Byung Chang Kim

Clinical application of self-expandable metallic stent for treatment of colorectal obstruction caused by extrinsic invasive tumors.

PurposeThe purpose of this study was to extend the application of self-expandable metallic stents by investigating their usefulness in treating colorectal obstructions caused by unresectable extrinsic tumors.MethodsFrom January 2000 to November 2005, a total of 60 colorectal stenting procedures were performed, and 57 stents were deployed in 39 patients with extrinsic tumors. The success rate and complications were analyzed retrospectively.ResultsThe most common etiology and location of obstruction were advanced gastric cancer and transverse colon. Technical success was 34 of 39 patients (87.2 percent). The causes of technical failure were immediate stent migration (n = 1), technical problems (n = 1), and access failure because of bowel immobilization (n = 3). Clinical success was 32 of 34 technical successes (82.1 percent). The two patients without clinical success had multifocal strictures of the bowel. Complications occurred in 22 of 57 stents (38.6 percent), including stent reobstruction (n = 14) and stent migration (n = 5). All of stent migrations except one developed with covered stents.ConclusionsIn patients with colonic obstruction caused by extrinsic tumors, stent insertion provided effective symptom relief and can be a reasonable alternative choice to a colostomy. An uncovered stent might be more preferable, considering less migration and remaining short life expectancy, compared with a covered stent.PURPOSE The purpose of this study was to extend the application of self-expandable metallic stents by investigating their usefulness in treating colorectal obstructions caused by unresectable extrinsic tumors. METHODS From January 2000 to November 2005, a total of 60 colorectal stenting procedures were performed, and 57 stents were deployed in 39 patients with extrinsic tumors. The success rate and complications were analyzed retrospectively. RESULTS The most common etiology and location of obstruction were advanced gastric cancer and transverse colon. Technical success was 34 of 39 patients (87.2 percent). The causes of technical failure were immediate stent migration (n = 1), technical problems (n = 1), and access failure because of bowel immobilization (n = 3). Clinical success was 32 of 34 technical successes (82.1 percent). The two patients without clinical success had multifocal strictures of the bowel. Complications occurred in 22 of 57 stents (38.6 percent), including stent reobstruction (n = 14) and stent migration (n = 5). All of stent migrations except one developed with covered stents. CONCLUSIONS In patients with colonic obstruction caused by extrinsic tumors, stent insertion provided effective symptom relief and can be a reasonable alternative choice to a colostomy. An uncovered stent might be more preferable, considering less migration and remaining short life expectancy, compared with a covered stent.

Abdominal Visceral Adipose Tissue Predicts Risk of Colorectal Adenoma in Both Sexes

BACKGROUND & AIMS Small studies have shown inconsistent results regarding the association between abdominal visceral adipose tissue and colorectal adenomas. We evaluated the effects of visceral adipose tissue volume on the development and growth of colorectal adenomas. METHODS A total of 3922 participants underwent colonoscopy and computed tomography from February to November 2008. The associations between waist circumference, visceral adipose tissue volume, and colorectal adenomas were estimated with adjusted odds ratios and 95% confidence intervals (CIs). In addition, the association between characteristics of colorectal adenomas and visceral adipose tissue volume was evaluated. RESULTS Compared with participants who had visceral adipose tissue volume of less than 500 cm(3), the odds ratio for colorectal adenoma was 1.09 (95% CI, 0.87-1.36) for a volume of 500 to 999 cm(3), 1.33 (95% CI, 1.04-1.69) for a volume of 1000 to 1499 cm(3), and 1.43 (95% CI, 1.06-1.94) for a volume of 1500 cm(3) or greater. The risk of colorectal adenomas increased with increasing visceral adipose tissue volume in both sexes (P trend = .004 in men and .009 in women). Waist circumference was associated with colorectal adenomas in men (P trend = .02), but not in women. High volume of visceral adipose tissue (>or=1000 cm(3)) had a positive association with larger adenomas (>or=10 mm) and multiple adenomas. CONCLUSIONS Abdominal visceral adipose tissue volume can contribute to the development and growth of colorectal adenomas, and it was a better predictor for risk of colorectal adenomas than body mass index or waist circumference in both sexes.

