Disparities in prevalence, location, and shape characteristics of colorectal neoplasia between South Korean and U.S. patients

Potential Factors Predicting Histopathologically Upgrade Discrepancies between Endoscopic Forceps Biopsy of the Colorectal Low-Grade Intraepithelial Neoplasia and Endoscopic Resection Specimens

Background

It was gradually accepted that endoscopic fragment biopsy (EFB) diagnosis cannot accurately guarantee the absence of higher-grade neoplasms within the lesion of the digestive tract. There are no well-established predictors for histopathologically upgrade discrepancies between EFB diagnosing colorectal low-grade intraepithelial neoplasia (LGIN) and endoscopic resection (ER) specimens.

Methods

A total of 918 colorectal LGINs was histopathologically diagnosed by EFB, including 162 cases with upgrade discrepancy and 756 concordant cases. We compared clinicopathological data of EFB and ER specimens between these two groups. Multivariate analysis was performed to identify predictors for this upgrade histopathology.

Results

The predominant upgrade discrepancy of LGINs diagnosed by EFB was upgrades to high-grade dysplasia (114/918, 12.4%), followed by upgrades to intramucosal carcinoma (33/918, 3.6%), submucosal adenocarcinoma (10/918, 1.1%), and advanced adenocarcinoma (5/918, 0.5%). NSAID history (OR 4.83; 95% CI, 2.27-10.27; p < 0.001), insufficient EFB number (OR 2.99; 95% CI, 1.91-4.68; p < 0.001), maximum diameter ≥ 1.0 cm (OR 6.18; 95% CI, 1.32-28.99; p = 0.021), lobulated shape (OR 2.68; 95% CI, 1.65-4.36; p < 0.001), erythema (OR 2.42; 95% CI, 1.50-3.91; p < 0.001), erosion (OR 7.12; 95% CI, 3.91-12.94; p < 0.001), surface unevenness (OR 2.31; 95% CI, 1.33-4.01; p = 0.003), and distal location of the target adenoma (OR 3.29; 95% CI, 1.68-6.41; p < 0.001) were associated with the histologically upgrade discrepancies.

Conclusion

NSAID history, insufficient EFB number, adenoma size and location, and abnormal macroscopic patterns are potential predictors for upgrade histopathology of LGINs diagnosed by EFBs. The standardization of EFB number and advanced imaging techniques could minimize the risk of neglecting the potential of this upgrade histopathology.

Risk Factors for High-Risk Adenoma on the First Lifetime Colonoscopy Using Decision Tree Method: A Cross-Sectional Study in 6,047 Asymptomatic Koreans

Background/Aims: As risk of colorectal neoplasm is varied even in persons with “average-risk,” risk evaluation and tailored screening are needed. This study aimed to evaluate the risk factors of high-risk adenoma (HRA) in healthy individuals and determine the characteristics of advanced neoplasia (AN) among individual polyps.

Methods: Asymptomatic adults who underwent the first lifetime screening colonoscopy at the Seoul National University Hospital Healthcare System Gangnam Center (SNUH GC) were recruited from 2004 to 2007 as SNUH GC Cohort and were followed for 10 years. Demographic and clinical characteristics were compared between the subjects with and without AN (≥10 mm in size, villous component, and/or high-grade dysplasia and/or cancer) or HRA (AN and/or 3 or more adenomas). For individual polyps, correlations between clinical or endoscopic features and histologic grades were evaluated using a decision tree method.

Results: A total of 6,047 subjects were included and 5,621 polyps were found in 2,604 (43%) subjects. Advanced age, male sex, and current smoking status were statistically significant with regards to AN and HRA. A lower incidence of AN was observed in subjects taking aspirin. In the decision tree model, the location, shape, and size of the polyp, and sex of the subject were key predictors of the pathologic type. A weak but significant association was observed between the prediction of the final tree and the histological grouping (Kendall's tau-c = 0.142, p < 0001).

Conclusions: Advanced neoplasia and HRA can be predicted using several individual characteristics and decision tree models.

