Kyu Yong Choi

Field Cancerization in Sporadic Colon Cancer

Background/Aims Aberrant DNA methylation has a specific role in field cancerization. Certain molecular markers, including secreted frizzled-related protein 2 (SFRP2), tissue factor pathway inhibitor 2 (TFPI2), N-Myc downstream-regulated gene 4 (NDRG4) and bone morphogenic protein 3 (BMP3), have previously been shown to be hypermethylated in colorectal cancer (CRC). We aim to examine field cancerization in CRC based on the presence of aberrant DNA methylation in normal-appearing tissue from CRC patients. Methods We investigated promoter methylation in 34 CRC patients and five individuals with normal colonoscopy results. CRC patients were divided into three tissue groups: tumor tissue, adjacent and nonadjacent normal-appearing tissue. The methylation status (positive: methylation level >20%) of SFRP2, TFPI2, NDRG4, and BMP3 promoters was investigated using methylation-specific PCR. Results The methylation frequencies of the SFRP2, TFPI2, NDRG4 and BMP3 promoters in tumor/adjacent/nonadjacent normal-appearing tissue were 79.4%/63.0%/70.4%, 82.4%/53.6%/60.7%, 76.5%/61.5%/69.2%, 41.2%/35.7%/50.0%, respectively. The methylation levels of the SFRP,TFPI2, NDRG4 and BMP3 promoters in tumor tissues were significantly higher than those in normal-appearing tissue (SFRP2, p=0.013; TFPI2, p<0.001; NDRG4, p=0.003; BMP3, p=0.001). No significant correlation was observed between the methylation levels of the promoters and the clinicopathological variables. Conclusions The field effect is present in CRC and affects both the adjacent and nonadjacent normal-appearing mucosa.

Does Low Threshold Value Use Improve Proximal Neoplasia Detection by Fecal Immunochemical Test

BackgroundSeveral studies have reported that the fecal immunochemical test (FIT) less sensitively detects proximal advanced neoplasia (AN) compared to distal AN. Low threshold value use may improve proximal AN detection.AimTo investigate whether FIT diagnostic accuracy for AN is different according to AN location and to compare FIT accuracy in proximal AN detection using different threshold values.MethodsThis retrospective study was conducted in a university hospital in Korea from June 2013 to May 2015. Out of 34,547 participants who underwent FITs, 3990 subjects aged ≥50xa0years who also underwent colonoscopies were analyzed. The FIT diagnostic accuracy for AN with differing locations (proximal vs. distal) and threshold values (20, 15, and 10xa0mcgxa0Hb/g feces) were assessed.ResultsThe sensitivity, specificity, positive predictive value, and negative predictive value of FIT in AN detection were 42.2, 84.3, 24.1, and 92.5xa0%, respectively. The FIT sensitivity for proximal AN detection was significantly lower than that for distal AN detection (32.7 and 49.0xa0%, respectively; Pxa0=xa00.001). Lowering FIT threshold values tended to increase the sensitivity for proximal AN, whereas it significantly decreased the specificity for proximal AN. As a result, there was no significant difference in the accuracy for proximal AN detection (80.1, 79.3, and 78.1xa0% for 20, 15, and 10xa0mcgxa0Hb/g feces, respectively; Pxa0=xa00.107).ConclusionsFIT was less sensitive in proximal AN detection than distal AN detection. Lowering the FIT cutoff threshold did not increase the accuracy for proximal AN detection. New biomarker development for colorectal cancer screening is required to improve proximal ACRN diagnostic accuracy.

Miss rate of colorectal neoplastic polyps and risk factors for missed polyps in consecutive colonoscopies

