Positive peritoneal cytology predicts unresectability of pancreatic adenocarcinoma

Peritoneal cytology is clinically useful in gastric and gynecologic malignancies. Its role in pancreatic adenocarcinoma remains less well defined. Controversy exists as to the relationship between percutaneous fine needle aspiration (FNA) of the pancreas and shedding of malignant cells with the peritoneum. The aim of this study was to determine whether positive peritoneal cytology (PPC) predicts unresectability of pancreatic adenocarcinoma and impacts on overall survival. In addition, the study aimed to determine whether antecedent FNA increases the incidence of PPC.

Between January 1993 and June 1996, 228 patients with radiographically resectable pancreatic adenocarcinoma underwent laparoscopic staging. Specimens were taken from right and left upper quadrants at the beginning of laparoscopy. Various prognostic factors were analyzed.

PPC was identified in 34 patients (15%). Of patients that had an antecedent FNA, 20% had PPC, and 13% of those without an antecedent FNA had PPC (p = 0.22). The majority of patients with PPC had stage IV disease (26 of 34 [76%]) and only 8 (24%) had no evidence of metastases. Overall survival was significantly higher in patients with negative peritoneal cytology (NPC) compared with PPC (p<0.0006). PPC had a positive predictive value of 94.1%, specificity of 98.1%, and a sensitivity of 25.6% for determining unresectability of pancreatic adenocarcinoma. PPC was not an independent prognostic variable for survival on multivariate analysis.

PPC is associated with advanced disease and is highly specific in predicting unresectability of pancreatic adenocarcinoma, resulting in decreased survival. Antecedent FNA is not associated with an increased the incidence of PPC, nor does it significantly impact on overall survival.