Purpose

To evaluate the safety and efficacy of high-dose-rate (HDR) prostate brachytherapy (BT) in patients with local relapse after initial treatment with radical prostatectomy and salvage external beam radiation therapy (EBRT).

Material and methods

Patients with local recurrence of prostate adenocarcinoma were retrospectively identified at a single-institution between 2015 and 2024. Recurrence was confirmed by imaging (MRI or choline PET) after prostatectomy and EBRT. Patients had no evidence of distant disease. A total HDR-BT dose of 17 Gy to 20 Gy was administered in two fractions.

Results

Seventeen patients received salvage HDR-BT. The median follow-up time was 74 months (range, 6-100). Twelve patients (70.6%) received salvage-intent EBRT after surgery, while five (29.4%) had adjuvant EBRT. Three patients received androgen deprivation therapy (ADT) concurrently with EBRT in a mean ADT duration of 72 months (range, 6-126). The median time to PSA nadir after EBRT was 14 months. The median interval between EBRT and HDR-BT was 4 years (range, 1-14). After a median follow-up of six years from HDR-BT, 9 (52.9%) patients remained free of local recurrence, and 11 (64.7%) were recurrence-free in the treated region. In terms of toxicity, one patient experienced chronic grade 4 genitourinary toxicity requiring cystectomy, but no acute or late gastrointestinal toxicity was observed. At last follow-up, 15 patients (88.2%) were alive.

Conclusions

In this long-term single-institution series, salvage HDR-BT demonstrates durable local control with acceptable toxicity in patients with local recurrence after prostatectomy and EBRT.