Purpose: Local failure after radiotherapy can arise with cancer extending beyond the capsule and/or involvement of seminal vesicles or positive surgical margins.
Methodology: After undergoing radical prostatectomy 1005 patients were randomly assigned (1999-2001) to a wait and see policy or an immediate postoperative irradiation (60 Gy delivered over 6 weeks); eligible patients had pN0 M0 tumors and one or more pathological risk factors mentioned above. The main end-point was 5-year biochemical progression free survival.
Results: After a median follow-up of 5-year biochemical progression free survival was significantly improved in the irradiated group (74%, 98% CI: 68.7-79.3 vs 52.6%, 98% CI: 46.6-58.5; P<0.0001) Clinical progression free survival was also significantly improved (P<0.0009). The cumulative rate of loco-regional failure was also significantly improved (P<0.0009). Grade 2 or 3 late effects were significantly more frequent in the postoperative irradiation group (P=0.0005), but severe 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=0.07).
Conclusion: Immediate external irradiation after radical prostatectomy improves biochemical progression free survival and local control in patients with positive surgical margin or pT3 prostate cancer who are at high risk of progression. Further follow-up is needed to assess the impact on overall survival.