DaeGon Ryu

Prof. Dr. DaeGon Ryu

orcid

Research Focus & Metrics

Academic Career Length

11Years (2016-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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Verified
Journal Article
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DRDaeGon Ryu
DaeGon Ryu
SKSu-Jin Kim
Su-Jin Kim
CCCheol Woong Choi
Cheol Woong Choi
SPSu Bum Park
Su Bum Park
HNHyeong-seok Nam
Hyeong-seok Nam
SHSun-Hwi Hwang
Sun-Hwi Hwang
Endoscopic submucosal dissection (ESD) is considered the treatment of choice for early gastric cancer (EGC) with a negligible risk of lymph node metastasis. Locally recurrent lesions on artificial ulcer scars are difficult to manage. Predicting the risk of local recurrence after ESD is important to manage and prevent the event. We aimed to elucidate the risk factors associated with local recurrence after ESD of EGC. Between November 2008 and February 2016, consecutive patients (n = 641; mean age, 69.3 ± 9.5 years; men, 77.2%) with EGC who underwent ESD at a single tertiary referral hospital were retrospectively analyzed to evaluate the incidence and factors associated with local recurrence. Local recurrence was defined as the development of neoplastic lesions at or adjacent to the site of the post-ESD scar. En bloc and complete resection rates were 97.8% and 93.6%, respectively. The local recurrence rate after ESD was 3.1%. The mean follow-up period after ESD was 50.7 ± 32.5 months. One case of gastric cancer-related death (0.15%) was noted, wherein the patient had refused additive surgical resection after ESD for EGC with lymphatic and deep submucosal invasion. Lesion size ≥15 mm, incomplete histologic resection, undifferentiated adenocarcinoma, scar, and the absence of erythema of the surface were associated with a higher risk of local recurrence. Predicting local recurrence during regular endoscopic surveillance after ESD is important, especially in patients with a larger lesion size (≥15 mm), incomplete histologic resection, surface changes of scars, and no erythema of the surface.

14 October 2022 in Medicine
Verified
Journal Article
Open access
SKSu Jin Kim
Su Jin Kim
TKTae Un Kim
Tae Un Kim
CCCheol Woong Choi
Cheol Woong Choi
HKHyung Wook Kim
Hyung Wook Kim
SPSu Bum Park
Su Bum Park
DRDaeGon Ryu
DaeGon Ryu
Introduction: Underwater endoscopic mucosal resection (UW-EMR) has been recently introduced as an effective technique for rectal third layer subepithelial tumors. Therefore, we aimed to assess the safety, efficacy, and procedure time of UW-EMR for upper gastrointestinal subepithelial tumors (SETs) originating from the deep mucosal and/or submucosal layers. Methods: Between August 2018 to July 2022, a total of 17 SETs (7 duodenal SETs, 6 gastric SETs, and 4 esophageal SETs) were included in this study. On endoscopic ultrasound examinations, the tumors were found to be embedded in the submucosa without muscularis propria invasion. All SETs were resected successfully using UW-EMR. The characteristics of the tumors and their R0 resection rate, adverse event rate, and recurrence rate were evaluated retrospectively. Results: The mean tumor size was 0.9 cm (range, 0.3-1.5 cm). En bloc resection and complete resection rates were 100%, respectively. The patients showed no complications such as perforation or bleeding. Histologic assessments of the resected tumors revealed 9 neuroendocrine tumors (7 on the duodenum, 2 on the stomach), 2 gastric cystica profunda, 1 gastric follicular lymphoma, 1 gastric fibromyxoma, 3 esophageal granular cell tumors, and 1 esophageal adenoid cystic carcinoma. The mean procedural time was 3.2 min (range, 1.3-8.7 minutes). The overall en bloc and complete resection rates were 100%, respectively. No recurrence was observed during the follow-up period. Conclusion: UW-EMR is a safe and effective treatment for upper gastrointestinal SETs embedded in the submucosal layer. Further studies are needed to compare other endoscopic resection techniques.

