Influential factors in the response to salvage radiotherapy after radical prostatectomy

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

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.

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).

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.