• Asian Pacific Journal of Cancer Prevention
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• v.14 no.4
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• pp.2567-2570
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• 2013

Background: This study analyzed Surveillance, Epidemiology and End Results (SEER) data to assess if socio-economic factors (SEFs) impact on endometrial cancer survival. Materials and Methods: Endometrial cancer patients treated from 2004-2007 were included in this study. SEER cause specific survival (CSS) data were used as end points. The areas under the receiver operating characteristic (ROC) curve were computed for predictors. Time to event data were analyzed with Kaplan-Meier method. Univariate and multivariate analyses were used to identify independent risk factors. Results: This study included 64,710 patients. The mean follow up time (S.D.) was 28.2 (20.8) months. SEER staging (ROC area of 0.81) was the best pretreatment predictor of CSS. Histology, grade, race/ethnicity and county level family income were also significant pretreatment predictors. African American race and low income neighborhoods decreased the CSS by 20% and 3% respectively at 5 years. Conclusions: This study has found significant endometrial survival disparities due to SEFs. Future studies should focus on eliminating socio-economic barriers to good outcomes.

• Journal of Korean Society for Quality Management
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• v.25 no.3
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• pp.96-107
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• 1997

The recent stream to reliability prediction is that it is totally inclusive in depth to consider even the operating and environmental condition at the level of finished goods as well as component itselves. In this study, firstly we present the reliability prediction methods by entire failure rate model which failure rate at the system level is added to the failure rate model at the component level. Secondly we build up the improved bases of reliability demonstration through a, pp.ication of Kaplan-Meier, Cumulative hazard, Johnson's methods as non-parametric and Maximum Likelihood Estimator under exponential & Weibull distribution as parametric. And also present the methods of curve fitting to piecewise failure rate under Weibull distribution, PRST (Probability Ratio Sequential Test), curve fitting to S-shaped reliability growth curve, computer programs of each methods. Lastly we show the practical for determination of optimal burn-in time as a method of reliability enhancement, and also verify the practical usefulness of the above study through the a, pp.ication of failure and test data during 1 year.

• The Korean Journal of Applied Statistics
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• v.20 no.2
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• pp.313-322
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• 2007

Several robust censored depth regression methods are compared under contamination. Park and Hwang(2003) suggested a way to circumvent the censoring issue by incorporating Kaplan-Meier type weight in halfspace regression depth and Park(2003) used a similar technique to simplicial regression depth. Hubert et al. (2001) suggested a high breakdown point regression depth based on projection called rcent. A new method to implement censoring in rcent is suggested and compared with two precedents under various contamination and censoring schemes.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.59 no.2
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• pp.154-157
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• 2010

In this paper, the Time-varying Failure Rates(TFR) of power distribution system components are extracted from the recorded failure data of KEPCO(Korea Electric Power Corporation) and the reliability of power distribution system is evaluated using Mean Failure Rate(MFR) and TFR. The TFR is approximated to bathtub curve using the exponential and Weibull distribution function. In addition, Kaplan-Meier estimation is applied to TFR extraction because of incomplete failure data of KEPCO. Also the reliability of the real power distribution system of Korea is evaluated using the MFR and TFR extracted from real failure data, respectively and the results of each case are compared with each other. As a result, it is proved that the reliability evaluation using the TFR is more realistic than MFR. In addition, it is presented that the application method at power distribution system maintenance and repair using the result of TFR.

• The Journal of the Korean bone and joint tumor society
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• v.18 no.1
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• pp.7-13
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• 2012

Purpose: The purpose of this study is to compare general survival rate and survival rate according to expectable prognostic factors by analyzing the result of treating a patient of squamous cell carcinoma. Materials and Methods: From Mar. 1999 to Feb. 2011, 151 patients were pathologically confirmed as squamous cell carcinoma of limbs and body in our hospital, and among those patients, 51 patients underwent the surgical treatment. This study included 41 patients who underwent the surgical treatment and were followed-up for more than 12 months. The mean age of population was 64.4 years. 31 males and 10 females were included. Wide excision with following skin grafts or flaps for reconstruction (29 cases) was mostly performed, but amputation (12 cases) was also performed for cases with extremities where resection margin was difficult to obtain and cases with neural or vascular invasion. 8 patients underwent chemotherapy or radiotherapy after resection, and 33 underwent the operation only. Stages were classified by AJCC Classification, survival rate was calculated by Kaplan-Meier method and survival rate of groups was compared by Log-rank test. For the expectable prognostic factors related to survival rate, location of primary lesion, cause of disease, pathologic grade, staging, surgical method, additional anticancer therapy were examined and each survival rate was compared. Results: The average follow-up period was 65.2 (12-132) months. Thirty patients survived out of 41 patients till last follow up. The overall survival rate in 5 years was 77%. Three cases (7.3%) had local recurrence, and 7 cases (17.0%) had metastasis. The average period of recurrence from operation was 27 (18-43) months. Possible prognostic factors such as location of primary lesion, cause of disease, pathologic grade, staging, additional anticancer therapy showed no significant difference in survival rates. However, patients with amputation showed significantly lower survival rate than those with wide excision. Conclusion: In analysis the results of treating 41 cases of squamous cell carcinoma, the overall 5-year survival rate was 77%. And, among the several prognostic factors, only the surgical method was significant statistically.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• v.11 no.2
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• pp.143-149
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• 2008

