Stereotactic radiotherapy for prostate bed recurrence after prostatectomy, a multicentric series

Objective: To assess the safety and effectiveness of stereotactic salvage radiotherapy (SSRT) in RT-naïve patients affected by macroscopic prostate bed recurrence. Patients and methods: Consecutive patients treated for prostate bed macroscopic recurrence in three different Italian institutes were reviewed. Patients were treated with SSRT, with a total dose of 30–40 Gy in five fractions, the mean pre-SSRT PSA level was 2.3 ng/mL. Two different PSA thresholds were defined and biochemical recurrence-free survival (BCRFS) was reported, in order to better express outcome: BCRFS1 (a PSA level increase of >10% compared to the pre-SSRT value) and BCRFS2 (a PSA level increase of >0.2 ng/mL for patients with a PSA nadir of <0.2 ng/mL or two consecutive PSA level increases of >25% compared to nadir in patients with a PSA nadir of <0.2 ng/mL). Results: In all, 90 patients were treated, with a mean (range) follow-up of 21.2 (2–64) months, and 17 of these patients (19%) had concomitant androgen-deprivation therapy (ADT) during SSRT. Complete biochemical response, defined as a PSA nadir of <0.2 ng/mL, was obtained in 39 of the 90 patients (43.3%). Considering BCRFS1, 25 patients (27.8%) had BCR, with an actuarial median BCRFS1 time of 36.4 months. For BCRFS2, BCR was reported in 32 patients (35.5%), with an actuarial median BCRFS2 time of 24.3 months. There was no Grade >2 toxicity. Conclusions: SSRT was found to yield significant biochemical control and allowed ADT delay despite adverse features.