title: Application of Censored Quantile Regression to Determine Overall Survival Related Factors in Breast Cancer.
abstract: BACKGROUND
  The occurrence and the mortality related to breast cancer (BC) in Iranian female population has increased over time. Although there are many studies on BC and related risk factors, however, the epidemiological aspects of this melanoma in Iranian females are uncertain. Therefore, the aim of this study was to determine the relationship between demographical and clinical factors on the shape of overall survival (OS) distribution in patients with BC.
  
  
  METHODS
  This historical cohort study was carried out using data from 522 participants with BC. Data were gathered from medical records of these patients admitted to Mahdieh Oncology Center of Hamadan Province, western Iran, from January 2000 to August 2011. Kaplan-Meier estimator was used to estimate the survival rates and, censored quantile regression (CQR) to provide in-depth insight in the multivariable association between prognosis factors and survival rates.
  
  
  RESULTS
  Patients' follow-up ranged from around 3 to 197 months. One-, three-, and five-year survival rates were 90%, 73% and 62.5%, respectively. Results of CQR model showed that change in the age at diagnosis, number of involved lymph nodes and tumor size could significantly change the median and some other quantiles of OS.
  
  
  CONCLUSIONS
  This study, confirm the importance of early detection of BC and usefulness of CQR because of possible changes in distribution family of survival time.
authors.affiliation: Modeling of Noncommunicable Diseases Research Center, Department of Biostatistics, School of Public Health, Hamadan University of Medical Sciences, Hamadan, Iran.
authors.forename: Javad
authors.initials: J
authors.lastname: Faradmal
authors.affiliation: Modeling of Noncommunicable Diseases Research Center, Department of Biostatistics, School of Public Health, Hamadan University of Medical Sciences, Hamadan, Iran. gh.roshanaei@umsha.ac.ir.
authors.forename: Ghodratollah
authors.initials: G
authors.lastname: Roshanaei
authors.affiliation: Department of Biostatistics, School of Public Health, Hamadan University of Medical Sciences, Hamadan, Iran.
authors.forename: Maryam
authors.initials: M
authors.lastname: Mafi
authors.affiliation: Radiology-Oncology Center, MRI Center of Hamadan Darol-Aitam, Hamadan, Iran.
authors.forename: Abdolazim
authors.initials: A
authors.lastname: Sadighi-Pashaki
authors.affiliation: Social Determinants of Health Research Center and Department of Epidemiology, School of Public Health, Hamadan University of Medical Sciences, Hamadan, Iran.
authors.forename: Manoochehr
authors.initials: M
authors.lastname: Karami
mesh_terms: D000328:Adult; D000368:Aged; D001943:Breast Neoplasms / Q000401:mortality*; D015331:Cohort Studies; D005260:Female; D006801:Humans; D007492:Iran / Q000453:epidemiology; D053208:Kaplan-Meier Estimate; D008875:Middle Aged; D012044:Regression Analysis; D012307:Risk Factors; D015996:Survival Rate
keywords: Breast Cancer; Quantiles; Survival Analysis