Metastasis free survival following salvage radiotherapy versus hormonal therapy alone in patients with biochemical recurrence after radical prostatectomy.

Abstract

130 Background: To describe metastasis-free survival (MFS) in patients with biochemical recurrence following radical prostatectomy (RP), and to define clinical prognostic factors for metastasis. Methods: From our institutional database, 1,408 patients underwent primary RP between 2005 and 2011. Of these, 267 patients who had biochemical recurrence (two consecutive PSA ≥ 0.2 ng/mL) and had post-biochemical recurrence follow-up greater than 12 months were used as the study cohort. As an initial management for biochemical recurrence, salvage radiotherapy (SRT) combined with or without androgen deprivation therapy (ADT) was administered to 186 patients, while 33 patients received salvage ADT alone. Remaining 48 patients had been observed without any treatments. We estimated MFS using the Kaplan–Meier method, and investigated factors influencing the risk of metastasis using Cox proportional hazards regression. Results: Median follow-up after RP was 6.0 years, and after biochemical recurrence was 4.2 years. At last follow-up, 28 of 267 patients (10.5%) had developed metastasis, while 5-year MFS rate was 88.6%. No one developed metastasis in patients under observation. SRT resulted in an improved 5-year MFS rate (89.3% vs. 76.7%; p =0.022) compared with salvage ADT alone. This inferiority of salvage ADT alone compared with salvage SRT was marginally significant in the multivariate analysis (hazard ratio [HR] 2.24; 95% confidence interval [CI] 0.93–5.36; p = 0.071). Gleason score ≥8 (HR 4.10; 95% CI 1.77–9.51; p = 0.001) and seminal vesicle invasion (HR 2.37; 95% CI 1.06–5.30; p = 0.036) were significantly associated with MFS in the multivariate analysis. Conclusions: In patients undergoing prostatectomy, MFS after biochemical recurrence is variable and is most strongly influenced by Gleason score and seminal vesicle invasion. These parameters serve to stratify patients into different risk groups with respect to metastatic progression. Salvage ADT alone should be used with caution with select patients.