The association between nonalcoholic fatty liver disease and esophageal, stomach, or colorectal cancer: National population-based cohort study

We investigated the association between nonalcoholic fatty liver disease (NAFLD) and gastrointestinal tract cancer in the general population. Retrospective data on individuals aged ≥20 years who received healthcare checkups from January 1, 2009 to December 31, 2009 were analyzed using the National Health Insurance Database in Korea. NAFLD was defined based on the fatty liver index (FLI ≥60). The primary outcome was newly diagnosed esophageal, stomach, or colorectal cancer using ICD-10 codes during follow-up until 31 December 2017. Cox regression analysis was used to estimate hazard ratios (HRs) and 95% confidence intervals (95% CIs). Among 8,120,674 subjects, 936,159 adults (11.5%) were identified as having NAFLD. Their mean age was 46.7 ± 14.1 years, and 52.1% were male. During the follow-up period (7.2 years), 3,792 esophageal, 57,292 stomach and 68,769 colorectal cancer cases were identified. FLI ≥60 was significantly associated with the development of esophageal (HR 2.10, 95% CI 1.88-2.35), stomach (HR 1.18, 95% CI 1.14-1.22), and colon cancer (HR, 1.23, 95% CI 1.19-1.26) after multivariable adjustment. Compared to subjects without NAFLD, all-cause mortality in patients with esophageal (HR 1.46, 95% CI 1.28-1.67), stomach (HR 1.26, 95% CI 1.18-1.34), and colorectal cancer (HR 1.16, 95% CI 1.10-1.22) was significantly increased in subjects with NAFLD (FLI ≥60). NAFLD defined using FLI was a good predictive indicator for GI tract malignancy and all-cause mortality in the general population. Subjects with NAFLD are needed for active surveillance of esophageal, stomach, and colorectal cancers.

Prevalence and risk factors of colorectal cancer in Asia

Globally, colorectal cancer (CRC) is a substantial public health burden, and it is increasingly affecting populations in Asian countries. The overall prevalence of CRC is reported to be low in Asia when compared with that in Western nations, yet it had the highest number of prevalent cases. This review described the prevalence of CRC in Asia according to the International Agency for Research on Cancer from World Health Organization (WHO) database and summarized its major risk factors. Non-modifiable factors include genetic factors, ethnicity, age, gender, family history and body height; smoking, alcohol drinking, weight, Westernized diet, physical inactivity, chronic diseases and microbiota were involved in environmental factors. These risk factors were separately discussed in this review according to published literature from Asian countries. CRC screening has been playing an important role in reducing its disease burden. Some recommendations on its screening practices have been formulated in guidelines for Asia Pacific countries.

Liver fibrosis is associated with risk for colorectal adenoma in patients with nonalcoholic fatty liver disease

Nonalcoholic fatty liver disease (NAFLD) is associated with risks for developing colorectal adenoma. This study aimed to evaluate the association between advanced fibrosis in NAFLD and the risk for colorectal adenoma.We retrospectively analyzed the data of 6332 adults who underwent abdominal ultrasound and 1st-time colonoscopy on the same day in a health screening program at a single center. We evaluated the presence of advanced fibrosis in NAFLD using various noninvasive score, which also analyzed the detection rate of colorectal adenoma according to the presence of advanced fibrosis in NAFLD.The subjects with NAFLD had a higher prevalence of colorectal adenoma. In the multivariate analysis, NAFLD was an independent risk factor for colorectal adenoma (adjusted odds ratio [OR], 1.15; 95% confidence interval [CI], 1.02-1.30), advanced adenoma (adjusted OR, 1.50; 95% CI, 1.12-2.01), and multiple adenomas (adjusted OR, 1.32; 95% CI, 1.01-1.73). When NAFLD was further stratified based on the stage of fibrosis using the noninvasive score models, the subjects with NAFLD and advanced fibrosis had a significantly higher risk for colorectal adenoma, advanced adenoma, and multiple adenomas than those with NAFLD without advanced fibrosis.NAFLD with advanced fibrosis might be risk factor for colorectal adenoma compared with NAFLD without advanced fibrosis.

An Adjusted Level of Adenoma Detection Rate is Necessary for Adults Below 50 Years Old

BACKGROUND

Although adenoma prevalence is lower in younger people compared with screening-aged adults 50 years old and above, there is no adjustment recommendation for the target adenoma detection rate (ADR) in young people. Herein, we estimated a different target ADR for adults below 50 years old based on screening colonoscopy findings.

MATERIALS AND METHODS

Asymptomatic, average-risk adults below 50 years old who underwent screening colonoscopy were enrolled at 12 endoscopy centers in Korea between February 2006 and March 2012. Screening colonoscopies were stratified into low or high ADR groups with ADR levels of 20% and 25%, respectively.

