A phase II study of preoperative chemotherapy with irinotecan(CPT) and cisplatin(CIS) for gastric cancer(NCI 5917): FDG-PET/CT predicts patient outcome

4502 Introduction: Preoperative chemotherapy is a standard option for the treatment of locally advanced gastric cancer(GC). FDG-PET scans have been examined to identify early treatment response in esophagus and GEJ adenocarcinoma. We evaluated the utility of an early change in FDG-PET/CT at several time points in predicting response to preoperative chemotherapy in gastric cancer. Methods: 42 pts with locally advanced GC(preoperative stage T2N+M0 or T3–4NanyM0) were treated with CPT 65 mg/m2 and CIS 30mg/m2 on day(d)1 and d8, every 21 days for 4 cycles. FDG-PET/CT scans were performed at baseline, and in FDG avid patients, again on d15 and d35. The primary objective was to demonstrate that a decrease in FDG-SUV discriminates treatment response. Response was defined pathologically based on microscopic inspection for residual cancer cells and fibrosis(Mandard, Cancer 1994). Disease free survival(DFS) and overall survival(OS) were secondary endpoints. Results: Pt characteristics are as follows: median age 59(...