Systemic inflammation response index (SIRI): A prognostic factor in pancreatic cancer (PC)

Abstract

Introduction: Cancer associated inflammation has been suggested as the seventh hallmark of PC. Systemic inflammation may affect the response to chemotherapy (CT) and studies evaluating the prognostic relevance of systemic inflammatory response (SIR) markers in patients with PC are lacking. The aim of this study was to determine the prognostic value of a baseline SIRI based on peripheral neutrophil, monocyte, and lymphocyte counts in PC. Methods: Retrospective analysis of the medical records of patients with pathologically confirmed PC between January 2011 and December 2016. Associations between time to progression (TTP), overall survival (OS) and clinically available SIR markers including SIRI (cutoff value≥1,9), neutrophil-lymphocyte ratio (NLR), platelet/lymphocyte ratio (PLR) and lymphocyte/monocyte ratio (LMR) were analyzed using Kaplan-Meier curves and Cox proportional models. Results: A total of 82 patients were included (47 men; mean age 64). Median TTP was 5 months and median OS was 11 months. 37 patients (45,1%) had stage IV disease: 18 (49%) more than one metastatic site, 13 (35%) with liver metastasis, 4 (11%) peritoneal carcinomatosis and 2 (5%) lung metastasis. 72 patients (87,8%) received CT: 37 (51%) Gemcitabine (GEM) in monotherapy, 22 (31%) GEM plus Nab-Paclitaxel, 7 (10%) GEM plus Erlotinib, 3 (4%) GEM+ Oxaliplatin, 2 (3%) FOLFIRINOX and 1 (1%) FOLFOX. Univariate analysis identified SIRI scores ≥1,9 and stage IV disease as significant risk factors for early TTP (3 months) and OS (3, 9, 12 months). However, age, sex, NLR≥5, LMR≥3, PLR≥150 and high CA 19,9 levels had no prognostic significance for TTP and OS. Patients with SIRI scores< 1,9 (55%) compared to those who had SIRI scores≥1,9 (45%) had a longer OS (p=0,018). Whereas, patients with high levels of CA 19.9 (67%) compared to normal CA 19.9 levels (33%) had no significant differences as a prognostic factor for OS (p=0,931). An SIRI≥1,9 resulted in a shorter TTP compared to an SIRI <1,9 (hazard ratio [HR] 2,305; 95% confidence interval [CI] 1,087-4889, p=0,029) and a shorter OS (HR 2,128; CI 1,103 - 4,105; p=0,024). Kaplan-Meier analysis showed significantly longer median duration to onset of early progression in patients with SIRI scores < 1,9 (log Rank 5,661; p=0,017) and longer median OS (log Rank 5,631; p=0,018). Conclusion: SIRI is associated with survival in patients with PC. CA19.9 in our series had no prognostic significance. A baseline SIRI≥1.9 is a significant risk factor for early TTP and OS with a greater predictive ability than NLR, LMR, PLR and CA19-9 levels. A baseline SIRI≥1.9 predicts a worse outcome, a finding that would allow better risk stratification in order to improve patient selection for aggressive treatment.