Prognostic importance of peritoneal washing cytology in patients with otherwise resectable pancreatic ductal adenocarcinoma who underwent pancreatectomy: A nationwide, cancer registry–based study from the Japan Pancreas Society

Abstract Background The importance of peritoneal washing cytology statusboth as a sign of irresectability and as a prognostic factor for pancreatic ductal adenocarcinoma remains controversial. The purpose of this nationwide, cancer registry–based study was to clarify the clinical implications of operative resection in patients who had positive cytology status. Methods Clinical data from 1,970 patients who underwent tumor resection were collected from the Pancreatic Cancer Registryin Japan. Clinicopathologic factors and overall survival curves were analyzed, and multivariate Cox proportional hazard modelswere evaluated. Results Among the 1,970 patients analyzed, positive cytology statuswas found in 106 patients and negative cytology statuswas found in 1,864 patients. The positive cytology status grouphad a greater frequency of pancreatic bodyand tail cancer and greater preoperative serum carbohydrate antigen 19-9 levels than the negative cytology status group(P Conclusion Positive cytology statuswas an adverse prognostic factor in patients who underwent resection for pancreatic ductal adenocarcinoma but did not preclude attempted curative resection. Curative resection followed by adjuvant chemotherapy may contribute to long-term prognosis in patients with positive cytology status.