Prediction of metastatic pancreatic cancer patients’ survival using both host immunity and tumor metabolic activity.

Abstract

411 Background: Host antitumor immunity measured by neutrophil-lymphocyte ratio (NLR) is reported to be associated with prognosis of cancer patients. Standard uptake value (SUV)by18F-FDG PET represents the metabolic activity of tumor itself. The correlation of host immunity and tumor metabolic activity has not been studied. We investigate the association of these two factors and evaluate their roles in prediction of overall survival (OS) in metastatic pancreatic cancer (MPC) patients who receive palliative chemotherapy. Methods: We reviewed 396 MPC patients receivingpalliative chemotherapy. NLR was obtained before initiation of chemotherapy and after 1st cycle of chemotherapy. In 118 patients who were evaluated with 18F-FDG PET before initiation of chemotherapy (PET cohort), maximum SUV (SUVmax) was collected. Cut-offs for each variable were determined by ROC curve. Results: In multivariate analysis, higher NLR was associated with worse OS ( < 2.5, 9.0 m; 2.5-4.4, 7.2 m; ≥ 4.5, 3.9 m; p< 0.001). Reduction of NLR after 1st cycle of chemotherapywas associated with betterOS (8.0 m vs 6.1 m; HR 0.653; p< 0.001). We made the risk scoring model considering both NLR (score 0, NLR < 2.5; score 1, 2.5 ≤ NLR < 4.5; score 2, NLR ≥ 4.5) and ΔNLR(score 0:ΔNLR < 0; score 1: ΔNLR ≥ 0), which identified 4 risk groups with different prognosis (group with risk score 0 vs 1 vs 2 vs 3: OS 9.7 vs 7.9 vs 5.7 vs 2.6 months; HR 1 vs 1.329 vs 2.137 vs 7.915, respectively; P < 0.001). In PET cohort (118 patients), NLR and SUVmax were independent prognostic factors for OS. The risk model considering both NLR (score 0, NLR < 2.5; score 1, 2.5 ≤ NLR < 4.5; score 2, NLR ≥ 4.5) and SUVmax (score 0:SUVmax < 4.5; score 1: SUVmax ≥ 4.5), which define 4 risk groups with different OS. (group with risk score 0 vs 1 vs 2 vs 3: OS 11.8 vs 9.8 vs 7.2 vs 4.6 months; HR 1 vs 1.536 vs 2.958 vs 5.336, respectively; P < 0.001). Conclusions: NLR and SUVmax as simple parameters of host antitumor immunity and tumor metabolic activity, respectively, have significant impacts on the survival of metastatic pancreatic cancer patients independently. Consideration of both aspects allows more precise prediction of patients’ prognosis.