Permanent prostate brachytherapy-induced morbidity in patients with grade II and III obesity.

OBJECTIVE

To determine the influence of obesity on the development of urinary, bowel, and sexual dysfunction after brachytherapy by means of patient-administered questionnaires. The effect of obesity on dosimetric quality and biochemical outcome was also evaluated.

METHODS

Thirty-two patients with grade II and III obesity underwent brachytherapy from June 1997 through April 2001. Grade II and III obesity was defined as a body mass index of 35.0 to 39.9 and 40.0 kg/m2 or greater, respectively. Serial International Prostate Symptom Score (IPSS) evaluations were obtained at predetermined intervals. Bowel and sexual function were assessed by a rectal function assessment score (R-FAS) and the specific erectile questions of the International Index of Erectile Function (IIEF). The median follow-up was 26.4 months. An alpha-blocker was initiated before implantation and continued at least until the IPSS normalized. Catheter dependency, alpha-blocker dependency, and the incidence of urethral strictures were also evaluated. The efficacy of sildenafil in brachytherapy-induced erectile dysfunction was also evaluated. Dosimetric parameters evaluated included the percentage of the prostate receiving 100%, 150%, and 200% of the prescribed dose (V100, V150, and V200), the minimal dose received by 90% of the prostate (D90), urethral doses, and rectal doses. Biochemical outcome was determined by the ASTRO consensus conference definition.

RESULTS

Of the 32 patients, 31 (97%) had the urinary catheter permanently removed on day 0, and no patient required a urinary catheter for longer than 1 day. One patient developed a urethral stricture. No patient required a transurethral resection or developed urinary incontinence. On average, the IPSS peaked 2 weeks after implantation and returned to baseline at a median of 8 weeks (mean 16). The post-treatment R-FAS was 3.6. No patient developed a rectal ulcer or fistula. Of the 22 patients who were potent before implantation, 7 (31.8%) maintained potency. With pharmacologic support, 59.1% maintained erections sufficient for vaginal penetration. Day 0 dosimetry demonstrated a median V100 and D90 of 96.5% and 113.5%. At last follow-up, all patients remained free of biochemical failure, with a median prostate-specific antigen level of 0.1 ng/mL.

CONCLUSIONS

No difference in quality-of-life parameters was discerned in patients with grade II and III obesity. In addition, the dosimetric quality of the implants was outstanding, and the short-term biochemical outcome was encouraging.