Permanent prostate brachytherapy: lessons learned, lessons to learn.

Current techniques for permanent prostate brachytherapy are associated with excellent biochemical control in patients with localized prostate cancer. Data now available confirm 5- to 10-year results with this treatment modality that are comparable to those with external-beam irradiation or radical prostatectomy. Nonetheless, treatment protocols and techniques for prostate brachytherapy vary from center to center. Controversy exists regarding the selection of patients for brachytherapy alone or in combination with external-beam irradiation. The role of neoadjuvant androgen deprivation also remains undefined in patients with localized prostate cancer. Matched-pair analysis studies performed at Memorial Sloan-Kettering Cancer Center have examined the role of isotope selection, the addition of external-beam irradiation, and the use of neoadjuvant androgen deprivation. These studies provide insights into the use of permanent brachytherapy in patients with localized prostate cancer. In addition, postimplant dosimetry needs to be a requirement for centers performing seed implants. Data now appear to support specific computed tomography-based criteria to evaluate implant quality and delivered dose to the prostate. Unfortunately, prostate edema and poor imaging techniques limit the evaluation of implant dosimetry. Treatment planning techniques that utilize new imaging modalities, coupled with computerized treatment planning, may help improve the implant procedure and dosimetry.