Tumor Volume Reduction Rate After Preoperative Chemoradiotherapy as a Prognostic Factor in Locally Advanced Rectal Cancer

PURPOSE To investigate the prognostic significance of tumor volume reduction rate (TVRR) after preoperative chemoradiotherapy (CRT) in locally advanced rectal cancer (LARC). METHODS AND MATERIALS In total, 430 primary LARC (cT3-4) patients who were treated with preoperative CRT and curative radical surgery between May 2002 and March 2008 were analyzed retrospectively. Pre- and post-CRT tumor volumes were measured using three-dimensional region-of-interest MR volumetry. Tumor volume reduction rate was determined using the equation TVRR (%) = (pre-CRT tumor volume--post-CRT tumor volume) × 100/pre-CRT tumor volume. The median follow-up period was 64 months (range, 27-99 months) for survivors. Endpoints were disease-free survival (DFS) and overall survival (OS). RESULTS The median TVRR was 70.2% (mean, 64.7% ± 22.6%; range, 0-100%). Downstaging (ypT0-2N0M0) occurred in 183 patients (42.6%). The 5-year DFS and OS rates were 77.7% and 86.3%, respectively. In the analysis that included pre-CRT and post-CRT tumor volumes and TVRR as continuous variables, only TVRR was an independent prognostic factor. Tumor volume reduction rate was categorized according to a cutoff value of 45% and included with clinicopathologic factors in the multivariate analysis; ypN status, circumferential resection margin, and TVRR were significant prognostic factors for both DFS and OS. CONCLUSIONS Tumor volume reduction rate was a significant prognostic factor in LARC patients receiving preoperative CRT. Tumor volume reduction rate data may be useful for tailoring surgery and postoperative adjuvant therapy after preoperative CRT.

Effect of Helicobacter pylori Infection and Its Eradication on Reflux Esophagitis and Reflux Symptoms

OBJECTIVES:We evaluated the association between current Helicobacter pylori infection and reflux esophagitis and the effect of H. pylori eradication on reflux esophagitis in a healthy screening population.METHODS:A total of 10,102 subjects in a comprehensive screening cohort were enrolled, and 4,007 subjects had follow-up after a median of 2 years. Effects of H. pylori infection on reflux esophagitis were estimated with odds ratios (ORs) and 95% confidence intervals (CIs) using multiple logistic regression analysis. We evaluated the change in prevalence of reflux esophagitis and reflux symptoms after H. pylori eradication vs. persistence.RESULTS:The prevalence of reflux esophagitis (as classified by the Los Angeles system) was 4.9% (490/10,102). Whereas the prevalence of reflux esophagitis was 6.4% (319/4,971) in subjects without H. pylori infection, it was 3.3% (171/5,131) in subjects with infection (P<0.001). H. pylori infection had a strong negative association with reflux esophagitis in multivariate analysis (OR 0.42; 95% CI, 0.34–0.51). Compared with the prevalence of reflux esophagitis in the persistent infection group, the prevalence of reflux esophagitis increased after successful H. pylori eradication (OR 2.34; 95% CI, 1.45–3.76; P<0.001), which was comparable to that of the H. pylori-negative group (OR 2.42; 95% CI, 1.73–3.36; P<0.001). However, reflux symptoms had no association with H. pylori infection or eradication.CONCLUSIONS:In a healthy screening population, H. pylori infection had a strong negative association with reflux esophagitis, but H. pylori eradication increased the prevalence of erosive esophagitis to the level of H. pylori-negative individuals. Long-term clinical significance of newly developed erosive esophagitis after H. pylori eradication should be evaluated prospectively.

Anti-Saccharomyces cerevisiae Antibody in Intestinal Behçet’s Disease Patients: Relation to Clinical Course

