Impact of combined resection of pancreas on long-term survival in patients with gastric cancer.

359 Background: In patients with advanced gastric cancer invading adjacent organs, extended multivisceral resection is required to achieve R0 resection. However, the survival benefit of combined resection of pancreas remains controversial. We investigated the safety and efficacy of combined pancreatic resection in gastric cancer. Methods: This study included 64 patients who underwent gastrectomy with pancreatectomy (pancreaticoduodenectomy (PD) or distal pancreatectomy with splenectomy (PS)) for primary gastric cancer with invasion to the pancreas by primary tumor or lymph node metastasis and invasion to the duodenum. Patients who underwent R2 resection were excluded. Short- and long-term outcomes were assessed. Results: PD was performed in 18 patients (28.1%) and PS in 46 patients (71.9%). Macroscopic invasion to the pancreas by primary tumor was observed in 47 patients (73.4%), by lymph node in 13 patients (20.3%), and the invasion to the duodenum by primary lesion was in 4 patients (6.3%). Pathologically, pancreatic invasion was confirmed in 27 out of 47 patients (57.4%). Postoperative intra-abdominal infectious complications (PIIC) of Clavien-Dindo (CD) Grade III or higher were observed in 33 patients (51.6%). The most common postoperative complication was pancreatic fistula, which was observed in 31 patients (48.4%). There was no mortality within 30 days after surgery. Univariate analysis revealed that invasion the duodenum was highly associated with PIIC (p=0.038). Twelve patients (18%) resulted in R1 resection due to positive peritoneal cytology in 11 patients and positive surgical margin in one patient. The 5-year overall survival (OS) rate was 42.9%, which was 53.6% in R0 resection and 0% in R1 resection. Multivariate analysis revealed R1 resection was an independent prognostic factor for OS (HR:5.315, p<0.001). The 5-year recurrence-free survival (RFS) rate was 44.5%. The 5-year RFS rate was significantly worse in patients with PIIC (28.7%) than in patients without it (58.7%). Multivariate analysis revealed that PIIC was an independent prognostic factor for RFS (HR:2.345, p=0.036). Conclusions: Pancreatic resection for gastric cancer is considered safe and effective when R0 resection is possible. However, surgeon should pay particular attention to avoid the postoperative complications.