Prognostic Impact of C-Reactive Protein-to-Lymphocyte Ratio in Non-small Cell Lung Cancer: A Propensity Score-Matching Analysis

Background: Many inflammatory and nutritional markers have been used to predict prognosis in lung cancer. The C-reactive protein (CRP)-to-lymphocyte ratio (CLR) is a useful prognostic factor in various cancers. However, the prognostic value of preoperative CLR in patients with non-small cell lung cancer (NSCLC) remains to be established. We examined the significance of the CLR compared with known markers. Methods: A total of 1380 surgically resected NSCLC patients treated at two centers were recruited and divided into derivation and validation cohorts. After CLRs were calculated, patients were classified into high and low CLR groups based on the cutoff value determined by receiver operating characteristics curve analysis. Subsequently, we determined the statistical associations of the CLR with clinicopathological factors and prognosis and further analyzed its prognostic impact by propensity-score matching. Results: Of all the inflammatory markers examined, CLR yielded the highest area-under-the-curve value. The prognostic impact of CLR remained significant after propensity-score matching. Prognosis was significantly worse in the high-CLR group than in the low-CLR group (5-year, disease-free survival [DFS]: 58.1% vs. 81.9%, P < 0.001; 5-year overall survival [OS]: 72.1% vs. 91.2%, P < 0.001). The results were confirmed in the validation cohorts. Multivariable analysis also showed high CLR as an independent factor for both DFS and OS (DFS: hazard ratio [HR] 1.42, P = 0.027; OS: HR 1.95, P = 0.0037). Conclusions: Preoperative CLR is a useful marker for predicting the prognosis of NSCLC patients who have undergone surgery.