Brachytherapy, another treatment option for patients with prostate cancer, is the implantation of radioactive isotopes into a body cavity or tissue.83 This mode of therapy is improved today with better isotopes (palladium-103), computed tomography and transrectal ultrasound. Potency rates after interstitial brachytherapy have generally been better than those for either radical prostatectomy or external beam radiation therapy. Brachytherapy potency rates have been reported between 47% and 97% in several studies.63'84-90 Factors that had negative impacts on postbrachytherapy potency were pretreatment erectile dysfunction, high implant dose (D90 ^ 160 Gy for I-125 and ^100 Gy for Pd-103), and short duration hormonal therapy of 5-6 months.89 No difference in postbrachyther-apy erectile dysfunction was noted between iodine-125 or palladium-103.91
The etiology of impotence after brachytherapy is thought to arise from either excessive radiation exposure to the neuro-vascular bundles92,93 or vascular etiologies.90 DiBiase et al. reported that the patients who developed early postimplant impotence had doses to the neurovascular bundles that far exceeded the average values.93
Sildenafil has proved successful in treating erectile dysfunction after interstitial brachytherapy as it has for radical prostatectomy and radiotherapy. Merrick etal. reported an 80% success rate in achieving erections sufficient for vaginal penetration after sildenafil use in brachytherapy patients.90 It was stated earlier that patients after bilateral nerve-sparing prostatectomy had a greater response to sildenafil. Here, too, brachytherapy patients have bilateral nerve integrity, which supports the vascular cause of impotence in these patients.
In terms of quality of life after brachytherapy, it compared well with radical prostatectomy. When brachytherapy was combined with external beam radiation therapy, sexual dysfunction did not improve over time.94 The dual therapy adversely affected patients' lives and reduced the frequency of satisfactory erections. Brachytherapy as monotherapy had similar results to radical prostatectomy in terms of sexual dysfunction.94
Was this article helpful?