Hypofractionated Radiotherapy as Acceptable Treatment Option Post-Prostatectomy

Results from the randomized phase 3 NRG-GU003 trial demonstrated that hypofractionated postprostatectomy radiotherapy did not significantly increase the likelihood of patient-reported genitourinary (GU) or gastrointestinal (GI) symptoms 1 to 2 years post radiotherapy, compared to conventionally fractionated postprostatectomy among patients with prostate cancer.

According to Mark K. Buyyounouski, MD, Stanford University School of Medicine, Stanford, California, and coauthors, “No prior trial has compared hypofractionated postprostatectomy radiotherapy to conventionally fractionated postprostatectomy in patients primarily treated with prostatectomy.” 

In this trial, 296 patients with a detectable prostate-specific antigen (PSA) score of ≥0.1 ng/mL postprostatectomy with pT2/3pNX/0 disease or an undetectable PSA score <0.1 ng/mL with either pT3 disease or pT2 disease with a positive surgical margin were randomized to receive either 62.5 Gy in 25 fractions of radiotherapy (hypofractionated ; n = 144) or 66.6 Gy in 37 fractions of radiotherapy (conventionally fractionated; n = 152). The primary end points were mean 24-month change in GU and GI domain scores from baseline assessed via the Expanded Prostate Cancer Composite Index Questionnaire. A key secondary end point was biochemical failure, defined as a PSA of ≥0.4 ng/mL. 

At analysis, the mean 24-month change in GU score from baseline was -5.01 in the hypofractionated radiotherapy arm and -4.07 in the conventionally fractionated arm (P = .005). The mean 24-month change in GI score from baseline was -4.17 hypofractionated radiotherapy arm and -1.41 in the conventionally fractionated arm (P = .02). At a follow-up of 2.1 years, biochemical failure was 12% in the hypofractionated arm and 8% in the conventionally fractionated arm (P = .28). 

“At 2 years, [hypofractionated postprostatectomy radiotherapy] was noninferior to [conventionally fractionated postprostatectomy radiotherapy] in terms of patient-reported GU or GI toxic effects,” concluded Dr Buyyounouski et al. “[Hypofractionated postprostatectomy radiotherapy] is a new acceptable practice standard for patients receiving postprostatectomy radiotherapy.”

Source:  

Buyyounouski MK, Pugh SL, Chen RC, et al. Noninferiority of hypofractionated vs conventional postprostatectomy radiotherapy for genitourinary and gastrointestinal symptoms. JAMA Oncol. Published online: March 14, 2024. doi: 10.1001/jamaoncol.2023.7291