[Survival rate of childhood leukemia and its determinants: cox proportional hazards model]

Leukemia is the most common childhood cancer and is a major public health problem in many countries. The aim of this study was to conduct a survival analysis among leukemia patients and determine the factors affecting survival rate in patients referring to Amir Kabir Hospital in Arak Province from 2006 to 2011. This survival analysis study included 72 leukemia patients. Then, necessary variables were collected and we assessed the survival status of the patients during follow up visits.Using stata software, data analysis was performed by Kaplan-Meier method, log-rank and Cox proportional hazard model were used to analyze the data. The mean follow-up time was 14.54 months [range: 1 to 53 months]. Mortality rate due to leukemia among children was 11.1 cases [95% CI 6.16-20.08] per 1000 person-months. Survival rates at the 1st, 2nd, 3rd and 4th years were 87, 79, 70 and 70 percent respectively. Only age had a significant effect on the survival rate in the Cox proportional hazard model. 4-year survival rate of leukemia was 70% and age was identified as one of the most important predictors of survival in leukemia patients