[Adjuvant vs. salvage radiotherapy after radical prostatectomy]

Abstract

Background: After radical prostatectomy (RP) the pre-RP PSA value, Gleason Score, pT-stage, state of seminal vesicles and state of surgical margins are key indicators for the risk of biochemical or clinical recurrence. Depending on the tumour stage, 50-70% of the high-risk patients suffer biochemical progression. The treatment options in these circumstances are adjuvant radiotherapy (ART, for an undetectable PSA) or salvage radiotherapy (SRT, for persisting PSA or PSA re-rising above detection limits). Data from ongoing randomised trials that compare ART and SRT directly have not yet been published.

Method: A search in PubMed for ART and SRT after RP for prostate cancer was undertaken to compare the results of the 2 treatment approaches.

Results: 3 randomised phase-III studies have shown a nearly 20% advantage in terms of biochemical progression after ART (60-64 Gy) compared with a wait-and-see strategy. The largest effect was seen in patients with pT3 prostate cancer with positive surgical margins. According to the German S3-guidelines, SRT with at least 66 Gy can be offered to patients with a post-RP persisting PSA or a PSA re-rising above detection limits. 30-70% of these patients re-achieve an undetectable PSA. Thus, there is a second option for curative treatment. Due to the lower total dose, ART seems to be connected with fewer late complications than SRT. SRT, on the other hand, reduces the risk of potential interactions with post-RP complications and of overtreatment. There is a controversial discussion about the inclusion of the pelvic lymph nodes in the treatment volume, the additional application of anti-androgens and the total dose of both ART and SRT.

Conclusions: The comparison of SRT after PSA progression with ART at a PSA below the detection limits cannot yet be judged conclusively. The indication for ART depends on the associated risk factors. However, regarding freedom from biochemical progression, it is backed up by high level evidence. If SRT is applied for biochemical progression, then it should be initiated early, i. e., at the lowest PSA possible.