Inflammatory biomarker score and cancer: A population-based prospective cohort study

Inflammation is associated with cancer but there are conflicting reports on associations of biomarkers of inflammation with cancer risk and mortality. We investigated the associations of C-reactive protein (CRP) and leukocyte count with cancer risk and mortality using individual biomarkers, and an inflammatory score derived from both biomarkers.

We conducted this analysis among 2,570 men enrolled in the population-based, prospective Kuopio Ischemic Heart Disease Risk Factor Study in Finland. During an average follow-up period of 26 years, 653 cancer cases and 287 cancer deaths occurred. We computed a z-score for each participant, with the combined z-score being the sum of each individual's CRP and leukocyte z-scores. Multivariable-adjusted Cox proportional hazard model was used to evaluate associations with cancer risk and mortality.

Using individual biomarkers, elevated leukocyte count was associated with an increased risk of cancer (RR = 1.31, 95% CI 1.04-1.66), and cancer mortality (RR=, 95% CI 1.39, 0.98-1.97). The corresponding results for CRP were (RR = 1.23, 95% CI 0.97-1.55) for risk and (RR = 1.15, 95% CI 0.81-1.64) for cancer mortality. Associations of the biomarkers with cancer appeared to be more robust using the combined z-score. HRs comparing men within the highest z-score quartile to those within the lowest z-score quartiles were 1.47 (95% CI 1.16-1.88, p-trend < 0.01) for cancer risk, and 1.48 (95% CI 1.03-2.14, p-trend = 0.09) for cancer mortality.

Our study suggests that inflammation is associated with cancer risk and mortality, and combining inflammatory biomarkers into a score is a robust method of elucidating this association.