Abstract
BACKGROUND: This multi-center cohort study aimed to investigate whether sex and prediagnosis lifestyle affect the prognosis of gastric cancer. METHODS: Patients with gastric cancer were from four gastric cancer cohorts of the National Cancer Center of China, The First Hospital of Lanzhou University, Lanzhou University Second Hospital, and Gansu Provincial Cancer Hospital. Prediagnosis lifestyle factors in our study included body mass index (BMI) at diagnosis, usual BMI, weight loss, the history of Helicobacter pylori (Hp) infection, and the status of smoking and drinking. RESULTS: Four gastric cancer cohorts with 29,779 gastric cancer patients were included. In total patients, female patients had a better prognosis than male patients (HR = 0.938, 95%CI: 0.881-0.999, P = 0.046). For prediagnosis lifestyle factors, BMI at diagnosis, usual BMI and the amount of smoking were statistically associated with the prognosis of gastric cancer patients. Female patients with smoking history had a poorer survival than non-smoking females (HR = 0.782, 95%CI: 0.616-0.993, P = 0.044). Tobacco consumption > 40 cigarettes per day (HR = 1.182, 95%CI: 1.035-1.350, P = 0.013) was independent adverse prognostic factors in male patients. Obesity paradox was observed only in male patients (BMI < 18.5, HR = 1.145, 95%CI: 1.019-1.286, P = 0.023; BMI: 23-27.4, HR = 0.875, 95%CI: 0.824-0.930, P < 0.001; BMI ≥ 27.5, HR = 0.807, 95%CI: 0.735-0.886, P < 0.001). CONCLUSIONS: Sex and some prediagnosis lifestyle factors, including BMI at diagnosis, usual BMI and the amount of smoking, were associated with the prognosis of gastric cancer.