The elevated C-reactive protein level is associated with poor prognosis in prostate cancer patients treated with radiotherapy

Abstract Background C-reactive protein (CRP) is a sensitive marker of inflammation that has been linked with prognosis in various solid tumours. In the present study, we analysed the prognostic relevance of elevated plasma CRP levels in prostate cancer patients treated with radiotherapy. Methods A total of 261 prostate cancer patients treated with 3D-conformal radiotherapy were evaluated retrospectively. Cancer specific survival (CSS), overall survival (OS) and clinical disease-free survival (DFS) were assessed using Kaplan–Meier analysis. To evaluate the independent prognostic significance of CRP plasma levels, multivariate Cox regression models were applied. Results The median follow-time was 80 months. Applying receiver operating characteristics (ROC) analysis, the optimal cut-off level for the plasma CRP was 8.6 mg l−1 . An elevated CRP level was associated with decreased CSS in univariate (hazard ratio (HR) 3.36, 95% confidence interval (CI) 1.42–7.91; p = 0.006) and multivariate analysis (HR 4.31, 95% CI 1.22–15.1; p = 0.023). Furthermore, a significant association with OS was detected in univariate (HR 2.69, 95% CI 1.57–4.59; p < 0.001) and multivariate analyses (HR 3.24, 95% CI 1.84–5.71, p < 0.001). Multivariate analysis also showed a significant association between plasma CRP and clinical DFS (HR 2.07, 95% CI 1.02–4.17; p = 0.043). Conclusions In the present study, an elevated plasma CRP (⩾8.6 mg l−1 ) has been identified as a prognostic factor for poor CSS, OS and DFS in prostate cancer patients undergoing radiotherapy. The association between elevated CRP levels and poor prognosis was independent of other measures of prognosis such as tumour stage, Gleason grading and prostate specific antigen (PSA) level at diagnosis. If confirmed by additional studies, our findings may contribute to future individual risk assessment in prostate cancer patients.