Purpose: Elevated C-reactive protein (CRP) is associated with poor prognosis in several tumor types. The purpose of this study was to investigate serum CRP as a prognostic marker in small cell lung cancer (SCLC).
Materials and methods: The pretreatment serum CRP level was measured in 157 newly diagnosed SCLC patients, and correlation between serum CRP level and other clinical parameters was analyzed. Multivariate analyses were performed to find prognostic markers using Cox's proportional hazards model.
Results: The initial CRP concentration was within the normal range in 72 (45.9%) patients and elevated in 85 (54.1%) patients. There was a significant correlation between serum CRP level and the extent of disease (p<0.001), weight loss (p=0.029) and chest radiation (p=0.001). Median overall survival (OS) in the normal CRP group was significantly longer than with the high CRP group (22.5 months vs. 11.2 months, p<0.001). Extent of disease (p<0.001), age (p=0.025), and performance status (p<0.001) were additional prognostic factors on univariate analysis. On multivariate analysis, elevated serum CRP level was an independent prognostic factor for poor survival (HR=1.8; p=0.014), regardless of the extent of disease (HR=3.7; p<0.001) and performance status (HR=2.2; p<0.001).
Conclusion: High level of CRP was an independent poor prognostic serum marker in addition to previously well-known prognosticators in patients with SCLC.