• Journal of the Korean Mathematical Society
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• v.42 no.4
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• pp.673-693
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• 2005

In this paper, we first find a necessary and sufficient condition for the existence of multiple orthogonal polynomials by the moments of a pair of measures $(d{\mu},\;dv)$ and then give representations for multiple orthogonal polynomials. We also prove four term recurrence relations for multiple orthogonal polynomials of type II and several interesting relations for multiple orthogonal polynomials are given. A generalized recurrence relation for multiple orthogonal polynomials of type I is found and then four term recurrence relations are obtained as a special case.

• Bulletin of the Korean Mathematical Society
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• v.56 no.6
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• pp.1577-1588
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• 2019

We show a multiple recurrence theorem for topological dynamical systems with countable directed partial semigroup actions, which generalizes the well-know IP-version of multiple recurrence theorem proved by Furstenberg and Weiss.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.14
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• pp.5539-5544
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• 2014

Background: To evaluate the location of tumor relapse and imaging modality for detection according to the breast cancer subtype: luminal A, luminal B, HER2 positive luminal B, nonluminal HER2 positive, and triple negative. Materials and Methods: A total of 1244 patients with breast cancer with known estrogen receptor (ER), progesterone receptor (PR), Ki-67 and human epidermal growth factor receptor 2 (HER2), who underwent breast surgery from 2009 to 2012 were analyzed. Patients were classified into the following categories: luminal A (n=458), luminal B (n=241), HER2 positive luminal B (n=227), nonluminal HER2 positive (n=145) and triple negative (n=173). A total of 105 cases of relapse were detected in 102 patients: locoregional recurrence (n=46), recurrence in the contralateral breast (n=28) and distant metastasis (n=31). Comparison of proportions was used to determine the difference between subtypes. Results: Relapse rates by subtypes are as follows: luminal A 23 of 458 (5.02%), luminal B 19 of 241(7.88%), HER2 positive luminal B 15 of 227 (6.61%), nonluminal HER2 postive 19 of 145 (13.10%) and triple negative 29 of 173(16.76%). Luminal A tumors had the lowest rate of recurrence and had significantly lower recurrence rate in comparison with nonluminal HER2 postive (p=0.0017) and triple negative subtypes (p<0.0001). Compared with all other subtypes except nonluminal HER2 positive, triple negative tumors had the highest rate of tumor recurrence (p<0.01). Triple negatives were most likely to develop contralateral recurrence against all subtypes (p<0.05). Detection rate of locoregional and contralateral tumor recurrence were 28.3% on mammography (n=17/60). Conclusions: Luminal A tumors are associated with a low risk of recurrence while triple negative lesions have a high risk. In case of triple negative tumors, the contralateral breast has much more recurrence as compared with all other subtype. In terms of detection rates, breast USG was the best modality for detecting tumor recurrence, compared with other modalities (p<0.05). Subtyping of breast tumors using a molecular gene expression panel can identify patients who have increased risk of recurrence and allow prediction of locations of tumor recurrence for each subtype.

• Journal of Korean Neurosurgical Society
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• v.30 no.sup2
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• pp.228-234
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• 2001

Objective : The goal of this study was to identify variables that were predictive of recurrence in primary intracranial ependymomas. Methods : We analyzed variables affecting recurrence in 30 patients with primary intracranial ependymomas. Age, location, CSF cytology, seeding on neuroimaging study, tumor grade, extent of surgery, use of chemotherapy, chemotherapy regimen, use of radiotherapy, and radiotherapy field were entered to test their impacts on recurrence. Results : Follow-up ranged from 2 to 110 months. Tumors were recurred at the primary tumor site only in 13 patients (43.3%). The overall average recurrence free period was 55 months, with overall recurrence free rates at 3 and 6 years of 61.0% and 20.9%, respectively. Extent of surgery was the strongest variable affecting recurrence. The median recurrence free period and 3-year recurrence free rate were 72 months and 78.4% for patients having complete excision and 33 months and 0% for those having incomplete excision(p=0.05). Other prognostic variables like age, location, tumor grade, use of chemotherapy, and use of radiotherapy did not affect recurrence(p=0.2848, 0.7899, 0.1714, 0.2157, 0.7076, respectively). Conclusions : Intracranial ependymomas have a propensity to recur after treatment, and recurrence at the primary site is still the main obstacle to cure. Among various variables, only extent of resection had the strongest impact on recurrence. Additional studies may still be needed to precisely define the prognostic variables on recurrence in intracranial ependymomas.

