Phase III results of adjuvant radiotherapy (RT) versus wait-and-see (WS) in patients with pT3 prostate cancer following radical prostatectomy (RP)(ARO 96–02/AUO AP 09/95)

Abstract

5060 Background: Adjuvant RT for pT3 R1 or R0 patients (pts.) after RP remains controversial. Results of an EORTC-phase-III- study (with unknown PSA-status after RP) suggested a 20% better biochemical control (bNED) after 5 years for RT. Methods: 385 men with prostate cancer were randomized to either 60 Gy RT (arm A; n=193) or WS (arm B; n=192) before achieving an undetectable PSA. Pts. were stratified for Gleason-score, margin status, neoadjuvant hormonal treatment and stage (pT3A+B vs. C). When the undetectable PSA-level after RP was not achieved, the pts. were stated as progressive disease and left arm A/B and were irradiated. PSA-progression for pts. with undetectable PSA was stated after two consecutive increasing PSA out of the undetectable range. Primary endpoint was bNED. Study was powered to demonstrate a 15% increase in bNED for RT. Results: 78 pts. (20%) did not achieve an undetectable PSA and were stated as progressive disease (arm A: 45 pts., arm B: 33 pts.). Additionally, 34 pts. (23%) from the RT-arm did not receive RT. Therefore, 114 pts. had RT (arm A) and 159 pts. WS (arm B). Median follow up was 53.6 months for arm A and 53.7 months for arm B. BNED at 5 years increased to 72% for arm A (RT) compared with 54% for arm B (WS) (p=0.0015, hazard ratio 0.53). Pts. with a preop. PSA > 10 ng/ml, tumor stage =pT3b, Gleason score =8 as well as positive margins profited significantly from adjuvant RT. The rate of late grade II side effects for the rectum was 1%. Conclusions: Adjuvant radiotherapy for pT3 prostate cancer significantly reduces the risk of biochemical progression after radical prostatectomy. The rate of side effects is very low. No significant financial relationships to disclose.