Sequential endoscopic ultrasound identifies predictive variables for relapse-free follow-up after neoadjuvant chemotherapy in gastric cancer.

BACKGROUND: The accuracy of endosonographic tumor staging after neoadjuvant therapy is less reliable than in primary staging. Therefore, the value of sequential endosonographic examinations after neaodjuvant chemotherapy in gastro-esophageal cancer is discussed controversially. Previous data suggest, that endoscopic ultrasound (EUS) after neoadjuvant treatment using other variables than classic uTN-criteria may identify patients with a better prognosis.

METHODS: In 67 patients with locally advanced gastric cancer treated in curative intent, we performed EUS before and after neoadjuvant chemotherapy. Endosonographic yTN-stage was compared to pathohistological yTN-stage after curative resection. The uTN-stage, yuTN-stage, maximal tumor thickness and maximal lymph node diameter as well as the shift of these variables after neoadjuvant therapy were analyzed for their usefulness to predict recurrence-free follow-up.

RESULTS: Accuracy of EUS for yTN-staging after neoadjuvant therapy was poor, especially in lower tumor stages. However, three heavily correlated variables analyzed by sequential EUS could be used for the prediction of prognosis: low endosonographic tumor stage (yuT0-2) after neoadjuvant chemotherapy, a decrease of two or more steps in uT-stage and a maximal tumor thickness of <15 mm after chemotherapy were significantly associated with recurrence-free follow-up. Endosonographic T-stage before neoadjuvant therapy, as well as lymph node variables before or after chemotherapy, were of no predictive value.

CONCLUSION: In spite of poor concordance between endosonographic and pathohistological TN-stage after neoadjuvant treatment, sequential EUS, performed before and after neoadjuvant therapy, possibly identify patients at risk for tumor relapse after multimodal treatment in gastric cancer. This finding should be validated in a larger patient cohort.