Clinicopathological characteristics of the whole cohort
The baseline characteristics of the whole cohort is listed inTable I . The 612 patients included 352 males (57.5) and 260 females (42.5). The age ranged from 31 to 82 years, and the media age was 61 years. The median levels of preoperative CA19-9, CEA and CA242 were 156.25 U/ml, 3.3550 ng/ml and 19.64 U/ml, respectively. There were 416 patients with PDAC located at the head of pancreas and 196 patients at body and tail. A total of 414 patients accepted pancreaticoduodenectomy, 195 patients accepted distal pancreatectomy and 3 patients accepted total pancreatectomy. Of the 264 patients with low histology grade, 23 patients were well differentiated and 241 patients were moderate differentiated. The remaining 348 patients who were poorly differentiated were classified into high histology grade. The median OS of the entire cohort was 18 months (6-126 months), with survival rates of 71.3, 43.3, 31.3 and 19.1% after 1, 2, 3 and 5 years of follow-up, respectively.