Sun-Jin Boo

Quantifying exposure to diagnostic radiation and factors associated with exposure to high levels of radiation in Korean patients with inflammatory bowel disease.

Background:Several recent studies have revealed that diagnostic imaging can result in exposure to potentially harmful levels of ionizing radiation in patients with inflammatory bowel disease (IBD). However, these studies have been conducted exclusively in Western countries, and no data are available in Asian populations. The aim of this study was to estimate the diagnostic radiation exposure in Korean patients with IBD and to determine the factors associated with high radiation exposure. Methods:Patients with an established diagnosis of IBD between July 1987 and January 2012 were investigated in 13 university hospitals in Korea. The cumulative effective dose (CED) was calculated retrospectively from standard tables. Results:A total of 777 patients with Crohn’s disease (CD) and 1422 patients with ulcerative colitis (UC) were included in the study. The mean CED for CD and UC were 53.6 and 16.4 mSv, respectively (P < 0.001). CTof CD and UC accounted for 81.6% and 71.2% of total effective dose, respectively. Importantly, 34.7% of patients with CD and 8.4% of patients with UC were exposed to high levels of radiation (CED > 50 mSv) (P < 0.001). High radiation exposure was associated with long disease duration, ileocolonic disease, upper gastrointestinal tract involvement, surgical intervention, hospitalization, and the requirement for oral steroids in CD, and with surgical intervention, hospitalization, and the requirement for infliximab in UC. Conclusions:A substantial proportion of patients with IBD, especially patients with CD, were exposed to significantly harmful amounts of diagnostic radiation, mainly as a result of CT examination. Given that IBD is a life-long illness, strategies to reduce radiation exposure from diagnostic imaging need to be considered.

Reduced Autophagy in 5-Fluorouracil Resistant Colon Cancer Cells

We investigated the role of autophagy in SNUC5/5-FUR, 5-fluorouracil (5-FU) resistant SNUC5 colon cancer cells. SNUC5/5-FUR cells exhibited low level of autophagy, as determined by light microscopy, confocal microscopy, and flow cytometry following acridine orange staining, and the decreased level of GFP-LC3 puncta. In addition, expression of critical autophagic proteins such as Atg5, Beclin-1 and LC3-II and autophagic flux was diminished in SNUC5/5-FUR cells. Whereas production of reactive oxygen species (ROS) was significantly elevated in SNUC5/5-FUR cells, treatment with the ROS inhibitor N-acetyl cysteine further reduced the level of autophagy. Taken together, these results indicate that decreased autophagy is linked to 5-FU resistance in SNUC5 colon cancer cells.

An adequate level of training for technically competent colonoscopic polypectomy.

Abstract Goals. The purpose of this study is to investigate the learning curve for colonoscopic polypectomy (CP) by trainee endoscopists. Background. The amount of training required to achieve technical competence for CP is uncertain. Study. The CP times and en bloc resection rates of three experienced colonoscopists were obtained from 240 procedures. These data were compared to those of three gastroenterology trainees who performed 750 CP procedures. A trainee procedure was deemed to be a success if en bloc resection was obtained and the CP time was within twice the median CP time of the experienced colonoscopists. Trainees were deemed to be technically competent when they achieved a CP success rate of greater than or equal to 80%. Results. The median CP times and en bloc resection rates for the experienced colonoscopists and trainees were 79 s (range, 20–301 s) and 99.6% (239/240), and 118 s (range, 36–1051 s) and 95.6% (717/750), respectively. The trainee success rate of CP was 72% (540/750). The success rate of the procedure was associated with increased trainee experience (p = 0.003) and reached 80% after 250 procedures. The CP time significantly decreased (p < 0.001) and en bloc resection rate significantly increased (p = 0.011) as trainee experience accumulated. The level of experience was an independent predictor for successful CP. Conclusions. The achievement of technical competence with CP was associated with an accumulation of approximately 250 procedures. These findings suggest that dedicated education and training programs for CP are warranted.

Patient descriptions of rectal effluents may help to predict the quality of bowel preparation with photographic examples.

Background/Aims Previous studies have suggested a weak correlation between self-reported rectal effluent status and bowel preparation quality. We aim to evaluate whether photographic examples of rectal effluents could improve the correlation between patient descriptions of rectal effluents and bowel preparation quality. Methods Before colonoscopy, patients were asked to describe the nature of their last three rectal effluents. Photographic examples of rectal effluents were provided as a reference for scoring. Bowel preparation was subsequently assessed by a single endoscopist using a global preparation assessment scale. Preparation outcomes were grouped into two levels (excellent to good vs. fair to inadequate). Both univariate and multivariate logistic regression models were used to find any association between bowel preparation quality and patient characteristics. Results A total of 138 patients completed the questionnaires. The mean age was 56.5±10.4 years. The mean sum of the last three rectal effluent scores was 5.9±2.0. Higher rectal effluent scores (odds ratio [OR], 0.82; P=0.043) and the presence of diverticula (OR, 0.16; P<0.001) were risk factors for suboptimal preparation. Conclusions Photographic example-guided patient descriptions of rectal effluents showed a statistically significant association with bowel preparation quality. However, clinical significance seemed to be low. The presence of diverticula was an independent predictive factor for suboptimal bowel preparation quality.