Verified
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HLHongqun Liu
Hongqun Liu
DRDaeGon Ryu
DaeGon Ryu
SHSangyoun Hwang
Sangyoun Hwang
SLSamuel Lee
Samuel Lee
Cirrhotic cardiomyopathy (CCM) is defined as cardiac dysfunction associated with cirrhosis in the absence of pre-existing heart disease. CCM manifests as the enlargement of cardiac chambers, attenuated systolic and diastolic contractile responses to stress stimuli, and repolarization changes. CCM significantly contributes to mortality and morbidity in patients who undergo liver transplantation and contributes to the pathogenesis of hepatorenal syndrome/acute kidney injury. There is currently no specific treatment. The traditional management for non-cirrhotic cardiomyopathies, such as vasodilators or diuretics, is not applicable because an important feature of cirrhosis is decreased systemic vascular resistance; therefore, vasodilators further worsen the peripheral vasodilatation and hypotension. Long-term diuretic use may cause electrolyte imbalances and potentially renal injury. The heart of the cirrhotic patient is insensitive to cardiac glycosides. Therefore, these types of medications are not useful in patients with CCM. Exploring the therapeutic strategies of CCM is of the utmost importance. The present review summarizes the possible treatment of CCM. We detail the current status of non-selective beta-blockers (NSBBs) in the management of cirrhotic patients and discuss the controversies surrounding NSBBs in clinical practice. Other possible therapeutic agents include drugs with antioxidant, anti-inflammatory, and anti-apoptotic functions; such effects may have potential clinical application. These drugs currently are mainly based on animal studies and include statins, taurine, spermidine, galectin inhibitors, albumin, and direct antioxidants. We conclude with speculations on the future research directions in CCM treatment.

16 July 2018 in Scandinavian Journal of Gastroenterology
Verified
Journal Article
Closed access
HNHyeong-seok Nam
Hyeong-seok Nam
CCCheol Woong Choi
Cheol Woong Choi
SKSu Jin Kim
Su Jin Kim
DKDae-Hwan Kang
Dae-Hwan Kang
HKHyung Wook Kim
Hyung Wook Kim
DRDaeGon Ryu
DaeGon Ryu
Objective: Endoscopic submucosal dissection (ESD) has been accepted as the treatment of choice for gastric epithelial neoplasia. Endoscopic characteristics of the primary lesion and post-ESD scars may be informative to predict the possibility of local recurrence. Methods: Between November 2008 and July 2015, a retrospective study was conducted in a single-tertiary referral hospital. Consecutive patients who underwent ESD for early gastric cancer (EGC) or high-grade dysplasia were analyzed to evaluate the incidence of local recurrence and associated endoscopic characteristics. Results: A total of 639 lesions were analyzed. The rates of en-bloc and complete resection were 98.1% and 95.5%, respectively. A total of 15 local recurrent lesions were found (2.3%). The endoscopic findings of primary lesions associated with local recurrence were a lesion size ≥20 mm (odds ratio, OR, 4.408; 95% confidence interval, CI, 1.369–14.186, p = .013) and incomplete endoscopic resection (OR 17.059, 95% CI 4.887–59.551, p < .001). During follow-up endoscopic examinations, atypical scar findings (non-flat morphology, erythematous color change and uneven surface pattern) were significant endoscopic findings to predict local recurrence. Local recurrence was absent for ESD scars with even-flat morphology without erythema. Conclusion: Lesions with larger size (≥ 20 mm) and incompletely resected lesions had higher risk of local recurrence. Endoscopic forceps biopsy is unnecessary for even-flat ESD scar without erythematous changes.

