Influential factors in the response to salvage radiotherapy after radical prostatectomy

Objective: To analyze the influential factors in the response in prostatectomized patients with subsequent biochemical relapse (BCR) and treated with salvage radiotherapy (RTP).

Material and methods: We analyzed 313 patients with pT2/pT3 prostate cancer who were receiving salvage therapy due to biochemical relapse (from a series of 1,310 radical prostatectomies between 1989-2012). Of the 313 patients; 159 (50.8%) only received androgen deprivation (AD), 63 (20.1%) Radiotherapy (RTP) plus concomitant AD and 91 (29.1%) only RTP. Of these, 57 (62.6%) have maintained complete response and 34 (37.4%) had failure response with post-RTP BCR.

Results: Study of the group treated exclusively with salvage RTP. Ninety-one patients were treated with salvage RTP. Median follow-up was 6.4 years and median to recurrence 11 months. Post-RTP biochemical relapse-free survival (PRBRFS) was 68 ± 7% and 30 ± 10% in 5 to 10 years. Median PRBRFS was 7.3 years (6.3-8.3). Initial PSA (HR: 1.08; 95% CI: 1.01-1.1 P=.02) with best PSA cut-off point PSA>20 ng/ml (HR: 13.6; 95% CI: 2.1-86 P=.005) and PSA pre-RTP (HR: 1.9; 95% CI: 1.2-3.3; P=.009), best PSA cut-off point PSA preRTP 0.92 ng/ml (HR: 4.5; 95% CI: 1.3-15.6; P=.01) showed independent influence in the response in the multivariate study. PRBRFS at 5 years, 81 ± 9% versus 58 ± 9% with initial PSA <20 or >20 ng/ml (P=.03). PRBRFS at 5 years, 93 ± 5% versus 53 ± 10% according to PSA pre-RTP <0.9 or >0.9 ng/ml (P=.02).

Conclusions: In patients treated with salvage RTP after radical prostatectomy, the preoperative PSA>20 ng/ml and PSA preRTP>0.92 ng/ml shows an independent influence on the response.