RESULTS

The ADRs from 12 endoscopy centers ranged from 12.1% to 43.8% (median ADR, 24.1%) based on 5272 young adults receiving screening colonoscopies. Using 20% as an ADR level, the risks for metachronous adenoma and advanced adenoma were significantly higher in the low ADR group than the high ADR group (35.4% vs. 25.7%, P<0.001; 8.3% vs. 3.7%, P=0.001, respectively). However, using ADR level of 25%, the risk for metachronous neoplasia was similar in the high and low ADR groups in young adults according to screening colonoscopy. In subgroup analysis, similar findings were found in males, but not in females.

CONCLUSIONS

Optimal target ADR may be different between younger and older populations, and the adoption of a 20% target ADR could be used as a performance indicator for young populations.

Predictive factors for missed adenoma on repeat colonoscopy in patients with suboptimal bowel preparation on initial colonoscopy: A KASID multicenter study

Suboptimal bowel preparation can result in missed colorectal adenoma that can evolve into interval colorectal cancer. This study aims to identify the predictive factors associated with missed adenoma on repeat colonoscopy in patients with suboptimal bowel preparation at initial colonoscopy. A total of 441 patients with suboptimal bowel preparation on initial colonoscopy and who had repeat colonoscopy within two years were included from 2007 to 2014 in six tertiary hospitals. Suboptimal bowel preparation was defined as 'poor' according to the Aronchick scale or a score ≤ 1 in at least one segment or total score < 6 according to the Boston bowel preparation scale. Of 441 patients, mean age at initial colonoscopy was 59.1 years, and 69.2% patients were male. The mean interval from initial to repeat colonoscopy was 14.1 months. The per-patient adenoma miss rate (AMR) was 42.4% for any adenoma and 5.4% for advanced adenoma. When the association between baseline clinical characteristics and missed lesions on repeat colonoscopy was analyzed, dyslipidemia (odds ratio [OR], 5.19; 95% confidence interval [CI], 1.14-23.66; P = 0.034), and high-risk adenoma (OR, 4.45; 95% CI, 1.12-17.68; P = 0.034) on initial colonoscopy were independent risk factors for missed advanced adenoma. In patients with suboptimal bowel preparation, dyslipidemia and high-risk adenoma on initial colonoscopy were independently predictive of missed advanced adenoma on repeat colonoscopy.

Predictive factors for missed adenoma on repeat colonoscopy in patients with suboptimal bowel preparation on initial colonoscopy: A KASID multicenter study

Suboptimal bowel preparation can result in missed colorectal adenoma that can evolve into interval colorectal cancer. This study aims to identify the predictive factors associated with missed adenoma on repeat colonoscopy in patients with suboptimal bowel preparation at initial colonoscopy. A total of 441 patients with suboptimal bowel preparation on initial colonoscopy and who had repeat colonoscopy within two years were included from 2007 to 2014 in six tertiary hospitals. Suboptimal bowel preparation was defined as ‘poor’ according to the Aronchick scale or a score ≤ 1 in at least one segment or total score < 6 according to the Boston bowel preparation scale. Of 441 patients, mean age at initial colonoscopy was 59.1 years, and 69.2% patients were male. The mean interval from initial to repeat colonoscopy was 14.1 months. The per-patient adenoma miss rate (AMR) was 42.4% for any adenoma and 5.4% for advanced adenoma. When the association between baseline clinical characteristics and missed lesions on repeat colonoscopy was analyzed, dyslipidemia (odds ratio [OR], 5.19; 95% confidence interval [CI], 1.14–23.66; P = 0.034), and high-risk adenoma (OR, 4.45; 95% CI, 1.12–17.68; P = 0.034) on initial colonoscopy were independent risk factors for missed advanced adenoma. In patients with suboptimal bowel preparation, dyslipidemia and high-risk adenoma on initial colonoscopy were independently predictive of missed advanced adenoma on repeat colonoscopy.

