Unveiling the mechanisms of immune evasion in pancreatic cancer: may it be a systemic inflammation responsible for dismal survival?

Objective: Pancreatic cancer (PC) is one of the most aggressive malignancies with no effective treatment if diagnosed in advanced stage. Systemic inflammation is a recognized characteristic of cancer progression, and we believe that the understanding of the influence of inflammatory parameters may contribute to therapeutic improvement in PC. Here, we validated the Eosinophil/Lymphocyte Ratio (ELR) together with the Neutrophil/Lymphocyte Ratio (NLR) and their components, as prognostic factors in PC patients treated with chemoradiation.

Methods: A total of 66 consecutive patients (p) diagnosed with PC stage I-III and treated with External Beam Radiotherapy + chemotherapy ± surgery (28p) in our institution from 2007 to 2018 were retrospectively evaluated. The impact of pre-treatment ELR ≥ 0.04, NLR ≥ 1.9, neutrophilia (≥ 7.0 × 10(9)/l), eosinophilia (≥ 0.5 × 10(9)/l) and lymphopenia (< 1.0 × 10(9)/l) on Overall Survival (OS) and Time-to-Progression (TTP) was evaluated both in the entire cohort and separately according to surgical status.

Results: Higher ELR was associated with longer OS and TTP, both in surgically treated and not operable patients. On univariate analysis, elevated ELR was associated with better OS (HR = 0.3, 95% IC 0.13-0.65, p = 0.003), contrarily to neutrophilia (HR = 2.7, 95% IC 1.2-6.5, p = 0.026) and age > 50 years (HR = 2.6, 95% IC 1.03-6.6, p = 0.044), while NLR, lymphopenia and Ca-19.9 were not significant. On multivariate regression, independent prognosticators for OS were: ELR, age and neutrophilia; while for TTP: ELR, neutrophilia, eosinophilia and lymphopenia.

Conclusions: The host's immune response influences survival outcomes of PC patients and may be of interest for future research.