• Genomics & Informatics
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• v.17 no.4
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• pp.41.1-41.12
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• 2019

Survival analysis mainly deals with the time to event, including death, onset of disease, and bankruptcy. The common characteristic of survival analysis is that it contains "censored" data, in which the time to event cannot be completely observed, but instead represents the lower bound of the time to event. Only the occurrence of either time to event or censoring time is observed. Many traditional statistical methods have been effectively used for analyzing survival data with censored observations. However, with the development of high-throughput technologies for producing "omics" data, more advanced statistical methods, such as regularization, should be required to construct the predictive survival model with high-dimensional genomic data. Furthermore, machine learning approaches have been adapted for survival analysis, to fit nonlinear and complex interaction effects between predictors, and achieve more accurate prediction of individual survival probability. Presently, since most clinicians and medical researchers can easily assess statistical programs for analyzing survival data, a review article is helpful for understanding statistical methods used in survival analysis. We review traditional survival methods and regularization methods, with various penalty functions, for the analysis of high-dimensional genomics, and describe machine learning techniques that have been adapted to survival analysis.

• Journal of the Korea Institute of Military Science and Technology
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• v.27 no.1
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• pp.94-106
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• 2024

In this study, we conducted a survival analysis on battalion-level commanders(leaders), focusing on infantry battalion defensive operations using the big data of brigade-level KCTC(Korea Combat Training Center) training results. Unlike previous studies, we utilized the brigade-level KCTC training results data for the first time to conduct a survival analysis, and the research subjects were battalion-level commanders(leaders), which can affect the battle. At this time, the battle results were defined, and through cluster analysis, infantry battalions were divided into excellent, average, and insufficient units, and the difference in the survival rate of the commanders was analyzed through the Kaplan-Meier survival analysis. This provided an opportunity to objectively compare the differences between excellent and insufficient units. Subsequently, factors affecting the survival of commanders were derived using the Cox proportional hazard model, and it was possible to confirm the influencing factors from various angles by also using the survival tree model. Significance and limitations confirmed in the research process were presented as policy suggestions and future research directions.

• Journal of Korean Institute of Industrial Engineers
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• v.42 no.2
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• pp.129-137
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• 2016

A colonoscopy is important because it detects the presence of polyps in the colon that can lead to colon cancer. How often one needs to repeat a colonoscopy may depend on various factors. The main purpose of this study is to determine personalized surveillance interval of colonoscopy based on characteristics of patients including their clinical information. The clustering analysis using a partitioning around medoids algorithm was conducted on 625 patients who had a medical examination at Korea University Anam Hospital and found several subgroups of patients. For each cluster, we then performed survival analysis that provides the probability of having polyps according to the number of days until next visit. The results of survival analysis indicated that different survival distributions exist among different patients' groups. We believe that the procedure proposed in this study can provide the patients with personalized medical information about how often they need to repeat a colonoscopy.

• 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.

• Tuberculosis and Respiratory Diseases
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• v.57 no.2
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• pp.148-159
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• 2004

Background : This study was conducted to evaluate the survival benefit of the bronchial arterial embolization (BAE) for patients presenting with non-traumatic hemoptysis. Methods : The clinical data were retrospectively collected from the medical records and the Order Communicating Systems (OCS). The information dealing with death was collected from national death certificates. After enrolled patients were divided with two group such as BAE group (patients who were managed with BAE) and non-BAE group (patients who were managed with conservative modality), the survival benefit of BAE was estimated during the observational period of 24 months through using the Kaplan-Meier survival graph and the Cox-proportional hazard regression analysis. Results : The number of total cases was 272. Of these, BAE group involved 63 and non-BAE group involved 209. 69 cases had the malignant pulmonary lesions, 149 cases had non-malignant chronic lung lesion such as the mycobacteria infection, fungus ball, or bronchiectasis (BE), and 54 cases had the other pathologic conditions. For each sub-groups such as 'malignant lung lesion' group, 'non-malignant chronic lung lesion' group as well as about all cases, the adjusted hazard ratios (HRs) of BAE for death was not significantly different compared to the conservative management. But the adjusted HRs as to underlying causes such as 'malignant lung lesion' group and 'the other conditions' group increased significantly compared to 'non-malignant chronic lung lesion' group. Conclusion : There was no significant survival benefit by BAE procedure on survival in patients presenting with non-traumatic hemoptysis.

