Min Seob Kwak

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.

Prognostic value of Kras codon 13 gene mutation for overall survival in colorectal cancer: Direct and indirect comparison meta-analysis

Background: The clinical significance of KRAS codon 13 mutation in patients with colorectal cancer (CRC) remains controversial. A systematic review and meta-analysis is necessary for a more precise estimation of the predictive role of KRAS codon 13 mutations in CRC patients. Methods: We performed a systematic search using the MEDLINE, EMBASE, and Cochrane library databases from January 2000 to November 2016. The prognostic value of KRAS codon 13 mutation for overall survival (OS) was investigated by measuring the hazard ratio (HR) and 95% confidence interval (CI). Data were analyzed with Review Manager Version 5.3 and the Canadian Agency for Drugs and Technologies in Health software. Results: OS in CRC patients with KRAS codon 13 mutation was worse than that in CRC patients with KRAS wild-type (pooled HR = 1.37, 95% CI: 1.03–1.81, P = .03). Subgroup analysis of studies of enrolled CRC patients treated with antiepidermal growth factor receptor (EGFR) therapy showed no significant difference in OS associated with KRAS codon 13 mutation in comparison to KRAS wild-type (pooled HR = 1.57, 95% CI: 0.98–2.51, P = .06). In the indirect comparison, no statistically significant association was observed between codon 12 and 13 mutations for OS in CRC patients (pooled HR = 0.88, 95% CI: 0.65–1.20, P = .43). Conclusion: The current meta-analysis suggests that Codon 13 mutation of KRAS gene seems to correlate with the OS of patients with CRC, but has similar OS to those with KRAS wild-type in patients receiving anti-EGFR therapy. No difference was detected in the OS of CRC patients with codon 13 mutation versus codon 12 mutation.

The Clinical Outcomes of Lower Gastrointestinal Bleeding Are Not Better than Those of Upper Gastrointestinal Bleeding

The incidence of lower gastrointestinal bleeding (LGIB) is increasing; however, predictors of outcomes for patients with LGIB are not as well defined as those for patients with upper gastrointestinal bleeding (UGIB). The aim of this study was to identify the clinical outcomes and the predictors of poor outcomes for patients with LGIB, compared to outcomes for patients with UGIB. We identified patients with LGIB or UGIB who underwent endoscopic procedures between July 2006 and February 2013. Propensity score matching was used to improve comparability between LGIB and UGIB groups. The clinical outcomes and predictors of 30-day rebleeding and mortality rate were analyzed between the two groups. In total, 601 patients with UGIB (n = 500) or LGIB (n = 101) were included in the study, and 202 patients with UGIB and 101 patients with LGIB were analyzed after 2:1 propensity score matching. The 30-day rebleeding and mortality rates were 9.9% and 4.5% for the UGIB group, and 16.8% and 5.0% for LGIB group, respectively. After logistic regression analysis, the Rockall score (P = 0.013) and C-reactive protein (CRP; P = 0.047) levels were significant predictors of 30-day mortality in patients with LGIB; however, we could not identify any predictors of rebleeding in patients with LGIB. The clinical outcomes for patients with LGIB are not better than clinical outcomes for patients with UGIB. The clinical Rockall score and serum CRP levels may be used to predict 30-day mortality in patients with LGIB.

Quality Metrics of a Fecal Immunochemical Test-Based Colorectal Cancer Screening Program in Korea

Background/Aims Knowledge regarding the quality metrics of fecal immunochemical test (FIT)-based colorectal cancer screening programs is limited. The aim of this study was to investigate the performance and quality metrics of a FIT-based screening program. Methods In our screening program, asymptomatic subjects aged ≥50 years underwent an annual FIT, and subjects with positive FIT results underwent a subsequent colonoscopy. The performance of the FIT and colonoscopy was analyzed in individuals with a positive FIT who completed the program between 2009 and 2015 at a university hospital. Results Among the 51,439 screened participants, 75.1% completed the FIT. The positive rate was 1.1%, and the colonoscopy completion rate in these patients was 68.6%. The positive predictive values of cancer and advanced neoplasia were 5.5% and 19.1%, respectively. The adenoma detection rate in the patients who underwent colonoscopy after a positive FIT was 48.2% (60.0% for men and 33.6% for women). The group with the highest tertile quantitative FIT level showed a significantly higher detection rate of advanced neoplasia than the group with the lowest tertile (odds ratio, 2.6; 95% confidence interval, 1.4 to 5.1; p<0.001). Conclusions The quality metrics used in the United States and Europe may be directly introduced to other countries, including Korea. However, the optimal quality metrics should be established in each country.

Evaluation of scoring systems without endoscopic findings for predicting outcomes in patients with upper gastrointestinal bleeding

BackgroundRisk scoring systems are used to evaluate patients with upper gastrointestinal bleeding (UGIB). We compared Glasgow-Blatchford score (GBS), modified GBS (mGBS), and Pre-endoscopy Rockall score (Pre-E RS) for immediate application without endoscopic findings in predicting the need of interventions and the 30-day mortality in patients with UGIB.MethodsPatients who visited the emergency room with UGIB from January 2007 to June 2016 were included. GBS, mGBS, and Pre-E RS were obtained for all patients. The area under the receiver-operating characteristic curves (AUC) was used to assess the accuracy of the scoring systems to determine the need for interventions and 30-day mortality. Also, we investigated the potential cutoff scores for predicting 30-day mortality and the need for interventions.ResultsIn predicting the need for interventions, GBS (AUC = 0.727) and mGBS (AUC = 0.733) outperformed Pre-E RS (AUC = 0.564, P < 0.0001). In predicting 30-day mortality, Pre-E RS (AUC = 0.929) outperformed GBS (AUC = 0.664, P < 0.0001) and mGBS (AUC = 0.652, P < 0.0001). Based on AUC analyses of sensitivities and specificities, the optimal cutoff mGBS and GBS for the need for interventions was 9 (70.71% sensitivity, 89.35% specificity) and 9 (73.57% sensitivity, 82.90% specificity) respectively, and optimal cutoff Pre-E RS for 30-day mortality was 4 (88.0% sensitivity, 97.52% specificity).ConclusionsGBS and mGBS are considered to be moderately accurate in making an early decision about the need of interventions in patients with UGIB. Pre-E RS is considered to be highly accurate in early detection of patients at high risk for 30-day mortality without endoscopic findings. In addition, we suggested potential cutoff scores to predict the need of interventions for GBS and mGBS, and 30-day mortality for Pre-E RS. Further studies are needed to confirm the clinical applicability of results.

