C-reactive protein as adverse prognostic marker for men with castration-resistant prostate cancer (CRPC): Confirmatory results.
J Clin Oncol. 2009 May 20 ;27(15_suppl):5168. PMID: 27964500
: 5168 Background: We previously reported that higher serum concentrations of C-reactive protein (CRP) are associated with shorter survival in men with metastatic CRPC treated with docetaxel-containing chemotherapy. We sought to confirm these hypothesis-generating findings in an independent data set.
METHODS: Baseline samples were stored (-80ºC) from 119 CRPC patients enrolled in 6 phase I or II clinical trials of chemotherapy as well as non-cytotoxic agents conducted at OHSU. 91% of patients had metastases and 9% had PSA-only disease. 16% had prior chemotherapy exposure. Median follow-up is 19.7 months (0.9-98.5 months) and 89% have died. In addition to CRP, we examined alkaline phosphatase, hemoglobin, age, ECOG PS, and PSA collected at study entry. After examining the form of the risk function using the generalized additive model method, univariate and multivariate Cox proportional hazard models were used to assess associations between baseline individual categorical and continuous variables.
RESULTS: Quartiles of CRP were: 1: 0-1.0, 1.1-4.9, 5.0-17.0, and 17.1 to 311 mg/L, somewhat lower than in our previous study. In a Cox multivariate model, log2(CRP) (HR 1.09 p = 0.036) as well as hemoglobin and log2(Alk Phos) were independently associated with survival. Thus, the risk of death increased 8.7% for every doubling of CRP.
CONCLUSIONS: In an independent data set from patients with CRPC, we confirmed that higher baseline CRP is associated with shorter survival. This readily measurable biomarker has the potential to improve prognostic models and should be validated in a prospective clinical trial. This finding also suggests that inflammation may play an important role in the natural history of advanced prostate cancer. Additional studies of the mechanisms that may explain the inverse relationship between CRP and survival are under way. No significant financial relationships to disclose.