INTRODUCTION: The current AJCC staging system for pancreatic adenocarcinoma classifies positive peritoneal cytology as stage IV disease. Data are limited, however, with respect to the prevalence of positive peritoneal cytology, and its influence on survival in patients with radiographically resectable, locally advanced, and metastatic disease. METHODS: Peritoneal cytology was obtained in 463 patients undergoing staging laparoscopy for pancreatic adenocarcinoma between Jan 1995 and Dec 2005. Cytology results were not available intraoperatively, and patients without ascites found to have resectable disease at laparoscopy underwent laparotomy and attempted resection. Kaplan-Meier survival comparisons were performed to evaluate the significance of positive peritoneal cytology on overall survival (OS) in resected patients, and in patients with locally advanced and metastatic disease. RESULTS: Pancreatic resection was performed in 218 of the 463 patients (47%) in the study. Locally advanced disease was identified in 104 patients (22%), and 139 (31%) patients had metastatic disease. Peritoneal cytology was positive in 17% of patients (77/463), and was associated with stage of disease (table 1). Cytology was more likely to be positive in the setting of peritoneal, rather than liver, metastases (peritoneal: 29/45, 64% vs. liver: 24/94, 26%; p<0.001; table 1). Positive cytology was not significantly associated with OS in patients with metastatic disease or locally advanced disease, but was associated with OS in resected patients (table 1). Node positive disease was present in eight of the ten patients resected with positive cytology. Within the sub-group of resected node positive patients cytologic results were also associated with survival (2yr OS 12% cytology positive vs. 26% negative, p=0.003). CONCLUSIONS: Cytology is positive in 5% of resectable cases. These patients have a similar survival to other patients with stage IV disease.
Table 1. Peritoneal cytology in patients with pancreatic adenocarcinoma