Comparative Analysis of Radiation, Lymph Node Dissection, and Metastatic Positive Rate on Prognosis in T3-4N+ Gastric Cancer and Gastroesophageal Junction: A Study Based on SEER Database and External Validation in China

Background Adjuvant radiotherapy and neoadjuvant radiation are recognized as a pivotal therapeutic modality capable of augmenting the overall survival (OS) outcomes in patients afflicted with gastroesophageal junction cancer (GEJ) at the T3-4N+ stage. However, the number of regional nodes examined (RNE) and the metastasis lymph node ratio (MLR) exert discernible impacts on the prognosis of such patients. Our study exploredthe relationship between radiotherapy and surgery, assesses RNE and MLR prognostic significance, and developed a nomogram for predicting 5-year survival in T3-4N+ gastric cancer patients. Patients and Methods The nomogram of gastric cancer was built using GEJ patients from the Surveillance, Epidemiology, and End Results (SEER) database, with our institutional cohort used exclusively for validation. All other analyses, such as restricted cubic splines (RCS) and competing risk curves, were conducted using SEER data. RESULTS Radiotherapy: Esophageal adenocarcinoma located at the GEJ demonstrated a better response to neoadjuvant radiotherapy(p<0.001), while those in the cardia and gastric adenocarcinoma did not exhibit improved outcomes. Surgery and lymph nodes: For gastric adenocarcinoma and cardia cancer, the removal of more than 36-37 lymph nodes may not offer additional benefit, similarly, the removal of 28-29 lymph nodes may provide no further survival advantage for esophageal adenocarcinoma. CONCLUSIONS First, the nomogram of T3-4N+ gastric cancer demonstrated relatively good accuracy. Second, for both esophageal adenocarcinoma and gastric adenocarcinoma, surgical approach did not significantly improve patient survival. For gastric junction tumors, removing more than 36-37 lymph nodes may not improve survival. Similarly, exceeding 28-29 lymph node removals may also show no added benefit for esophageal tumors.