Why this matters
For men with localized prostate cancer who are candidates for either surgery or radiotherapy, treatment selection is often driven as much by expected functional outcomes as by cancer control.
But randomized comparisons between radical prostatectomy and modern radiotherapy are rare, and direct randomized evidence comparing surgery with prostate SBRT has been essentially absent.
PACE-A provides that comparison.
After a median follow-up of 8 years, both radical prostatectomy and 5-fraction SBRT achieved excellent biochemical and clinical disease control, with no statistically significant difference between the treatment strategies.
Study design
PACE-A is part of the international phase III PACE platform.
Men with localized prostate cancer who were suitable candidates for radical prostatectomy were randomized 1:1 to:
- radical prostatectomy
- SBRT to 36.25 Gy in 5 fractions over 1-2 weeks
Eligible patients had:
- clinical stage T1-T2 disease
- Gleason score no higher than 3+4
- PSA no higher than 20 ng/mL
Androgen deprivation therapy was not permitted.
Radical prostatectomy could be performed using open, laparoscopic, or robotic techniques.
A total of 123 patients were randomized:
- 60 to prostatectomy
- 63 to SBRT
Approximately 94% had intermediate-risk disease.
Median age was 65.5 years, and median baseline PSA was 7.9 ng/mL.
Median follow-up was 8 years.
The current efficacy analysis evaluated freedom from biochemical or clinical failure, defined by PSA progression, initiation of ADT, recurrence, metastases, or prostate cancer death.
Key results
Only 13 biochemical or clinical failure events occurred:
- 5 after SBRT
- 8 after prostatectomy
The unadjusted hazard ratio was:
- HR 0.48
- 95% CI 0.16-1.46
- p=0.18
There was therefore no statistically significant difference between treatments.
At 5 years, freedom from biochemical or clinical failure was:
- 94.8% with SBRT
- 94.1% with prostatectomy
At 8 years:
- 91.2% with SBRT
- 83.7% with prostatectomy
The later numerical separation favored SBRT, but with very few events and wide confidence intervals, this should not be interpreted as evidence that SBRT is oncologically superior to surgery.
Overall survival
Overall survival was also high in both groups.
There were:
- 3 deaths after SBRT
- 4 deaths after prostatectomy
There were no prostate cancer deaths in either treatment arm.
No significant difference in overall survival was observed.
Subsequent treatment
Treatment for disease progression remained uncommon.
Among patients initially treated with SBRT:
- 1 subsequently underwent salvage prostatectomy
- 2 received ADT
Among patients initially treated with prostatectomy:
- 5 subsequently received prostate-bed radiotherapy
- 3 received ADT
These data reinforce that most patients in both randomized groups remained free from clinically meaningful progression during long-term follow-up.
Urinary and bowel outcomes
The functional differences between treatment strategies remained clinically important.
At 5 years, use of at least one urinary pad was reported by:
- 8.3% after SBRT
- 48% after prostatectomy
This represents a large persistent difference in urinary continence between the two treatment strategies.
Patient-reported moderate or major bowel problems were uncommon:
- 0% after SBRT
- 3.6% after prostatectomy
Clinician-reported grade 2 or higher gastrointestinal toxicity at 5 years remained very low:
- 2% with SBRT
- 0% with prostatectomy
Grade 2 or higher genitourinary toxicity was similarly uncommon:
- approximately 4% with SBRT
- approximately 3% with prostatectomy
Interpretation
PACE-A addresses one of the most important questions faced by patients with localized prostate cancer: if surgery and modern radiotherapy offer different functional tradeoffs, are patients sacrificing cancer control by choosing one strategy over the other?
So far, the randomized data are reassuring.
Five-fraction SBRT produced excellent long-term disease control, with approximately 95% of patients free from biochemical or clinical failure at 5 years and more than 90% remaining failure-free at 8 years.
Radical prostatectomy also produced excellent outcomes.
The trial did not detect a significant efficacy difference between the two treatments.
The functional outcomes make the comparison particularly relevant. Urinary pad use at 5 years remained substantially more common after prostatectomy, while clinically relevant bowel toxicity after SBRT was uncommon.
However, the oncologic interpretation requires restraint.
Only 13 biochemical or clinical failure events occurred in the entire study. The confidence interval around the hazard ratio is therefore wide, and PACE-A was not powered to establish oncologic equivalence or noninferiority between SBRT and surgery.
The 8-year numerical difference in disease control should also not be overinterpreted as evidence favoring SBRT.
The strongest conclusion is simpler: modern 5-fraction SBRT produced durable disease control that remained excellent through long-term randomized follow-up.
For a patient eligible for either treatment, SBRT can therefore be discussed as a serious definitive treatment option rather than simply a less invasive alternative chosen at the expense of established cancer control.
Limitations
The randomized cohort was small, with only 123 patients.
Only 13 biochemical or clinical failure events occurred, limiting statistical power for efficacy comparisons.
The trial was not designed to establish formal oncologic equivalence or noninferiority between prostatectomy and SBRT.
Most patients had intermediate-risk disease with Gleason score 3+4 or lower, so the findings should not be extrapolated to high-risk prostate cancer.
The treatment era extended from 2012 to 2022, during which surgical and radiotherapy techniques continued to evolve.
Patient-reported outcome completion also decreased during long-term follow-up, particularly for the 5-year functional analyses.