Comparative analysis of diagnostic colonoscopy in symptomatic young adults from South Korea and the United States

To date, not much is known about ethnic differences in the prevalence of colorectal neoplasia in symptomatic young patients with lower gastrointestinal symptoms. This study sought to compare diagnostic colonoscopic findings in symptomatic young patients from South Korea and the United States. Results from the first diagnostic colonoscopies in symptomatic 18- to 49-year-old patients were compared between the United States and Korean cohorts. The US cohort data were collected at Virginia Mason Medical Center in Seattle, Washington between January 2007 and January 2010, and the Korean cohort data were collected at 14 university hospitals in Korea between June 2006 and June 2015.The prevalence of advanced neoplasias was similar in both cohorts for bleeding and nonbleeding symptoms (P = .966 and P = .076, respectively). In a subgroup analysis for 40- to 49-year-old patients, the prevalence of advanced neoplasias was similar for bleeding symptoms; however, nonbleeding symptoms were significantly higher in the Korean cohort than in the US cohort (6.2% vs 2.6%, P < .001). In an age subgroup analysis for 18- to 39-year-old patients, the prevalence of advanced neoplasias was similar for bleeding and nonbleeding symptoms in both cohorts. Multivariate analysis showed that lower gastrointestinal symptoms were not associated with the risk of any type of advanced neoplasia in young Korean patients.Ethnic disparities in the prevalence of advanced neoplasia on diagnostic colonoscopy were not noticeable between Korean and US young patients. However, 40- to 49-year-old patients with nonbleeding symptoms require more attention to detect advanced neoplasia in Korea than similarly aged patients in the United States.

Distribution of colorectal polyps: Implications for screening

BACKGROUND

During the last decades data from different studies reported modifications of the topographic distribution of colorectal cancers (CRCs), with an increased frequency of tumours in proximal colonic segments. Given the documented link between adenomas and CRC, a proximal migration of adenomas over time could be expected as well.

AIM

To evaluate available evidence about the prevalence of adenomas and of sessile serrated polyps across colonic segments, the changing trends in their distribution across the colon and the diagnostic performance of screening tests currently adopted in population based screening programs for lesions located in different colonic segments.

METHODS

Literature search on PubMed, Embase, and Cochrane Database of Systematic Reviews, Database of Abstracts of Reviews of Effects with reference to preferred reporting items for systematic reviews and meta-analysis (PRISMA), considering all adult human studies in English, published between January 2000 and February 2017.

RESULTS

Cross-sectional analysis of endoscopy and pathology data-bases are consistently showing a trend toward an increase with age of the proportion of adenomas located in the proximal colon. Several observational studies analysed the site distribution of adenomas, testing the hypothesis of a proximal shift of these lesions, and most of them reported an increase in the proportion of right-sided adenomas over time, although a similar trend was not confirmed by others. Also the quality of the retrieved evidence was low. Both endoscopy and FIT are showing a different level of sensitivity for lesions arising in different colonic segments, depending also on screenees characteristics.

CONCLUSION

Available evidence is supporting the hypothesis of an increase in the proportion of right-sided adenomas with age, while a similar increase has not been reported for SSP/A, at least among subjects aged 50 or older. The trend toward a proximalization of colorectal adenomas over time, reported by some authors, likely results from improved diagnostic performances and/or the process of population ageing.

Metabolically-healthy obesity is associated with higher prevalence of colorectal adenoma

Background

The risk of colorectal adenoma (CRA), an important precursor of colorectal cancer, is largely unknown among obese individuals without obesity-related metabolic abnormalities, a condition described as metabolically-healthy obese (MHO). The aim of this study was to examine the association among metabolic status, the different categories of body mass index (BMI), and CRA in a large cohort of adults.

Methods

We analyzed the association among metabolic status, BMI categories and CRA in asymptomatic adults who underwent a first-time colonoscopy as part of the comprehensive health check-up program at the Health Promotion Center of Samsung Medical Center, from January 2005 to December 2012. Being metabolically healthy was defined as lacking any metabolic syndrome components and having a homeostasis model assessment of insulin resistance <2.5.

Results

The prevalence of “any,” “multiple,” and “high-risk” CRA was 25.6%, 8.3%, and 4.4% among 9,182 metabolically-healthy participants, and 35.9%, 12.5%, and 7.0% among 17,407 metabolically-unhealthy participants, respectively. Increased BMI showed a significant dose-dependent relationship with the prevalence of “any,” “multiple,” and “high-risk” CRA, in both metabolically-healthy and unhealthy participants. In multivariable-adjusted models that accounted for potential confounders including age, sex, smoking, alcohol, first-degree family history of colorectal cancer, and aspirin use, the odds ratio (OR) for any CRA comparing MHO with metabolically-healthy normal-weight (MHNW) participants was 1.25 (95% confidence interval (CI), 1.09–1.43). Further adjustment for metabolic components associated with obesity did not significantly change the association. Similarly, the ORs for multiple CRAs and high risk CRA were higher in MHO participants than MHNW participants [ORs (95% CI), 1.63 (1.31–2.04) and 1.53 (1.14–2.04), respectively].

