Clinical and Translational Radiation Oncology · Published 2026-07-25 · DOI 10.1016/j.ctro.2026.101240
Abrahams Ocanto, María González, Macarena Teja, Gloria Guardia, Gloria Sánchez, Daniela Gonsalves, Castalia Fernández, Lisselott Torres, Luis Glaría, Israel Thuissard, Miren Gaztañaga, José García, Sigfredo Elías Romero Zoghbi, Jon Andreescu, Álvaro Flores, Maia Dzhugashvili, David Esteban, Evita Krumina, Loubna Aaki, Jaume Fernández, José González, Antonio Ristori, José Begara, Daniel Rivas, Jasuani Bravo, Ana Vílchez, Luis Clemente, Juan Martínez-Salamanca, Luca Nicosia, Filippo Alongi, Andrew Loblaw, Fernando López-Campos, Felipe Couñago
Background and Purpose: Magnetic resonance-guided radiotherapy (MRgRT) enables reduced treatment margins, real-time motion management, and daily online adaptation for prostate stereotactic body radiotherapy (SBRT). However, prospective evidence on fully adaptive workflows remains limited. We evaluated the feasibility, early safety, and patient-reported outcomes of online adaptive MR-guided SBRT for localized prostate cancer. Materials and Methods: In this prospective single-center study, 108 patients with nonmetastatic prostate cancer were treated between July 2023 and July 2025 using a 0.35-T MR-Linac with daily online adaptive replanning and 2-mm planning target volume margins. Prescribed dose was 36.25 Gy in five fractions for low-risk disease, 36.25–40 Gy in five fractions for intermediate-risk disease, and 40 Gy in five fractions for high-risk disease. The primary endpoint was grade ≥ 2 genitourinary (GU) or gastrointestinal (GI) adverse events according to CTCAE v4.03. Secondary endpoints included patient-reported outcomes using IPSS, EPIC-26, and EORTC QLQ-C30 questionnaires, as well as biochemical response. Results: Median age was 74 years (IQR 68–81); 62% of patients had intermediate-risk disease, 15% had high-risk disease, and 31% received androgen deprivation therapy. At 2 weeks after treatment, grade ≥ 2 GU adverse events occurred in 22%, whereas grade ≥ 2 GI adverse events occurred in 1%. At 3 months, grade ≥ 2 GU adverse events declined to 3%, with no grade ≥ 2 GI events, and remained low at 6 months. Patientreported urinary, bowel, sexual, and global quality-of-life outcomes were largely preserved over time. At a median follow-up of 12 months, median PSA decreased from 8.56 to 0.76 ng/mL, and no biochemical failures were observed. Conclusion: Online adaptive MR-guided SBRT was feasible and associated with low rates of clinically significant adverse events and limited short-term deterioration in patient-reported quality of life. Longer follow-up is required to determine long-term safety and oncological outcomes.
Abstract from DOAJ. Public domain (CC0 1.0).
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Ocanto, A., González, M., Teja, M., et al. (2026). Early outcomes of online adaptive MR-guided SBRT for localized prostate cancer: a prospective study. Clinical and Translational Radiation Oncology. https://doi.org/10.1016/j.ctro.2026.101240