Neutrophil-to-lymphocyte ratio and carbohydrate antigen 19-9 as prognostic markers for advanced pancreatic cancer patients receiving first-line chemotherapy.

Background: A decline in serum carbohydrate antigen 19-9 (CA19-9) levels during systemic chemotherapy is considered as a prognostic marker for patients with advanced pancreatic cancer. Neutrophil-to-lymphocyte ratio (NLR) has been extensively studied as a simple and useful indicator of prognosis in various cancers including pancreatic cancer.

Aim: To assess the prognostic significance of NLR and CA19-9 in patients with advanced pancreatic adenocarcinoma received first-line chemotherapy according to CA19-9 positivity.

Methods: We retrospectively analyzed patients diagnosed with advanced pancreatic cancer who received first-line chemotherapy between January 2010 and July 2017 at the Catholic University of Seoul St. Mary's Hospital. Patients were divided according to CA19-9 positivity (CA19-9-positive -negative groups) and pre-and post-treatment NLR levels. To determine cut-off value of NLR and CA19-9 reduction, time-dependent receiver operating characteristic curve was applied. We evaluated overall survival (OS) and progression-free survival (PFS) for each group using Kaplan-Meier method, and we performed multivariate analyses on the entire cohort.

Results: We included 271 patients in this study. Cut-off value of NLR and CA19-9 reduction was determined as 2.62 and 18%. Multivariate analysis showed that post-treatment NLR < 2.62 and reduction of ≥ 18% of baseline CA19-9 were significantly associated with OS and PFS. Post-treatment NLR ≥ 2.62 showed hazard ratio (HR) of 2.47 [95% confidence interval (CI): 1.84-3.32, < 0.001] and CA19-9 decline (≥ 18%) showed HR of 0.51 (95%CI: 0.39-0.67, < 0.001) for OS. When CA19-9-positive patients were divided into groups according to CA19-9 response (responder non-responder) and post-treatment NLR (< 2.62 ≥ 2.62), CA19-9 responder and post-treatment NLR < 2.62 group showed better survival than CA19-9 non-responder and post-treatment NLR ≥ 2.62 group (OS 11.0 mo 3.9 mo, < 0.001; PFS 6.3 mo 2.0 mo, < 0.001). The combination of CA19-9 decline and post-treatment NLR showed a significant correlation with clinical response in CA 19-9 positive group. Within the CA19-9-negative group, the post-treatment NLR < 2.62 group showed better survival than the post-treatment NLR ≥ 2.62 group (OS 12.7 mo 7.7 mo, < 0.001; PFS 6.7 mo 2.1 mo, < 0.001), and post-treatment NLR showed correlation with clinical response.

Conclusion: In advanced pancreatic cancer patients positive for CA19-9 and treated with systemic chemotherapy, the combination of post-treatment NLR < 2.62 and 18% decline of CA19-9 at the first response evaluation is a good prognostic marker. Post-treatment NLR < 2.62 alone could be used as a prognostic marker and an adjunctive tool for response evaluation in CA19-9-negative patients.