Application of platelet/lymphocyte and neutrophil/lymphocyte ratios in early diagnosis and prognostic prediction in patients with resectable gastric cancer

BACKGROUND: Gastric cancer is the fourth most frequent cancer and the second cause of cancer-related deaths worldwide. China has a high incidence of gastric cancer. Inflammation is a critical component of tumor progression. It has been widely accepted that gastric cancer is an inflammation-driven cancer. In this study, we investigated the application value of systemic inflammatory response (SIR) markers, platelet to lymphocyte ratio (PLR) and neutrophil to lymphocyte ratio (NLR), in early diagnosis and prognostic prediction in patients with resectable gastric cancer. MATERIALS AND METHODS: One hundred and sixty-two patients with resectable gastric cancer were included and separated into groups according to median pre-operative PLR or NLR values (PLR low: < 208 or PLR high: >= 208, and NLR low: < 4.02 or NLR high: >= 4.02, respectively). To evaluate the changes in PLR or NLR values after operation, we introduced the concept of post-/pre-operative PLR or NLR ratios (< 1 indicated PLR or NLR values were decreased after operation, while >= 1 suggested not decreased PLR or NLR values). RESULTS: Pre-operative PLR and NLR levels were significantly higher in gastric cancer patients compared with the healthy subjects. Low pre-operative PLR and NLR levels correlated with better clinicopathological features, including decreased depth of invasion, less lymph node metastasis and early tumor stage. Kaplan-Meier plots illustrated that higher pre-operative NLR and PLR had decreased overall survival (OS) and disease-free survival (DFS). Surgical tumor resection resulted in a significant decrease in both PLR and NLR levels. Patients whose post-/pre-operative PLR or NLR ratios < 1 had better OS. Multivariate Cox regression analysis revealed that tumor stage, pre-operative NLR level, and post/pre-operative NLR ratio are prognostic factors affecting DFS, while depth of invasion, lymph node metastasis, tumor stage, pre-operative PLR level, and post/pre-operative PLR ratio are prognostic factors affecting OS. CONCLUSIONS: PLR and NLR measurements can provide important diagnostic and prognostic results in patients with resectable gastric cancer.