The hypo-FLAME trial showed that once-weekly (QW) focal boosted prostate stereotactic body radiotherapy (SBRT) is associated with acceptable acute genitourinary (GU) and gastrointestinal (GI) toxicity. Currently, we investigated the safety of reducing the overall treatment time (OTT) of focal boosted prostate SBRT from 29 to 15 days.
Patients with intermediate- and high-risk prostate cancer were treated with SBRT delivering 35 Gy in 5 fractions to the whole prostate gland with an iso-toxic boost up to 50 Gy to the intraprostatic lesion(s) in a semi-weekly (BIW) schedule. The primary endpoint was radiation-induced acute toxicity (CTCAE v5.0). Changes in quality of life (QoL) were examined in terms of proportions achieving a minimal clinically important change (MCIC). Finally, acute toxicity and QoL scores of the BIW schedule were compared with the results of the prior QW hypo-FLAME schedule (n = 100).
Between August 2020 and February 2022, 124 patients were enrolled and treated BIW. No grade ≥ 3 GU or GI toxicity was observed. The 90-days cumulative incidence of grade 2 GU and GI toxicity rates were 47.5% and 7.4%, respectively. Patients treated QW scored significant less grade 2 GU toxicity (34.0%, p = 0.01). No significant differences in acute GI toxicity were observed. Furthermore, patients treated QW had a superior acute bowel and urinary QoL.
Semi-weekly prostate SBRT with iso-toxic focal boosting is associated with acceptable acute GU and GI toxicity. Based on the comparison between the QW and BIW schedule, patients should be counselled regarding the short-term advantages of a more protracted schedule.
Radiotherapy and oncology : journal of the European Society for Therapeutic Radiology and Oncology. 2023 May 11 [Epub ahead of print]
Lisa De Cock, Cédric Draulans, Floris J Pos, Sofie Isebaert, Robin De Roover, Uulke A van der Heide, Robert J Smeenk, Martina Kunze-Busch, Jochem van der Voort van Zyp, Hans de Boer, Linda G W Kerkmeijer, Karin Haustermans
Department of Oncology, KU Leuven, Leuven, Belgium. Electronic address: ., Department of Oncology, KU Leuven, Leuven, Belgium. Electronic address: ., Department of Radiation Oncology, The Netherlands Cancer Institute, Amsterdam, The Netherlands. Electronic address: ., Department of Oncology, KU Leuven, Leuven, Belgium; Department of Radiation Oncology, University Hospitals Leuven, Leuven, Belgium. Electronic address: ., Department of Radiation Oncology, University Hospitals Leuven, Leuven, Belgium. Electronic address: ., Department of Radiation Oncology, The Netherlands Cancer Institute, Amsterdam, The Netherlands. Electronic address: ., Department of Radiation Oncology, Radboud University Medical Center, Nijmegen, The Netherlands. Electronic address: ., Department of Radiation Oncology, Radboud University Medical Center, Nijmegen, The Netherlands. Electronic address: ., Department of Radiation Oncology, University Medical Center, Utrecht, The Netherlands. Electronic address: ., Department of Radiation Oncology, University Medical Center, Utrecht, The Netherlands. Electronic address: ., Department of Radiation Oncology, Radboud University Medical Center, Nijmegen, The Netherlands; Department of Radiation Oncology, University Medical Center, Utrecht, The Netherlands. Electronic address: ., Department of Oncology, KU Leuven, Leuven, Belgium; Department of Radiation Oncology, University Hospitals Leuven, Leuven, Belgium. Electronic address: .