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 EGFR-mutated 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.