Low prostate-specific antigen and no Gleason score upgrade despite more extensive cancer during active surveillance predicts insignificant prostate cancer at radical prostatectomy

Abstract

Objective: To identify parameters that predict insignificant prostate cancer in 67 radical prostatectomies after biopsy reclassification to worse disease on active surveillance.

Methods: Parameters evaluated at diagnosis and at biopsy reclassification included serum prostate-specific antigen, prostate-specific antigen density, number of positive cores, maximum percent involvement of cancer per core, and any interval negative biopsies. Gleason upgrading at biopsy reclassification was also assessed to predict insignificant cancer.

Results: Mean time between diagnosis and radical prostatectomies was 30.3 months with a median of 3 biopsies (range 2-9). Nineteen of 67 (28.4%) had clinically insignificant cancer at radical prostatectomy. In the entire group, there were no variables significantly associated with insignificant cancer at radical prostatectomy. In a subgroup analysis of 37 patients without Gleason pattern 4/5 at biopsy reclassification, 16/37 (43.2%) showed insignificant cancer at radical prostatectomy. In this subgroup, prostate-specific antigen at diagnosis was significantly lower in men with insignificant cancer (3.7 ng/mL) vs significant cancer (5.4 ng/mL) (P = .0005). With prostate-specific antigen <4 ng/mL at diagnosis or at biopsy reclassification, 12/13 (92.3%) men showed insignificant cancer, whereas only 4/24 (16.7%) men with prostate-specific antigen >4 ng/mL both at diagnosis and at biopsy reclassification showed insignificant cancer.

Conclusion: Most men with biopsy reclassification while on active surveillance have significant disease at radical prostatectomy, justifying their treatment. Low prostate-specific antigen at diagnosis or at biopsy reclassification can predict a high probability of insignificant cancer in the absence of Gleason pattern 4/5 on biopsy. These men may be candidates for continuing active surveillance.

Figure 1

Number of insignificant and significant cancer in different categories classified by presence of Gleason pattern 4/5 and PSA at diagnosis and at time of reclassification on surveillance biopsy. (Color version available online.)