Combination conformal radiotherapy and radioimmunoguided transperineal 103Pd implantation for patients with intermediate and unfavorable risk prostate adenocarcinoma

Purpose To report outcomes for prostate cancer patients treated with external beam radiation therapy (EBRT) and permanent prostate brachytherapy utilizing radioimmunoguided targeting of biological tumor volumes (BTVs). Methods and materials Between February 1997 and October 2001, 66 patients with intermediate- to high-risk prostate cancer underwent EBRT and ProstaScint®-guided transperineal brachytherapy. Thirty patients received neoadjuvant hormonal manipulation, while 36 patients did not. Median patient age was 66 years (range, 49–78 years). The median follow-up was 41 months (range, 24–78 months). No patients were lost to follow-up. Risk factors (RF) used for risk stratification included PSA >10 ng/ml (35 patients), Stage T2b or greater (22 patients), and Gleason score 7 (55 patients). Results for biochemical disease free survival (bDFS) were reported using the ASTRO consensus definition for biochemical failure, PSA 1.0 ng/mL or PSA 0.5 ng/mL. Survival was estimated by the Kaplan–Meier method. Results Five-year overall survival was 93.1% and 5-year bDFS by the ASTRO definition was 89.3% with a median follow up of 41 months. Patients with intermediate- (1 RF) and high-risk (2–3 RF) prostate cancer exhibited 5-year ASTRO-defined bDFS of 100% and 81.9%, respectively. There was no significant difference in bDFS between the patients treated with or without hormone therapy (HT). The 5-year ASTRO-defined bDFS was 89.8% for the 30 patients treated with HT and 88.9% for the 36 patients who did not receive HT (p = 0.843). For the patients without HT the median PSA nadir was 0.11 ng/mL. The median time to nadir was 23 months (range, 6–66 months). Conclusions With limited follow-up, the results of EBRT plus radioimmunoguided brachytherapy for intermediate- to high-risk prostate cancer appear favorable. The addition of HT did not appear to affect bDFS significantly, but interpretation is confounded by possible selection bias and the limited power of this study.