High serum C-reactive protein levels predict survival in patients with treated advanced lung adenocarcinoma

Background: The prognosis of non-small cell lung cancer (NSCLC) varies greatly depending on whether or not it can receive molecular-targeted drug treatment including epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs). We investigated the clinical utility of C-reactive protein (CRP) levels measured at the time of diagnosis in EGFR-mutant and wild-type NSCLC patients who had undergone first-line therapy. Methods: Serum CRP levels were analyzed in 213 patients, of whom 89 patients had advanced EGFRmutated NSCLC who underwent first-line EGFR-TKI treatment. We used Cox proportional hazards models to study the relationship between CRP and overall survival (OS). CRP cutoff values were obtained from the receiver operating characteristic curve. Results: Mean serum CRP level in treated NSCLC patients were not significantly different in patients with or without EGFR mutations. The optimal CRP cutoff values were 8.1 mg/L for EGFR-mutated NSCLC and 16.7 mg/L for EGFR-wild NSCLC. Based on multivariate analysis, high CRP level (EGFR-mutated, HR: 2.479, 95% CI: 1.331-4.619, P=0.004; EGFR-wild, HR: 3.625, 95% CI: 2.149-6.116, P<0.001) was a significant and independent negative prognostic factor for OS in patients with or without EGFR mutations. Conclusions: High CRP levels predicted a lack of response to treatment in patients with advanced lung adenocarcinoma with or without EGFR mutations. Thus, the CRP level is a good and easy to use prognostic factor and objective indicator for clinical practice.