Updated results of MR-assisted focal salvage HDR prostate brachytherapy: a prospective study

Focal salvage high dose-rate (HDR) prostate brachytherapy has emerged as a standard option for radiorecurrent prostate cancer. However, long-term prospective data remains limited. Our prospective study aimed to explore the toxicities, health-related quality of life (HRQOL) and efficacy of focal salvage HDR prostate brachytherapy. This report represents the updated results of the final cohort of patients. Patients with biopsy-confirmed, MR-visible local recurrent prostate cancer after previous external-beam radiotherapy (XRT) and/or brachytherapy were eligible. MR-assisted, ultrasound-based focal HDR prostate brachytherapy with a prescription dose of 27 Gy in 2 fractions separated by 1-2 weeks apart was delivered. Adjuvant androgen deprivation therapy (ADT) was not used. 59 patients were enrolled in the study. Median follow up from salvage HDR was 54 months (11-132). The initial treatment was XRT only in 20 (34 %) and brachytherapy +/- XRT in 39 (66 %). The pre-HDR median PSA was 4.13 ng/mL (1.30-11.63). Twenty-five (42 %) were staged with a PSMA PET scan. One patient (1.7 %) required temporary urinary catheterization. There was only 1 grade 3-5 toxicity, a late grade 3 GU toxicity. Three-year biochemical failure-free survival and freedom from ADT or repeat salvage therapy rate was 54 % and 82 %, respectively. Of the 55 patients who had a post-HDR MRI (median 464 days), 46 (84 %) patients had a complete response and 9 had persistent disease. 8 (15 %) patients recurred elsewhere in the prostate. Our toxicity and PSA failure-free results suggest that focal gland salvage HDR brachytherapy is well tolerated and effective. gov identifier NCT01583920.