Outcomes of patients with localized prostate cancer treated with combined external beam radiotherapy and high-dose-rate brachytherapy boost: A single-center retrospective study

Abstract Background Temporary prostate brachytherapy, in combination with external beam radiotherapy (EBRT), is an established and evolving treatment technique for non-metastatic, intermediate and high-risk prostate cancer. This study aimed to evaluate the outcomes of patients with localized intermediate and high-risk prostate cancer treated with combined EBRT and high-dose-rate brachytherapy boost (HDR-BT) at a single centre. Patients & Methods A retrospective review of patients who underwent EBRT and HDR-BT treatment between January 2015 and December 2020. Patient and tumor characteristics, treatment outcomes (Kaplan-Meier analysis), and toxicities were analysed. Results 127 patients with intermediate (28.3%) or high-risk (71.7%) prostate cancer were included. Median follow-up was 42 months. Five-year bDFS, CSS and OS rate was 77.5%, 98.1% and 93.0%, respectively, with no significant difference between risk groups. The most frequent toxicity was acute grade 1 urinary obstruction (7.9%). One patient experienced acute and late grade 3 urinary obstruction. No grade ≥4 were observed. Conclusions Combined EBRT and HDR-BT demonstrated favourable disease control rates and manageable toxicities in patients with localized intermediate and high-risk prostate cancer. The 5-year bDFS rate was consistent with previous studies, supporting the effectiveness of this treatment approach. The low incidence of toxicities highlights the conformality and biological efficiency of HDR-BT boost. This treatment strategy provides an effective, safe and convenient option for this group of patients. To the best of our knowledge, this is the first report of the use of helical tomotherapy based intensity-modulated radiation therapy in combination with prostate HDR-BT (81.1% of cases).