[Survival analysis of gastric cancer patients refering to Emam-Khomeini hospital using Weibull cure model]

ABSTRACT

Due to its high prevalence, the survey on gastric cancer survival in Iran seems too important. In the case of relative long-term survival of the cases, using standard models is not conventional. So cure models are used to estimate the proportion of the cured patients that will never experience the event of interest and also to evaluate the survival function of susceptible individuals who may experience the event and effective factors. This study was carried out to determine the five-year survival rate of gastric cancer patients who have undergone surgical treatment. Three hundred and thirty gastric cancer operated patients with a maximum 10-year survival were enrolled in the study. The patients' life expectancy after surgery and cure fraction and their relationships with some variables were evaluated. Kaplan-Meier and Weibull Cure models were utilized for analyses. The five-year survival rate and the median life expectancy were 24% and 19.9 months, respectively. Univariate analysis using the Weibull model showed that age, existence/site of metastasis and stage of disease influenced on the probability of curing [P<0.05]. On assessing the simultaneous effect of different variables the age and stage of disease proved to be effective on curing [P<0.05], but none of the variables affected the life expectancy of patients [P>0.05]. Using the cure models is beneficial in situations which the population under study suggests the presence of subpopulation. The cure/immune model methodology may separeltery identify the sets of covariates related to the cured proportion and also the failure time distribution of uncured one