• Structural Engineering and Mechanics
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• v.27 no.6
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• pp.773-776
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• 2007

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2006.09a
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• pp.596-596
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• 2006

• Korean Journal of Radiology
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• v.23 no.11
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• pp.1115-1117
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• 2022

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.9
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• pp.4109-4115
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• 2014

Background: Accurate assessment of disease progression requires proper understanding of natural disease process which is often hidden and unobservable. For this purpose, disease status should be clearly detected. But in most diseases it is not possible to detect such status. This study, therefore, aims to present a model which both investigates the unobservable disease process and considers the error probability in diagnosis of disease states. Materials and Methods: Data from 330 patients with gastric cancer undergoing surgery at the Iran Cancer Institute from 1995 to 1999 were analyzed. Moreover, to estimate and assess the effect of demographic, diagnostic and clinical factors as well as medical and post-surgical variables on transition rates and the probability of misdiagnosis of relapse, a hidden Markov multi-state model was employed. Results: Classification errors of patients in alive state without a relapse ($e_{21}$) and with a relapse ($e_{12}$) were 0.22 (95% CI: 0.04-0.63) and 0.02 (95% CI: 0.00-0.09), respectively. Only variables of age and number of renewed treatments affected misdiagnosis of relapse. In addition, patient age and distant metastasis were among factors affecting the occurrence of relapse (state1${\rightarrow}$state2) while the number of renewed treatments and the type and extent of surgery had a significant effect on death hazard without relapse (state2${\rightarrow}$state3)and death hazard with relapse (state2${\rightarrow}$state3). Conclusions: A hidden Markov multi-state model provides the possibility of estimating classification error between different states of disease. Moreover, based on this model, factors affecting the probability of this error can be identified and researchers can be helped with understanding the mechanisms of classification error.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.1
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• pp.441-447
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• 2014

Background: Multi-state models are appropriate for cancer studies such as gastrectomy which have high mortality statistics. These models can be used to better describe the natural disease process. But reaching that goal requires making assumptions like Markov and homogeneity with time. The present study aims to investigate these hypotheses. Materials and Methods: Data from 330 patients with gastric cancer undergoing surgery at Iran Cancer Institute from 1995 to 1999 were analyzed. To assess Markov assumption and time homogeneity in modeling transition rates among states of multi-state model, Cox-Snell residuals, Akaikie information criteria and Schoenfeld residuals were used, respectively. Results: The assessment of Markov assumption based on Cox-Snell residuals and Akaikie information criterion showed that Markov assumption was not held just for transition rate of relapse (state 1 ${\rightarrow}$ state 2) and for other transition rates - death hazard without relapse (state 1 ${\rightarrow}$ state 3) and death hazard with relapse (state 2 ${\rightarrow}$ state 3) - this assumption could also be made. Moreover, the assessment of time homogeneity assumption based on Schoenfeld residuals revealed that this assumption - regarding the general test and each of the variables in the model- was held just for relapse (state 1 ${\rightarrow}$ state 2) and death hazard with a relapse (state 2 ${\rightarrow}$ state 3). Conclusions: Most researchers take account of assumptions such as Markov and time homogeneity in modeling transition rates. These assumptions can make the multi-state model simpler but if these assumptions are not made, they will lead to incorrect inferences and improper fitting.

• Asian Pacific Journal of Cancer Prevention
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• v.16 no.17
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• pp.7721-7725
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• 2015

Background: The aim of this study was to assess the predictive role of religious coping in quality of life of breast cancer patients. Materials and Methods: This multi-center cross-sectional study was conducted in Tehran, Iran, from October 2014 to May 2015. A total of 224 women with breast cancer completed measures of socio-demographic information, religious coping (brief RCOPE), and quality of life (FACT-B). Data were analyzed using descriptive statistics and the t-test, ANOVA, and linear regression analysis. Results: The mean age was 47.1 (SD=9.07) years and the majority were married (81.3%). The mean score for positive religious coping was 22.98 (SD=4.09) while it was 10.13 (SD=3.90) for negative religious coping. Multiple linear regression showed positive and negative religious coping as predictor variables explained a significant amount of variance in overall QOL score ($R^2=.22$, P=.001) after controlling for socio-demographic, and clinical variables. Positive religious coping was associated with improved QOL (${\beta}=0.29$; p=0.001). In contrast, negative religious coping was significantly associated with worse QOL (${\beta}=-0.26$; p=0.005). Conclusions: The results indicated the used types of religious coping strategies are related to better or poorer QOL and highlight the importance of religious support in breast cancer care.

