13 Treatment of localised prostate cancer using a combination of high dose‐rate Ir‐192 brachytherapy (HDRB) and external beam radiation therapy (EBRT): a 7 year experience

Abstract

To June 2005, over 600 patients received HDRB treatment according to the Seattle protocols. It involves interstitial prostate dose of 1650–1800 cGy in three fractions and 24 h with EBRT 4500 cGy in 5 weeks. 98% of high and intermediate‐risk patients received concomitant 6–12 months androgen suppression. 237 patients were treated between April 1998 and April 2002. 232 patients were suitable for analysis – 158 high‐risk, 56 intermediate‐risk, 18 low‐risk. Minimum follow‐up was 3 years (median 56 months). 7‐year actuarial bNED outcomes were 84%, 94%, 100% using Houston Definition for biochemical failure. Kaplan–Meier estimates for disease‐specific survival failed to discriminate between the risk groups (P = 0.15) and negated the clinical impact of adverse cancer presentation. There were four deaths due to prostate cancer in high‐risk group. Overall cause‐specific survival was 98%, overall survival 93%. HDRB/EBRT treatment toxicity was minimal. RTOG late GI toxicity was less than 1%. Overall RTOG late GU toxicity was 10%. 7/24 G3/G4 injuries occurred within 3–24 months of acute G2 toxicity suggestive of a consequential late effect. One G4 late injury, urethral necrosis, was related to early TURP; the other G4 represented focal bladder base necrosis. There were 13 G3 toxicities. One patient was G3 classified due to early TURP (3 months) with resultant incontinence and permanent IDC. Eight late G2 effects were managed with up to 12 months of alpha‐blockade. Erectile dysfunction occurred in 56% initially potent men postirradiation and testosterone recovery. HDRB/EBRT dose escalation is safe and efficacious and dedicated urology‐radiation oncology team is critical.