Incidence, Survival, and Predictors of Lymph Node Involvement in Early-Stage Gastric Signet Ring Cell Carcinoma in the US

Introduction The incidence, survival, and propensity for nodal metastasis in early-stage gastric signet ring cell carcinoma have not been defined in the United States. These data are critical determinants for treatment allocation. Methods Cases of gastric signet ring cell carcinoma were extracted from the national SEER database for the years 2004–2013. Age-standardized incidence was derived. Survival was calculated using the Kaplan-Meier method. Univariate and multivariate analyses were performed to identify predictors of nodal metastasis. Exclusion criteria included neoadjuvant radiotherapy and lack of histologic or nodal data. Results A total of 10,624 cases were initially identified. The analysis cohort included 506 cases with early T-stage N0M0 disease following exclusions. The incidence was 0.094 per 100,000 person-years. The 5-year survival rate was 82.8%. Tumor stage ( p < 0.001) and size ( p < 0.001) were independent predictors of nodal metastasis. The incidence of nodal involvement for T1a tumors <2 cm was 5.4% ( p < 0.004). Conclusion The incidence of potentially resectable signet ring gastric carcinoma has not changed significantly over the past decade. While presenting with predominantly high-grade histology, early T-stage disease has a high survival rate. Small T1a tumors have low rates of nodal metastasis, suggesting that an endoscopic resection could be considered in this subset.