Objective: To explore the association between the erythrocyte sedimentation rate, serum C-reactive protein (CRP) and the risk of lung cancer.
Methods: One hundred and three patients with newly diagnosed lung cancer and 85 homochronous hospitalized patients with chronic respiratory diseases (including chronic obstructive pulmonary disease, asthma, bronchiectasis and pulmonary fibrosis) were included in this study. ESR, serum levels of CRP, CEA, CA19-9 and CA125 were analyzed in the two groups before the initiation of any therapy after hospitalization. The association with clinicopathological characteristics of lung cancer and the risk of lung cancer were estimated by logistic regression.
Results: Both the ESR and CRP levels were significantly higher in the lung cancer group, as compared with that in the chronic respiratory diseases group (P < 0.001). There was no significant association of ESR and CRP with lung cancer stage and type. Spearman correlation analysis showed a positive correlation between ESR and CRP (r = 0.56, P < 0.001), ESR and CA125 (r = 0.33, P < 0.001), and CRP and CA125 (r = 0.32, P < 0.001). The results of multivariate logistic analysis showed that the level of CRP was associated with an increased risk of lung cancer. Adjusting the confounding factors such as age, gender and smoking condition, the risk increased along with the elevation of CRP. Compared with the first quantile patients, the risk of the second quantile patients increased twice (OR: 2.46, 95%CI: 1.16 - 5.20), the risk of the third quantile patients increased ten-fold (OR: 10.52, 95%CI: 4.40 - 25.18).
Conclusion: The level of CRP is associated with an increased risk of lung cancer. The results of this study suggest that early detection of CRP may have a potential predicting value for high risk group of lung cancer.