Abstract

Background: Breast cancer is one of the most common causes of cancer mortality in Iran. Social determinants of health are among the key factors affecting the pathogenesis of diseases. This study aimed to determine those influencing breast cancer survival time with parametric and semi-parametric regression models. Materials and Methods: This cross-sectional study was conducted on male and female patients diagnosed with breast cancer presenting to the Cancer Research Center of Shohada-E-Tajrish Hospital from 2006 to 2010. Cox proportional hazard and parametric models including the Weibull, lognormal and log-logistic were applied to determine the social determinants of survival time of breast cancer patients. The Akaike information criterion (AIC) was used to assess the best fit. Statistical analysis was performed with STATA (version 11) software. Results: This study was performed on 797 breast cancer patients, aged 25-93 years with a mean age of 54.7 (±11.9) years. With both semi-parametric and parametric models, the three-year survival was related to level of education and municipal district of residence (P<0.05). The AIC suggested that the lognormal distribution was the best fit. Conclusion: A lognormal distribution is the best fit for the three-year survival time of breast cancer patients. Social determinants of health such as level of education and municipal district of residence affect survival. Future studies should focus on the effect of childhood social class on the survival times of cancers, which have hitherto attracted limited attention.