Salvage radiotherapy in patients with persistently detectable PSA or PSA rising from an undetectable range after radical prostatectomy gives comparable results.

PURPOSE: Salvage radiotherapy (SRT) is applied routinely in patients with a biochemical relapse after radical prostatectomy (RP). Although the detection threshold for relapse after RP has steadily been lowered, only about 30% of the SRT patients achieve a durable response. We have previously shown the association between a PSA decrease below detectable levels after SRT and biochemical progression-free survival (BPFS). After recalculating our data according to a more recent definition of biochemical failure after SRT, we now show the significance of the post-RP PSA nadir.
MATERIALS AND METHODS: Among 159 prostate cancer patients without hormonal treatment after RP, SRT was given to 72 patients with persistently detectable PSA after RP and to 87 whose PSA increased out of an undetectable range. The median pre-SRT PSA was 0.29 ng/ml for the former group and 0.34 ng/ml for the latter group. A radiation dose of 66.6 Gy was applied to the prostate bed.
RESULTS: The overall median follow-up time was 41.7 months. The probability for BPFS after this period was 52.8% in 72 patients with persistently detectable PSA after RP and 65.4% in 87 patients who had a post-RP PSA nadir below detection limit. Univariate and multivariate analyses showed no significant difference in BPFS of both patient groups (p > 0.05).
CONCLUSION: Our findings suggest that SRT is a viable treatment option for patients with persistently detectable PSA, giving similar results as in patients whose PSA increases out of an undetectable range after RP.