The Relationship Between Tumor Inflammatory Cell Infiltrate and Outcome in Patients with Pancreatic Ductal Adenocarcinoma

The tumor-associated inflammatory cell infiltrate is recognized to have prognostic value in various common solid tumors. However, the prognostic value of the tumor inflammatory cell infiltrate has not been established in pancreatic ductal adenocarcinoma (PDAC) nor has its relationship with the systemic inflammatory response. Retrospective study was made of 173 patients who underwent surgery between 1997 and 2009. Routine pathology specimens were scored according to density of the tumor inflammatory cell infiltrate, and biochemical data were collected preoperatively. Low-grade tumor inflammatory cell infiltrate was associated with earlier tumor recurrence (P < 0.001) and particularly in the liver (P = 0.027). It was also associated with T3 tumors (P < 0.05), lymph node involvement (P < 0.05), and resection margin involvement (P < 0.05). On univariate survival analysis, age < 65 years (P < 0.05), mGPS (P < 0.001), increased tumor stage (P < 0.01), nodal involvement (P < 0.01), size (P < 0.05), grade (P < 0.05), perineural invasion (P < 0.05), venous invasion (P < 0.01), resection margin involvement (P a parts per thousand currency sign 0.001), vascular reconstruction (P < 0.05), and no adjuvant chemotherapy (P < 0.05) were associated with poor survival. In contrast, high-grade tumor inflammatory cell infiltrate was associated with better survival (P < 0.001). On multivariate survival analysis, mGPS [hazard ratio (HR): 1.77, 95 % confidence interval (95 % CI): 1.19-2.62, P = 0.005], tumor stage (HR: 2.21, 95 % CI: 1.16-4.23, P = 0.016), resection margin involvement (HR: 2.19, 95 % CI: 1.41-3.44, P = 0.001), venous invasion (HR: 1.79, 95 % CI: 1.22-2.63, P = 0.003), tumor inflammatory cell infiltrate (HR: 0.37, 95 % CI: 0.25-0.55, P = 0.0001), and adjuvant chemotherapy (P = 0.04) were independently prognostic. The results of the study show, for the first time, that the presence of a high-grade tumor inflammatory cell infiltrate is an independent predictor of prolonged overall survival following resection for PDAC. Furthermore, measures of the local and the systemic inflammatory response were inversely associated.