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Dive into the research topics where Tak Geun Oh is active.

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Featured researches published by Tak Geun Oh.


Journal of Gastrointestinal Surgery | 2013

Comparison of the sixth and seventh editions of the AJCC TNM classification for gallbladder cancer.

Tak Geun Oh; Moon Jae Chung; Seungmin Bang; Seung Woo Park; Jae Bock Chung; Si Young Song; Gi Hong Choi; Kyung Sik Kim; Woo Jung Lee; Jeong Youp Park

BackgroundThis study aimed to compare the seventh edition of the tumor node metastasis (TNM) staging system to the sixth edition to validate its usefulness in predicting prognosis for gallbladder cancer.MethodsGallbladder cancer patients were staged according to both the sixth and seventh editions of the American Joint Committee on Cancer (AJCC) staging system.ResultsA total of 142 patients underwent cholecystectomy for gallbladder cancer. According to the seventh edition, the survival time of N1 and N2 was different (P = 0.006), and the survival difference between N0 and N1 became significant after excluding cases with no lymph node dissection (P = 0.035). The −2 log likelihoods of the sixth and seventh edition TNM stages were 216.282 and 217.460, respectively, suggesting non-superiority of the seventh edition. Excluding cases with no lymph node dissection resulted in a lower −2 log likelihood score for both editions (sixth, 157.002; seventh, 158.758).ConclusionsSufficient lymph node dissection allows better prognostic stratification by application of the AJCC staging system. Even though the new N stage of the seventh edition showed some improvement in predicting prognosis, the overall performance of the seventh edition was not much better than the sixth. Further improvement is needed in the gallbladder cancer staging system.


Endoscopy | 2014

Intramuscular diclofenac for the prevention of post-ERCP pancreatitis: A randomized trial

Se Woo Park; Moon Jae Chung; Tak Geun Oh; Jeong Youp Park; Seungmin Bang; Seung Woo Park; Si Young Song

BACKGROUND AND STUDY AIMS Rectal nonsteroidal anti-inflammatory drugs have been shown to reduce the incidence of postendoscopic retrograde cholangiopancreatography (ERCP) pancreatitis (PEP). The aim of this study was to determine whether intramuscular diclofenac reduces the risk of PEP. PATIENTS AND METHODS Patients who underwent ERCP were randomized to receive either 90 mg of diclofenac or placebo by intramuscular injection immediately after the procedure. PEP was defined as elevated serum amylase levels (at least three times the upper limit of normal 24 hours after the procedure) associated with new or worsened upper abdominal, epigastric, or back pain. RESULTS In total, 380 patients were randomized, and 343 were eligible for analysis. The two groups were similar regarding clinical and demographic factors, as well as patient- and procedure-related risk factors for PEP. PEP developed in 20/170 patients (11.8 %) in the placebo group and in 22/173 patients (12.7 %) in the diclofenac group (P = 0.87). Multivariate regression analysis failed to illustrate that intramuscular diclofenac prevented PEP (odds ratio 0.79; 95 % confidence interval 0.39 - 1.25; P = 0.51). CONCLUSION Prophylactic intramuscular diclofenac had no beneficial preventive effect on PEP.Clinicaltrials.gov NCT01717599.


Yonsei Medical Journal | 2012

Prognostic factors and characteristics of pancreatic neuroendocrine tumors: single center experience.

Tak Geun Oh; Moon Jae Chung; Jeong Yeop Park; Seung Min Bang; Seung Woo Park; Jae Bok Chung; Si Young Song

Purpose Pancreatic neuroendocrine tumors (PNET) are a rare subgroup of tumors. For PNETs, the predictive factors for survival and prognosis are not well known. The purpose of our study was to evaluate the predictive factors for survival and disease progression in PNETs. Materials and Methods We retrospectively analyzed 37 patients who were diagnosed with PNET at Severance Hospital between November 2005 and March 2010. Prognostic factors for survival and disease progression were evaluated using the Kaplan-Meier method. Results The mean age of the patients was 50.0±15.0 years. Eight cases (21.6%) were described as functioning tumors and 29 cases (78.4%) as non-functioning tumors. In univariate analysis of clinical factors, patients with liver metastasis (p=0.002), without resection of primary tumors (p=0.002), or American Joint Committee on Cancer/Union for International Cancer Control (AJCC/UICC) stage III/IV (p=0.002) were more likely to demonstrate shorter overall survival (OS). Patients with bile duct or pancreatic duct invasion (p=0.031), sized-lesions larger than 20 mm (p=0.036), liver metastasis (p=0.020), distant metastasis (p=0.005), lymph node metastasis (p=0.009) or without resection of primary tumors (p=0.020) were more likely to demonstrate shorter progression-free survival (PFS). In multivariate analysis of clinical factors, bile duct or pancreatic duct invasion [p=0.010, hazard ratio (HR)=95.046] and tumor location (non-head of pancreas) (p=0.036, HR=7.381) were confirmed as independent factors for predicting shorter PFS. Conclusion Patients with liver metastasis or without resection of primary tumors were more likely to demonstrate shorter OS. Patients with bile duct or pancreatic duct invasion or tumors located at body or tail of pancreas were more likely to demonstrate shorter PFS.


