Brachytherapy boost improves survival and decreases risk of developing distant metastases compared to external beam radiotherapy alone in intermediate and high risk group prostate cancer patients

Marcin Miszczyk ,Piotr Wojcieszek,Tomasz Krzysztofiak,Rafał Suwiński ,J Sadowski ,Zuzanna Nowicka ,Marta Gmerek ,Barbara Czapla ,Paweł Rajwa ,Oliwia Masri ,Franciszek Cichur ,Iwona Jabłońska ,Jakub Ciepał ,Małgorzata Masri ,Gabriela Depowska ,Gregor Goldner ,Łukasz Magrowski ,Gabriela Bylica ,Wojciech Majewski ,Krystyna Chimiak ,Konrad Stawiski ,Rafał Stando ,Matthias Moll

doi:10.1016/j.radonc.2023.109632

Marcin Miszczyk , Piotr Wojcieszek + Show 21 more

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https://doi.org/10.1016/j.radonc.2023.109632

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Abstract

Background and purposeDespite several prospective trials showing a clinical benefit of combining external beam radiotherapy (EBRT) with brachytherapy boost (BTB) for the treatment of intermediate- and high-risk prostate cancer (PCa) patients, none of these trials was designed to test for a survival difference. In this study, we aimed to collect a large multi-institutional database to determine whether BT boost was associated with a statistically significant improvement in survival and a reduction of distant metastases based on real-world data. Material and methodsWe collected the data of patients treated for intermediate- or high-risk PCa with definitive EBRT or BTB, with or without androgen deprivation therapy (ADT), between January 2003 and December 2014 at two tertiary institutions. The statistical endpoints included overall survival (OS), freedom from distant metastases (FFDM), and metastases-free survival (MFS). The impact of treatment modality was assessed using Cox regression models and log-rank testing after one-to-one propensity score matching. ResultsA total of 1641 patients treated with EBRT (n = 1148) or high-dose-rate BTB (n = 493) were analyzed. The median survival and clinical follow-up were 117.8 (IQR 78–143.3) and 60.7 months, respectively. The radiotherapy modality (BTB) remained an independent prognostic factor for OS (HR 0.75; 95% CI 0.63–0.88; p < 0.001), FFDM (HR 0.54; 95% CI 0.4–0.73; p < 0.001), and MFS (HR 0.72; 95% CI 0.61–0.85; p < 0.001). After propensity score matching, the remaining 986 patients were well-balanced in terms of age, maximum PSA, ISUP grade group, and TNM T stage. OS (p < 0.001), FFDM (p = 0.001) and MFS (p < 0.001) were significantly higher in the BTB group. ConclusionsThere is a strong positive association between BTB and OS, FFDM, and MFS in PCa patients treated with definitive RT for intermediate- or high-risk PCa.

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