The current capacity and quality of colonoscopy in Korea

Background/Aims Little is known for the capacity and quality of colonoscopy, and adherence to colonoscopy surveillance guidelines in Korea. This study aimed to investigate the present and potential colonoscopic capacity, colonoscopic quality, and adherence to colonoscopy surveillance guidelines in Korea. Methods We surveyed representative endoscopists of 72 endoscopy units from June to August 2015, using a 36-item questionnaire regarding colonoscopic capacity, quality, and adherence to colonoscopy surveillance guidelines of each hospitals. Results Among the 62 respondents who answered the questionnaire, 51 respondents were analyzed after exclusion of 11 incomplete answers. Only 1 of 3 of endoscopy units can afford to perform additional colonoscopies in addition to current practice, and the potential maximum number of colonoscopies per week was only 42. The quality of colonoscopy was variable as reporting of quality indicators of colonoscopy were considerably variable (29.4%–94.1%) between endoscopy units. Furthermore, there are substantial gaps in the adherence to colonoscopy surveillance guidelines, as concordance rate for guideline recommendation was less than 50% in most scenarios. Conclusions The potential capacity and quality of colonoscopy in Korea was suboptimal. Considering suboptimal reporting of colonoscopic quality indicators and low adherence rate for colonoscopy surveillance guidelines, quality improvement of colonoscopy should be underlined in Korea.

Small Bowel Perforation Caused by Press-through Package

With an increased use of the press-through package (PTP) tablet, there has also been an increase in mis-swallowing cases, especially in elderly patients. We report a rare case of PTP-induced small bowel perforation and fistula formation with adjacent small bowel in a healthy elderly patient, who experienced persistent abdominal pain of unknown cause. A 62-year-old healthy man was admitted to our hospital with left abdominal pain that started one month ago. Neither abdominal tenderness nor rebound tenderness was present on physical examination. His vital signs and all other test results were within normal limits. However, a 2.5 cm curved radiopaque material within his thickened small intestine was incidentally detected on an abdominal computed tomography. He underwent laparoscopic small bowel resection, which revealed foreign body in the distal small intestine. Edema, perforation, and adhesions with the surrounding tissues were also noticed in the distal small intestine. Foreign body was turned out to be PTP, and this was considered to be responsible for the small bowel perforation and fistula formation. Precautions regarding PTP usage are necessary to prevent inadvertent PTP ingestion and its related complications, such as perforation, especially in the elderly population.

Small Bowel Obstruction Caused by Aloe vera Bezoars: A Case Report

Small bowel obstruction is a clinical condition commonly caused by postoperative adhesion, volvulus, intussusceptions, and hernia. Small bowel obstruction due to bezoars is clinically uncommon, accounting for approximately 2-4% of all obstructions. Computed tomography (CT) is a useful method in diagnosing the cause of small bowel obstruction. However, small bowel obstruction caused by bezoars may not be detected by an abdominal CT examination. Herein, we report a rare case of small bowel obstruction by Aloe vera bezoars, which were undetected by an abdominal CT. Phytobezoars should be included in the differential diagnosis of small bowel obstruction in patients with predisposing factors, such as excessive consumption of high-fiber food and diabetes.

Age-adapted Variation in Screening Interval of Fecal Immunochemical Test May Improve its Participation and Colonoscopy Acceptance.

Goals: We determined appropriate intervals for administering the fecal immunochemical test (FIT) and performance outcomes in an Asian national colorectal cancer (CRC) screening program. Background: The optimal interval for FIT in CRC screening is unclear, especially in Asian populations. Study: Between January 2009 and December 2015, 13,480 individuals aged 50 years or older with an initial negative FIT result underwent 2 rounds of FIT screening at intervals of 1 (annual group, 5333), 2 (biennial group, 7363), or 3 years (triennial group, 784). Positive rates of FIT, colonoscopy acceptance, colonoscopy findings, and detection rates for CRC and advanced neoplasia were compared according to FIT intervals. Results: The overall positivity rate of FIT in the second screening round was significantly higher in men and in older subjects than in the entire sample. Younger subjects were less likely to undergo annual FIT (36.0% vs. 46.4%, P<0.001). The colonoscopy acceptance rate was decreased in the biennial and triennial groups compared with an annual group among younger subjects (odds ratio, 0.56; 95% confidence interval, 0.33-0.95 for the biennial group vs. odds ratio, 0.19; 95% confidence interval, 0.03-1.37 for the triennial group). Detection rates for CRC and advanced neoplasia in the second round were significantly higher and accompanied by increased FIT screening intervals in older, but not younger subjects. Conclusions: Age-adapted variation in FIT screening intervals, such as annual screening for elderly subjects and biennial screening for younger subject, may improve FIT participation and colonoscopy acceptance.