• Asian Pacific Journal of Cancer Prevention
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• v.14 no.11
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• pp.6529-6532
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• 2013

Background: Breast cancer is mostly the disease of postmenopausal women but very young affected women are seen more than occasionally in developing countries. We reviewed our cases of very young breast cancer in order to help in better understanding of such cases. Materials and Methods: The records of patients 25 years of age or less who had been admitted for breast cancer surgery in the Cancer Institute of Tehran from 1979 to 2012 were reviewed and relevant data were extracted. Results: From 5,265 cases of breast cancer, 62 patients had 25 years of age or less. There were 55 cases of breast adenocarcinoma, all female. More than 78% of the patients had presented with a palpable mass, the family history was positive in 2% of cases, and about 94% of the histologies were invasive ductal carcinoma. Gestational breast cancer constituted 10% of the cancers; another 10%were bilateral. The median size of the tumors was 5.72 centimeters, 63.2% of them had axillary lymphatic involvement, and more than half were negative for hormone receptors. Conclusions: Our study shows an incidence of 1.17% for very young breast cancer and a 10% rate of bilaterality which probably warrants special guidelines for contralateral screening. Cancer stage and features were poor in comparison with breast cancer in all ages.

• Asian Pacific Journal of Cancer Prevention
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• v.14 no.11
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• pp.6369-6373
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• 2013

Background: Gastric cancer is one of the most common causes of cancer deaths all over the world and the most important reason for its high rate of death is its belated diagnosis at advanced stages of the disease. Events occur in patients which are regarded not only as themselves factors affecting patients' survival but also which can be affected by other factors. This study was designed and implemented aiming to identify these events and to investigate factors affecting their occurrence. Materials and Methods: Data from 330 patients with gastric cancer undergoing surgery at the Iran Cancer Institute from 1995-1999 were analyzed. The survival time of these patients was determined after surgery and the effects of various factors including demographic, diagnostic and clinical as well as medical, and post-surgical varuiables on the occurrence of death hazard without relapse, hazard of relapse, and death hazard with a relapse were assessed. Results: The median survival time for these patients was 16.3 months and the 5-year survival rate was 21.6%. Based on the results of multi-state model, age and distant metastases affected relapse whereas disease stage, type and extent of surgery, lymph nodes metastases, and number of renewed treatments affected death hazard without relapse. Moreover, age, type and extent of surgery, number of renewed treatments, and liver metastases were identified as factors affecting death hazard in patients with relapse. Conclusions: Most cancer studies pay heed to factors which have effect on death occurrence, but some events occur which should be taken into consideration to better describe the natural process of the disease and provide researchers with more accurate data.

• Asian Pacific Journal of Cancer Prevention
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• v.14 no.10
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• pp.6189-6193
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• 2013

In December 2011, the Cancer Research Centre of the Cancer Institute of Iran sponsored a 3-day workshop on "Cancer Registration Principle and Challenges in Iran", which convened cancer registry experts. The objectives of the workshop were: to introduce standard cancer registration, to review the policy and procedure of cancer registration in Iran, and to review the best practices in the cancer registries in Iran. Challenges to cancer registration were discussed and recommendations were developed. The workshop was evaluated by participants for better organization of subsequent workshops. The objective of publication of this report is that based on Cancer in 5 Continents, many low- or middle-income countries do not meet the criteria for a standard population-based cancer registry (PBCR); on the other hand cancer is the most important cause of mortality and the essential part of any cancer control program is the cancer registry. Therefore this report focuses on problems and challenges of PBCR and provides recommendations which might help other developing countries to decrease their PBCR defects.

• Asian Pacific Journal of Cancer Prevention
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• v.16 no.3
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• pp.1057-1062
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• 2015

Background: Since the survival rate of breast cancer patients has improved, harmful effects of new treatment modalities on fertility of the young breast cancer patients has become a focus of attention. This study aimed to systematically review and critically appraise all available guidelines for fertility preservation in young breast cancer patients. Materials and Methods: Major citation databases were searched for treatment guidelines. Experts from relevant disciplines appraised the available guidelines. The AGREE II Instrument that includes 23 criteria in seven domains (scope and purpose of the guidelines, stakeholder involvement, rigor of development, clarity, applicability, editorial independence, and overall quality) was used to apprise and score the guidelines. Results: The search strategy retrieved 2,606 citations; 72 were considered for full-text screening and seven guidelines were included in the study. There was variability in the scores assigned to different domains among the guidelines. ASCO (2013), with an overall score of 68.0%, had the highest score, and St Gallen, with an overall score of 24.7%, had the lowest scores among the guidelines. Conclusions: With the promising survival rate among breast cancer patients, more attention should be given to include specific fertility preservation recommendations for young breast cancer patients.