The Significance of Plasma C-reactive Protein in Patients With Elevated Serum Prostate-specific Antigen Levels

Abstract

Prostatic infection/inflammation may increase serum prostate-specific antigen (PSA) levels. We hypothesized that prostatic infection/inflammation can be identified by elevated plasma C-reactive protein (CRP) levels. Measuring plasma CRP levels may help to differentiate benign conditions from prostate cancer in patients with elevated serum PSA levels. A total of 139 patients with serum PSA levels greater than 4.0 ng/mL received transrectal ultrasound guided biopsy. All of the patients had plasma high-sensitivity CRP levels measured. CRP levels higher than 0.5 mg/dL were considered abnormal. CRP and PSA levels, and prostate size were compared between benign and malignant groups. The association of CRP levels with cancer stages was also analyzed. Thirty-four out of 139 (24.5%) patients were found to have prostate cancer. There was no significant difference in CRP levels between the malignant and benign groups. Five out of 34 (14.7%) patients with prostate cancer and 13 of 105 (12.4%) patients with benign lesions had elevated CRP levels. The incidence of abnormal CRP levels was not significantly different between the groups ( p = 0.77). Patients with high PSA and CRP levels did not have a higher probability of a benign condition. It is interesting to note that in the malignant group, there was a significant positive correlation between CRP and PSA levels ( r = 0.44, p = 0.01). No significant correlation between CRP levels and cancer stages was noted. Measuring plasma CRP levels does not assist in the identification of benign conditions in patients with elevated PSA levels. However, plasma CRP levels are well-correlated with serum PSA levels in prostate cancer patients, suggesting a potential correlation between prostate inflammation and prostate cancer.