• Radiation Oncology Journal
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• v.19 no.4
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• pp.306-311
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• 2001

Purpose : In this retrospective study, we attempted to evaluate the treatment outcome and the prognostic factors of thymoma treated with surgery, radiotherapy and chemotherapy. Methods and materials : Between 1979 and 1998, 55 patients with thymoma were treated at the Seoul National University Hospital. Of these, 11 patients underwent surgery only, 33 patients received post-operative radiotherapy and 11 patients received radiotherapy only. Twenty-three patients had gross total resection and 21 patients subtotal resection. For postoperative radiotherapy, the radiation dose consisted of $41.4\~55.8\;Gy$. The average follow-up was 64 months, and ranged from 2 to 160 months. The sex ratio was 1:1 and the median age was 48 years $(15\~74\;years)$. Overall survival and disease-free survival were determined via the Kaplan-Meier method, and the log-rank was employed to evaluate for differences in prognostic factor. Results : The five- and 10-year survivai rates were $87\%\;and\;65\%$ respectively, and the median survival was 103 months. By univariate analysis, only stage (p=0.0017) turned out to be significant prognostic factors of overall survival. Also, stage (p=0.0007) was significantly predictive for overall survival in mutivariated analysis. Conclusion : This study showed the stage was found to be important prognostic factors, which influenced survival. Especially, as incomplete resection is related with poor results, complete resection is important to cure the invasive thymoma.

• Asian Pacific Journal of Cancer Prevention
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• v.13 no.7
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• pp.3451-3454
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• 2012

Background: Esophageal cancer in Iran is the sixth most common cancer and is particularly important in east Azerbaijan. The aim of this study was to calculate survival rates and define prognostic factors in esophageal cancer patients. Methods: In this study, all patients with esophageal cancer registered in the Radiation Therapy Center, during March 2006 to March 2011, were analyzed and followed up for vital status. Data were analyzed using the Kaplan-Meier method and the Cox proportional hazard models. Results: Out of 532 patients, survival information was available for 460, including 205 (44/ 5%) females and 255 (55/4%) males. The mean age was $65.8{\pm}12.2$, ranging from 29 to 90 years at the time of diagnosis. 1-, 3- and 5-year survival rates after diagnosis were 55%, 18% and 12%, respectively, with a median survival time of $13.2{\pm}.7$ (CI 95% =11.8-14.6) months. In the univariate analysis, age (P=0/001), education (P=0/001), smoking status (P= 0/001), surgery (P= 0/001), tumor differentiation (P= 0/003) and tumor stage (P= 0/001) were significant prognostic factors. Tumor morphology, sex, place of residence, tumor histology and tumor location did not show any significant effects on the survival rate. In multivariate analysis, age (P = 0/003), smoking (P= 0/01) and tumor stage (P= 0/001) were significant independent predictors of survival. Conclusion: In summary, prognosis of esophageal cancer in North West of Iran is poor. Therefore, reduction in exposure to risk factors and early detection should be emphasized to improve survival.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.8
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• pp.3613-3618
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• 2014

Stathmin, also called oncoprotein 18, is a founding member of the family of microtubule-destabilizing proteins that play a critical role in the regulation of mitosis. At the same time stathmin has been recognized as one of responsible factors in cancer cells. The aim of this study was to assess stathmin status, its correlations with clinicopathological parameters and its role as a progosnostic marker in EC patients. The protein and mRNA levels of stathmin were examined byimmunohistochemistry (IHC) and in situ hybridization in 100EC tissues and adjacent noncancerous tissues. mRNA and protein expression of stathmin in three EC cell lines(EC9706, ECa109, EC1 commonly used in research) were also analyzed using immunocytochemistry, western blot and in situ hybridization. The prognostic value of Stathmin expression within the tumor tissues were assessed by Cox regression and Kaplan-Meier analysis. We showed that stathmin expression was significantly higher in EC tissues than in adjacent noncancerous tissues. High stathmin immunostaining score in the EC was positively correlated with tumor differentiation, Tumor invasion, Lymph node metastases, and TNM stage. In addition, we demonstrated that three EC cell lines examined, were constitutively expressing a high level of stathmin. Of those, EC-1 showed the strongest mRNA and protein expression for the stathmin analyzed. Kaplan-Meier analysis showed that significantly longer 5-year survival rate was seen in EC patients with high Stathmin expression, compared to those with low expression of Stathmin expression. Furthermore, multivariate Cox proportional hazard analyses revealed that Stathmin was an independent factors affecting the overall survival probability. In conclusion, our data provide a basis for the concept that stathmin might be associated with EC development and progression. High levels of Stathmin expression in the tumor tissues may be a good prognostic marker for patients with EC.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.7
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• pp.3299-3304
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• 2014

