Background: Response on FDG-PET scan during preoperative chemotherapy has prognostic significance. We performed a phase II trial to examine the effectiveness of FDG-PET directed early switching to salvage chemotherapy measured by 2-year disease free survival (DFS). Methods: Pts with PET avid, endoscopic ultrasound and laparoscopically staged T3 or N+ resectable gastric or GEJ adenocarcinoma received induction epirubicin 50mg/m², cisplatin 60mg/m² Day 1, capecitabine 625mg/m² BID Days 1-21 (ECX) and bevacizumab 15mg/kg Day 1. PET scan was repeated at Week 3. PET responders (≥35% decline in SUV) continued with ECX for 2 more cycles. PET non-responders were switched to 2 cycles of salvage therapy: docetaxel 30mg/m² and irinotecan 50mg/m²Days 1 and 8 q21 days and bevacizumab 15mg/kg Day 1. All pts went to surgery 4 weeks after Cycle 3. Results: Twenty of planned 60 pts were enrolled before the study closed for poor accrual. Eleven (55%) had a PET response after induction. Ten of 11 underwent R0 resection: 1/10 path complete response, 3/10 path partial response. Nine PET non-responders were switched to the salvage regimen. Seven of 9 non-responders had R0 resection, none achieved a pathological response. The median DFS for PET responders was 27.8 mos (95% CI 10.3-27.8) and DFS in salvage group has not been reached. There was no significant difference in DFS between the two groups (p= 0.4). Follow up for overall survival is ongoing. Conclusions: Response on PET scan during induction chemotherapy can identify early treatment failures. The results for therapy cross-over indicate a potentially improved DFS with salvage chemotherapy. Results from this trial are hypothesis generating and merit evaluation in a larger clinical trial. Updated survival data will be presented. Clinical trial information: NCT00737438.