Salvage brachytherapy and short-term androgen deprivation therapy for locally recurrent prostate cancer after external beam irradiation

Abstract

4788 Background: Patients (pts) who develop local relapse of prostate cancer after external beam irradiation (EBRT) are often treated with androgen deprivation therapy (ADT) because of their advanced age and co-morbid conditions. Salvage treatment with curative intent may be considered in selected pts. We have treated 13 pts with combined brachytherapy (BT) and short-term ADT between 1999 and 2002. Methods: The median pre-EBRT PSA was 12 ng/ml (range: 4–24 ng/ml) and the median dose of prior EBRT was 68 Gy. At the time of biochemical (6 pts) or palpable local failure (7 pts), prostate biopsy was obtained to confirm local relapse. The median time between EBRT to biopsy was 5.9 years. Bone scans and CT scans were negative for metastasis. Five pts were treated on a protocol that combined 3 months of neoadjuvant and 6 months of adjuvant leuprolide with I-125 BT. The prescribed dose was 126 Gy. Another 8 pts were treated with neoadjuvant leuprolide (median: 4 months) before Pd-103 BT. The prescribed dose was 103.5–112.5 Gy. The ASTRO definition of biochemical failure (PSAF) was used. Toxicity was graded by a modified RTOG scale. Results: The median age of was 67 (range: 62–80). The Gleason score of the biopsies at relapse were 6 (5 pts), 7 (5 pts), 8 (2 pts), and 9 (1 pt). The median PSA at the time of relapse was 4.7 ng/ml (range: 1.2–11.8 ng/ml). The median follow-up time was 34 months (range:13–60 months). Two pts developed PSAF, and the 4-year actuarial biochemical control rate was 79%. The were no clinically apparent local or distant failures. One pt died of intercurrent disease. Grade 3 GU toxicity developed in 5 pts (38%), requiring minor surgical procedures. One pt (8%) had grade 4 GU toxicity, resulting in an ileal conduit. No patient developed grade 3 GI toxicity. On univariate analysis, biochemical control was not significantly associated with Gleason score, PSA or T-stage at time of local relapse, probably due to the small number of pts. Conclusions: Our series suggests that biochemical control can be achieved with salvage brachytherapy and short-term ADT in selected patients with local relapse after prior EBRT. The treatment resulted in 38% grade 3 and 8% grade 4 GU toxicity. No significant financial relationships to disclose.