PurposeThis study was designed to assess anti-Saccharomyces cerevisiae antibody positive rate in Behçet’s disease and intestinal Behçet’s disease and to evaluate whether anti-Saccharomyces cerevisiae antibody expression is associated with clinical findings at diagnosis and clinical course of intestinal Behçet’s disease.MethodsOne hundred six patients with intestinal Behçet’s disease, 30 patients with Behçet’s disease, and 45 healthy control subjects were included. Anti-Saccharomyces cerevisiae antibody was detected by indirect immunofluorescence assay. According to anti-Saccharomyces cerevisiae antibody expression, the various parameters at diagnosis, cumulative relapse rates, and cumulative probabilities of operation were analyzed.ResultsAnti-Saccharomyces cerevisiae antibody positive rate was 44.3 percent in intestinal Behçet’s disease, 3.3 percent in Behçet’s disease, and 8.8 percent in healthy control subjects. In patients with intestinal Behçet’s disease, age, gender, distribution of Behçet’s disease subtype, symptoms, laboratory tests, and colonoscopic findings at diagnosis were not different according to anti-Saccharomyces cerevisiae antibody expression. Cumulative probability of a first operation was significantly higher in anti-Saccharomyces cerevisiae antibody (+) intestinal Behçet’s disease than in anti-Saccharomyces cerevisiae antibody (−) intestinal Behçet’s disease: 44.8 and 17.2 percent at one year, and 53 and 24.3 percent at two years after diagnosis, respectively (P = 0.006). The number of patients who underwent two or more operations was higher in anti-Saccharomyces cerevisiae antibody (+) intestinal Behçet’s disease than in anti-Saccharomyces cerevisiae antibody (−) intestinal Behçet’s disease (21.3 vs. 8.5 percent). The cumulative relapse rates were not different between the two groups.ConclusionsAnti-Saccharomyces cerevisiae antibody positive rate was 44.3 percent in intestinal Behçet’s disease. Clinical findings at diagnosis and cumulative relapse rates of intestinal Behçet’s disease were not found to be associated with anti-Saccharomyces cerevisiae antibody expression. However, patients with anti-Saccharomyces cerevisiae antibody (+) intestinal Behçet’s disease were more likely to receive surgical treatment.

Associations of Cigarette Smoking and Alcohol Consumption With Advanced or Multiple Colorectal Adenoma Risks: A Colonoscopy-based Case-Control Study in Korea

The associations between alcohol consumption and cigarette smoking habits and the risk for colorectal adenomatous polyps according to the detailed clinical information about polyps were assessed in a large colonoscopy-based study. The study enrolled participants who visited the National Cancer Center of the Republic of Korea for cancer screening between April 2007 and April 2009. In 1,242 newly diagnosed colorectal adenoma patients and 3,019 polyp-free controls, past smokers (odds ratio (OR) = 1.31, 95% confidence interval (CI): 1.04, 1.65) and current smokers (OR = 1.70, 95% CI: 1.37, 2.11) had increased risks for adenomas compared with nonsmokers. Cigarette smoking conferred an even higher risk for advanced adenomas and 3 or more adenomas than for low-risk adenomas or a single adenoma. Dose-response relations were observed among the daily number of cigarettes smoked, the duration of smoking, the pack-years of smoking, and the risk for adenomas. A longer duration of alcohol consumption was associated with a higher risk for advanced adenomas (for >28 years of consumption: OR = 2.0, 95% CI: 1.10, 3.64) and 3 or more adenomas (OR = 2.19, 95% CI: 1.27, 3.76). In conclusion, cigarette smoking and alcohol consumption play roles in colorectal carcinogenesis, and the association differs by the clinical features of the adenomas.

Impact of prior abdominal or pelvic surgery on colonoscopy outcomes

Goals This large prospective study attempted to analyze the effect of various prior surgery on colonoscopy performance. Background It is generally presumed that colonoscopy in patients with a history of abdominal or pelvic surgery is difficult. This difficulty is apparently due to adhesions and anatomic alterations after surgery but the incidence, site, and severity of adhesions are different according to the types of surgery. Study We analyzed completion rate and insertion time in 4089 consecutive colonoscopies in patients with intact colon. Results The adjusted completion rate for colonoscopy was 96.7%. The mean insertion time was 6.2±4.0 minutes. Not only old age [odds ratio (OR) 1.46; 95% confidence interval (CI) [1.04, 2.04]] and inadequate bowel cleansing (OR 5.82; 95% CI [4.19, 8.09]) but also a surgical history (OR 1.71; 95% CI [1.18, 2.48]) were independent factors associated with procedural incompleteness. Of surgical history, gastrectomy and hysterectomy were significantly associated with procedural incompleteness (P<0.001 and P=0.001, respectively). Old age (OR 1.48; 95% CI [1.22, 1.79]), female sex (OR 1.22; 95% CI [1.01, 1.48]), constipation as an indication (OR 1.58; 95% CI [1.24, 2.02]), and inadequate bowel cleansing (OR 1.46; 95% CI [1.13, 1.88]) were independent factors associated with prolonged insertion time (>10 min), but a surgical history lost statistical power as a predictor for prolonged insertion time in multivariate analysis. Conclusions Although the difference in insertion time was not substantial, a history of abdominal or pelvic surgery is associated with difficulty in colonoscopy.

Validity of fecal occult blood test in the national cancer screening program, Korea.

