Long-term urinary function after transperineal brachytherapy for patients with large prostate glands

Abstract

Purpose: To summarize longer-term postbrachytherapy morbidity in patients with prostate glands >50 cm3.

Methods and materials: From 1997 to 1998, 33 patients with a transrectal ultrasound-based prostate volume >50 cm3 were treated at the University of Washington by 125I (144 Gy) or 103Pd (115 Gy) implantation for prostate carcinoma. These 33 patients comprised 7% of the total implant patient population. Twelve patients were treated with neoadjuvant androgen ablation before implantation. The (125)I source strength ranged from 0.34 to 0.5 mCi and the 103Pd source strength ranged from 1.1 to 1.4 mCi (pre-NIST-99). The total number of sources implanted was 94-223 (median 155). Despite the typical implant-related volume increase, the postimplant CT-defined prostate volumes were generally well-covered by the prescription isodose (median coverage 92%, range 80-100%). The preimplant urinary obstructive symptoms were quantified by the criteria of the American Urological Association.

Results: Of the 33 patients, 12 developed acute postimplant urinary retention, all presenting within 24 h of implantation. Patients who developed postimplant retention lasting >1 week were generally treated with intermittent self-catheterization. By 1 month, 85% of patients were catheter free. By 1 year, only 1 patient (4%) remained in urinary retention; the remainder of cases had resolved spontaneously. With follow-up of 1.7-2.6 years, the last American Urological Association scores were higher than the pretreatment scores in 15 patients and lower in 7 patients. No patient developed permanent urinary incontinence. Long-term changes in the American Urological Association scores were unrelated to whether the patient had been in urinary retention after implantation. Two patients developed rectal fistulas; they had preimplant transrectal ultrasound prostate volumes of 53 and 59 cm3, in the low range for this group of patients. No other patient had persistent rectal bleeding suggestive of clinically significant proctitis. The pretreatment serum prostate-specific antigen level was 3.3-15 ng/mL (median 7.2) and the last serum prostate-specific antigen level 0.1-1.6 ng/mL (median 0.2).

Conclusion: Patients with larger prostate volumes appear to have moderate morbidity and a satisfactory technical outcome with brachytherapy. We do not believe the occurrence of two severe rectal complications was related to the prostate volume per se. Our experience and that of others calls into question the validity of using prostate volume as a criterion for patient suitability for prostate brachytherapy.