• Progress in Superconductivity and Cryogenics
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• v.7 no.2
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• pp.21-26
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• 2005

Breakdown characteristics and survival probability of turn-to-turn models were investigated under ac and impulse voltage at 77K. For experiments, two test electrode models were fabricated: One is point contact model and the other is surface contact model. Both are made of copper wrapped by O.025mm thick polyimide film(Kapton). The experimental results were analyzed statistically using Weibull distribution in order to examine the wrapping number effects on voltage-time characteristics under ac voltage as well as under impulse voltage in LN$_{2}$. Also survival analysis were performed according to the Kaplan-Meier method. The breakdown voltages of surface contact model are lower than that of point contact model, because the contact area of surface contact model is wider than that of point contact model. Besides, the shape parameter of point contact model is a little bit larger than that of surface contact model. The time to breakdown t$_{50}$ is decreased as the applied voltage is increased, and the lifetime indices slightly are increased as the number of layers is increased. According to the increasing applied voltage and decreasing wrapping number, the survival probability is increased.

• Communications for Statistical Applications and Methods
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• v.26 no.5
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• pp.445-461
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• 2019

It is possible that data are not always fitted with sufficient precision by the existing distributions; therefore this article presents a methodology that enables the use of families of asymmetric distributions as alternative probabilistic models for survival analysis, with censorship on the right, different from those usually studied (the Exponential, Gamma, Weibull, and Lognormal distributions). We use a more flexible parametric model in terms of density behavior, assuming that data can be fit by a distribution of stable distribution families considered unconventional in the analyses of survival data that are appropriate when extreme values occur, with small probabilities that should not be ignored. In the methodology, the determination of the analytical expression of the risk function h(t) of the $L{\acute{e}}vy$ distribution is included, as it is not usually reported in the literature. A simulation was conducted to evaluate the performance of the candidate distribution when modeling survival times, including the estimation of parameters via the maximum likelihood method, survival function ${\hat{S}}$(t) and Kaplan-Meier estimator. The obtained estimates did not exhibit significant changes for different sample sizes and censorship fractions in the sample. To illustrate the usefulness of the proposed methodology, an application with real data, regarding the survival times of patients with colon cancer, was considered.

• Asian Pacific Journal of Cancer Prevention
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• v.13 no.9
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• pp.4281-4284
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• 2012

Background: Osteosarcoma is the most common bone cancer in children, responsible for a high rate of amputation and death. This is the first long-term, population-based, epidemiologic and survival study in Thailand. Objective: To study the incidence and survival rates of pediatric osteosarcoma in Khon Kaen. Method: Childhood osteosarcoma cases (0-19 years) diagnosed between 1985-2010 were reviewed. The data were retrieved from the population-based data set of the Khon Kaen Cancer Registry and medical records from Srinagarind Hospital, Faculty of Medicine, Khon Kaen University. All cases were censored until the end of April 2012. The age-standardized incidence rate (ASR) was calculated using the standard method. Survival experience was analyzed using the standard survival function (STATA 9.0) and presented with a Kaplan-Meier curve. Results: 58 cases were enrolled. The overall ASR was 14.1 per million. Males and females were equally affected. The peak incidence was for 15-19 year-olds in both sexes (ASR=10.4 per million in males and 8.5 in females). The 5-year overall survival rate was 27.6% (95% CI: 15.8-40.8%). The median survival time was 1.6 years (95% CI: 1.2-2.1). In a subgroup analysis, the patients who received only chemotherapy survived longer (5-year survival 45.7%, median survival time 4.1 years, p=0.12). Conclusion: The incidence rate for childhood osteosarcoma was slightly less than those reported for Western countries. The survival rate was also lower than reports from developed countries. Further evaluation of the treatment protocol and risk factor stratification is needed.

• The Journal of the Korean dental association
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• v.55 no.2
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• pp.116-127
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• 2017

Objectives : The aim of this study was to evaluate the cumulative survival rates of the implants placed into grafted sinus and determine the effect of age, gender, smoking, and systemic disease on the implant cumulative survival rates. Materials and Methods : The retrospective study was performed on 51 implants placed in 26 patients by one dentist at the Dental Implant Center, Seoul National University Dental Hospital in the years 2000-2010. The cumulative survival rates were calculated by the Kaplan-Meier method. The differences within the factors were analyzed using log-rank test and the correlations between the factors and implant survival rates were analyzed using Cox proportional hazard model. Results : 1. Among the total of 51 implants placed in 26 patients, 7 implants failed and 44 implants remained stable. The 1-year, 5-year, and 10-year cumulative survival rates were 92%, 88%, and 85%, respectively. 2. Patients in their 50s and in their 70s showed statistically significant difference in the cumulative survival rates (P < 0.05). Gender and the existence of systemic disease did not show significant results. 3. In the implant treatment, smokers showed 7.5 times higher risk of implant failure than non-smokers (P < 0.05). Conclusion: Implants installed in combination with sinus elevation can be considered as a reliable treatment method.