Yonsei Medical Journal | 2016

Cholecystectomy for prevention of recurrence after endoscopic clearance of bile duct stones in Korea

Myung Eun Song; Moon Jae Chung; Dong Jun Lee; Tak Geun Oh; Jeong Youp Park; Seungmin Bang; Seung Woo Park; Si Young Song; Jae Bock Chung

Purpose Cholecystectomy in patients with an intact gallbladder after endoscopic removal of stones from the common bile duct (CBD) remains controversial. We conducted a case-control study to determine the risk of recurrent CBD stones and the benefit of cholecystectomy for prevention of recurrence after endoscopic removal of stones from the CBD in Korean patients. Materials and Methods A total of 317 patients who underwent endoscopic CBD stone extraction between 2006 and 2012 were included. Possible risk factors for the recurrence of CBD stones including previous cholecystectomy history, bile duct diameter, stone size, number of stones, stone composition, and the presence of a periampullary diverticulum were analyzed. Results The mean duration of follow-up after CBD stone extraction was 25.4±22.0 months. A CBD diameter of 15 mm or larger [odds ratio (OR), 1.930; 95% confidence interval (CI), 1.098 to 3.391; p=0.022] and the presence of a periampullary diverticulum (OR, 1.859; 95% CI, 1.014 to 3.408; p=0.045) were independent predictive factors for CBD stone recurrence. Seventeen patients (26.6%) in the recurrence group underwent elective cholecystectomy soon after endoscopic extraction of CBD stones, compared to 88 (34.8%) in the non-recurrence group; the difference was not statistically significant (p=0.212). Conclusion A CBD diameter of 15 mm or larger and the presence of a periampullary diverticulum were found to be potential predictive factors for recurrence after endoscopic extraction of CBD stones. Elective cholecystectomy after clearance of CBD stones did not reduce the incidence of recurrent CBD stones in Korean patients.


PLOS ONE | 2015

Conventional versus Analgesia-Oriented Combination Sedation on Recovery Profiles and Satisfaction after ERCP: A Randomized Trial

Seokyung Shin; Tak Geun Oh; Moon Jae Chung; Jeong Youp Park; Seung Woo Park; Jae Bok Chung; Si Young Song; Jooyoun Cho; Sang Hun Park; Young Chul Yoo; Seungmin Bang

Background The importance of providing effective analgesia during sedation for complex endoscopic procedures has been widely recognized. However, repeated administration of opioids in order to achieve sufficient analgesia may carry the risk of delayed recovery after propofol based sedation. This study was done to compare recovery profiles and the satisfaction of the endoscopists and patients between conventional balanced propofol sedation and analgesia-oriented combination sedation for patients undergoing endoscopic retrograde cholangiopancreatography (ERCP). Methods Two hundred and two adult patients scheduled for ERCP were sedated by either the Conventional (initial bolus of meperidine with propofol infusion) or Combination (repeated bolus doses of fentanyl with propofol infusion) method. Recovery profiles, satisfaction levels of the endoscopists and patients, drug requirements and complications were compared between groups. Results Patients of the Combination Group required significantly less propofol compared to the Conventional Group (135.0 ± 68.8 mg vs. 165.3 ± 81.7 mg, P = 0.005). Modified Aldrete scores were not different between groups throughout the recovery period, and recovery times were also comparable between groups. Satisfaction scores were not different between the two groups in both the endoscopists and patients (P = 0.868 and 0.890, respectively). Conclusions Considering the significant reduction in propofol dose, the non-inferiority of recovery profiles and satisfaction scores of the endoscopists and patients, analgesia oriented combination sedation may be a more safe yet effective sedative method compared to conventional balanced propofol sedation during ERCP.


Gut and Liver | 2014

Validation of Group B Borderline Resectable Pancreatic Cancer: Retrospective Analysis

Tak Geun Oh; Moon Jae Chung; Seungmin Bang; Seung Woo Park; Jae Bok Chung; Si Young Song; Jinsil Seong; Chang Moo Kang; Woo Jung Lee; Jeong Youp Park

Background/Aims Among borderline resectable pancreatic cancer (BRPC), group B BRPC patients have findings that are suggestive but not diagnostic of metastasis. In this study, we attempted to validate whether group B could truly be categorized as a borderline resectable group. Methods We placed the BRPC patients into group A or group B. The survival outcomes were compared between the groups. Results A total of 53 patients with pancreatic adenocarcinoma was classified as either group A or B borderline resectable. In group A, 23 (60.5%) of 38 patients underwent pancreatectomy after concurrent chemoradiotherapy or chemotherapy, but in group B, only five (33.3%) of 15 patients underwent pancreatectomy, mainly because of the progression of suspected distant metastasis. There was a significant difference in overall survival (OS) between group A and B patients (median OS, 21.2 months vs 10.2 months, respectively; p=0.007). Of the patients who underwent pancreatectomy, group B had a higher recurrence rate compared to group A (recurrence rate: 11 of 23 patients [47.8%] vs five of five patients [100%], respectively; p=0.033). Conclusions This report is the first to validate the definition of BPRC. Group B had much worse outcomes, and whether group B BRPC can be categorized as BRPC together with group A is questionable.


