Previous Transurethral Resection of the Prostate Is Not a Contraindication for Interstitial High-Dose-Rate Brachytherapy for Prostate Cancer

Abstract

Purpose: Transrectal ultrasound (TRUS)-guided interstitial implant for prostate cancer using low-dose-rate (LDR) and high-dose-rate (HDR) technique has been reported with results comparing favorably to surgery and external beam radiation therapy (EBRT). Previous TURP has been considered a relative contraindication for LDR permanent seed implant because of higher rates of urinary incontinence. There are little data on previous TURP and subsequent incontinence after HDR implant. We report our urinary incontinence results with HDR with or without previous TURP. Materials and Methods: Between 1997 and 2009, 410 patients with T1 and T2 localized prostate underwent TRUS guided interstitial implant. There were no Gleason score or PSA exclusions. After discussion of treatment options, 109 patients elected HDR Implant + IMRT and 301 patients underwent HDR monotherapy. No patient received hormonal blockade. Median Gleason score was 7 (range: 4 to 10). Median PSA was 9.8 (0.60 to 39.8). IMRT treatment volume included the prostate + seminal vesicles + 2 cm margin. Implant treatment volumes ranged from 32 cm3 to 196 cm3. In patients who received IMRT + HDR, 4500 cGy in 25 fractions was given via IMRT and 1650 cGy to 2000 cGy in 3 fractions via HDR. Our protocol for HDR alone, has called for two HDR implants. The treatment volume received 2,250 cGy in 3 fractions prescribed to the 100% isodose line, given over 24 hours. A 2nd implant was performed 4 weeks later, delivering a further 2,250 cGy in 3 fractions, bringing the final dose to the prostate to 4,500 cGy in 6 fractions. Urethral dose points (12-16) were followed, and limited to ≤105% of the prescription dose. Care was also taken to limit dose to the bladder sphincter regions. Results: There was no significant difference between the treatment groups with respect to T-Stage, Gleason score, and PSA. With a median followup of 96 months (range: 6 months to 156 months), urinary stress incontinence has occurred in 2.9% (12/410). Previous TURP was performed in 62 patients. Incontinence has developed in 3.2% (2/62) undergoing previous TURP vs. 2.9% (10/348) in the non-TURP group (p=0.70). RTOG late bladder toxicities were: 0% Grade 4, 0% Grade 3, and 2.9% (12/410) Grade 2. Urinary stress incontinence has occurred in 3.1% (9/301), undergoing HDR alone, vs. 2.8% (3/109) treated with HDR + IMRT (p = 0.60). Conclusions: Urinary stress incontinence after HDR implant occurs in rates comparable to LDR implant. Previous TURP is not a contraindication to HDR implant for prostate cancer.