Background/Aims Colonoscopic polypectomy is the best diagnostic and therapeutic tool to detect and prevent colorectal neoplasms. However, previous studies have reported that 17% to 28% of colorectal polyps are missed during colonoscopy. We investigated the miss rate of neoplastic polyps and the factors associated with missed polyps from quality-adjusted consecutive colonoscopies. Methods We reviewed the medical records of patients who were found to have colorectal polyps at a medical examination center of the Kangbuk Samsung Hospital between March 2012 and February 2013. Patients who were referred to a single tertiary academic medical center and underwent colonoscopic polypectomy on the same day were enrolled in our study. The odds ratios (ORs) associated with polyp-related and patient-related factors were evaluated using logistic regression analyses. Results A total of 463 patients and 1,294 neoplastic polyps were analyzed. The miss rates for adenomas, advanced adenomas, and carcinomas were 24.1% (312/1,294), 1.2% (15/1,294), and 0% (0/1,294), respectively. Flat/sessile-shaped adenomas (adjusted OR, 3.62; 95% confidence interval [CI], 2.40–5.46) and smaller adenomas (adjusted OR, 5.63; 95% CI, 2.84– 11.15 for ≤5 mm; adjusted OR, 3.18; 95% CI, 1.60–6.30 for 6–9 mm, respectively) were more frequently missed than pedunculated/sub-pedunculated adenomas and larger adenomas. In patients with 2 or more polyps compared with only one detected (adjusted OR, 2.37; 95% CI, 1.55–3.61 for 2–4 polyps; adjusted OR, 11.52; 95% CI, 4.61–28.79 for ≥5 polyps, respectively) during the first endoscopy, the risk of missing an additional polyp was significantly higher. Conclusions One-quarter of neoplastic polyps was missed during colonoscopy. We encourage endoscopists to detect smaller and flat or sessile polyps by using the optimal withdrawal technique.

The fecal immunochemical test has high accuracy for detecting advanced colorectal neoplasia before age 50

BACKGROUNDnIn contrast to the decreasing incidence of colorectal cancer (CRC) in adults ≥50 years, the CRC incidence in young adults <50 years is increasing. The fecal immunochemical test (FIT) may be useful for advanced colorectal neoplasia (ACRN) screening in a young population.nnnAIMSnTo evaluate the diagnostic accuracy of FIT in a young population.nnnMETHODSnThe diagnostic performance of FIT for detecting ACRN was compared among the following age groups who underwent FIT and colonoscopy as part of a comprehensive health screening program: 30-39, 40-49, and ≥50 years.nnnRESULTSnOf 26,316 participants, 464 (1.8%) had ACRN and 805 (3.1%) showed positive FIT results. No significant differences in the sensitivity (22.1%, 17.2%, and 22.0%; p=0.435) and specificity (97.2%, 97.4%, and 96.9%; p=0.344) of FIT for detecting ACRN were observed among the groups. However, 30-39 age group had a significantly higher accuracy of FIT for ACRN (96.7%) than 40-49 and ≥50 age groups (95.9% and 93.8%; p<0.001). The areas under the receiver operating characteristic curves of FIT for ACRN of three age groups were not significantly different (67.2, 66.2, and 61.7; p=0.952).nnnCONCLUSIONSnThe diagnostic performance of FIT for ACRN in a young population (<50 years) was not inferior to that in the current screening-age population (≥50 years). The FIT may be a good choice for detecting ACRN in a young population.

Factors Associated with Anxiety and Depression in Korean Patients with Inactive Inflammatory Bowel Disease

Background/Aims Psychological distress is highly prevalent in patients with inflammatory bowel disease (IBD). We evaluated the disease characteristics and socioeconomic factors associated with anxiety and depression in Korean patients with quiescent IBD. Methods In total, 142 IBD patients (67 with Crohn’s disease [CD] and 75 with ulcerative colitis [UC]) completed self-report questionnaires, including the Hospital Anxiety and Depression Score, the Modified Morisky Adherence Scale-8, the socioeconomic deprivation score, and the Crohn’s and Colitis Knowledge Score questionnaires. Results In the CD group, 30 patients (44%) were anxious, and 10 patients (15%) were depressed; in the UC group, 31 patients (41%) were anxious, and 18 patients (24%) were depressed. Using multivariate analysis, in the CD group, socioeconomic deprivation was associated with anxiety (p=0.03), whereas disease duration (p=0.04) and socioeconomic deprivation (p=0.013) were associated with depression. In the UC group, there was no significant independent predictor of anxiety and/or depression; however, low income tended to be associated with depression (p=0.096). Conclusions Despite clinical remission, a significant number of IBD patients present with anxiety and depression. IBD patients in remission, particularly those who are socioeconomically deprived, should be provided with appropriate psychological support.

