The relation between systemic inflammation and incident cancer in patients with stable cardiovascular disease: a cohort study

Aims Low-grade inflammation, measured by elevated plasma concentrations of high-sensitive C-reactive protein (CRP), is a risk factor for cardiovascular disease (CVD). There is evidence that low-grade inflammation is also related to a higher risk of cancer. The present prospective cohort study evaluates the relation between low-grade systemic inflammation and risk of cancer in patients with stable CVD. Methods and results In total, 7178 patients with stable CVD and plasma CRP levels <= 10 mg/L were included. Data were linked to the Dutch national cancer registry. Cox regression models were fitted to study the relation between CRP and incident CVD and cancer. After a median follow-up time of 8.3 years (interquartile range 4.6-12.3) 1072 incident cancer diagnoses were observed. C-reactive protein concentration was related to total cancer [hazard ratio (HR) 1.35; 95% confidence interval (CI) 1.10-1.65] comparing last quintile to first quintile of CRP. Especially lung cancer, independent of histopathological subtype, was related to CRP (HR 3.39; 95% CI 2.02-5.69 comparing last to first quintile of CRP). Incidence of epithelial neoplasms and especially squamous cell neoplasms were related to CRP concentration, irrespective of anatomical location. Sensitivity analyses after excluding patients with a cancer diagnosis within 1, 2, and 5 years of follow-up showed similar results. No effect modification was observed by smoking status or time since smoking cessation (P-values for interaction > 0.05). Conclusion Chronic systemic low-grade inflammation, measured by CRP levels <_10 mg/L, is a risk factor for incident cancer, markedly lung cancer, in patients with stable CVD. The relation between inflammation and incident cancer is seen in former and current smokers and is uncertain in never smokers.