Salvage brachytherapy for prostate bed recurrence following radical prostatectomy.

218 Background: Approximately 10% of patients who undergo a radical prostatectomy (RP) for localized prostate cancer subsequently experience a local recurrence. A small percentage of these patients present with prostate bed nodules (PBN). We present here, a case series of 12 patients treated with low dose rate brachytherapy (BT) for a PBN post RP. METHODS All 12 patients had biopsy confirmed cases of recurrent adenocarcinoma in the prostatic bed. At the time of PBN diagnosis, 2 patients had received EBRT, 2 patients had received ADT, and 1 patient had undergone HIFU. Patients were confirmed to have a negative CT and bone scan prior to salvage BT. All patients received salvage BT with I-125 prescribed to 144 Gray. RESULTS The median interval between RP and BT was 8 years (range 0.5- 17.9), median PSA prior to BT was 4.53 ng/ml (range 0.55-15.2), and the median age was 69 (range 59-86). Forty-two percent of patients had a PBN Gleason score of 8, 33% had a score of 7, and a score was not reported for 25% of patients due to prior EBRT or ADT use. The median follow up for this series is 26.5 months (range 1-69). At the time of this analysis, 10 patients were evaluable for biochemical failure (bF) (nadir+2) and distant metastases (DM). The one and two year rates of bF were 0% and 52%. There was no association between pre-BT PSA and bF, nor between pre-BT Gleason score and bF. Two patients subsequently developed DM at 17 months and 55 months after BT. The pelvic lymph nodes were the site of DM for both patients. The median PSA velocity post BT was -0.120 ng/ml/yr (range -1.404- 9.096). Five patients had a negative PSA velocity at last follow-up, while 4 had an increasing PSA velocity. Velocity could not be defined for 3 patients (insufficient PSA n=2, ADT n=1). To date, no gastrointestinal or urinary toxicities have been noted. CONCLUSIONS Brachytherapy as a salvage treatment for a PBN appears to be well tolerated. The rates of bF and DM following salvage BT are comparable to those of salvage EBRT for this patient population. Intermediate-term biochemical control was attained in a sub-set of patients with declining PSA at last follow-up.