C-Reactive Protein Linked to Increased Lung Cancer Risk
Patients with highest baseline levels may have twice the risk of those with lowest levels
FRIDAY, April 30 (HealthDay News) -- Elevated levels of circulating high-sensitivity C-reactive protein (CRP) are associated with an increased risk of lung cancer, suggesting that chronic inflammation may play a role in lung carcinogenesis, according to a study published online April 26 in the Journal of Clinical Oncology.
Anil K. Chaturvedi, Ph.D., of the National Institutes of Health in Rockville, Md., and colleagues conducted a nested case-control study of 592 lung cancer patients and 670 controls who had available pre-diagnostic serum, as well as 378 patients and 447 controls who had DNA in the screening arm of the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial. They measured CRP levels in baseline serum samples, and they also genotyped five common CRP single-nucleotide polymorphisms.
Compared to subjects in the lowest quartile for CRP levels (less than 1.0 mg/L), the researchers found that those in the highest quartile (at least 5.6 mg/L) had an increased lung cancer risk (odds ratio [OR], 1.98). Although they found that the CRP association did not significantly differ by histology, follow-up time or smoking status, they found that it was strongly apparent for squamous cell carcinomas or a lung cancer diagnosis within two to five years (ORs, 2.92 and 2.33, respectively), and among former and current smokers (ORs, 2.48 and 1.90, respectively). They also found that CRP single-nucleotide polymorphisms were not associated with lung cancer risk.
"Our key observation was that elevated CRP levels preceded lung cancer diagnosis by several years," the authors conclude. "The separation in lung cancer absolute risks across circulating CRP levels among former and current smokers provides preliminary evidence for the utility of CRP measurements in lung cancer risk stratification. These results also highlight the possibility that interventions targeting pulmonary inflammation may be effective in reducing lung cancer risk."