Prognostic Impact of Positive Peritoneal Lavage Cytology on Resectable Pancreatic Body and Tail Cancer: A Retrospective Study

Background: The prognostic impact of positive peritoneal lavage cytology on pancreatic cancer is unclear. Therefore, this study aimed to evaluate its impact in resectable pancreatic body and tail cancer. Methods: Between January 2006 and December 2019, 97 patients with pancreatic body and tail cancer underwent peritoneal lavage cytology and curative resection at our institution. We analyzed the impact of positive peritoneal lavage cytology on clinicopathological factors and on the prognosis of pancreatic body and tail cancer. Results: Malignant cells were detected in 14 patients (14.4%) using peritoneal lavage cytology. In these patients, the tumor diameter was significantly larger (p < 0.001) and anterior serosal invasion (p = 0.034), splenic artery invasion (p = 0.013), lympho-vessel invasion (p = 0.025), and perineural invasion (p = 0.008) were significantly more frequent. The R1 resection rate was also significantly higher in patients with positive peritoneal lavage cytology than in negative patients (p = 0.015). Positive peritoneal lavage cytology had a significantly poor impact on overall survival (p = 0.001) and recurrence-free survival (p < 0.001). This cytology was also an independent poor prognostic factor for recurrence (p = 0.022) and was associated with peritoneal dissemination and liver metastasis. Conclusions: Positive peritoneal lavage cytology is considered to be indicative of more systemic disease in patients with resectable pancreatic body and tail cancer than in patients with negative peritoneal lavage cytology. Early detection of pancreatic cancer before it develops micrometastases is important to improve prognosis, and CY+ patients require more intensive multimodality treatment than standard treatment for resectable pancreatic cancer.