Rates of lymph node metastasis and survival in T1a gastric adenocarcinoma in Western populations

Background and Aims EMR and endoscopic submucosal dissection (ESD) are widely accepted in Asia for treatment of early gastric cancer (EGC). Few studies have examined lymph node (LN) metastasis of EGC in Western populations. We sought to examine EGC and LN metastasis in a heterogeneous Western population. Methods Patients with surgically resected, histologically confirmed American Joint Committee on Cancer T1a gastric adenocarcinoma were identified in the Surveillance, Epidemiology, and End Results (SEER) database from 2002 to 2012. Patients were excluded if they had stage IV disease, had multiple primary cancers, or received neoadjuvant therapy. Rates of LN metastasis were calculated, and survival analyses were performed. Results Of 923 patients in the cohort, 72 (7.8%) had at least 1 positive LN on final pathology. When stratified by race, Asian/Pacific Islanders (APIs) demonstrated the lowest rate of LN metastases (n = 17/327, 5.2%), followed by Hispanics (n = 12/171, 7.0%), whites (n = 27/278, 9.7%), and blacks (n = 16/147, 10.9%). The highest rates of stage IA disease were observed in API (93.9%) and Hispanic (92.4%) patients, followed by white (89.9%) and black (87.1%) patients (P =.04). Survival analysis of T1a gastric cancer patients by race/ethnicity showed that 5-year overall survival was highest for API patients (API, 88%; Hispanic, 81%; black, 79%; and white, 77%; P <.01). Conclusions The rate of LN metastasis in T1a gastric cancers in the United States is higher than the rates reported in Asia. Survival outcomes in T1a gastric cancers varied significantly by race, suggesting that definitive endoscopic treatment may not be appropriate for all patients in the United States.