• Journal of Korean Neurosurgical Society
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• v.57 no.4
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• pp.266-270
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• 2015

Objective : Chronic subdural hematoma (CSDH) is one of the most frequent problems encountered in neurosurgery. Although burr-hole trephination is widely performed to treat CSDH, the incidence rate of recurrent CSDH is still 2-37%. The goal of this study is to determine the risk factors that affect recurrent CSDH. Methods : A total of 182 patients were included in this study who underwent burr-hole trephination. The clinical factors and radiographic features between the recurrence and the no recurrence groups were analyzed to find the parameters related to the postoperative recurrence of CSDH. Results : For the recurrence of CSDH that occurred in 25 patients (13.7%), among various risk factors, pre and postoperative midline displacements, which are more than 10 mm (p=0.000), and preoperative hemiparesis (p=0.026) had contributed to recurrent CSDH with statistical significance by univariate analysis. Unilateral CSDH were more frequently related to recurrent CSDH (16.3%), although it was not a statistical significant result (p=0.052). Furthermore, preoperative midline displacement only had statistical meaning for the recurrence of CSDH by multivariate analysis. Conclusion : This study indicates that the midline displacement on the preoperative computed tomography scan is the only independent predictor for the recurrence of CSDH.

• Journal of Korean Neurosurgical Society
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• v.40 no.4
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• pp.262-266
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• 2006

Objective : Chronic subdural hematoma[CSDH] is usually treated by burr hole trephination and hematoma evacuation with closed drainage and the surgical result is relatively good in most reported series. But, some patients experience the recurrence of CSDH. We study the clinical factors related to the recurrence of CSDH. Methods : 213 consecutive patients with CSDH who were treated with burr hole trephination and hematoma evacuation with closed drainage. The medical records, radiologic findings were reviewed retrospectively and clinical factors associated with the recurrent CSDH were analysed statistically. Results : 8.4%[18 cases] of the 213 patients who were treated due to CSDH were recurred. The demographic variables such as age, sex, coexisting diseases were not related to the recurrence. The preoperative hematoma thickness and postoperative hematoma thickness were not associated with the recurrence. The only factor related to the recurrence is postoperative hematoma density in this study. Conclusion : This study shows that postoperative hematoma density was strongly related to the recurrence of CSDH. However, several factors associated with the recurrent CSDH were reported in the liletrature. Thus, further study will be needed to uncover the factors related to the recurrence of CSDH.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.20
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• pp.8587-8589
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• 2014

Background: Although a great deal of progress has been made in the management of colorectal cancer in terms of neoadjuvant modalities, surgical techniques and adjuvant therapies, the recurrence of tumors remains an enigmatic complication in patients. A better understanding of colorectal cancer and of factors that lead to recurrence of disease can provide helpful information for designing more effective screening and surveillance methods. Aim: To investigate the factors that may lead to local recurrence of colorectal cancers. Materials and Methods: The current retrospective case study evaluated 617 patients admitted to the Iranian Cancer Institute (the largest referral cancer center in the country) from 1995 to 2009 with confirmed colorectal cancer. Patients with distant metastasis, or with pathology other than adenocarcinoma and no follow-up, were excluded (175 patients). The remainder (442) included 294 (66.5%) with rectal cancer and 148 (33.5%) with colon cancer. The median duration of follow-up was 26 months. Results: The total rate of recurrence was 17.4%, comprising 19.6% and 16.3% recurrence rates in colon and rectal cancer, respectively. Conclusions: Recurrence of colorectal cancer was significantly correlated to tumor grade (p<0.008).

