ABSTRACT
PURPOSE: Evaluate the feasibility and toxicity of radiation dose escalation delivered with a single fraction high-dose-rate (HDR) brachytherapy boost followed by external beam radiotherapy for intermediate and high risk localized prostate cancer - a retrospective study. PATIENTS AND METHODS: Between December 2004 and December 2008, 61 patients with intermediate risk or high-risk localized prostate cancer received a single 10 Gy fraction of interstitial HDR brachytherapy followed by a 64 Gy course of external beam radiation therapy. Dose volume histograms, conformity index and side effects were systematically analyzed. RESULTS: HDR brachytherapy dosimetric criteria were respected. Early side effects (< or = 3 months after full treatment): 30 % reported grade 2 or grade 3 urinary toxicity and 26 % reported grade 2 or grade 3 bowel toxicity were reported. Late side effects (> 3 months): 12 % reported grade 2 or grade 3 urinary toxicity and 5 % reported grade 2 or grade 3 bowel toxicity were reported. No patients reported any grade 4 late toxicity events. Three months after treatment, 7 % grade 1, 25 % grade 2 and 39 % grade 3 erectile dysfunction were reported. CONCLUSION: Our monofractionation protocol is an easy technique to implement logistically. Acute and late toxicities are acceptable and comparable to those published by various teams mostly using multifractionation protocols. A longer follow-up is required to assess the effect of this dose escalation protocol on long-term biological control.
