Endoscopic ultrasound restaging of gastric cancer following neoadjuvant therapy predicts survival

Background: There is a resurgent role for endoscopic ultrasound (EUS) in the staging of gastric cancer due to its value in selecting patients with locally advanced disease for neoadjuvant therapy (MAGIC Trial, Cunningham et al, NEJM 2007). There is also an emerging interest in EUS for assessing response to therapy to decide upon continued treatment, change in treatment, or surgery. The aim of this study was to assess the predictive value of a 2nd look restaging EUS in gastric cancer after neoadjuvant therapy. Methods: Patients undergoing EUS for gastric cancer before and after neoadjuvant therapy at UCLA from 2005- 2011 were studied. Downstaging was defined as an objective decrease in EUS T stage after neoadjuvant therapy. Survival was defined as the date of the initial endoscopic ultrasound to the date of death or last follow-up. Downstaging by EUS was correlated with survival using Kaplan Meir and Chi Square analysis (p <0.05 is significant). Results: 20 patients with locally advanced gastric cancer (T2(1), T3(18), T4(1)) underwent EUS evaluation prior to and immediately after neoadjuvant chemotherapy. 9 were defined as having a downstaging response based on improvement in EUS T stage. Response based on EUS T downstaging was associated with improved overall survival, compared with patients who were not downstaged on followup EUS (H.R. = 8.573 (95% CI 2-32, p=0.0025) (Figure 1). Conclusions: Response to treatment as defined by downstaging of T stage by EUS after neoadjuvant therapy correlates with improved survival. The incorporation of pre and post neoadjuvant endoscopic ultrasound in treatment protocols for locally advanced gastric cancer can help physicians predict survival and alter treatment regimens in patients with a poor initial response. (Figure presented).