Effects of dietary, drinking, and smoking habits on the prognosis of gastric cancer

Although it has been clarified that dietary, drinking, and smoking habits contribute to the onset of gastric cancer, little is known about their impact on prognosis of gastric cancer. To examine this question, a prognostic analysis was conducted using data from Aichi Cancer Center Research Institute and Hospital. From January 1988 to December 1994, information on 877 gastric cancer patients (578 men and 299 women) regarding habitual smoking and drinking, food consumption, histological grade, and clinical stage of tumor as well as follow-up results were collected. Survival status of all patients was followed up until December 1998, and the survival function was estimated by the Kaplan-Meier method. Proportional hazard analysis was used to test the effect of each lifestyle item on gastric cancer death. After controlling for age, gender, histological grade, and stage of disease, hazard ratios (HR) were calculated. Values for consumption of raw vegetables [HR = 0.74, 95% confidence interval (CI) = 0.5-0.98] tofu (HR = 0.65, 95% CI = 0.42-0.99), and chicken meat (HR = 0.61, 95% CI = 0.39-0.95) more than three times per week demonstrated significantly decreased risk. However the risk ratio was 2.53 (95% CI = 1.22-5.29) for habitual smokers, and an inverse dose-response relationship was also found between ever smoking and gastric cancer patient survival. Therefore, this study suggested that frequent intake of raw vegetables and tofu is favorable, whereas habitual smoking is an adverse prognostic factor for gastric cancer. Our study implies that an improvement of survival of Japanese gastric cancer might be achieved by lifestyle improvement.