• Journal of Preventive Medicine and Public Health
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• v.50 no.5
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• pp.283-293
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• 2017

Objectives: The objective of the present study was to compare prognosis of patients with gastric or colorectal cancer according to places where they received surgeries. Methods: The cancer patients underwent surgeries in sampled hospitals located in Daegu were matched 1:1 to the patients who visited sampled hospitals in Seoul using propensity score method. After the occurrences of death were examined, Kaplan-Meier method was used for survival analysis and the log-rank test was performed to compare the survival curves. Results: A total of six out of 291 gastric cancer patients who had surgeries in Daegu died (2.1%) and ten deaths (3.4%) occurred from patients went Seoul hospitals. Out of 84 gastric cancer patients who had chemotherapy after surgeries in Daegu, 13 (15.5%) patients died while 18 (21.4%) deaths occurred among patients underwent surgeries in Seoul. Six deaths (6.9%) out of 87 colorectal cancer patients who had surgeries in Daegu were reported. Five patients (5.7%) died among the patients underwent surgeries in Seoul. Among the colorectal cancer patients with chemotherapy after surgeries, 13 patients (12.4%) who visited hospitals in Daegu and 14 (13.3%) patients who used medical centers in Seoul died. There were no significant differences according to places where patients used medical services. Conclusions: The result of this study is expected to be used as basic data for policy making to resolve centralization problem of cancer patients and to help patients to make rational choices in selection of medical centers.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.1
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• pp.343-347
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• 2014

Background: Maspin expression is a potential prognostic factor for various malignancies but its relation with gallbladder cancer is unknown and needs to be investigated needs to be investigated. We therefore here focused on maspin mRNA expression in normal, gall stone disease and gallbladder cancer subjects, with particular attention to prognostic importance in individuals with malignancies. Materials and Methods: This study was carried out at the Department of Surgical Gastroenterology, King George's Medical University, Lucknow, India. Gallbladder samples from normal (n=25), gall stone disease (n=25) and cancer patients (n=38) were analysed for maspin mRNA expression by semi-quantitative reverse transcriptase PCR and quantitative real time PCR. Statistical analysis was carried out using the Students t test or ANOVA. Survival analysis was conducted according to the Kaplan-Meier method and correlations were assessed using the Pearson correlation method. p<0.05 was considered statistically significant. Results: Significant increase (p=0.028) in expression of maspin mRNA was observed in gallbladder cancer as compared to gall stone disease, whereas no expression was found in normal tissues. Significant correlation (Pearson's coefficient(r)=-0.798, p<0.0001) was observed between relative quantification of maspin mRNA and survival of cancer patients after surgery, with significantly shorter (p=0.002) survival in patients having relative quantification >1.5 as compared to those having relative quantification <1.5. Similarly, significant differences in patient survival for maspin mRNA expression was observed for stage II (p=0.025) and III (p=0.011) cancer. Conclusions: Higher expression of maspin mRNA in gallbladder cancer has prognostic significance for stage II and III cancer, which needs to be investigated further.

• Journal of Gastric Cancer
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• v.1 no.3
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• pp.168-173
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• 2001

Purpose: A positive esophageal margin is encountered in a total gastrectomy not infrequently. The aim of this retrospective review was to evaluate whether a positive esophageal margin predisposes a patient to loco-regional recurrence and whether it has an independent impact on long-term survival. Materials and Methods: A retrospective review of 224 total gastrectomies for adenocarcinomas was undertaken. The Chisquare test was used to determine the statistical significance of differences, and the Kaplan-Meier method was used to calculate survival rates. Significant differences in the survival rates were assessed using the log-rank test, and independent prognostic significance was evaluated using the Cox regression method. Results: The prevalence of esophageal margin involvement was $3.6\%$ (8/224). Univariate analysis showed that advanced stage (stage III/IV), tumor size ($\geq$5 cm), tumor site (whole or upper one-third of the stomach), macroscopic type (Borrmann type 4), esophageal invasion, esophageal margin involvement, lymphatic invasion, and venous invasion affected survival. Multivariate analysis demonstrated that TNM stage, venous invasion, and esophageal margin involvement were the only significant factors influencing the prognosis. All patients with a positive esophageal margin died with metastasis before local recurrence became a problem. A macroscopic proximal distance of more than 6 cm of esophagus was needed to be free of tumors, excluding one exceptional case which involved 15 cm of esophagus. Conclusion: All of the patients with a positive proximal resection margin after a total gastrectomy had advanced disease with a poor prognosis, but they were not predisposed to anastomotic recurrence. Early detection and extended, but reasonable, surgical resection of curable lesions are mandatory to improve the prognosis.

