The association between C-reactive protein (CRP) level and biochemical failure-free survival in patients after radiation therapy for nonmetastatic adenocarcinoma of the prostate

Abstract

Background: C-reactive protein (CRP) has been associated with outcomes in patients with metastatic adenocarcinoma of the prostate. Associations between prostate adenocarcinoma-specific endpoints and CRP in patients who are treated for localized disease remain unknown.

Methods: In total, 206 patients who received radiation therapy for adenocarcinoma of the prostate had at least 1 CRP measured in follow-up and were analyzed. The primary outcome was biochemical failure-free survival. In addition, associations were examined between CRP and prostate-specific antigen (PSA).

Results: On univariate analysis, higher CRP levels were associated significantly with shorter biochemical failure-free survival for patients who received radiation therapy after undergoing radical prostatectomy. For patients who were managed with definitive radiation therapy alone, higher CRP levels also were associated significantly with shorter biochemical failure-free survival on univariate and multivariable analyses (hazard ratio, 2.03; 95% confidence interval, 1.19-3.47; P = .009). In addition, CRP levels were associated significantly with PSA after radical prostatectomy for patients who had Gleason scores ≥ 8 (P = .037), for high-risk patients (P = .008), and for those with pretreatment PSA levels > 20 ng/mL (P = .05). In patients who received definitive radiation therapy, CRP levels also were associated with PSA both for those with pretreatment PSA levels > 20 ng/mL (P < .001), and for the intermediate-risk (P = .029) and high-risk (P = .009) subgroups.

Conclusions: A higher CRP level was associated with shorter biochemical failure-free survival on univariate and multivariable analyses in patients who received definitive radiation therapy. CRP was also associated with PSA in exploratory subgroups. These findings warrant further exploration in a prospectively enrolled patient cohort.

Keywords: C-reactive protein and adenocarcinoma of the prostate; C-reactive protein and prostate cancer; C-reactive protein and radiation therapy; prostate cancer biomarkers.