Prognostic factors for salvage radiotherapy with an analysis of post-prostatectomy PSA kinetics

Abstract

Objectives: To identify prognostic factors for biochemical control including post-prostatectomy prostate-specific antigen(PSA) kinetics in prostate cancer patients undergoing salvage radiotherapy (SRT).

Methods and Materials: Ninety patients who received SRT following radical prostatectomy (RP) were retrospectivelyanalyzed to determine factors associated with biochemical failure.

Results: Median follow-up was 30 months (range 6-120). The projected 3-year biochemical freedom from progression(bFFP) was 70%. Factors significantly associated with biochemical failure on univariate analysis included Gleason score(GS), seminal vesicle invasion (SVI), a length of time from prostatectomy to SRT of less than 12 months, pre-RT PSAgreater than 1.0 ng/mL, a persistently detectable PSA following RP, PSA doubling time (PSADT) of 6 months or less,PSA velocity (PSAV) of 1.0 ng/mL/y or greater, and a rising PSA trend during treatment. There was a trend towarddecreased bFFP among patients with pathologic tumor stage of T3-T4 (p=0.136) and positive surgical margins (p=0.301).Pre-RT PSA was found to be a significant predictor of progression with a HR of 3.659 (CI 1.981-8.755) for each increasein PSA of 1.0 ng/mL.

Conclusion: Early consideration of SRT should be given for patients with high-risk features and rising PSA. Clinical trialsevaluating systemic therapy should be considered for patients with persistently detectable PSA after RP or a rising PSAtrend during SRT.