HERMES: Randomized Trial of 2-Fraction or 5-Fraction Magnetic Resonance Imaging–Guided Adaptive Prostate Radiation Therapy
Year: 2025
Type: article
Study design: Clinical Trial
Abstract: PURPOSE: To demonstrate the safety and feasibility of 2-fraction stereotactic body radiation therapy (SBRT) for prostate cancer. METHODS AND MATERIALS: This single-center, noncomparative, phase 2/R-IDEAL 2b trial randomized 46 patients with intermediate/lower high-risk prostate cancer with visible gross tumor volume on multiparametric magnetic resonance imaging to receive 36.25 Gy in 5 fractions over 10 days or 24 Gy in 2 fractions with a gross tumor volume boost up to 27 Gy over 8 days. All treatment was delivered on a magnetic resonance linac with daily adaptive replanning. The primary endpoint was acute grade ≥2 (G2+) genitourinary (GU) toxicity (Common Terminology Criteria for Adverse Events version 5.0). Secondary endpoints include gastrointestinal (GI) toxicity and patient-reported outcomes. RESULTS: G2+ GU acute toxicity was observed in 6 of 22 patients (27.3%; 95% CI, 0.11-0.50) in the 2-fraction group and 7 of 24 patients (29.2%; 95% CI, 0.13-0.50) in the 5-fraction group. There were no grade 3 GU toxicities. G2+ urinary frequency rose from 4.5% (1 of 22) at week 2 to 13.6% (3 of 22) at week 4 in 2-fraction SBRT. G2+ urinary frequency peaked earlier in 5-fraction SBRT at 16.7% (4 of 24) in week 2, falling to 12.5% (3 of 24) at week 4. At 12 weeks, median Expanded Prostate Cancer Index Composite-26 urinary incontinence score was 85.5 (IQR, 75-100) for 2-fraction SBRT and 100 (IQR, 93.8-100) for 5-fraction SBRT. Urinary irritative-obstructive scores were higher at 12 weeks in the 2-fraction group (93.8; IQR, 87.5-100) than in the 5-fraction group (87.5; IQR, 81.3-93.8). Peak International Prostate Symptoms Score was lower in the 2-fraction group (8; IQR, 4-11) than in the 5-fraction group (13.5; IQR, 10-17). G2+ GI acute toxicity occurred in 3 of 24 (6.8%) after 5-fraction SBRT, but none after 2-fraction SBRT. CONCLUSIONS: Acceptable acute GU toxicity was seen after 2-fraction SBRT. Acute GI toxicity was low. Randomized trials are warranted to explore late toxicity and biochemical control.
Authors: Sian Cooper, Rosalyne L. Westley, Katie Biscombe, Alex Dunlop, Adam Mitchell, Uwe Oelfke, Simeon Nill, Georgina Manning, Stephanie Burnett, Julia Murray, Anna Wilkins, Nina Tunariu, Derek Price, Aidan Adkins, Angela Pathmanathan, Greta Bucinskaite, Shaista Hafeez, Chris Parker, Ragu Ratnakumaran, Helena Verkooijen, Sophie Alexander, Trina Herbert, Emma Hall, Alison C. Tree
Language: English
Subfield: Pulmonary and Respiratory Medicine
Field: Medicine
Domain: Health Sciences
Open Access status: hybrid
Estimated APC paid: $4,130
Funders: AstraZeneca, Francis Crick Institute, Elekta, Royal Marsden NHS Foundation Trust, NIHR Biomedical Research Centre, Royal Marsden NHS Foundation Trust/Institute of Cancer Research, Accuray, Veracyte, Cancer Research UK, National Institute for Health and Care Research, Elekta, Astellas Pharma, Siemens Healthineers, Jon Moulton Charity Trust, Genentech, Medical Research Council, Cilag
OpenAlex ID: W4410529917