Dynamic correlation of serum C-reactive protein (CRP) levels with serum prostate-specific antigen (PSA) levels in patients with prostate cancer (PCa) on androgen deprivation therapy (ADT).

Abstract

181 Background: CRP, a marker of inflammation, has been associated with disease extent and prognosis in urologic cancers (Huang J, et al. Mol Aspects Med, 2015). In this study we wanted to see whether CRP is dynamically correlated with PSA in patients with PCa when they were on ADT. Methods: 83 patients on ADT were included in this analysis. Their CRP and PSA were recorded longitudinally and the range of length of follow up time is from 3 to 47 (median 16) months. All patients had at least 3 pairs of CRP and PSA measurements available. Statistical analysis was conducted using Dynamic Correlation (Dubin JA, Muller H-G. J Am Stat Assoc, 2005) package ‘dynCorr’ in R 3.1.2, and SAS Version 9.4. Significance levels were set at 0.05. We calculated dynamical correlation as function of time lag between CRP and PSA measurements along with 95% bootstrap confidence intervals and p value. Results: See below table. Conclusions: We found that at lag = 30 days (CRP leads PSA by 30 days), the correlation is significant at level of < 0.05, which means any increase or decrease of CRP at a given time point will lead to about same change in PSA 30 days later. Though these findings must be verified in a larger setting, our results support, in the setting of ADT use, the role of CRP as an early marker of PCa progression and treatment response. [Table: see text]