To determine whether addition of external beam radiation therapy (EBRT) to brachytherapy (BT) (COMBO) compared with BT alone would improve 5-year freedom from progression (FFP) in intermediate-risk prostate cancer.
Men with prostate cancer stage cT1c-T2bN0M0, Gleason Score (GS) 2-6 and prostate-specific antigen (PSA) 10-20 or GS 7, and PSA < 10 were eligible. The COMBO arm was EBRT (45 Gy in 25 fractions) to prostate and seminal vesicles followed by BT prostate boost (110 Gy if 125-Iodine, 100 Gy if 103-Pd). BT arm was delivered to prostate only (145 Gy if 125-Iodine, 125 Gy if 103-Pd). The primary end point was FFP: PSA failure (American Society for Therapeutic Radiology and Oncology [ASTRO] or Phoenix definitions), local failure, distant failure, or death.
Five hundred eighty-eight men were randomly assigned; 579 were eligible: 287 and 292 in COMBO and BT arms, respectively. The median age was 67 years; 89.1% had PSA < 10 ng/mL, 89.1% had GS 7, and 66.7% had T1 disease. There were no differences in FFP. The 5-year FFP-ASTRO (95% CI) was 85.6% (81.4 to 89.7) with COMBO compared with 82.7% (78.3 to 87.1) with BT (odds ratio [OR], 0.80; 95% CI, 0.51 to 1.26; Greenwood T P = .18). The 5-year FFP-Phoenix was 88.0% (84.2 to 91.9) with COMBO compared with 85.5% (81.3 to 89.6) with BT (OR, 0.80; 95% CI, 0.49 to 1.30; Greenwood T P = .19). There were no differences in the rates of genitourinary (GU) or GI acute toxicities. The 5-year cumulative incidence for late GU/GI grade 2+ toxicity is 42.8% (37.0 to 48.6) for COMBO compared with 25.8% (20.9 to 31.0) for BT (P < .0001). The 5-year cumulative incidence for late GU/GI grade 3+ toxicity is 8.2% (5.4 to 11.8) compared with 3.8% (2.0 to 6.5; P = .006).
Compared with BT, COMBO did not improve FFP for prostate cancer but caused greater toxicity. BT alone can be considered as a standard treatment for men with intermediate-risk prostate cancer.
Journal of clinical oncology : official journal of the American Society of Clinical Oncology. 2023 Jun 14 [Epub ahead of print]
Jeff M Michalski, Kathryn A Winter, Bradley R Prestidge, Martin G Sanda, Mahul Amin, William S Bice, Hiram A Gay, Geoffrey S Ibbott, Juanita M Crook, Charles N Catton, Adam Raben, Walter Bosch, David C Beyer, Steven J Frank, Michael A Papagikos, Seth A Rosenthal, H Joseph Barthold, Mack Roach, Jennifer Moughan, Howard M Sandler
Washington University-Siteman Cancer Center, St. Louis, MO., NRG Oncology Statistics and Data Management Center/ACR, Philadelphia, PA., Bon Secours DePaul Medical Center, Norfolk, VA., Emory University Hospital/Winship Cancer Institute, Atlanta, GA., University of Tennessee Health Science Center, Memphis, TN., John Muir Medical Center, Walnut Creek, CA., University of Texas MD Anderson Cancer Center, Houston, TX., BCCA-Cancer Centre for the Southern Interior, Kelowna, British Columbia, Canada., University Health Network-Princess Margaret Hospital, Toronto, Ontario, Canada., Delaware/Christiana Care NCI Community Oncology Research Program, Newark, DE., Arizona Oncology Services Foundation, Tucson, AZ., Novant Health New Hanover Regional Medical Center-Zimmer Cancer Institute, Wilmington, NC., Sutter Cancer Research Consortium, Roseville, CA., Beth Israel Deaconess Hospital-Plymouth, Plymouth, MA., UCSF Medical Center-Mount Zion, San Francisco, CA., Cedars-Sinai Medical Center, Los Angeles, CA.