The effect of small or diminutive adenomas at baseline colonoscopy on the risk of developing metachronous advanced colorectal neoplasia: KASID multicenter study

BACKGROUND The clinical significance of diminutive or small adenomas remains ill defined. AIMS We evaluated the clinical impact of diminutive or small adenomas at baseline on the risk of developing metachronous advanced colorectal neoplasia (CRN). METHODS This multicenter, retrospective cohort study included 2252 patients with 1 or more colorectal adenomas at baseline and subsequent follow-up colonoscopy. Baseline colonoscopy findings were classified into 5 groups: 1 or 2 tubular adenomas (TAs) (<10 mm); 3-10 diminutive TAs (≤5 mm); 3-10 TAs, including 1 or 2 small adenomas (6-10 mm); 3-10 TAs, including 3 or more small adenomas; and advanced adenoma. RESULTS In multivariate analysis, after adjusting for possible confounding variables (age at baseline, sex, body mass index, smoking habits, family history of colorectal cancer, regular use of aspirin or NSAIDs, and adenoma location), 3-10 TAs including 3 or more small adenomas (hazard ratio [HR] = 2.36, p = 0.034) and advanced adenoma (HR = 2.14, p < 0.001) were independent predictors for the risk of developing metachronous advanced CRN. However, 3-10 diminutive TAs or 3-10 TAs, including 1 or 2 small adenomas, were not associated with this outcome. CONCLUSIONS Multiplicity of diminutive TAs, without advanced lesions, showed no clinical significance for risk of developing metachronous advanced CRN.

Higher body mass index is associated with an increased risk of multiplicity in surveillance colonoscopy within 5 years

We aimed to evaluate whether obesity was associated with a certain clinicopathologic characteristics of metachronous CRA. This retrospective longitudinal cohort study included 2,904 subjects who had at least one resected CRA at index colonoscopy and who subsequently underwent one or more surveillance colonoscopies within 5 years. Of the 2,904 subjects, 60.9% (n = 1,769) were normal, 35.8% (n = 1,040) were overweight, and 3.3% (n = 95) were obese. Patients with any metachronous CRA were 53.7% (n = 1,559). In multivariate analyses, higher BMI at index colonoscopy was significantly associated with any metachronous CRA (overweight, OR = 1.07; obese, OR = 1.82; p for trend = 0.049). Regarding the multiplicity, the ORs of ≥ 3, ≥ 4 and ≥ 5 metachronous CRAs significantly increased as index BMI increased (p for trend < 0.001, = 0.007 and = 0.004, respectively). In negative binomial regression regarding the incidence for total number of metachronous CRA, the higher BMI the subject has at the time of index colonoscopy, the more metachronous CRAs the subject will have at the surveillance colonoscopy (p for trend = 0.016). Higher index BMI was significantly associated with the risk of multiple metachronous CRAs on surveillance colonoscopy within 5 years.

[Clinical Efficacy of Dynamic Contrast-enhanced Multidetector-row Computed Tomography in Patients with Obscure Gastrointestinal Bleeding].

BACKGROUND/AIMS Obscure gastrointestinal bleeding (OGIB) accounts for 5% of all gastrointestinal (GI) bleeding cases. Dynamic contrast-enhanced multidetector-row CT (DCE-MDCT) is not generally recommended in OGIB patients due to its low sensitivity. However, it can be used to quickly and simply diagnose OGIB according to some guidelines. The aim of this study was to evaluate the clinical efficacy of DCE-MDCT in OGIB patients. METHODS We retrospectively analyzed the medical records of 362 patients who underwent DCE-MDCT between March 2009 and January 2014. A total of 45 patients diagnosed with OGIB were included in this study. Their baseline characteristics and treatment procedure were analyzed retrospectively. The positive rates of DCE-MDCT for the detection of bleeding and associated factors were assessed. RESULTS The mean age of the patients was 59 years, and males represented 51.1%. Melena was the most common symptom (44.4%). Positive rate of DCE-MDCT findings was 20.0% (9/45). Among these patients, intraluminal contrast extravasation was found in 5 patients (55.6%) and intraluminal hematoma or mass lesions were found in 2 patients each (22.2%). Thirty nine patients (86.7%) underwent conservative management, and 6 patients (13.3%) underwent specific treatment, such as endoscopic treatment, embolization, or surgery. Patients who showed positivity in DCE-MDCT more frequently received specific treatment compared with those who were negative (44.4% vs. 5.6%, p=0.010). CONCLUSIONS Although DCE-MDCT showed a low positive rate (20.0%), positive findings of DCE-MDCT could lead to specific treatment. Positive DCE-MDCT findings play a useful role in the management of patients with OGIB.

Esophageal Foreign Body: Treatment and Complications

The most common cause of esophageal foreign bodies in adults is meat in Western countries and fish bones in Asian countries, including Korea. Although most ingested foreign bodies pass spontaneously through the esophagus without any clinical sequelae, some sharp foreign bodies, such as fish bones embedded in the esophagus, require treatment. Endoscopic management is the first choice in the treatment of esophageal foreign bodies because it is quite safe and effective. Major complications occur as a result of esophageal perforation; in particular, sharp foreign bodies, such as fish bones, are more likely to cause perforation. Complications include mediastinitis, paraesophageal abscess, pneumomediastinum, subcutaneous emphysema, pneumothorax, tracheoesophagal fistula, aortoesophageal fistula, aspiration, and asphyxia. Unnecessary delays should be avoided in endoscopic intervention for esophageal foreign bodies to prevent complications.

Risks of colorectal advanced neoplasia in young adults versus those of screening colonoscopy in patients aged 50 to 54 years

The role of screening or diagnostic colonoscopy to detect advanced neoplasia in young cohorts of age < 50 is unclear. This study compared the risk of colorectal neoplasia in a young age cohort against that in 50–54s screening cohort.

Risk of advanced colorectal neoplasm in patients with more than 10 adenomas on index colonoscopy: A Korean Association for the Study of Intestinal Diseases (KASID) Study

The number of patients with >10 adenomas is relatively small, and few studies have investigated the risk of colorectal neoplasm (CRN) in these patients. Thus, we aimed to investigate the risk of developing CRN in patients with >10 adenomas and to compare their risk with that of patients with 3–10 adenomas.