Risk of Colorectal Neoplasia According to Fatty Liver Severity and Presence of Gall Bladder Polyps

BackgroundFatty liver is the hepatic manifestation of metabolic syndrome (MetS) and is a known risk factor for colorectal neoplasia (CRN). Gallbladder (GB) polyps share many common risk factors with CRN. However, studies evaluating CRN risk according to fatty liver severity and the presence of GB polyps are rare.AimTo investigate CRN risk according to the fatty liver severity and the presence of GB polyps.MethodsA retrospective cross-sectional study was performed on 44,220 participants undergoing colonoscopy and abdominal ultrasonography (US) as part of a health-screening program.ResultsOf the participants, fatty liver was diagnosed as mild in 27.7xa0%, moderate in 5.1xa0%, and severe in 0.4xa0% and 13.4xa0% were diagnosed with GB polyps. Mean age of participants was 42.7xa0years. In adjusted models, risk of overall CRN and non-advanced CRN increased with worsening fatty liver severity (P for trendxa0=xa00.007 and 0.020, respectively). Adjusted odd ratios for overall CRN and non-advanced CRN comparing participants with mild, moderate, and severe fatty liver to participants without fatty liver were 1.13 and 1.12 for mild, 1.12 and 1.10 for moderate, and 1.56 and 1.65 for severe. The presence of GB polyps did not correlate with CRN risk after adjusting for confounders.ConclusionsCRN risk increased with worsening fatty liver severity. However the association between GB polyp and CRN was not significant in the presence of other variables. Considering that many people undergo noninvasive abdominal US as a health screen, our study will contribute to colonoscopy screening strategies in people undergoing abdominal US.

Parameters of Glucose and Lipid Metabolism Affect the Occurrence of Colorectal Adenomas Detected by Surveillance Colonoscopies

Purpose Limited data are available regarding the associations between parameters of glucose and lipid metabolism and the occurrence of metachronous adenomas. We investigated whether these parameters affect the occurrence of adenomas detected on surveillance colonoscopy. Materials and Methods This longitudinal study was performed on 5289 subjects who underwent follow-up colonoscopy between 2012 and 2013 among 62171 asymptomatic subjects who underwent an initial colonoscopy for a health check-up between 2010 and 2011. The risk of adenoma occurrence was assessed using Cox proportional hazards modeling. Results The mean interval between the initial and follow-up colonoscopy was 2.2±0.6 years. The occurrence of adenomas detected by the follow-up colonoscopy increased linearly with the increasing quartiles of fasting glucose, hemoglobin A1c (HbA1c), insulin, homeostasis model assessment of insulin resistance (HOMA-IR), and triglycerides measured at the initial colonoscopy. These associations persisted after adjusting for confounding factors. The adjusted hazard ratios for adenoma occurrence comparing the fourth with the first quartiles of fasting glucose, HbA1c, insulin, HOMA-IR, and triglycerides were 1.50 [95% confidence interval (CI), 1.26–1.77; ptrend<0.001], 1.22 (95% CI, 1.04–1.43; ptrend=0.024), 1.22 (95% CI, 1.02–1.46; ptrend=0.046), 1.36 (95% CI, 1.14–1.63; ptrend=0.004), and 1.19 (95% CI, 0.99–1.42; ptrend=0.041), respectively. In addition, increasing quartiles of low-density lipoprotein-cholesterol and apolipoprotein B were associated with an increasing occurrence of adenomas. Conclusion The levels of parameters of glucose and lipid metabolism were significantly associated with the occurrence of adenomas detected on surveillance colonoscopy. Improving the parameters of glucose and lipid metabolism through lifestyle changes or medications may be helpful in preventing metachronous adenomas.

Are Hemorrhoids Associated with False-Positive Fecal Immunochemical Test Results?

