Patients with locally recurrent prostate cancer after definitive prostate brachytherapy have few evidence-based salvage options. We evaluate the efficacy and treatment-related side-effects of salvage external-beam radiotherapy (EBRT) after definitive prostate brachytherapy (PBT).

Eleven patients previously treated with definitive PBT and with biopsy-proven local-only recurrence received salvage reirradiation with EBRT. Genitourinary (GU) function was assessed with International Prostate Symptom Scores. Treatment-related toxicities were graded using CTCAE v 4.03.

Median follow-up was 26.5 months (range, 1-53.6 months); median age at EBRT salvage was 67 years (range, 61-81 years). Salvage EBRT included the whole pelvis in 8 patients. Two patients were treated with 3D-CRT; 9 underwent IMRT. Five patients (45%) received androgen deprivation therapy concurrent with salvage EBRT as part of long- or short-course hormone therapy. The median prostate dose was 70.2 Gy (range, 64.8-75.6 Gy). Actuarial 3-year overall and biochemical failure-free survival were 77% and 69%, respectively. Five patients (45%) had worsening GU symptoms, and 9 (82%) experienced a decline in erectile function. One patient experienced acute grade 2 GU toxicity. Four patients (36%) experienced late grade ≥2 GI/GU toxicities, including 2 who experienced grade 3 toxicities (rectourethral fistula/incontinence, bladder outlet obstruction). No grade 4/5 toxicities were noted.

Our data suggest that salvage EBRT can provide similar disease control and treatment-related toxicity to more established salvage therapies. This approach warrants further investigation on a larger scale.