Survival Analysis of Gastric Cancer Patients Using Illness-Death Model In Kerman City, Southeast Iran during 2001-2016

Gastric cancer (GC) is the fifth most common cancer and the third most common causes of cancer death worldwide. The aim of this study was to investigate the factors affecting the survival of patients with GC with metastatic as an intermediate event using illness-death model.

In this retrospective cohort study, 339 patients with GC who referred to Shahid Bahonar and Afzalipour hospitals in Kerman during 2001 to 2016, were included. Demographic, therapeutic, and clinical data were collected from medical records of patients. To evaluate the factors affecting the survival of patients and the relationship between these factors, with metastatic as an intermediate event the illness -death model was used.

One, three, and five-year survival of patients with GC was estimated to be 63, 40, and 30%, respectively. The results of analysis of illness-death model showed that age (HR=0.98, P=0.007) and histological grade (HR=1.77, P=0.007) affected metastasis whereas history cigarette smoking (HR=1.89, P=0.02) and chemotherapy (HR=0.63, P=0.02) affected death hazard without metastasis. history of opium use (HR=2.11, P=0.002), family history of GC (HR=2.48, P=0.01) and histological grade (HR=1.85, P=0.02) were identified as factors affecting death hazard in patients with metastasis.

In this study, age of patients at the time of diagnosis and effect of histological have a significant effect on the occurrence of metastasis. Therefore, it is recommended to pay more attention and provide care to patients at lower ages of metastasis for timely diagnosis in order to prevent metastasis and death.