• Journal of Genetic Medicine
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• v.15 no.2
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• pp.72-78
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• 2018

Purpose: Physicians' attitudes may have a strong influence on women's decision regarding prenatal screening options. The aim of this study is to assess the physicians' attitudes toward prenatal screening for fetal aneuploidy including non-invasive prenatal testing (NIPT) in South Korea. Materials and Methods: Questionnaires were distributed and collected at several obstetrics-gynecological conferences and meetings. The questionnaire included 31 multiple choice and 5 fill-in-the-blank questions. Seven questions requested physicians' demographic information, 17 questions requested information about the NIPT with cell-free fetal DNA, and 12 questions requested information about general prenatal screening practices. Results: Of the 203 obstetricians that completed the survey. In contrast with professional guidelines recommending the universal offering of aneuploidy screening, only 53.7% answered that prenatal aneuploidy testing (screening and/or invasive diagnostic testing) should be offered to all pregnant women. Physicians tended to have positive attitudes toward the clinical application of NIPT as both primary and secondary screening methods for patients at high-risk for fetal trisomy. However, for patients at average-risk for fetal trisomy, physicians tended to have positive attitudes only as a secondary screening method. Physicians with more knowledge about NIPT were found to tend to inform their patients that the detection rate of NIPT is higher. Conclusion: This is the first study to investigate expert opinion on prenatal screening in South Korea. Education of physicians is essential to ensure responsible patient counseling, informed consent, and appropriate management after NIPT.

• Journal of Gastric Cancer
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• v.13 no.1
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• pp.51-57
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• 2013

Purpose: Additional gastrectomy is needed after endoscopic resection for early gastric cancer when pathology confirms any possibility of lymph node metastasis or margin involvement. No studies depicted the optimal type of surgery to apply in these patients. We compared the short-term and long-term outcomes of laparoscopic gastrectomy with those of open gastrectomy after endoscopic resection to identify the optimal type of surgery. Materials and Methods: From 2003 to 2010, 110 consecutive patients who underwent gastrectomy with lymphadenectomy either by laparoscopic (n=74) or by open (n=36) for gastric cancer after endoscopic resection were retrospectively analyzed. Postoperative and oncological outcomes were compared according to types of surgical approach. Results: Clinicopathological characteristics were comparable between the two groups. Laparoscopic group showed significantly shorter time to gas passing and soft diet and hospital day than open group while operation time and rate of postoperative complications were comparable between the two groups. All specimens had negative margins regardless of types of approach. Mean number of retrieved lymph nodes did not differ significantly between the two groups. During the median follow-up of 47 months, there were no statistical differences in recurrence rate (1.4% for laparoscopic and 5.6% for open, P=0.25) and in overall (P=0.22) and disease-free survival (P=0.19) between the two groups. Type of approach was not an independent risk factor for recurrence and survival. Conclusions: Laparoscopic gastrectomy after endoscopic resection showed comparable oncologic outcomes to open approach while maintaining benefits of minimally invasive surgery. Thus, laparoscopic gastrectomy can be a treatment of choice for patients previously treated by endoscopic resection.

• Asian Pacific Journal of Cancer Prevention
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• v.13 no.6
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• pp.2467-2471
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• 2012

Introduction: Although bleomycin/etoposide/cisplatinum (BEP) chemotherapy is established as the standard treatment for germ cell tumours, it requires significant experience in administration and toxicity management to maintain optimal dose intensity. A retrospective review of 30 patients was conducted at UKMMC to study treatment outcomes. Methods & Materials: Patients with GCTs and treated with at least two cycles of BEP chemotherapy between January 2003 and Oct 2009 were eligible for this study. Patients received 4-6 cycles of bleomycin 30,000IU IV D1, D8 & D15 and either etoposide $100mg/m^2$ IV D1-D5 and cisplatin $20mg/m^2$ IV D1-D5 (5 day BEP regimen) or etoposide $165mg/m^2$ D1-D3 and cisplatin $50mg/m^2$ D1-3 (3 day BEP regimen) every three weeks per cycle. All patients received prophylactic granulocyte colony-stimulating factor (GCSF) from days 6 to 10 of each cycle. The overall response rates, 2 year progression-free survival and overall survival of the whole cohort were assessed. Results: Thirty patients fulfilled the inclusion criteria. Non-seminomatous GCTs comprised 93.3% of cases and gonadal and mediastinal primary sites were the most common. Sixty percent were classified as IGCCCG poor risk disease. Median follow-up was 26.6 months. The overall response rate (CR+PR) was 70%. The two year PFS and OS were 70% and 66%. There was a significant difference in terms of the overall response rate (85% vs 40%, p = 0.03) and in PFS (94.7% vs 50%, p = 0.003) between gonadal and extragonadal primary sites. Conclusion: It is possible to achieve outcomes similar to those in international clinical trials with close monitoring and good supportive care of patients undergoing BEP chemotherapy. There is a strong argument for patients with IGCCCG poor prognosis disease to be treated in specialist tertiary centres to optimize treatment outcomes.