Purpose: To estimate the long-term therapeutic efficacy and safety of adefovir dipivoxil in children and adolescents with chronic hepatitis B who have developed lamivudine resistance. Methods: Sixteen patients (12 boys and 4 girls; ages 4.3~20.9 years; mean age 14.2 years) with chronic hepatitis B infection resistant to lamivudine therapy received adefovir (0.3 mg/kg/day, maximal dose 10 mg) orally for at least 9 months between March 2004 and April 2008. Each patient was followed up for a mean period of 27 months (range 9~49 months) until April 2008 at Kyungpook National University Hospital in Korea. Therapeutic responses to adefovir were evaluated at 12, 24, 36, and 48 months from the initiation of therapy using the Kaplan-Meier method. Response measurements included ALT normalization, HBV DNA negativization, 2 $log_{10}$ IU/mL decrement of HBeAg titer, HBeAg loss, and HBeAg/Ab seroconversion rate. Results: Three (18.8%) of the 16 patients treated with adefovir showed HBeAg/Ab seroconversion. Kaplan-Meier estimates of cumulative ALT normalization were 12.5% (12 months), 43.8% (24 months), 63.5% (36 months), and 92.7% (48 months), respectively. Cumulative HBV DNA negativization was 6.7%, 30.0%, 45.6%, and 78.2% at 12, 24, 36, and 48 months, respectively. Cumulative 2 $log_{10}$ copies/mL decrement of HBeAg titer was 12.5%, 43.8%, 56.3%, and 86.9% at 12, 24, 36, and 48 months, respectively. Cumulative HBeAg loss and HBeAg/Ab seroconversion were 6.7% (12 months) and 22.2% (24 months), respectively. Conclusion: The long-term therapeutic efficacy of adefovir dipivoxil was favorable in children and adolescents with chronic hepatitis B who had developed lamivudine resistance. The long-term use of adefovir should be safe in children.

• Journal of Chest Surgery
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• v.31 no.10
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• pp.973-981
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• 1998

Background: About 30% to 40% of the patients with pathologic stage I non-small cell lung cancer (NSCLC) die within 5 years after complete resection. The identification of poor prognostic factors and the application of additional treatment are very important to improve the survival rate in resected stage I NSCLC. Materials and methods: Sixty-eight(68) patients who had been diagnosed postoperatively between Janury 1989 and December 1995 as having stage I non-small cell lung cancer according to the TNM classification were studied. The postoperative 5-year survival rate was calculated with the Kaplan-Meier method, and clinico- histopathologic factors including age, sex, operative method, type of tumor cell, T factor, grade of the differentiation in a squamous cell carcinoma, invasion of blood vessel and expression of the nm23-H1 protein were investigated and analyzed. Results: The median survival of the entire group of patients was 58$\pm$3 months, with a 5-year survival of 58.9%. In univariate analysis, invasion of blood vessel and poor differentiation of the tumor cell in a squamous cell carcinoma significantly worsened the survival. In multivariate analysis, invasion of blood vessel and grade of the differentiation of the tumor cells in a squamous cell carcinoma remained independent prognostic factors. High expression of the nm23-H1 protein was related to a high postoperative 5-year survival in comparision with low expression of the nm23-H1 pretein (73.0% vs 50.7%), but there was no statistical significance. Conclusions: These results highlight the negative prognostic value of poor differentiation of tumor cells in a squamous cell carcinoma and invasion of blood vessel in stage I non-small cell lung cancer. Also, further studies are necessary to be determined prognostic value of the T factor and expression of the nm23 protein in non-small cell lung cancer.

