Background & The necessity of collaboration - Currently, neoadjuvant treatment is increasing in the treatment of pancreatic cancer. In the case of patients who received neoadjuvant treatment, the nutritional risk is predicted, but there is no study related to the nutrition index. This study aims to investigate the differences in nutrition and inflammation markers of patients who received neoadjuvant treatment compared to those of pancreatic cancer patients who underwent upfront surgery. The collaborative study will prove that preoperative nutritional support will be required in neoadjuvant treatment patients for pancreatic cancer. Objectives - To evaluate and compare preoperative nutrition index and inflammatory marker of neoadjuvant treatment group and upfront surgery group in resectable pancreatic cancer patients. - To compare postoperative outcome according to preoperative nutrition index and inflammatory marker in resectable pancreatic cancer patients including neoadjuvant and upfront surgery groups. - To compare the overall survival and disease free survival rates of resectable pancreatic cancer according to nutrition index and inflammatory marker. - The final goal of this study is to evaluate preoperative nutrition status in neoadjuvant treatment group of resectable pancreatic cancer patients Endpoints - Primary endpoint : 3 year & 5 year overall survival and disease free survival according to nutrition index and inflammatory marker. - Secondary endpoint : Comparison of nutrition index and inflammatory marker in patients with upfront surgery and neoadjuvant treatment. Study design & Methodology - Inclusion criteria : Patients who underwent operation for pancreatic cancer and diagnosis confirmed by histopathology between 2016. 1 and 2020.12. Patients who underwent completed resection of tumor (included only R0/R1 resection) . Patients with radiologic resectable pancreatic cancer at diagnosis. Patients with upfront surgery or neoadjuvant treatment ( Chemotherapy and concurrent chemoradiotherapy) - Exclusion criteria: Patients without available data in the case report form. Patients with combined cancer. Patients with R2 resection of tumor. - Methodology : Retrospective data collection about patient’s characteristics [preoperative baseline characteristics, nutrition index, inflammatory marker, operation record, postoperative outcome, recurrence, survival]