• Journal of Chest Surgery
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• v.51 no.1
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• pp.41-52
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• 2018

Background: Few studies have evaluated the long-term impact of postoperative infectious complications in patients with non-small cell lung cancer (NSCLC). We aimed to determine the impact of infectious complications on long-term outcomes after surgical resection for NSCLC. Methods: We performed a retrospective study of 1,380 eligible patients who underwent pulmonary resection for NSCLC from 2003 to 2012. Complications were divided into infectious complications and non-infectious complications. Kaplan-Meier survival analysis was used to compare unadjusted 5-year cancer-specific survival (CSS) rates and recurrence-free survival (RFS) rates. Cox regression was used to determine the impact of infectious complications on 5-year CSS and RFS. Results: The rate of total complications and infectious complications was 24.3% and 4.3%, respectively. In the node-negative subgroup, the 5-year CSS and RFS rates were 75.9% and 57.1% in patients who had infectious complications, compared to 87.9% and 78.4% in patients who had no complications. Infectious complications were a negative prognostic factor for 5-year RFS (hazard ratio, 1.92; 95% confidence interval, 1.00-3.69; p=0.049). In the node-positive subgroup, the 5-year CSS rate and RFS were 44.6% and 48.4% in patients who had infectious complications, compared to 70.5% and 48.4% for patients who had no complications. Conclusion: Postoperative infectious complications had a negative impact on CSS and RFS in node-negative NSCLC. Our findings may help improve risk assessment for tumor recurrence after pulmonary resection for node-negative NSCLC.

• Journal of Chest Surgery
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• v.27 no.4
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• pp.266-271
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• 1994

Between 1985 and 1993, 29 children from 1 to 15 years of age have undergone cardiac valve replacements at Buchon Sejong Hospital. The patients were composed of 20 males and 9 females and 17 patient had congenital heart disease and 12 patients had acquired heart disease. Two of these patients have had second valve replacements due to paravalvular leakage and valve thrombosis. Single valve replacements were 29 and double valve replacements were 2. All the patients had received prosthetic valves except one. Among the 25 patients who had definite post-operative records, the overall mortality was 12%[4% was early mortality and 8% was late mortality].25 patients were followed up with coumadin anticoagulation for total 633 patient-months[minimum 2 months to maximum 93 months, mean 25.3 months] and actuarial survival rate was 88.5 $\pm$ 6.3% at 7 years and event free rate was 70.3 $\pm$ 11.7% at 7 years. These results suggest that pediatric valve replacements can now be performed at a low operative risk although various problems are still remained and the choice of valve is prosthetic valve mainly due to its durability at the present time.

• Journal of the Korean Data and Information Science Society
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• v.25 no.3
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• pp.513-522
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• 2014

Using the assumption that the price of a stock follows a geometric Brownian motion with constant volatility, Black and Scholes (BS) derived a formula that gives the price of a European call option on the stock as a function of the stock price, the strike price, the time to maturity, the risk-free interest rate, the dividend rate paid by the stock, and the volatility of the stock's return. However, implied volatilities of BS method tend to depend on the stock prices and the time to maturity in practice. To address this shortcoming, we estimate the implied volatility function as a function of the strike priceand the time to maturity for data consisting of the daily prices for KOSPI200 call options from January 2007 to May 2009 using support vector regression (SVR), the multiple additive regression trees (MART) algorithm, and ordinary least squaress (OLS) regression. In conclusion, use of MART or SVR in the BS pricing model reduced both RMSE and MAE, compared to the OLS-based BS pricing model.

• The Korean Journal of Urological Oncology
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• v.16 no.3
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• pp.89-96
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• 2018

Upper tract urothelial carcinoma (UTUC) has a relatively low prevalence rate of about 1.8 per 100,000 people. According to the recent literature, the development of diagnostic techniques has gradually increased the prevalence and diagnosis rate. In the past, when UTUC was diagnosed, more than 60% of the patients were diagnosed as locally advanced or metastatic cancer. However, since 2010, approximately 70% of the patients have been diagnosed as operable stage. Although radical nephroureterectomy is known as the basis of treatment for UTUC, overall survival is poor in patients with lymph node invasion. Especially, the finding that a localized UTUC is associated with a high risk of cancer metastasis in approximately 50% of patients suggests that these patients may not have sufficient treatment through surgery alone. The European Association of Urology and the National Comprehensive Cancer Network guideline 2017 suggested that postoperative adjuvant chemotherapy may be considered in patients with advanced UTUC beyond pT2. Also, recent meta-analyses have reported that cisplatin-based adjuvant chemotherapy can be expected to have a synergistic effect of overall survival and disease-free survival. However, many patients with UTUC undergo postoperative renal failure, which may result in failure to perform cisplatin-based adjuvant chemotherapy with adequate dose. For this reason, several researchers have suggested that it is beneficial to apply neoadjuvant chemotherapy when the preoperative renal function is maintained to a certain extent. But, neoadjuvant chemotherapy has not been used by many clinicians because of the lack of studies and the rarity of the disease. We are currently discussing the outcomes and prospects of perioperative chemotherapy.

