Thrombosis risk and survival in cancer patients with elevated C-reactive protein

Background: The incidence of venous thromboembolism (VTE) is increased among cancer patients. Objective: We assessed serum levels of C-reactive protein (CRP) in order to study their prognostic significance for VTE and survival in the prospective observational Cancer and Thrombosis Study (CATS). Patients and methods: This study includes patients with recently diagnosed cancer or progression of disease after remission. Occurrence of VTE and information on the patients' anti-cancer-treatment are recorded. Observation ends with occurrence of objectively confirmed VTE, death or after 2 years. CRP levels were determined by an immunonephelometric method. Results: We included 705 consecutive patients with solid tumors. During the observation period, VTE occurred in 43 (6.1%) patients and 413 (58.6%) died. The cumulative probability of VTE was 6.6% after 1 year. In univariate analysis, CRP (as metric variable, per double increase) was associated with VTE [hazard ratio (HR) 1.2, 95% confidence interval (CI) 1.1-1.3 P = 0.048]. However, in multivariable analysis including chemotherapy, surgery and radiotherapy, metastasis, cancer-site and sP-selectin the association with VTE (HR 1.0, 95% CI 0.9-1.2 P = 0.932) was no longer observed. CRP was clearly associated with worse survival probability with a HR of 1.3 (95% CI 1.2-1.3, P < 0.0001) in multivariable analysis. The cumulative survival after 12 months was 43% in patients with CRP above the 75th percentile (1.8 mg dL-1) and 82% in those below the 75th percentile. Conclusions: In cancer patients elevated CRP was not independently associated with VTE. CRP was significantly associated with worse survival.