Stereotactic Body Radiotherapy vs Moderately Hypofractionated IMRT for Localized Intermediate-Risk Prostate Cancer
Rodney J. Ellis, Stephanie L. Pugh, James B. Yu, Felix Y. Feng, Andre A. Konski, Robert L. Grubb, Robert E. Wallace, David J. Gladstone, Cynthia Ménard, Joseph A. Miccio, Arthur J. Frazier, J. Daniel Pennington, Jeff M. Michalski, Daniel E. Spratt, Alvaro Martinez, Scott C. Morgan, Alina Mihai, Abhishek Ashok Solanki, Asim Amjad, Michael W. Straza, Guila Delouya, Thomas M. Schroeder, David T. Marshall, Nirav Kapadia, Akshar N. Patel, Terrence P. Cescon, Ali El-Gayed, Harold A. Yoon, Rebecca Paulus, Howard M. Sandler,Importance
The treatment of prostate cancer with radiotherapy is evolving. How quickly radiotherapy can be delivered, and the relative risks and benefits of such a treatment, is of significant public interest.
Objective
To determine whether stereotactic body radiotherapy (SBRT) was superior to moderately hypofractionated intensity-modulated radiation therapy (MH-IMRT) in terms of patient-reported urinary irritative/obstructive and bowel quality of life and disease-free survival (DFS).
Design, Setting, and Participants
NRG-GU005 was a phase-3, international, open-label, randomized clinical trial. The study was activated on November 16, 2017, and closed to accrual on June 8, 2022. Date of last follow-up was October 13, 2024. There were 136 centers in Asia, Canada, Europe, and the United States that accrued patients to the study. Patients with localized prostate cancer, clinical stage T1-T2b with Gleason 3 + 4 (grade group 2) and prostate-specific antigen (PSA) level less than 20 ng/mL or Gleason 3 + 3 (grade group 1) and PSA level 10 to 20 ng/mL were eligible. Intended accrual of 692 patients provided reductions of 8% and 10% in minimal clinically important decline (MCID) frequency for urinary-irritative/obstructive and bowel domains of the Expanded Prostate Cancer Index Composite–26 Item (EPIC-26) instrument at 2 years and greater than 80% power to detect a hazard ratio of 0.62 in DFS.
Interventions
Patients were randomized 1:1 to receive SBRT (36.25 Gy in 5 fractions; n = 353) or MH-IMRT (70 Gy in 28 fractions or 60 Gy in 20 fractions; n =345).
Main Outcomes and Measures
Primary outcomes were the frequency of an MCID in the urinary irritative/obstructive and bowel domains of the EPIC-26 at 2 years and DFS at 3 years.
Results
A total of 698 patients were randomized. Median age was 68 years; 3% were Asian, 13% Black, and 80% White. Median follow-up was 3.2 years (range, 0-6.5). At 2 years, there was no significant difference in the urinary-irritative domain (35.4% vs 33.7%, P = .68). Urinary incontinence at 1 and 2 years after treatment and sexual function at 1 year after treatment favored SBRT. Fewer grade 3 + 4 genitourinary adverse events occurred in the SBRT vs MH-IMRT group (0.6% vs 2.5%, P = .04). There were significantly fewer MCIDs with SBRT vs MH-IMRT in the bowel domain (34.9% vs 43.8%, P = .03). At 3 years, DFS for MH-IMRT was 92.1% (95% CI, 88.9%-95.2%) vs 88.6% for SBRT (95% CI, 85.2%-92.1%) (1-sided log-rank P < .001).
Conclusions and Relevance
Stereotactic body radiotherapy using a modest dose prescription improved multiple quality-of-life domains but was not superior to MH-IMRT in terms of DFS. The rate of PSA failure was not significantly improved in the SBRT vs MH-IMRT group.
Trial Registration
ClinicalTrials.gov Identifier: