BACKGROUND

Local failure after prostatectomy can arise in patients with cancer extending beyond the capsule. We did a randomised controlled trial to compare radical prostatectomy followed by immediate external irradiation with prostatectomy alone for patients with positive surgical margin or pT3 prostate cancer.

METHODS

After undergoing radical retropubic prostatectomy, 503 patients were randomly assigned to a wait-and-see policy, and 502 to immediate postoperative radiotherapy (60 Gy conventional irradiation delivered over 6 weeks). Eligible patients had pN0M0 tumours and one or more pathological risk factors: capsule perforation, positive surgical margins, invasion of seminal vesicles. Our revised primary endpoint was biochemical progression-free survival. Analysis was by intention to treat.

FINDINGS

The median age was 65 years (IQR 61-69). After a median follow-up of 5 years, biochemical progression-free survival was significantly improved in the irradiated group (74.0%, 98% CI 68.7-79.3 vs 52.6%, 46.6-58.5; p<0.0001). Clinical progression-free survival was also significantly improved (p=0.0009). The cumulative rate of locoregional failure was significantly lower in the irradiated group (p<0.0001). Grade 2 or 3 late effects were significantly more frequent in the postoperative irradiation group (p=0.0005), but severe toxic toxicity (grade 3 or higher) were rare, with a 5-year rate of 2.6% in the wait-and-see group and 4.2% in the postoperative irradiation group (p=0.0726).

INTERPRETATION

Immediate external irradiation after radical prostatectomy improves biochemical progression-free survival and local control in patients with positive surgical margins or pT3 prostate cancer who are at high risk of progression. Further follow-up is needed to assess the effect on overall survival.