7 April 2021 in BMC Gastroenterology
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Journal Article
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BPByung-Soo Park
Byung-Soo Park
SCSung Hwan Cho
Sung Hwan Cho
GSGyung Mo Son
Gyung Mo Son
YCYong-Hoon Cho
Yong-Hoon Cho
DRDaeGon Ryu
DaeGon Ryu
HJHong Jae Jo
Hong Jae Jo
Background: Clinically diagnosing high-grade (III–V) rectal prolapse might be difficult, and the prolapse can often be overlooked. Even though defecography is the significant diagnostic tool for rectal prolapse, it is noticed that rectoanal inhibitory reflex (RAIR) can be associated with rectal prolapse. This study investigated whether RAIR can be used as a diagnostic factor for rectal prolapse. Methods: In this retrospective study, we evaluated 107 patients who underwent both anorectal manometry and defecography between July 2012 and December 2019. Rectal prolapse was classified in accordance with the Oxford Rectal Prolapse Grading System. Patients in the high-grade (III–V) rectal prolapse (high-grade group, n = 30), and patients with no rectal prolapse or low-grade (I, II) rectal prolapse (low-grade group, n = 77) were analyzed. Clinical variables, including symptoms such as fecal incontinence, feeling of prolapse, and history were collected. Symptoms were assessed using yes/no surveys answered by the patients. The manometric results were also evaluated. Results: Frequencies of fecal incontinence (p = 0.002) and feeling of prolapse (p < 0.001) were significantly higher in the high-grade group. The maximum resting (77.5 vs. 96 mmHg, p = 0.011) and squeezing (128.7 vs. 165 mmHg, p = 0.010) anal pressures were significantly lower in the high-grade group. The frequency of absent or impaired RAIR was significantly higher in the high-grade group (19 cases, 63% vs. 20 cases, 26%, p < 0.001). In a multivariate analysis, the feeling of prolapse (odds ratio [OR], 23.88; 95% confidence interval [CI], 4.43–128.78; p < 0.001) and absent or impaired RAIR (OR, 5.36; 95% CI, 1.91–15.04, p = 0.001) were independent factors of high-grade (III–V) rectal prolapse. In addition, the percentage of the absent or impaired RAIR significantly increased with grading increase of rectal prolapse (p < 0.001). The sensitivity of absent or impaired RAIR as a predictor of high-grade prolapse was 63.3% and specificity 74.0%. Conclusions: Absent or impaired RAIR was a meaningful diagnostic factor of high-grade (III–V) rectal prolapse. Furthermore, the absent or impaired reflex had a positive linear trend according to the increase of rectal prolapse grading.

11 November 2022 in Medicine
Verified
Journal Article
Open access
DRDaeGon Ryu
DaeGon Ryu
SKSu Jin Kim
Su Jin Kim
CCCheol Woong Choi
Cheol Woong Choi
CHChung Su Hwang
Chung Su Hwang
HKHyung Wook Kim
Hyung Wook Kim
BSBong Soo Son
Bong Soo Son
Esophageal leiomyomas and granular cell tumors (GCTs) are the 2 most common subepithelial tumors found in the esophagus. We attempted to differentiate the 2 tumors using endoscopic findings and endoscopic ultrasound (EUS) features. Between December 2008 and June 2021, a total of 38 esophageal GCTs and 11 esophageal leiomyomas originating from the muscularis mucosa were selected. Clinical characteristics and endoscopic features were retrospectively reviewed. Although esophageal GCTs are mainly located in the lower third of the esophagus (81.6%), esophageal leiomyomas are mainly located in the upper third of the esophagus (45.5%). Broad-based (84.2%, P = .002) and whitish-to-yellowish color changes (97.4%, P < .001) are significant endoscopic features of esophageal GCTs. The echogenicity of esophageal leiomyoma was similar to that of proper muscle echogenicity. However, the echogenicity of esophageal GCTs was hyperechoic compared to that of the proper muscle layer (90.0% vs 9.1%, respectively, P < .001). EUS revealed a clearer hyperechoic epithelial lining in the esophageal leiomyoma than in esophageal GCTs (100% vs 26.7%, respectively, P < .001). The 5 endoscopic factors (location of the lower third, broad base, whitish-to-yellowish color, hyper-echogenic, and unclear demarcated hyperechoic epithelial line) were counted to differentiate esophageal GCTs from esophageal leiomyomas. Tumors with 3 or more endoscopic factors were all esophageal GCTs. The characteristic endoscopic and EUS features of esophageal GCTs were broad-based, whitish-to-yellowish colored subepithelial tumors located in the lower third of the esophagus and hyperechoic tumor with an unclear demarcated hyperechoic epithelial line. A combination of these features can predict esophageal GCTs before endoscopic resection.