Clinical importance of intraoperative peritoneal cytology in patients with pancreatic cancer

Background The clinical importance of intraoperative peritoneal cytology in patients with pancreatic cancer remains incompletely understood. Methods Peritoneal washing samples were collected from 411 consecutive patients with pancreatic ductal adenocarcinoma from 1996 to 2014. Of the 411 patients, 335 underwent macroscopically curative resection and 76 with noncurative factors did not undergo resection. We compared long-term outcomes between patients with positive cytology (cytology+) and those with negative cytology (cytology−) and investigated the importance of clinicopathologic factors. Results Of 335 patients with curative resection, 300 (89.6%) were cytology− and 35 (10.4%) were cytology+. The median overall survival of cytology+ patients was less than that of cytology− patients (16 vs 31 months, respectively; P