Login to Access Video or Poster Abstract: MP14-18
Sources of Funding: none

Introduction

Most patients undergoing radical prostatectomy (RP) for treatment of prostate cancer (CaP) will not develop biochemical recurrence (BCR) or distant metastasis (dMET). Risk factors have been difficult to establish and the role of neo-adjuvant, adjuvant, and/or salvage therapy in preventing or delaying these events is not well understood. This study builds on previous work examining alkaline phosphatase velocity (APV) in predicting dMET for castrate-resistant CaP (CRPC) patients, in a large, racially diverse cohort of patients treated in an equal access military health care system.

Methods

This retrospective cohort study examined CaP patients enrolled in the Center for Prostate Disease Research (CPDR) multi-center national database who underwent RP and subsequently experienced BCR (n=1725). BCR was defined as a PSA ≥ 0.2 ng/mL at ≥ 8 weeks post-RP, followed by a confirmatory PSA ≥ 0.2 ng/mL. APV was computed as the slope of the linear regression line of all alkaline phosphatase (AP) values after RP and prior to dMETs. APV values in the uppermost quartile were defined as &[Prime]rapid&[Prime] and compared to those in the lower 3 quartiles combined. Salvage therapies were categorized as: hormone therapy only, external radiation therapy only, or multi-treatment. Unadjusted Kaplan Meier curves and multivariable Cox Proportional Hazards analysis were used to model time to dMET.

Results

Of the 1725 eligible patients, 736 (42.7%) had sufficient data to calculate APV. Those without APV data had a greater proportion of dMET and a faster time to dMET, as well as poorer pathologic features than those who had sufficient APV data. dMET was observed in 11% of patients. We observed a significantly faster time to dMET among the rapid APV group (p<0.001). In multivariable analysis, rapid APV was predictive of over a two-fold increased odds in dMET (HOR = 2.08, p = 0.0215).

Conclusions

In CaP patients with BCR after RP, rapid APV is a useful predictor of dMET over time. Salvage therapy did not appear to predict dMET. This study builds on previous work demonstrating APV as predictive of dMET among castrate resistant CaP (CRPC) patients. APV may be a valuable tool for prognosticating dMET in a broader patient group, at a time point upstream of CRPC, namely CaP patients who experience BCR after RP.

Funding

none