• Journal of Chest Surgery
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• v.52 no.2
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• pp.61-69
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• 2019

Background: Scarce data have been reported on the efficacy of concomitant atrial fibrillation (AF) ablation in patients undergoing bioprosthetic valve replacement. Methods: From 2001 and 2014, 146 consecutive patients ($69.3{\pm}9.4years$, 84 females) who underwent bioprosthetic heart valve replacement concomitant with AF ablation were assessed. We evaluated long-term rhythm and valve-related outcomes. Results: During 49.1 months of follow-up (interquartile range, 22.5-96.8 months), 7 in-hospital and 49 (6.7% per person-year) post-discharge deaths occurred. The thromboembolic event-free survival rate at 5 years was $79.2%{\pm}3.5%$. The freedom from AF recurrence rate at 5 years was $59.8%{\pm}4.9%$. Multivariate analysis showed that old age (hazard ratio [HR], 1.06; 95% confidence interval [CI], 1.02-1.11; p=0.002), previous cardiac operation (HR, 3.01; 95% CI, 1.22-7.43; p=0.02), and a large left atrial (LA) dimension (HR, 1.02; 95% CI, 1.00-1.05; p=0.045) were significantly associated with AF recurrence. Conclusion: The overall long-term clinical outcomes in these predominantly elderly patients undergoing AF ablation concomitantly with bioprosthetic valve replacement were satisfactory; however, AF recurrence was frequent. Older age, a history of prior cardiac surgery, and large LA size were associated with an increased risk of AF recurrence.

• Journal of Korean Neurosurgical Society
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• v.65 no.3
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• pp.415-421
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• 2022

Objective : Seizure recurrence after the first-ever seizure in patients with a supratentorial cerebral cavernous malformation (CCM) is almost certain, so the diagnosis and treatment of epilepsy is justified. The optimal method of management of these patients is still a matter of debate. The aim of our study was to identify factors associated with postoperative seizure control and assess the surgical morbidity rate. Methods : We retrospectively analysed 45 consecutive patients with a supratentorial CCM and symptomatic epilepsy in a single centre. Pre- and postoperative epidemiological data, seizure-related patient histories, neuroimaging results, surgery details and outcomes were obtained from hospital medical records. Seizure outcomes were assessed at least 12 months after surgery. Results : Thirty-five patients (77.8%) were seizure free at the long-term follow-up (Engel class I); six (13,3%) had rare, nocturnal seizures (Engel class II); and four (8.9%) showed meaningful improvement (Engel class III). In 15 patients (33%) in the Engel I group; it was possible to discontinue antiepileptic medication. Although there was not statistical significance, our results suggest that patients can benefit from early surgery. No deaths occurred in our study, and mild postoperative neurologic deficits were observed in two patients (4%) at the long-term follow-up. Conclusion : Surgical resection of CCMs should be considered in all patients with a supratentorial malformation and epilepsy due to the favourable surgical results in terms of the epileptic seizure control rate and low postoperative morbidity risk, despite the use of different predictors for the seizure outcome.

• Journal of Chest Surgery
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• v.57 no.2
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• pp.184-194
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• 2024

Background: Left ventricular assist devices (LVADs) are widely employed as a therapeutic option for end-stage heart failure. We evaluated the outcomes associated with centrifugal-flow LVAD implantation, comparing 2 device models: the Heartmate 3 (HM3) and the Heartware Ventricular Assist Device (HVAD). Methods: Data were collected from patients who underwent LVAD implantation between June 1, 2015 and December 31, 2022. We analyzed overall survival, first rehospitalization, and early, late, and LVAD-related complications. Results: In total, 74 patients underwent LVAD implantation, with 42 receiving the HM3 and 32 the HVAD. A mild Interagency Registry for Mechanically Assisted Circulatory Support score was more common among HM3 than HVAD recipients (p=0.006), and patients receiving the HM3 exhibited lower rates of preoperative ventilator use (p=0.010) and extracorporeal membrane oxygenation (p=0.039). The overall early mortality rate was 5.4% (4 of 74 patients), with no significant difference between groups. Regarding early right ventricular (RV) failure, HM3 implantation was associated with a lower rate (13 of 42 [31.0%]) than HVAD implantation (18 of 32 [56.2%], p=0.051). The median rehospitalization-free period was longer for HM3 recipients (16.9 months) than HVAD recipients (5.3 months, p=0.013). Furthermore, HM3 recipients displayed a lower incidence of late hemorrhagic stroke (p=0.016). In the multivariable analysis, preoperative use of continuous renal replacement therapy (odds ratio, 22.31; p=0.002) was the only significant predictor of postoperative RV failure. Conclusion: The LVAD models (HM3 and HVAD) demonstrated comparable overall survival rates. However, the HM3 was associated with a lower risk of late hemorrhagic stroke.