Prognostic factors for overall survival in patients with early gastric cancer: a retrospective cohort study based on SEER database.

Background: Early gastric cancer (EGC) represents a critical subgroup, with a significantly better prognosis compared to advanced-stage disease. However, even among patients with EGC, there are substantial variations in survival outcomes. This study aims to investigate the prognostic factors associated with overall survival (OS) in patients with EGC. Methods: The clinicopathological data of 1,340 patients diagnosed with EGC who underwent surgery in the Surveillance, Epidemiology, and End Results (SEER) database from 2010 to 2015 were collected, with those with incomplete data excluded. Potential predictors, including age, gender, race, the number of lymph nodes resected, lymph node metastasis (LNM), submucosal invasion, and tumor size were assessed. OS was measured from diagnosis to death or last follow-up. The X-tile program was used to identify the optimal cutoff value of tumor size. Univariate and multivariate Cox proportional hazards regression was used to explore the possible risk factors of EGC Subgroup analyses were performed on the independent prognostic factors of the patients. Results: The optimal cutoff value for tumor diameter in EGC was determined to be 20 mm using X-tile software. There were 741 patients with a tumor diameter of ≤20 mm [small-size tumors (SST)] and 599 patients with a tumor diameter of >20 mm [large-size tumors (LST)]. The 5-year survival rates of the two groups were 64.9% and 52.8%, respectively, with statistical significance (P<0.001). The Cox proportional hazards regression model indicated that age (P<0.001), gender (P<0.001), race (P<0.001), the number of lymph nodes resected (P=0.003), LNM (P<0.001), submucosal invasion (P=0.002), and tumor size (P<0.001) were independent prognostic factors affecting survival. Further stratified analysis indicated that the survival rate of patients with LST was significantly lower than that of those with SST in patients without LNM (P<0.001). In patients aged ≥60 years, LST was independently associated with worse OS [hazard ratio (HR) =1.505; 95% confidence interval (CI): 1.210-1.871; P<0.001]. Conclusions: Age, gender, race, the number of dissected lymph nodes, LNM, invasion depth, and tumor size are independent factors affecting the prognosis of EGC patients. There are also differences in risk factors affecting prognosis among different age groups and different gender groups. The optimal cut-off point for tumor size was 20 mm, which can exert a significant impact on the prognosis of EGC patients without LNM or those aged ≥60 years. These findings can provide guidance for clinical decision-making. Identifying high-risk patients with different clinical characteristics can offer certain evidence-based support for the precise treatment of patients with EGC, thereby improving the overall patient management.