NRG Oncology RTOG 0415: A randomized phase III non-inferiority study comparing two fractionation schedules in patients with low-risk prostate cancer.

Genitourinary Cancer
Session Type and Session Title: 
Oral Abstract Session A: Prostate Cancer
Poster Session A: Prostate Cancer
Abstract Number: 


Poster Board Number: 
Poster Session A Board #A1
J Clin Oncol 34, 2016 (suppl 2S; abstr 1)
W. Robert Lee, James J. Dignam, Mahul Amin, Deborah Bruner, Daniel Low, Gregory P. Swanson, Amit Shah, David D'Souza, Jeff M. Michalski, Ian Dayes, Samantha A. Seaward, William Adrian Hall, Paul L. Nguyen, Thomas Michael Pisansky, Sergio Faria, Yuhchyau Chen, Bridget F. Koontz, Rebecca Paulus, Howard M. Sandler; Duke University School of Medicine, Durham, NC; The University of Chicago, Chicago, IL; Cedars-Sinai Medical Center, Los Angeles, CA; Winship Cancer Institute at Emory University, Atlanta, GA; University of California, Los Angeles, Los Angeles, CA; The University of Texas Health Science Center at San Antonio, San Antonio, TX; York Cancer Center, York, PA; Department of Radiation Oncology, London Regional Cancer Program, London, ON, Canada; Washington University School of Medicine in St. Louis, St. Louis, MO; McMaster University, Hamilton, ON, Canada; Kaiser Permanente, Santa Clara, CA; Medical College of Wisconsin, Milwaukee, WI; Brigham and Women's Hospital, Dana-Farber Cancer Institute, Boston, MA; Mayo Clinic, Rochester, MN; McGill University, Montreal, QC, Canada; University of Rochester Medical Center, Rochester, NY; Duke University Medical Center, Durham, NC; NRG Oncology, Philadelphia, PA

Abstract Disclosures


Background: To determine whether the efficacy of a hypofractionated (H) schedule is no worse than a conventional (C) schedule in men with low-risk prostate cancer. Methods: From April 2006 to December 2009, one thousand one hundred fifteen men with low-risk prostate cancer (clinical stage T1-2a, Gleason ≤ 6, PSA < 10) were randomly assigned 1:1 to a conventional (C) schedule (73.8 Gy in 41 fractions over 8.2 weeks) or to a hypofractionated (H) schedule (70 Gy in 28 fractions over 5.6 weeks). The trial was designed to establish with 90% power and alpha = 0.05 that (H) results in 5-year disease-free survival (DFS) that is not lower than (C) by more than 7% (hazard ratio (HR) < 1.52). Secondary endpoints include freedom from biochemical recurrence (FFBR) and overall survival. At the third planned interim analysis (July 2015), the NRG Oncology Data Monitoring Committee recommended that the results of the trial be reported. Results: One thousand one hundred and one protocol eligible men were randomized: 547 to C and 554 to H. Median follow-up is 5.9 years. Baseline characteristics are not different according to treatment arm. At the time of analysis 185 DFS events have been observed; 99 in the C arm and 86 in the H arm. The estimated 7-year disease-free survival is 75.6% (95% CI 70.3, 80.1) in the C arm and 81.8% (77.5, 85.3) in the H arm. The DFS HR (C/H) is 0.85 (0.64, 1.14). Comparison of biochemical recurrence (HR = 0.77, (0.51, 1.17)) and overall survival (HR = 0.95, (0.65, 1.41)) also met protocol non-inferiority criteria. Grade ≥ 3 GI toxicity is 3.0% (C) vs. 4.6% (H), Relative risk (RR) for H vs. C 1.53, (95% CI 0.86, 2.83); grade ≥ 3 GU toxicity is 4.5% (C) vs. 6.4% (H), RR = 1.43 (0.86,2.37). Conclusions: In men with low-risk prostate cancer, 70 Gy in 28 fractions over 5.6 weeks is non-inferior to 73.8 Gy in 41 fractions over 8.2 weeks. Clinical trial information: NCT00331773