Long Term Survival and Prognostic Factors in Metastatic Pancreatic Adenocarcinoma Undergone Pancreatic Resection after Downstaging

Abstract

Background: Patients with metastatic pancreatic adenocarcinoma receive palliative chemotherapy to control disease progression and related symptoms.Surgical resection of primary tumor has been proposed, best after a course of neoadjuvant chemotherapy with a benefit in survival if compared to CHT alone. Early recurrence or long disease-free survival occurs, regardless of therapy, histology or other known factors. Aim: Investigate long term survival and recurrence of disease in patients undergone surgical resection after downstaging of liver metastatic pancreatic carcinoma and eventually factors associated to best/worst survival. Patients and Methods: A prospective collected database from two centers, Pederzoli Hospital(PH) and The Pancreas Institute(IP) was retrospectively reviewed. All patients undergone pancreatic resection for PDAC after a complete downstaging of liver lesions were considered for survival analysis using Kaplan-Meier method. Results: Between 2008 and 2020 a total of 1129 patients with PDAC and liver mets were observed in the two centers. 54(4.8%) experienced downstaging of liver lesions after chemotherapy (63% FLX, 31% Gem-Abr, 6% Gem alone) and received resection of primary tumor (PD 69%, DP 29%, TP 2 %) with no mortality. Ca19.9 decreased from 1142U/mL at diagnosis to 50U/mL after CHT(p< 0,005). Median interval between diagnosis, surgery and recurrence was 12 and 10 months respectively.Site of recurrence was liver (35 %), peritoneum (7%), local (9%) or multiple sites (16%). DFS and OS were 10 (1-19) and 35 (14-56) months. PD combined with vascular resection and persistent high Ca19.9 post CHT, were associated to overall survival <18 months (p=0.02 and p=0.005, respectively) versus pancreatic resection alone. Conclusions: In patients with liver mPDAC at diagnosis, when downstaging seems to occur, surgery should be considered as an option in very selected cases. Simple tools like Ca19.9 or vascular involvement assessment may help to force or deny surgical resection, despite the apparences, with appropriate criteria.