SBRT Matches Disease Control of Prostatectomy in Localized Prostate Cancer

Stereotactic body radiotherapy (SBRT) and radical prostatectomy both produced excellent biochemical and clinical disease control in patients with low- or intermediate-risk localized prostate cancer after a median follow-up of 8 years, according to results from the phase 3 PACE-A trial (NCT01584258) presented at the 2026 American Society for Radiation Oncology (ASTRO) Annual Meeting.

Among 123 patients who were randomly assigned to undergo surgery or 5-fraction SBRT, the 8-year freedom from biochemical or clinical failure (BCF) rate was 91% (95% CI, 80%-96%) with SBRT compared with 84% (95% CI, 68%-92%) with prostatectomy. The between-group difference was not statistically significant (unadjusted HR, 0.48; 95% CI, 0.16-1.46; log-rank P = .18), and relatively few events occurred in either arm, with 5 events in the SBRT group and 8 events in the surgery group.

At 5 years, the BCF-free rates were 94% (95% CI, 83%-98%) in the prostatectomy arm and 95% (95% CI, 84%-98%) in the SBRT arm. The absolute difference at 5 years, estimated from the HR, was 3.1% (90% CI, –2.6% to 5.0%).

“Patients considering a radical prostatectomy should be given the information on SBRT before making a decision,” presenting author Professor Nicholas van As, MD, MB, medical director of The Royal Marsden Hospital NHS Foundation Trust, consent clinical oncologist of the Urology Unit, and reader at the Institute of Cancer Research, said during the presentation.

Overall survival (OS) was also similar between the 2 treatment approaches. The 5-year OS rate was 98% in both arms (prostatectomy 95% CI, 86%-99%; SBRT 95% CI, 89%-99%), and the 8-year OS rates were 92% (95% CI, 76%-97%) and 95% (95% CI, 82%-99%), respectively (unadjusted HR, 0.55; 95% CI, 0.12-2.46; log-rank P = .43). A total of 4 deaths occurred in the surgery arm and 3 in the SBRT arm, and there were no prostate cancer deaths in either arm.

Differences emerged in patient-reported urinary function. At 5 years, 48% (n = 14/29) of patients who underwent prostatectomy reported using at least 1 urinary pad compared with 8% (n = 3/36) of those who received SBRT. Pad use in the surgical arm peaked shortly after treatment, when most patients reported wearing at least 1 pad at 4 weeks, and remained elevated relative to the SBRT arm at each subsequent time point through 60 months.

Patient-reported bowel bother was low in both groups. Based on the EPIC-26 question asking how big a problem bowel function was, 4% (n = 1/28) of patients in the prostatectomy arm reported a moderate or big problem at 5 years vs none in the SBRT arm.

Clinician-assessed late toxicity per CTCAE was also infrequent. At 5 years, no patients in the prostatectomy arm and 1 patient (2%) in the SBRT arm had grade 2 or higher gastrointestinal (GI) toxicity. Grade 2 or higher genitourinary (GU) toxicity at 5 years occurred in 1 patient (3%) in the surgery arm and 2 patients (4%) in the SBRT arm.

Regarding subsequent treatments, 1 patient in the SBRT arm underwent salvage prostatectomy, and 5 patients in the prostatectomy arm received prostate bed radiotherapy. Five patients started androgen deprivation therapy (ADT), including 3 in the surgical arm and 2 in the SBRT arm.

PACE-A is part of the broader PACE platform, which comprises 4 randomized questions in localized prostate cancer, with 5-fraction SBRT serving as the common arm across all studies. Investigators noted that treatment selection for localized prostate cancer is often influenced by expected functional outcomes and that randomized evidence comparing the efficacy of radical prostatectomy with SBRT has been lacking.

In PACE-A, patients with localized low- or intermediate-risk prostate cancer who were candidates for surgery were randomly assigned 1:1 to radical prostatectomy or SBRT at a dose of 36.25 Gy in 5 fractions. Eligible patients had T1c to T2c disease, a Gleason score of 3+4 or lower, a prostate-specific antigen (PSA) level of 20 ng/mL or less, and MRI-based staging; ADT was not permitted. The co-primary end points were patient-reported urinary incontinence and bowel bother at 2 years, which were reported previously. Secondary end points for the 5-year analysis included freedom from BCF, OS, clinician-reported late effects per CTCAE, and 5-year patient-reported pad wearing and bowel bother.

Patients were recruited from 10 centers in the United Kingdom, with 60 assigned to surgery and 63 to SBRT. The median age was 65.5 years (IQR, 60.5-68.6), and most patients had intermediate-risk disease (92%) and a Gleason score of 3+4 (79%). Overall, 65% of patients had a PSA level below 10 ng/mL, and 40% each had T2a and T2c disease. The median follow-up at the time of analysis was 8 years (IQR, 6.9-10.1).

Investigators concluded that the randomized findings support SBRT as an effective nonsurgical treatment option, with low rates of clinician- and patient-reported adverse effects for both approaches. They also highlighted that the PACE-B trial, which used the same eligibility criteria, showed a 96% biochemical control rate at 5 years.

Reference

van As N, Patel J, Tree A, et al. Efficacy of radical prostatectomy versus stereotactic body radiotherapy (SBRT) for localised prostate cancer: results from an international phase III randomised controlled trial (PACE-A). Presented at: 2026 ASTRO Annual Meeting; September 26-30, 2026; Boston, MA. Abstract LBA 32.