High-dose-rate (HDR) brachytherapy boost in combination with external beam radiotherapy for localized prostate cancer: An evidence-based consensus statement

Abstract

PURPOSE: This guideline presents evidence-based consensus recommendations for high-dose-rate (HDR) brachytherapy boost in combination with external beam radiotherapy (EBRT) for the primary treatment of localized prostate cancer. METHODS AND MATERIALS: The American Brachytherapy Society convened a task force for addressing key questions concerning prostate HDR brachytherapy boost with EBRT for the primary treatment of localized prostate cancer. A comprehensive literature search was conducted to identify prospective and large retrospective studies involving HDR brachytherapy combined with EBRT. Outcomes of interest included biochemical and/or disease control, toxicity, patient-reported quality of life, and the role of androgen deprivation therapy. RESULTS: HDR brachytherapy using Ir-192 in combination with EBRT is an appropriate treatment option for men with intermediate- and high-risk prostate cancer. CT, ultrasound, and/or MRI are imaging platforms that may be utilized for treatment planning and delivery. A single implant/fraction of 15 Gy or 2 implants/fractions of 9.5-11 Gy each are acceptable regimens in combination with EBRT at a dose equivalent of 45-50.4 Gy in 1.8-2.0 Gy fractions. The addition of HDR brachytherapy is expected to improve biochemical control compared with dose escalated EBRT alone. HDR brachytherapy boost is expected to achieve similar biochemical control outcomes as a low dose rate (LDR) brachytherapy boost. Androgen deprivation therapy is recommended for men with unfavorable intermediate and high-risk disease, with varying duration dependent on cancer risk. Use of an HDR brachytherapy technique, as opposed to LDR permanent seeds, has been shown to have less acute genitourinary (GU) and gastrointestinal (GI) toxicity following treatment. CONCLUSIONS: For men with intermediate- and high-risk prostate cancer, HDR brachytherapy boost is a safe and effective technique for dose-escalation that can achieve superior biochemical control compared with EBRT alone, possibly with an improved GU and GI side effect profile compared with an LDR brachytherapy technique.