Objective:The aim of our study was to investigate the prognosis of obese breast cancer patients.Methods:This study was conducted on a total of 317 breast cancer patients who were histopathologically and clinically diagnosed at the General Hospital of Shenyang Military Region(China)from 2004 to 2006.Clinical data including height,weight,age at diagnosis,tumor size,lymph node status,menopausal status,family history of cancer and hormone receptor status were collected.Log-rank test was performed to compare the disease free survival(DFS)and overall survival(OS).Cox proportional hazards regression analysis was conducted to make multivariate analysis.The Chi square test was used to compare the clinical features among normal weight group,overweight group,and obese group.Results:Obesity was an independent prognostic factor for DFS(P=0.022)and OS(P=0.032)in breast cancer patients.In the stratified analysis based on the hormone receptor status,obesity was independently associated with OS in patients with negative ER/PR(P=0.002),but such association was not observed in patients with positive hormone receptors.Obesity was also associated with lymph node status(P=0.001)and smoking(P=0.009).Conclusion:Obesity is associated with poor DFS and OS in patients with breast cancer.Therefore,maintaining normal weight may benefit breast cancer patients. Objective: The aim of our study was to investigate the prognosis of obese breast cancer patients. Methods: This study was conducted on a total of 317 breast cancer patients who were histopathologically and clinically diagnosed at the General Hospital of Shenyang Military Region (China) from 2004 to 2006. Clinical data including height, weight, age at diagnosis, tumor size, lymph node status, menopausal status, family history of cancer and hormone receptor status were collected. Log-rank test was performed to compare the disease free survival (DFS ) and overall survival (OS). Cox proportional hazards regression analysis was conducted to make multivariate analysis. The Chi square test was used to compare the clinical features among normal weight groups, overweight group, and obese group. Results: Obesity was an independent prognostic factor for DFS (P = 0.022) and OS (P = 0.032) in breast cancer patients. The stratified analysis based on the hormone receptor status, obesity was dependent associated with OS in pati ents with negative ER / PR (P = 0.002), but such association was not observed in patients with positive hormone receptors. Obesity was also associated with lymph node status (P = 0.001) and smoking associated with poor DFS and OS in patients with breast cancer.Therefore, maintaining normal weight may benefit breast cancer patients.