Defining Biochemical Recurrence of Prostate Cancer After Radical Prostatectomy: A Proposal for a Standardized Definition

Abstract
Purpose Prostate-specific antigen (PSA) defined biochemical recurrence (BCR) of prostate cancer is widely used for reporting the outcome of radical prostatectomy (RP). A standardized BCR definition is lacking, and overall progression-free probability and risk of subsequent metastatic disease progression may vary greatly depending on the PSA criterion used. Ten definitions of BCR were evaluated to identify the one that best explains metastatic progression. Methods Of 3,125 patients who underwent RP at our institution since 1985, 75 developed distant metastasis during a median follow-up of 49 months. To predict metastasis progression, we modeled the clinical information using multivariable Cox regression analysis. BCR was included in the model as a time-dependent covariate, and separate models were developed for each definition. A goodness-of-fit (R2) statistic was used to determine the Cox model (and thereby the BCR definition) that best explained metastatic progression. Results The 10-year progression-fre...