Comparison of the Effect of Chemotherapeutic Treatments Followed by Conversion Surgery for Initially Unresectable Locally Advanced Pancreatic Ductal Adenocarcinoma

Abstract

Introduction: Surgical resection with multidisciplinary therapy, so called conversion surgery is needed to improve the prognosis of patients with initially unresectable locally advanced (UR-LA) pancreatic ductal adenocarcinoma (PDAC). Method: Seventy-seven consecutive patients with UR-LA PDAC who were performed chemotherapy and/or followed by conversion surgery (CS) at Chiba University hospital from Jan 2010 to Dec 2019 were retrospectively analyzed. We assessed the clinical significance of CS, and compared the impact of efficacy between gemcitabine plus S-1 (GS) and gemcitabine plus nab-paclitaxel (GnP) before CS in UR-LA PDAC. Results: The patients were classified into CS (n=32) and non-CS group (n=45). Comparing between CS and non-CS group, the SMA involvement was significantly lower in CS (40.6%) than that in non-CS (64.4%) group (p=0.038). The median survival time (MST) for overall survival were 13.1 months for non-CS and 30.1 months for CS group (p<0.0001). Comparing chemotherapies between GS (n=35) and GnP group (n=41), the conversion rates were 54.3% (19/35) in GS and 29.3% (12/41) in GnP (p=0.027). The median percentage of tumor shrinkage were 23% for GS and 32% for GnP (p=0.047), the decrease rate of CA19-9 level were 74% for GS and 83% for GnP (p=0.37) in CS group. The Kaplan-Meier analysis revealed that the MST for overall survival were 14.3 months for GS and 12.0 months for GnP in non-CS, and 26.8 months for GS and 45.9 months for GnP in CS group. Conclusions: Randomized prospective studies will be warranted for the strategy of treatment for patients with UR-LA PDAC.