Does lymphocyte-to-monocyte ratio before, during, or after definitive chemoradiation for locally advanced pancreatic cancer predict for clinical outcomes?

BACKGROUND

Elevated pre-treatment lymphocyte (L) to monocyte (M) ratio (LMR) in peripheral blood has been suggested to correlate with improved survival in some malignancies, but data in the context of pancreatic cancer (PC) is limited. The aim of this study was to evaluate the prognostic significance of LMR before, during and after definitive chemoradiotherapy (CRT) for locally advanced pancreatic cancer (LAPC).

METHODS

We retrospectively reviewed 57 patients with LAPC treated with definitive CRT at a single institution from 2005 to 2013. Complete blood counts were obtained before (TP1), during the third week (TP2) and at the end of CRT (TP3). Univariate analysis (UVA) included gender, age, body mass index, pre-treatment CA19-9, T stage, N stage, induction chemotherapy (ICT), absolute L count (TP1, TP2, TP3), absolute M count (TP1, TP2, TP3), LMR (TP1, TP2, TP3), and relative LMR changes (TP2 ÷ TP1, TP3 ÷ TP1, TP3 ÷ TP2).

RESULTS

Median follow-up was 14 months. Twelve patients received ICT. Median LMR was 2.7 (range, 0.8-5.25), 1.4 (range, 0.3-5) and 0.98 (range, 0.3-3.4) at TP1, TP2 and TP3, respectively. Superior PFS was significantly associated with an absolute M count during CRT <0.1 (P=0.04) while pre-CRT L count ≥1.1 trended towards significance (P=0.09). Superior OS was significantly associated with change in LMR (TP3 ÷ TP2) > 0.32 (P<0.0001) while pre-CRT LMR ≥2.6 trended towards significance (P=0.06).

CONCLUSIONS

Factors significantly associated with overall survival (OS) and progression-free survival (PFS) were change in LMR at the end of CRT and absolute M count during CRT. This analysis suggests treatment-time-specific immune system parameters may affect clinical outcomes and warrant continued investigation.