M. Kilcoyne1, N. Goel1, K. Ang1, A. Nadler1, W. H. Ward1, J. M. Farma1, N. F. Esnaola1, A. Karachristos1, J. P. Hoffman1, S. Reddy1 1Fox Chase Cancer Center,Department Of Surgical Oncology,Philadelphia, PA, USA
Introduction: Although positive peritoneal cytology (PPC) in patients with potentially resectable pancreatic adenocarcinoma is known to be associated with poor outcome, there is limited data regarding the location and prognostic significance of subsequent intra/extraperitoneal distant metastases. The objective of this study was to describe common sites of subsequent distant metastases in patients with potentially resectable pancreatic adenocarcinoma and PPC, and compare their respective impact on overall survival (OS).
Methods: We retrospectively analyzed patients with potentially resectable pancreatic adenocarcinoma treated at our institution from 2000-2017 who underwent peritoneal washings prior to surgical resection. Clinical and pathologic data was directly abstracted from the clinical record. Survival curves were constructed by the Kaplan-Meier product limit method.
Results: Eleven out of 287 patients with potentially resectable pancreatic adenocarcinoma (4%) were found to have PPC on final cytology. Nine out of these 11 patients (82%) subsequently developed distant metastatic disease: 5/9 (56%) subsequently developed radiologically evident peritoneal carcinomatosis, 2/9 patients (22%) developed liver metastases, 1/9 (11%) developed bony metastases, and 1/9 (11%) developed lung metastases. Two patients were lost to follow-up before evidence of distant metastasis. Among the 11 patients with PPC, the median OS was 16.3 months. The median OS of patients with subsequent liver metastases and peritoneal carcinomatosis were 12.3 months and 16.3 months, respectively. In contrast, the median OS of patients with subsequent bony metastases and lung metastases were 27.3 months and 64.9 months, respectively.
Conclusion: PPC is associated with poor prognosis in patients with (otherwise) potentially resectable pancreatic adenocarcinoma. The peritoneal cavity is the most common site for subsequent distant disease progression, followed by the liver. Longer than expected OS was observed in a limited number of patients with subsequent bony metastases and lung metastases. Additional studies are needed to validate these findings and determine whether surgical resection and potential bone/lung directed therapies may be of therapeutic value in these patients.