ViewRay highlighted results from its phase III Magnetic Resonance Imaging-Guided Stereotactic Body Radiotherapy for Prostate Cancer (MIRAGE) trial at the recent American Society for Radiation Oncology (ASTRO) annual meeting in San Antonio.
The trial compared MRIdian MRI-guided stereotactic body radiation therapy (SBRT) with CT-guided SBRT for localized prostate cancer in 156 patients. A team led by Dr. Amar Kishan of the University of California, Los Angeles (UCLA) found that MRI guidance significantly reduced acute grade ≥ 2 genitourinary and gastrointestinal toxicity. This included genitourinary toxicity rates of 24.4% in the MRI group compared with 43.4% in the CT group and gastrointestinal toxicity rates of 0% in the MRI group compared with 10.5% in the CT group.
The MRI-guided arm of the trial was associated with a 60% reduction in odds of grade ≥ 2 genitourinary toxicity, ViewRay said. Significantly more patients receiving CT-guided SBRT experienced increases in urinary symptoms, at 19.4% compared with 6.8% in the MRI group. Similarly, a significantly greater percentage of patients in the CT-guided arm experienced a clinically notable decrease in bowel-related quality of life: 50% compared with 25% in the MRI group, according to the firm.
