Abstracts
2000 Digestive Disease Week

# 2331 Peritoneal Fluid Cytology Predicts Outcome in Locally Advanced Gastric Cancer.
Martin R. Weiser, Patricia Saigo, Murray F. Brennan, Martin S. Karpeh, New York, NY

Introduction: Current clinical studies suggest patients with locally advanced gastric cancer are candidates for investigational, preoperative chemotherapy. Pretreatment staging will be critical in upcoming phase III trails of neoadjuvant therapy for these patients. Peritoneal fluid containing malignant cells has been associated with poor outcome in patients with gastric cancer. However, the significance of positive peritoneal cytology in the absence of identified M1 disease is unknown. This study examines the impact of peritoneal cytology in predicting outcome of patients resected for locally advanced, stage III gastric cancer. Methods: At laparoscopy prior to complete resection, peritoneal fluid was obtained and analyzed by the Papanicolaou technique in 59 patients with subsequently proven pathologic stage III (T2-4,N0-2,MO) gastric cancer. Disease specific survival (DSS) and disease free survival(DFS)were the endpoints of the study. Clinicopathologic factors including T-stage, N-stage, lymphovascular invasion, tumor grade, and peritoneal cytology, were correlated with outcome using univariate and multivariate statistical techniques. Significance was considered for p<0.05. Results: Seven of 59 (12%) patients with pathologically proven stage III disease had positive peritoneal cytology. Median DFS was 7 mo in the peritoneal cytology positive group and 16 mo in the cytology negative group (p<0.05). Median DSS was 12 mo in the peritoneal cytology positive group and 33 mo in the cytology negative group (p<0.01). Peritoneal cytology positive patients had similar survival to a cohort of 38 patients resected with M1 disease (median DSS 17 mo). Within this cohort of III patients, peritoneal cytology was the only independent predictor of both DSS and DFS. Conclusion: In patients with locally advanced, stage III gastric cancer, positive peritoneal cytology predicts early recurrence and poor survival. In the absence of known metastatic disease, patients with positive peritoneal cytology is an M1 equivalent. Future neoadjuvant trials for locally advanced gastric cancer should exclude peritoneal cytology positive patients.