[Brachytherapy for prostate carcinoma]

Abstract

This review aims to provide an overview of prostate brachytherapy and disseminate consensus guidelines formed by the American Brachytherapy Society. In Japan, permanent transperineal prostate brachytherapy with I-125 started in September 2003. Patients with high probability of organ-confined disease are appropriately treated with brachytherapy. Brachytherapy candidates with a significant risk of extraprostatic extension should be treated with supplemental external beam radiation therapy. The recommended prescription doses for monotherapy are 145 Gy. The corresponding boost doses after 40-50 Gy of external beam are 100-110 Gy. Dosimetric planning of the implant should be carried out for all patients before seed insertion. Post-implant dosimetry and evaluation must be performed on all patients. A dose-volume histogram of the prostate should be performed. The dose that covers 90% of the prostate volume, the percentage of prostate volume receiving 100%, 150%, and 200% of the prescribed dose, and the rectal dose and urethral dose should be reported. ABS recommends standardization of the reporting of brachytherapy-related prostate morbidity, including urinary, rectal, and sexual function. These morbidities should be correlated with the doses to normal tissues. High-dose-rate (HDR) brachytherapy with Ir- 192 has preceded seed implants in Japan. HDR has some theoretical advantages. We should develop techniques of both types of brachytherapy in Japan.