Inflammation and cancer are tightly linked. This study tests the hypothesis that an inflammatory score based on plasma levels of C-reactive protein (CRP) and fibrinogen and whole blood leukocyte count is associated with risk of colorectal, lung, breast and prostate cancer. A score ranging from none through three elevated biomarkers was constructed in 84,000 individuals from the Danish general population. During a median follow-up time of 4.8 years, 4,081 incident cancers occurred. Cox proportional hazards regression models were used to estimate hazard ratios (HRs) of incident cancer. Multifactor-adjusted HRs for colorectal cancer were 1.28 (95% CI, 1.01 to 1.62), 1.79 (95% CI, 1.41 to 2.27) and 2.18 (95% CI, 1.67 to 2.86) for individuals with elevated levels of one, two and three inflammatory biomarkers compared to individuals with none elevated biomarkers. A similar stepwise increasing risk was observed for lung and breast cancer with HRs of 3.03 (95% CI, 2.25 to 4.08) and 1.42 (95% CI, 1.11 to 1.80) for three versus none elevated biomarkers. HRs were highest within the first years of follow-up. Absolute 5-year risk of lung cancer was 7.8 (95% CI, 6.1 to 10)% among older smokers with three elevated biomarkers compared to 3.8 (95% CI, 2.6 to 5.6)% among those with none elevated biomarkers. In conclusion, simultaneously elevated CRP, fibrinogen and leukocyte count are associated with an increased risk of colorectal, lung and breast cancer. Cancer as a promoter of inflammation may be more likely to account for our findings than low-grade inflammation promoting cancer development.What's new?
Inflammation and cancer are tightly linked. In this prospective study of 84,000 individuals, the authors tested the hypothesis that an inflammatory score based on plasma levels of C-reactive protein (CRP) and fibrinogen and whole blood leukocyte count is associated with cancer risk. Simultaneously elevated CRP and fibrinogen levels and leukocyte count were associated with an increased risk of colorectal, lung and breast cancer: among those with three versus none elevated biomarkers, the risk was increased 2.2-, 3.0- and 1.4-fold, respectively. The association was strongest within the first few years after blood sampling, suggesting occult cancer eliciting inflammation as an explanation.