Oncologic Outcomes of Adjuvant versus Salvage Radiotherapy after Prostatectomy

Introduction: The benefit of adjuvant radiotherapy (AR) or salvage radiotherapy (SR) after prostatectomy is still unclear. We wanted to compare both types of radiotherapy after prostatectomy in terms of oncological and functional results.

Methods: We included 173 patients treated at a single center between January 2005 and December 2008. All patients were treated with the same radiotherapy protocol (3D conformal radiotherapy accelerator 6 mV, 66 GY). AR was defined as radiotherapy initiated in a patient with a PSA level <0.2 ng/mL after prostatectomy otherwise it was defined as SR. No patients received neoadjuvant therapy prior to prostatectomy (whether hormone therapy or chemotherapy). Patients in the SR group had a PSA level ≥0.2 ng/mL during the treatment in accordance with the Phoenix criteria. The lymph nodes were irradiated if the patient had no lymph node dissection and if the risk of nodal involvement was >10%. Both groups were compared in terms of biological progression-free, metastasis-free, and overall survival (OS) using log-rank tests. Moreover, acute and late urinary and gastrointestinal toxicity were also compared.

Results: One hundred and fifty-seven patients underwent an open retropubic prostatectomy whereas 16 underwent a laparoscopy (6 subperitoneal and 10 transperitoneal). Eighty-six patients had AR with a median time of 6.7 months after surgery and 87 had SR with a median time of 21.4 months after surgery. Median follow-up was 6.7 years. Metastasis-free survival (MFS) was better in the AR than in the SR group (p = 0.01, 6-year MFS 95 and 89%, respectively). OS was also better in the AR than in the SR group (p = 0.02, 6-year OS 100 vs. 95%, respectively). AR was associated with better survival with no biochemical recurrence (85 vs. 63%, p < 0.00001). There was no significant difference between groups for acute or late urinary or gastrointestinal toxicity.

Conclusion: Our study suggests that patients treated by AR have better results in terms of OS, disease-specific survival, survival without metastatic recurrence, and survival without biochemical recurrence compared with SR. Toxicity was comparable between both groups.