Background: The aim of the present study was to analyze whether Homer1 is a potential prognostic marker for intrahepatic cholangiocarcinoma (ICC). Materials and Methods: The expression of Homer1 in ICC tissue was detected with immunohistochemistry and levels of protein in ICC and paratumor tissues were evaluated by Western blotting. Survival analysis by the Kaplan-Meier method was performed to assess prognostic significance. Results: Homer1 expression was high in 67.4% (58/86) of ICC samples, and there was significant difference between ICC and adjacent noncancerous tissues (p<0.001); high expression was associated with poor histologic differentiation (p=0.019), TNM stage (p=0.014), lymph node metastasis (p=0.040), and lymphatic invasion (p=0.025). On Kaplan-Meier analysis, a comparison of survival curves of low versus high expressors of Homer1 revealed a highly significant difference in OS (p=0.001) and DFS (p=0.006), indicating that high expression of Homer1 was linked with a worse prognosis. Multivariate analyses showed that Homer1 expression was an independent risk factor predicting overall survival[Hazard ratio(HR), 7.52; 95% confidence interval (CI), 2.63-21.47; p=0.002] and disease-free survival (HR, 11.56; 95%CI, 5.17-25.96; p<0.001) in ICC. Conclusions: Homer1 promotes lymphatic invasion and associates with lymph node metastasis and poor prognosis of ICC. The current study shows that Homer1 may be an independent prognostic factor for ICC patients after curative resection, and it provides an important basis for screening/treating high-risk patients.

• Journal of Yeungnam Medical Science
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• v.19 no.2
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• pp.126-135
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• 2002

Background: Neovascular glaucoma is common secondary glaucoma at high risk for failure of glaucoma filtering surgery. Recently, trabeculectomy with adjunctive mitomycin C trabeculectomy has been tried to improve the surgical success rate of conventional trabeculectomy. But, the long-term effects of mitomycin C trabeculectomy for neovascular glaucoma are unknown. Thus, we evaluated the long-term effects of mitomycin C trabeculectomy and its prognostic factors influencing the outcome. Materials and Methods: Medical records of 62 eyes of 55 neovascular glaucoma who had undergone mitomycin C trabeculectomy were retrospectively reviewed. Surgical success was defined as intraocular pressures of 21 mmHg or less with or without glaucoma medications and no loss of light perception. Surgical failure was defined as postoperative loss of light perception in patients with preoperative vision better than light perception, additional glaucoma surgery, or phthisis bulbi in patients with preoperative vision of no light perception. Results: Postoperative success was obtained in 37 (60%) out of 62 eyes after mean followup period of $23.9{\pm}16.2$ months. Using Kaplan-Meier survival analysis, cumulative success rate at the 6-, 12-, 24- and 36-month intervals were 85%, 71%, 57% and 52%, respectively. Success rate was greater in eyes with diabetic retinopathy than other causes(p=0.005) and in eyes with preoperative panretinal photocoagulation(PRP) than without PRP(p=0.015). However, Cox proportional hazard regression analysis revealed that preoperative PRP was not a significant risk factor for surgical failure. Conclusion: Prognosis of neovascular glaucoma caused by diabetic retinopathy was better than that caused by the other disorders following mitomycin C trabeculectomy. The author would suggest that mitomycin C trabeculectomy could be effective and relatively safe as the first procedure of choice before performing glaucoma drainage device implantation or cyclodestructive procedure.