Prognostic Factors After Pancreatectomy for Pancreatic Cancer Initially Metastatic to the Liver

BACKGROUND: Resection of initially oligometastatic pancreatic ductal adenocarcinoma (PDAC) following response to first-line chemotherapy is controversial. We herein updated a previous case series to investigate the oncologic outcomes and preoperative factors that could drive the decision-making process. METHODS: This retrospective analysis was limited to patients with liver-only synchronous metastases who experienced complete regression of the metastatic component and underwent pancreatectomy between October 2008 and July 2020 at two high-volume institutions. Clinical-pathologic variables were captured, and inflammation-based prognostic scores were calculated. Recurrence and survival analyses were performed using standard statistical methods. RESULTS: Overall, 52 patients were included. FOLFIRINOX was the most employed chemotherapy regimen (63.5%). Post-treatment tumor size, serum carbohydrate antigen (CA) 19-9 and carcinoembryonic antigen (CEA) were significantly decreased relative to baseline evaluation. The median time from diagnosis to pancreatectomy was 10.2 months, while the median time from chemotherapy completion to pancreatectomy was 2 months. Major postoperative complications occurred in 26.9% of patients, while postoperative mortality was nil. The median disease-free survival (DFS) and overall survival (OS) from pancreatectomy were 16.5 and 23.0 months, respectively, and the median OS from diagnosis was 37.2 months. At multivariable analysis, vascular resection, operative time, prognostic nutrition index (PNI) and neutrophil-to-lymphocyte ratio (NLR) were associated with OS. Operative time, platelet × neutrophil/lymphocyte count (SII), and PNI were associated with DFS. CONCLUSIONS: We confirm promising outcomes of selected patients who underwent pancreatectomy following downstaging of liver metastases. The absence of vascular involvement of the primary tumor, good nutritional status, and low inflammatory index scores could be useful to select candidates for resection.