• Journal of Chest Surgery
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• v.38 no.5 s.250
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• pp.377-381
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• 2005

Background: Extra-anatomic bypass was performed in the patient who could not use anatomic bypass due to many causes. The purpose of this study is to evaluate the efficacy of extra-anatomic bypass surgery. Material and Method: We reviewed 31 patients who underwent extra-anatomic bypass surgery at Pusan national university hospital. We analysed the combined diseases, etiologic diseases, symptoms, patency rate and the factors affecting patency rate retrospectively. Result: There were 26 cases of femoro-femoral bypass and 5 cases of axillo-bifemoral bypass among 31 patients. The mean age was 70.23 years. Combined disease were hypertension, hyperlipidemia, and ischemic heart disease in order of frequency. The indications for surgery were disabled claudication, tissue necrosis, rest pain, and a cute ischemia. We analysed the ages, smoking history, hypertension, ischemic heart disease, severity of limb ischemia, and hyperlipidemia as factors affecting patency rate. We could not find any statistical differences between these factors. The primary graft patency rates were $73.65\%$ one year, $73.65\%$ two year, and $65.46\%$ three year respectively according to the Kaplan-Meier method. Conclusion: Nevertheless extra-anatomic bypass has a relatively low patency rate, it has good merits that is less dangerous, simple and easy re-do surgery compared to anatomic bypass. We think that extra-anatomic bypass is one of the good treatment modalities for the high risk vascular patients.

• Journal of Chest Surgery
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• v.40 no.10
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• pp.680-684
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• 2007

Background: Complete surgical resection is the most effective treatment for stage IB non-small cell lung cancer (NSCLC). Recurrence accounts for the disappointing survival rates after resection. There has been renewed interest in adjuvant therapy after complete resection. Appropriate selection of effective adjuvant therapy will depend on the prognostic factors for recurrence. Material and Method: The study included 114 patients with completely resected stage IB NSCLC. The variables selected for the study were gender, age, the type of resection, cell type, the degree of differentiation, the tumor size and the presence of visceral pleura invasion. The Kaplan-Meier method was used to estimate the survival and disease-free survival rate. The results were compared using the log rank test. Multivariate analysis was performed by Cox's proportional hazard model. Two-sided p-valves < 0.05 were considered to be statistically significant. Result: The 3-year overall survival and the disease-free survival rates were 87.0% and 79.4%, respectively. The degree of differentiation showed a significant influence on disease-free survival according to the univariate analysis. According to the multivariate analysis, a poor grade of differentiation was a significant poor prognostic factor. Conclusion: These results demonstrate that poor differentiation may be a poor prognostic factor for patients with completely resected IB NSCLC. Therefore, the patients with a poor grade of differentiation may require adjuvant therapies.

• Journal of Chest Surgery
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• v.32 no.3
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• pp.262-269
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• 1999

Background: To review the middle and long term results of aortic valve replacement(AVR) for 11 years, we surveyed and followed up the patients who underwent AVR. Material and Method: Between Feb. 1986 and May 1997, 134 patients underwent AVR. The patients consisted of 71 men and 63 women whose mean age was 38.9 years, ranging from 17 to 70. Result: The concomitant operations were 62 mitral valve replacement(MVR), 14 MVR + tricuspid valve annuloplasty, 10 Cabrol operation, 16 aortic annulus widening, and so forth. We used 119 mechanical(75 St. Jude Medical, 38 CarboMedics, 6 Sorin) and 15 tissue (Carpentier-Edwards) valves. Early postoperative complications occurred in 35 cases; 9 congestive heart failure, 6 low cardiac output, 5 postoperative bleeding, 5 pleural effusion, and so forth. There were 13 early postoperative deaths(9.7%) due to low cardiac output(5), CHF (2), disseminated intravascular coagulopathy(2), and so forth. The cumulative total follow-up period was 452.7 patient-years with a mean of 3.4${\pm}$3.1 years/patient. There were 9 cases of valve-related complications; anticoagulant-related bleeding(4), prosthetic valve endocarditis(2), thromboembolism(2) and prosthetic valve failure(1) occured at rate of 0.9, 0.4, 0.4, 0.2%/ pt-yr, respectively. Late valve-related death occurred in 3 cases(2.0%/pt-yr) associated with anticoagulant-related bleeding(2) and prosthetic valve endocarditis(1). Conclusion: Actuarial survival rate by Kaplan-Meier method was 91.0${\pm}$4.3 % at 11 years.