Lifestyle factors and long-term survival of gastric cancer patients: A large bidirectional cohort study from China

BACKGROUND: Lifestyle factors such as body mass index (BMI), alcohol drinking, and cigarette smoking, are likely to impact the prognosis of gastric cancer, but the evidence has been inconsistent. AIM: To investigate the association of lifestyle factors and long-term prognosis of gastric cancer patients in the China National Cancer Center. METHODS: Patients with gastric cancer were identified from the China National Cancer Center Gastric Cancer Database 1998-2018. Survival analysis was performed via Kaplan-Meier estimates and Cox proportional hazards models. RESULTS: In this study, we reviewed 18441 cases of gastric cancer. Individuals who were overweight or obese were associated with a positive smoking and drinking history (P = 0.002 and P < 0.001, respectively). Current smokers were more likely to be current alcohol drinkers (61.3% vs 10.1% vs 43.2% for current, never, and former smokers, respectively, P < 0.001). Multivariable results indicated that BMI at diagnosis had no significant effect on prognosis. In gastrectomy patients, factors independently associated with poor survival included older age (HR = 1.20, 95%CI: 1.05-1.38, P = 0.001), any weight loss (P < 0.001), smoking history of more than 30 years (HR = 1.14, 95%CI: 1.04-1.24, P = 0.004), and increasing pTNM stage (P < 0.001). CONCLUSION: In conclusion, our results contribute to a better understanding of lifestyle factors on the overall burden of gastric cancer and long-term prognosis. In these patients, weight loss (both in the 0 to 10% and > 10% groups) but not BMI at diagnosis was related to survival outcomes. With regard to other factors, smoking history of more than 30 years conferred a worse prognosis only in patients who underwent gastrectomy. Extensive efforts are needed to elucidate mechanisms targeting the complex effects of lifestyle factors.