Stereotactic body radiation therapy improves bowel health-related quality of life for patients with localized intermediate-risk prostate cancer compared to moderately hypofractionated intensity-modulated radiation therapy, according to findings from the NRG-GU005 clinical trial published in the Journal of the American Medical Association.
NRG-GU005 Trial Design and Patient Demographics
The Phase III NRG-GU005 trial evaluated 698 evaluable patients diagnosed with intermediate-risk prostate cancer. According to trial documentation, participants were randomized to receive either stereotactic body radiation therapy at 36.25 Gy delivered across 5 fractions, or intensity-modulated radiation therapy at 70 Gy across 28 fractions or 60 Gy across 20 fractions. The study featured co-primary endpoints examining disease-free survival and health-related quality of life, with the latter evaluated through the bowel and urinary irritative or obstructive domains of the EPIC-26 instrument.
Bowel Health Improvements and Quality of Life Metrics
Patient-reported outcomes showed that fewer individuals in the stereotactic body radiation therapy arm experienced a minimally clinically important difference in bowel health-related quality of life at two years compared to those receiving intensity-modulated radiation therapy, at 34.9% versus 43.8% with a p-value of 0.034, according to the study data. Longitudinal models demonstrated that the radiation therapy technique paired with rectal spacers led to improved bowel domain scores. However, the trial did not meet its overall health-related quality of life co-primary endpoint because urinary irritative or obstructive symptom domains showed no significant difference between the two cohorts, with 33.7% for stereotactic body radiation therapy versus 34.7% for intensity-modulated radiation therapy, according to trial findings.
Did you know? The NRG-GU005 trial was supported by grants from the National Cancer Institute, part of the National Institutes of Health, including support through the National Clinical Trials Network.
Disease-Free Survival and Clinical Implications
The disease-free survival co-primary endpoint was reported early due to futility of superiority, which researchers attributed solely to higher biochemical failure determined by prostate-specific antigen levels in the stereotactic body radiation therapy arm, according to lead author Rodney J. Ellis, MD, from the University of South Florida. While the trial was categorized as not positive overall, secondary genitourinary endpoints indicated that stereotactic body radiation therapy was associated with lower incontinence-related quality of life impacts and improved maintenance of erectile dysfunction compared to moderately hypofractionated intensity-modulated radiation therapy, as stated by Ellis.
Pro Tip: Radiation oncology practices utilize patient-reported outcomes from trials like NRG-GU005 and PACE-B to counsel intermediate-risk prostate cancer patients on the trade-offs between different hypofractionated delivery schedules and toxicity risks.
Frequently Asked Questions
What was the main finding of the NRG-GU005 clinical study?
According to published results in JAMA, stereotactic body radiation therapy improved bowel health-related quality of life compared to moderately hypofractionated intensity-modulated radiation therapy, though it did not show significant improvement in urinary quality of life or disease-free survival.
How many patients participated in the trial?
The Phase III trial enrolled 698 evaluable patients with localized intermediate-risk prostate cancer, according to study records.
Did the trial meet its co-primary endpoints?
No, the trial’s health-related quality of life co-primary endpoint was not met because urinary irritative and obstructive symptoms showed no significant difference between treatment arms, and disease-free survival crossed the futility boundary early.
Who led the NRG-GU005 trial?
The trial was led by NRG Oncology, conducted via the National Clinical Trials Network, and featured Dr. Rodney J. Ellis as the lead author of the abstract.
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