Purpose False-positive (FP) results of fecal immunochemical tests (FITs) conducted in colorectal cancer (CRC) screening could lead to performing unnecessary colonoscopies. Hemorrhoids are a possible cause of FP FIT results; however, studies on this topic are extremely rare. We investigated whether hemorrhoids are associated with FP FIT results. Materials and Methods A retrospective study was conducted at a university hospital in Korea from June 2013 to May 2015. Of the 34547 individuals who underwent FITs, 3946 aged ≥50 years who underwent colonoscopies were analyzed. Logistic regression analysis was performed to determine factors associated with FP FIT results. Results Among 3946 participants, 704 (17.8%) showed positive FIT results and 1303 (33.0%) had hemorrhoids. Of the 704 participants with positive FIT results, 165 had advanced colorectal neoplasia (ACRN) and 539 had no ACRN (FP results). Of the 1303 participants with hemorrhoids, 291 showed FP results, of whom 81 showed FP results because of hemorrhoids only. Participants with hemorrhoids had a higher rate of FP results than those without hemorrhoids (291/1176, 24.7% vs. 248/2361, 10.5%; p<0.001). Additionally, the participants with hemorrhoids as the only abnormality had a higher rate of FP results than those experiencing no such abnormalities (81/531, 15.3% vs. 38/1173, 3.2%; p<0.001). In multivariate analysis, the presence of hemorrhoids was identified as an independent predictor of FP results (adjusted odds ratio, 2.76; 95% confidence interval, 2.24–3.40; p<0.001). Conclusion Hemorrhoids are significantly associated with FP FIT results. Their presence seemed to be a non-negligible contributor of FP results in FIT-based CRC screening programs.

External Validation of the Endoscopic Features of Sessile Serrated Adenomas in Expert and Trainee Colonoscopists

Background/Aims It is unclear whether the endoscopic features of sessile serrated adenomas (SSAs) would be useful to trainee colonoscopists to predict SSA. Therefore, the present study aimed to identify features that expert and trainee colonoscopists can use to independently and reliably predict SSA by using high-resolution white-light endoscopy. Methods Endoscopic images of 81 polyps (39 SSAs, 22 hyperplastic polyps, and 20 tubular adenomas) from 43 patients were retrospectively evaluated by 10 colonoscopists (four experts and six trainees). Eight endoscopic features of SSAs were assessed for each polyp. Results According to multivariable analysis, a mucous cap (odds ratio [OR], 10.44; 95% confidence interval [CI], 5.72 to 19.07), indistinctive borders (OR, 4.21; 95% CI, 2.74 to 7.16), dark spots (OR, 3.64; 95% CI, 1.89 to 7.00), and cloud-like surface (OR, 2.43; 95% CI, 1.27 to 4.668) were independent predictors of SSAs. Among these, a mucous cap, indistinctive borders, and cloud-like surface showed moderate interobserver agreement (mean κ >0.40) among experts and trainees. When ≥1 of the three predictors was observed, the sensitivity and specificity for diagnosing SSAs were 79.0% and 81.4%, respectively. Conclusions Colonoscopy trainees and experts can use several specific endoscopic features to independently and reliably predict SSAs.

Endosonographer's macroscopic evaluation of EUS-FNAB specimens after interactive cytopathologic training: a single-center prospective validation cohort study.

AbstractBackgroundnIn many centers, rapid on-site evaluation (ROSE) for the specimens obtained from endoscopic ultrasound-guided fine-needle aspiration biopsy (EUS-FNAB) is not available. The aim of this study was to compare the diagnostic yields of EUS-FNAB in the presence or absence of ROSE.MethodsSeventy-five patients who underwent EUS-FNAB for the pancreatic, gastric subepithelial, and mesenteric mass lesions at our institution from November 2013 to August 2014 were included. For 20 patients in the pilot cohort, EUS-FNAB was performed with ROSE, and simultaneously, training of the staff endosonographer for tissue adequacy by an on-site cytopathologist was also performed.ResultsThe sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy of EUS-FNAB in the pilot cohort were 91.7, 100.0, 100.0, 88.9, and 95.0xa0%, respectively. The 3.2xa0±xa00.8 [meanxa0±xa0standard deviation (SD)] needle passes were needed in this cohort. Fifty-five patients were enrolled as a validation cohort from April 2014 to August 2014, and tissue adequacies were assessed by an experienced endosonographer without ROSE in this cohort. The sensitivity, specificity, PPV, NPV, and accuracy of EUS-FNAB in this validation cohort were 92.1, 100.0, 100.0, 85.0, and 94.6xa0%, respectively. The 4.5xa0±xa00.6 (meanxa0±xa0SD) needle passes were needed in this cohort (pxa0<xa00.01 compared to pilot cohort).ConclusionsDiagnostic accuracy of EUS-FNAB in which the adequacy of sample was assessed by an attending endosonographer was acceptable. This study suggests that on-site evaluation by a trained endosonographer may be an alternative tool to ROSE where ROSE is not available.