• Korean Journal of Head & Neck Oncology
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• v.33 no.1
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• pp.15-19
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• 2017

Background/Objective: The survival and recurrence pattern of the patients with primary cancer of the external auditory canal was evaluated. Materials & Methods: Seventeen patients with primary cancer of the external auditory canal from 2002 to 2013 was analyzed retrospectively. Overall survival, recurrence free survival, local recurrence free survival and distant metastasis free survival was calculated by Kaplan-Meyer's method. Results: Five year overall survival rate, 5 year recurrence free survival rate, 5 year local recurrence free survival rate and 5 year distant metastasis free survival rate were 49.3% 54.9%, 64.7% and 69.6% respectively. The recurrence pattern is different to the pathologic type, squamous cell carcinoma or adenoid cystic carcinoma. The patients with squamous cell carcinoma showed local recurrence and the patients with adenoid cystic carcinoma showed distant metastasis mainly. Conclusion: Primary cancer of external auditory canal showed different clinical course depend on the pathologic diagnosis.

• Kosin Medical Journal
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• v.33 no.3
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• pp.289-296
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• 2018

Objectives: In these days, patients with stage I breast cancer have increased by regular health examination and diagnostic tool development. The aim of this retrospective study is to identify systemic recurrence related factors after breast conserving surgery (BCS) for stage I breast cancer. Methods: In this study, we analyzed the correlation between systemic recurrence and pathologic factors. We reviewed 223 patients who underwent BCS for stage I breast cancer. Postoperative pathologic factors, recurrent rates and sites were studied. In addition, preoperative patients'data were also collected. Statistical analysis was done by using PASW 16.0 (SPSS Inc., Chicago, IL, USA). Results: Systemic recurrence was found in 16 patients (7.17%) within 5 years after primary surgery. 5 patients had lymphatic invasion and 6 patients had vascular invasion. Lymphatic and vascular invasion had statistical correlation with systemic recurrence (P = 0.004, P = 0.001). Conclusions: In this retrospective study, we can conclude that vascular invasion and lymphatic invasion are related systemic recurrence after BCS for stage I patients. Further studies with large cohort will be required to fully understand the risk factors of systemic recurrence for stage I breast cancer patients.

• International Journal of Advanced Culture Technology
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• v.8 no.4
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• pp.220-228
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• 2020

Breast cancer incidence continues to increase, and survival rates are also increasing compared to the past. An increase in breast cancer survivors means an increase in the number of women who return to their life after treatment. These patients feared cancer recurrence, which makes it an important aspect to be studied among breast cancer survivors. Therefore, this study was aimed at analyzing the concept of breast cancer survivors' fear of recurrence. The procedure of concept analysis developed by Walker and Avant (2011) was used to clarify and describe the concept. Studies published from 2007 to 2017 were searched through domestic and foreign electronic databases. Finally, 15 studies were selected and included in analysis. Through concept analysis, the scope of use of the fear of recurrence among breast cancer survivors was confirmed, and concept analysis was performed to confirm the antecedent, consequences, attributes and empirical criteria. Based on the analysis, the attributes of the fear of recurrence among breast cancer survivors included 1) worry about health status, 2) ineffective coping, and 3) possibility of changes. The antecedents of the fear of recurrence among breast cancer survivors were 1) healthcare-related activity, 2) perception of cancer, and 3) perceived severity; the consequences were 1) increase in distress, 2) difficulty in role function, and 3) decrease in the quality of life. This study provides a clear definition of the fear of recurrence among breast cancer survivors, and the results can be applied to improve the understanding of breast cancer survivors who have finished treatment and to help them return to daily life.