Prognostic role of serum C-reactive protein in patients with advanced-stage NSCLC treated with pemetrexed

Pemetrexed is an intravenously administered antifolate cytostatic agent targeting several folate-dependent enzymatic pathways, widely used in the treatment of patients with advanced non-small cell lung cancer (NSCLC). It has been previously demonstrated that the superiority of pemetrexed is limited to patients with non-squamous histology. Aside from the non-squamous histology, there is still no available molecular biomarker predicting treatment efficacy of pemetrexed-based chemotherapy. The aim of our retrospective study was to evaluate the association of baseline serum levels of C-reactive protein (CRP) with outcomes in a large cohort of patients with non-squamous NSCLC treated with pemetrexed. Clinical data of 325 patients were analysed. Serum samples were collected within one week before the initiation of treatment. The median progression-free (PFS) and overall survival (OS) for patients with high CRP was 2.1 and 9.5 compared to 4.2 and 20.5 months for those with normal CRP (p=0.002 and p<0.001, respectively). The multivariable Cox proportional hazards model revealed that serum CRP (HR=1.46, p=0.002) was significantly associated with PFS and also with OS (HR=1.95, p<0.001). In conclusion, the study results suggest that pretreatment serum CRP is associated with poor outcome of non-squamous NSCLC patients treated with pemetrexed.