study

BACKGROUND

Accurate locoregional staging is crucial in rectal cancer for deciding patient management because the administration of neoadjuvant therapy depends on it. EUS and magnetic resonance imaging (MRI) are used indistinctly in the pretherapeutic workup of rectal cancer.

OBJECTIVE

To prospectively compare the performance of EUS and MRI in the locoregional staging of rectal cancer in a large series of patients.

DESIGN

Prospective and comparative study.

SETTING

Tertiary center.

PATIENTS

Patients with histologically proven rectal cancer.

INTERVENTIONS

EUS and MRI were performed in all patients by a different operator unaware of the results of the other procedure.

MAIN OUTCOME MEASUREMENTS

Epidemiological, clinical, radiological, and echographic variables were evaluated. Pathological examination of the surgical specimen was used as the criterion standard.

RESULTS

Ninety patients (54 men and 36 women with a mean age of 68 ± 12 years; range 33-87 years) constitute the final sample of this study. Most of the tumors were stages T2-T3 (85%; 95% CI, 77%-92%). Twenty of them (22%; 95% CI, 14%-32%) were stenotic and 24 (27%; 95% CI, 18%-37%) had polypoid morphology. The accuracy of T staging was very similar for EUS and MRI for stage T2 (76%; 95% CI, 65%-84% and 77%; 95% CI, 67%-85%, respectively; P = not significant) and stage T3 (76%; 95% CI, 65%-84% and 83%, 95% CI, 73%-90%, respectively; P = not significant). MRI was not able to visualize any T1 tumor, whereas EUS understaged all T4 tumors. The univariate analysis showed that the polypoid morphology of the tumor inversely correlated with T staging on MRI. The accuracy of MRI for N staging was higher than that of EUS, although the difference did not reach statistical significance (79%; 95% CI, 65%-88% and 65%; 95% CI, 51%-78%, respectively). When performing the univariate analysis to assess the reasons for this difference, the presence of a stenotic tumor was the only parameter significantly related to a poorer performance of EUS in N staging.

LIMITATIONS

The small number of early and locally advanced lesions.

CONCLUSIONS

EUS and MRI have similar accuracy in the T and N staging in rectal cancer. The presence of stenosis and polypoid morphology is inversely associated with accuracy for either EUS or MRI.