Chemotherapy | 2014

Full-Dose Gemcitabine Is a More Effective Chemotherapeutic Agent Than 5-Fluorouracil for Concurrent Chemoradiotherapy as First-Line Treatment in Locally Advanced Pancreatic Cancer

Huapyong Kang; Jee Suk Chang; Tak Geun Oh; Moon Jae Chung; Jeong Youp Park; Seung Woo Park; Jinsil Seong; Si Young Song; Jae Bock Chung; Seungmin Bang

Objectives: To compare the efficacy of full-dose gemcitabine-based concurrent chemoradiotherapy (FG-CCRT) and conventional 5-fluorouracil CCRT (5FU-CCRT) for locally advanced pancreatic cancer (LAPC). Methods: 109 LAPC cases treated with FG-CCRT (n = 89) or 5FU-CCRT (n = 20) were reviewed retrospectively. The FG-CCRT group was composed of a full-dose gemcitabine monotherapy (1,000 mg/m2) arm and a combination therapy with cisplatin (70 mg/m2) arm. The 5FU-CCRT group used a radiosensitizing dose of 5-FU (500 mg/m2) plus leucovorin (20 mg/m2). Concurrent radiotherapy was targeted at the tumor with a 5-mm margin without lymph node irradiation. Results: Objective response rate (ORR) and disease control rate (DCR) was significantly higher in the FG-CCRT group (ORR: 32.6 vs. 5%, p = 0.013; DCR: 79.8 vs. 50.0%, p = 0.006). FG-CCRT showed remarkable superiority to 5FU-CCRT for suppressing distant metastasis (18.0 vs. 45.0%, p = 0.017). Neutropenia (34.8 vs. 10%, p = 0.032) and thrombocytopenia (21.3 vs. 0.0%, p = 0.021) were more frequent in the FG-CCRT group as originally expected. When dividing the FG-CCRT group to gemcitabine monotherapy (GEM) and gemcitabine plus cisplatin, toxicities of the GEM subgroup were not different than those of the 5FU-CCRT group. Conclusion: FG-CCRT, especially full-dose gemcitabine monotherapy-based CCRT was more effective for the initial control of LAPC than 5FU-CCRT, and also relatively safe.


Gastrointestinal Endoscopy | 2012

Sa1574 Usefulness of Contrast Enhanced Harmonic-EUS (CEH-EUS) in the Diagnosis of Neoplastic Gallbladder Polyps

Tak Geun Oh; Chan Hyuk Park; Jeong Youp Park; Seungmin Bang; Seung Woo Park; Si Young Song; Jae Bock Chung; Moon Jae Chung

underwent EUS-guided FNA of pancreatic lesions, and 76 of these (33%) had nondiagnostic cytology despite imaging findings and clinical scenario suspicious for pancreatic neoplasm. Fourteen patients underwent repeat EUS-guided FNA. All patients had a measurable mass, with mean size 34.5mm in maximal diameter. Eight lesions were sampled via transduodenal approach, while the other 6 six were sampled via transgastric FNA. Of the patients who underwent repeat FNA, 5/14 (36%) were positive. Three of these patients had ductal adenocarcinoma, one had a neuroendocrine tumor, and one had lymphoma presenting as a pancreatic mass. There was no difference in the number of needle passes between the initial FNA (3.21 /1.65 passes) and the repeat FNA (3.64 /1.95 passes). A larger needle gauge was used in 3 of the 5 patients (60%) who had positive cytology on their repeat FNA, and in 1 of 9 (11%) whose cytology remained inconclusive (p NS). The patients with positive repeat FNAs underwent repeat exams slightly sooner (median 18 days) than the patients with indeterminate repeat FNAs (median 21 days). Conclusions: Repeat EUSguided FNA leads to a conclusive cytological result in 36% of patients with high clinical suspicion for neoplasm and an inconclusive initial EUS-guided FNA. Repeating EUS-guided FNA on these suspicious lesions should be considered prior to surgical referral.


Surgical Endoscopy and Other Interventional Techniques | 2013

Differential diagnosis between gallbladder adenomas and cholesterol polyps on contrast-enhanced harmonic endoscopic ultrasonography.

Chan Hyuk Park; Moon Jae Chung; Tak Geun Oh; Jeong Youp Park; Seungmin Bang; Seung Woo Park; Hyunki Kim; Ho Kyoung Hwang; Woo Jung Lee; Si Young Song


Clinical Nutrition Research | 2013

The Use of Health Functional Foods in Gastrointestinal Cancer Patients

Hwa Pyoung Kang; Hosun Lee; Tak Geun Oh; Kyong Joo Lee; Soo Jung Park; Moon Jae Chung; Seung Up Kim; Hyuk Lee; Jun Chul Park; Sung Pil Hong; Jun Yong Park; Jeong Youp Park; Seungmin Bang; Do Young Kim; Jae Hee Cheon; Sang Hoon Ahn; Tae Il Kim; Seung Woo Park; Si Young Song

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