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

Summary. 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.