Factors Associated with Worse Outcome in Early Stage Gastric Cancer Using the Surveillance, Epidemiology, and End Results (SEER) Database

Background The benefit of adjuvant treatment in gastric adenocarcinoma patients with involvement of the muscularis propria but not beyond is unclear. We aim to establish a model that identifies the factors that adversely affect the prognosis in these patients. Methods We used the Surveillance, Epidemiology, and End Results (SEER) database to identify subjects with stage T2aN0M0 gastric adenocarcinoma who had tumor resection between 2004 and 2015. Data pertaining to the following variables were collected: age, gender, ethnicity, tumor size, grade, site, number of lymph nodes (LNs) being examined, and extent of surgery. Results A total of 1307 patients met our inclusion criteria. The five-year overall survival (OS) was 65%. The following factors were significantly associated with a shorter OS in univariate analysis. Age > 60 years, non-Hispanic whites and non-Hispanic blacks, patients with less than 15 lymph nodes examined at the time of surgery, tumors at the fundus and cardia of the stomach, and those who underwent endoscopic resection or had partial esophagectomy. On multivariate Cox regression, the following factors were predictors for worse OS: age > 60 years with a hazards ratio (HR) = 2.03 (95% CI: 1.49-2.76), patients with less than 15 lymph nodes examined with HR = 1.72 (95% CI: 1.34-2.20), non-Hispanic whites and non-Hispanic blacks with HR = 1.62 (95% CI: 1.26-2.08), and tumors within the cardia and fundus of the stomach with HR = 1.51 (95% CI: 1.21-1.89). Conclusion Patients with stage T2aN0M0 gastric cancer who had their tumor located at the cardia or fundus of the stomach or those with inadequate lymph nodes resection had inferior survival and could potentially benefit from adjuvant chemotherapy.