Aim The aims of the current study were to assess the validity of the fecal occult blood test (FOBT) in an organized screening setting in Korea and to determine factors associated with FOBT validity, such as screening round, age group, and anatomical location of the cancer. Methods Study participants were those who were 50 years and older who received an FOBT through the National Cancer Screening Program between 2004 and 2007. Colorectal cancer diagnoses were ascertained through linkage with the Korean National Cancer Incidence Database. The positivity rate, colorectal cancer detection rate, interval cancer rate, sensitivity, specificity, and positive predictive value of the FOBT were calculated. Results A total of 2,193,093 tests were included in the analysis. Overall, the sensitivity of the FOBT for colorectal cancer was 59.7% for the first round and 56.1% for the subsequent round. Sensitivity was highest for distal colon cancer (65.9%) in the first round, and for rectal cancer (58.4%) for the subsequent round. The sensitivity and positive predictive value of the FOBT generally improved between 2004 and 2008. Conclusions The FOBT showed reasonable validity in an organized screening setting, and the validity of the FOBT varied by screening round, anatomical location, and screening year.

Carbonic anhydrase 9 is a predictive marker of survival benefit from lower dose of bevacizumab in patients with previously treated metastatic colorectal cancer.

BackgroundCarbonic anhydrase 9 (CA9) is a marker for hypoxia and acidosis, which is linked to a poor prognosis in human tumors. The purpose of this comparative analysis was to evaluate whether CA9 and VEGF expression are associated with survival outcomes in patients with metastatic colorectal cancer (mCRC) after treatment with bevacizumab as second or later line treatment.MethodsThirty-one mCRC patients who were treated with bevacizumab-containing chemotherapy as second or later line treatment and who had analyzable tumor paraffin blocks were selected for this study. The planned dose of bevacizumab was 5 mg/kg/2-week. Immunohistochemical (IHC) staining of CA9 and VEGF was performed and their expression was scored by the intensity multiplied by percentage of stained area.ResultsThe overall response rate was 19.4% and the disease control rate (DCR) was 61.3% with 6 partial responses and 13 cases of stable disease. The DCR was significantly higher in patients with a lower CA9 expression score compared to those with a higher score (80.0% vs. 27.3%, respectively, P = 0.004). The patients with a low CA9 expression score also showed better outcomes with regard to the median progression-free survival (P = 0.028) and overall survival (P = 0.026). However, VEGF expression was not associated with the DCR and survival.ConclusionLower degree of CA9 expression was associated with better clinical outcomes in patients with mCRC treated with lower dose bevacizumab-based chemotherapy. Prospective studies are now needed to determine the correlation between CA9 expression and clinical outcomes after bevacizumab treatment, at different doses and in varied settings.

Prevalence and Risk Factors of Irritable Bowel Syndrome in Healthy Screenee Undergoing Colonoscopy and Laboratory Tests

Introduction The prevalence of irritable bowel syndrome (IBS) after excluding organic disease has not been reported in Korea. Methods Of 5,605 participants in a health screening program, inclusion criteria were persons who underwent colonoscopy and completed questionnaires. Exclusion criteria were persons diagnosed with colon cancer, inflammatory bowel disease, previous colectomy, and abnormal results of thyroid function tests. IBS was defined by Rome III criteria. Physical and psychological stress was evaluated with visual analogue scales, ranging from 0 to 10. Risk factors for IBS were estimated with odds ratios (OR) and 95% confidence intervals (CI) using logistic regression analysis. Results The prevalence of IBS was 8.2% (5,605) in the total population and 9.1% (393/4,296) in the final study sample. IBS had a positive association with female sex (adjusted OR, 1.33; 95% CI, 1.00-1.79; p = 0.05) and current smoking (adjusted OR, 1.31; 95% CI, 1.00-1.71; p = 0.05). The prevalence of IBS increased with increased psychological stress (adjusted p for trend = 0.005) and decreased with increasing age (adjusted p for trend <0.001), with adjusted OR of 0.95 (95% CI, 0.68-1.33) for age of 40.0 to 49.9 years; 0.79 (95% CI, 0.54-1.15) for age of 50.0 to 59.9 years; and 0.51 (95% CI, 0.30-0.86) for age of 60 years or more, compared with age less than 40 years. Drinking status, body mass index, hypertension, diabetes, and use of sedatives had no association with IBS. Conclusions The prevalence of IBS increased with decreasing age and increasing psychological stress, and was positively associated with female sex and current smoking.