• Asian Pacific Journal of Cancer Prevention
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• v.13 no.4
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• pp.1105-1109
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• 2012

Breast cancer is the second most common cancer in women in India and the disease burden is increasing annually. The lack of awareness initiatives, structured screening, and affordable treatment facilities continue to result in poor survival. We present a breast cancer survival scenario, in urban population in India, where standardised care is distributed equitably and free of charge through an employees' healthcare scheme. We studied 99 patients who were treated at our hospital during the period 2005 to 2010 and our follow-up rates were 95.95%. Patients received evidence-based standardised care in line with the tertiary cancer centre in Mumbai. One-, three- and five-year survival rates were calculated using Kaplan-Meier method. Socio-demographic, reproductive and tumor factors, relevant to survival, were analysed. Mortality hazard ratios (HR) were calculated using Cox proportional hazard method. Survival in this series was compared to that in registries across India and discrepancies were discussed. Patients mean age was 56 years, mean tumor size was 3.2 cms, 85% of the tumors belonged to T1 and T2 stages, and 45% of the patients belonged to the composite stages I and IIA. Overall 5-year survival was 74.9%. Patients who presented with large-sized tumors (HR 3.06; 95% CI 0.4-9.0), higher composite stage (HR 1.91; 0.55-6.58) and undergone mastectomy (HR 2.94; 0.63-13.62) had a higher risk of mortality than women who had higher levels of education (HR 0.25; 0.05-1.16), although none of these results reached the significant statistical level. We observed 25% better survival compared to other Indian populations. Our results are comparable to those from the European Union and North America, owing to early presentation, equitable access to standardised free healthcare and complete follow-up ensured under the scheme. This emphasises that equitable and affordable delivery of standardised healthcare can translate into early presentation and better survival in India.

• Asian Pacific Journal of Cancer Prevention
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• v.13 no.5
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• pp.2213-2218
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• 2012

Introduction: Worldwide, breast cancer is the commonest cause of cancer death in women. However, the survival rate varies across regions at averages of 73%and 57% in the developed and developing countries, respectively. Objective: This study aimed to determine the survival rate of breast cancer among the women of Malaysia and characteristics of the survivors. Method: A retrospective cohort study was conducted on secondary data obtained from the Breast Cancer Registry and medical records of breast cancer patients admitted to Hospital Kuala Lumpur from 2005 to 2009. Survival data were validated with National Birth and Death Registry. Statistical analysis applied logistic regression, the Cox proportional hazard model, the Kaplan-Meier method and log rank test. Results: A total of 868 women were diagnosed with breast cancer between January 2005 and December 2009, comprising 58%, 25% and 17% Malays, Chinese and Indians, respectively. The overall survival rate was 43.5% (CI 0.573-0.597), with Chinese, Indians and Malays having 5 year survival rates of 48.2% (CI 0.444-0.520), 47.2% (CI 0.432-0.512) and 39.7% (CI 0.373-0.421), respectively (p<0.05). The survival rate was lower as the stages increased, with the late stages were mostly seen among the Malays (46%), followed by Chinese (36%) and Indians (34%). Size of tumor>3.0cm; lymph node involvement, ERPR, and HER 2 status, delayed presentation and involvement of both breasts were among other factors that were associated with poor survival. Conclusions: The overall survival rate of Malaysian women with breast cancer was lower than the western figures with Malays having the lowest because they presented at late stage, after a long duration of symptoms, had larger tumor size, and had more lymph nodes affected. There is an urgent need to conduct studies on why there is delay in diagnosis and treatment of breast cancer women in Malaysia.

• Asian Pacific Journal of Cancer Prevention
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• v.14 no.2
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• pp.1107-1110
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• 2013

Intrahepatic cholangiocarcinoma (ICC), one of the primary liver cancers, is frequent in the northeastern part of Thailand. Surgical resection remains the best method of treatment, but patients suffering from ICC usually present at a late stage of the disease. Studies of survival and prognostic factors after surgery remain rare. The aim here was to evaluate the survival rate and factors affecting the survival of patients with intrahepatic cholangiocarcinoma after surgery. The study used a retrospective cohort design. The subjects were 73 consecutive patients with ICC, who were admitted for surgery to Srinagarind Hospital, Khon Kaen University, during the period 2005-2009. The censoring date was 31 December, 2011, data being evaluated using uni- and multivariate analyses. Postoperative survival analysis was performed by the Kaplan-Meier method, and the Cox proportional hazard model was used to identify independent prognostic factors. The total follow-up time was 99 person-years. The total number of deaths was 59, giving a mortality rate of 59 per 100 person-years. The cumulative 1-, 3-, and 5-year survival rates were 52.1%, 21.7%, and 11.2%, respectively. The median duration of survival after resection was 12.4 months. Univariate analysis revealed stage of disease, lymph node metastasis, histological type, histological grade and macroscopic classification to be statistically significant (p-value<0.05) prognostic factors. In the multivariate analysis, only macroscopic classification was statistically significant (p-value<0.05). In conclusion, macroscopic classification was the only independent factor found to be significantly associated with survival following surgical treatment of ICC.