M Asghari Jafarabadi, E Hajizadeh, A Kazemnejad, Sr Fatemi,
Volume 6, Issue 3 (12-2010)
Abstract
Background & Objectives: Cholera is always being considered as a public health threat in poor and developing countries. However outbreaks of cholera are not very common in central area of Iran in 2008 district health authority reported a cluster of diarrhea cases. We investigated this cluster to identify the etiological agent, source of transmission and propose control measures.
Methods: We analyzed the data of total of 1219 patients with colorectal cancer who registered between 1 January 2002 to 1 October 2007. Data were analyzed using univariate and multivariate Accelerated Failure Time (AFT) parametric survival model with frailty, utilizing STATA statistical software.
Results: In the univariate analysis for age at diagnosis, gender, marital status, race and education level, the survival of patients with colon cancer were approximately between half to one fourth and for BMI, alcohol history, Inflammatory Bowel Disease (IBD), familial history of cancer and the pathologic stage of tumor, the survival of patients with colon cancer were significantly (between 0.12 to 0.56 times) shorter than those patients with rectal cancer. In the multivariate analysis, for age at diagnosis (45-65 years), there was significant difference between colon and rectum cancer. But for BMI, alcohol history, IBD and pathologic stage there were not significant differences. The adjusted survival and 1, 2, 3, 4 and 5 year survival of patients with rectal cancer were better than those with colon cancer.
Conclusions: Site-specific evaluation of colon and rectum could give a better perspective of factors affecting these cancers. It may help to design of clinical trials, better diagnosis of diseases and optimal administration of specific treatments.
A Saki Malehi, E Hajizadeh, R Fatemi,
Volume 8, Issue 2 (9-2012)
Abstract
Background
& Objectives: Identifying
the important influential factors is a great challenge in oncology studies.
Decision tree is one of methods that could be used to evaluate the prognostic
factors and classifying the patients' homogeneously. This method identifies the
main prognostic factors and then determines the subgroups of patients based on
those prognostic factors. The aim of this study was to assess the prognostic
factors and homogeneous subgroups of colorectal patient through survival tree.
Methods: Data collected from an observational
of 739 colorectal patients registered in the cancer registry affiliated to the
center of Research Center of Gastroenterology and Liver Disease (RCGLD), Shahid
Beheshti Medical University, Tehran, Iran. Death was the interested event and
the survival time was calculated from date of diagnosis until occurrence of
event (or censoring) in months. Finally we used decision tree based method for
classifying and analyzing the data.
Results: Based on our result, decision tree
identified four covariates as important prognostic factors in 0.05 significant
levels: general stage of cancer, age of diagnosis, histology of tumor and
morphology type of tumor. Also patients based on these prognostic factors
divided into five homogeneous subgroups. The greater values of measure of
separation (SEP) criterion support the appropriateness of this model for such
the data.
Conclusion:
Decision tree is powerful and intuitive method. It has a key feature that is in
addition to evaluate the prognostic factors, provides the homogeneous subgroups
for future analysis.