Conclusions

The MHO phenotype was closely associated with higher prevalence of CRA, including high-risk adenoma. This finding supports the conclusion that MHO increases the risk of colorectal cancer.

Determining the optimal surveillance interval after a colonoscopic polypectomy for the Korean population?

Background/Aims

Western surveillance strategies cannot be directly adapted to the Korean population. The aim of this study was to estimate the risk of metachronous neoplasia and the optimal surveillance interval in the Korean population.

Methods

Clinical and pathological data from index colonoscopy performed between June 2006 and July 2008 and who had surveillance colonoscopies up to May 2015 were compared between low- and high-risk adenoma (LRA and HRA) groups. The 3- and 5-year cumulative risk of metachronous colorectal neoplasia in both groups were compared.

Results

Among 895 eligible patients, surveillance colonoscopy was performed in 399 (44.6%). Most (83.3%) patients with LRA had a surveillance colonoscopy within 5 years and 70.2% of patients with HRA had a surveillance colonoscopy within 3 years. The cumulative risk of metachronous advanced adenoma was 3.2% within 5 years in the LRA group and only 1.7% within 3 years in the HRA group. The risk of metachronous neoplasia was similar between the surveillance interval of <5 and ≥5 years in the LRA group; however, it was slightly higher at surveillance interval of ≥3 than <3 years in the HRA group (9.4% vs. 2.4%). In multivariate analysis, age and the ≥3-year surveillance interval were significant independent risk factors for metachronous advanced adenoma (P=0.024 and P=0.030, respectively).

Conclusions

Patients had a surveillance colonoscopy before the recommended guidelines despite a low risk of metachronous neoplasia. However, the risk of metachronous advanced adenoma was increased in elderly patients and those with a ≥3-year surveillance interval.

Non-alcoholic fatty liver diseases and risk of colorectal neoplasia

BACKGROUND

Non-alcoholic fatty liver disease (NAFLD) is associated with colorectal neoplasia. Yet, NAFLD ranges from simple steatosis to steatohepatitis with advanced fibrosis.

AIM

To investigate the risk of colorectal neoplasia according to the presence and severity of NAFLD.

METHODS

A total of 26 540 asymptomatic adults who underwent same day first-time colonoscopy and abdominal ultrasonography as a health check-up programme were analysed. NAFLD was diagnosed by ultrasonography. Advanced colorectal neoplasia was defined as an invasive cancer or adenoma that was at least 10 mm in diameter, had high-grade dysplasia, or had villous histological characteristics or any combination thereof.

RESULTS

NAFLD patients had a higher prevalence of any colorectal neoplasia (38.0% vs. 28.9%) and advanced colorectal neoplasia (2.8% vs. 1.9%) compared to those without NAFLD. In a multivariable model adjusted for age, sex, smoking, alcohol, body mass index, first-degree family history of colorectal cancer, aspirin use and metabolic factors, the odd ratios comparing patients with NAFLD to those without were 1.10 [95% confidence interval (CI): 1.03-1.17] for any colorectal neoplasia and 1.21 (95% CI: 0.99-1.47) for advanced colorectal neoplasia. When NAFLD patients were further stratified according to the non-invasive parameters of liver disease severity, the risk of any colorectal neoplasia or advanced colorectal neoplasia was higher for those with severe liver diseases than those with mild liver diseases.

CONCLUSIONS

The presence and severity of NAFLD were closely associated with any colorectal neoplasia and advanced colorectal neoplasia, suggesting that clinicians should be aware of the increased risk of colorectal neoplasia in patients with NAFLD.

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

BACKGROUND

Several 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.

AIM

To 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.

METHODS

This 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 ≥50 years who also underwent colonoscopies were analyzed. The FIT diagnostic accuracy for AN with differing locations (proximal vs. distal) and threshold values (20, 15, and 10 mcg Hb/g feces) were assessed.

RESULTS

The sensitivity, specificity, positive predictive value, and negative predictive value of FIT in AN detection were 42.2, 84.3, 24.1, and 92.5 %, respectively. The FIT sensitivity for proximal AN detection was significantly lower than that for distal AN detection (32.7 and 49.0 %, respectively; P = 0.001). 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 78.1 % for 20, 15, and 10 mcg Hb/g feces, respectively; P = 0.107).

CONCLUSIONS

FIT 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.