PACE-A NCT01584258
ForLocalised low/intermediate-risk PCa, Gleason ≤3+4, PSA ≤20, RP candidate
TL;DRSBRT 36.25 Gy/5fx vs prostatectomy: 13 BCF events, HR 0.48 (95% CI 0.16-1.46), p=0.18; 5-yr BCF-free 94.8% vs 94.1% in localised low/intermediate-risk PCa.
Failure was scored at nadir+2 ng/ml after SBRT but >0.2 ng/ml after prostatectomy, so the BCF comparison is not symmetric; salvage is the cleaner read (RT in 5 prostatectomy pts, surgery in 1 SBRT pt). At 36.25 Gy in 5 fractions without ADT, this informs counselling surgical candidates on definitive SBRT.
In a man with low or intermediate-risk localised prostate cancer (cT1-T2, Gleason ≤3+4, PSA ≤20) who is a prostatectomy candidate, this supports presenting SBRT without ADT as a definitive alternative; it does not extend to disease above Gleason 3+4 or PSA 20.
Failure was scored at nadir+2 ng/ml after SBRT but >0.2 ng/ml after prostatectomy, so the BCF comparison is not symmetric; salvage is the cleaner read (RT in 5 prostatectomy pts, surgery in 1 SBRT pt). At 36.25 Gy in 5 fractions without ADT, this informs counselling surgical candidates on definitive SBRT.
For the operating surgeon the functional contrast is the read: ≥1 urinary pad at 5 years in 14/29 (48%) after prostatectomy vs 3/36 (8.3%) after SBRT, with 5 prostatectomy pts going on to salvage RT. Approach (open, laparoscopic, robot assisted) was mixed and its split is not reported in source.
Also covered Oct 4
| Arm | N | Events | 5-Year event-free (95% CI) | 8-Year event-free (95% CI) |
|---|---|---|---|---|
| Prostatectomy | 60 | 8 | 94% (83, 98) | 84% (68, 92) |
| SBRT | 63 | 5 | 95% (84, 98) | 91% (80, 96) |
+2 more figures
14 details
Phase III, open-label, multicohort RCT (PACE); PACE-A randomised 1:1 to SBRT or prostatectomy. N=123 (63 SBRT, 60 prostatectomy) from 8 centres per the abstract, August 2012 to February 2022. Median follow-up 8 years (IQR 6.1-8.0); analysis by intention to treat.
Men with localised prostate cancer, cT1-T2, Gleason ≤3+4, PSA ≤20 ng/mL, MRI staged, who were suitable candidates for prostatectomy. Median age 65.5 years (IQR 60.5-68.6), median PSA 7.9 ng/mL (IQR 5.9-11.0); 5.7% low-risk and 94.3% intermediate-risk.
SBRT 36.25 Gy in 5 fractions over 1-2 weeks, with no ADT permitted. Target volume, margins, platform and any intraprostatic boost are not reported in source.
Comparator was radical prostatectomy by open, laparoscopic or robot-assisted approach. The split between approaches and nodal dissection practice is not reported in source.
Freedom from biochemical/clinical failure: PSA rise (nadir+2 ng/ml post-RT or >0.2 ng/ml post-prostatectomy), ADT start, recurrence, metastases or prostate cancer death. The source does not state whether this was the prespecified primary endpoint or give a non-inferiority margin. Function by EPIC-26 and clinician-reported CTCAE.
13 BCF events (5 SBRT, 8 prostatectomy), unadjusted HR 0.48 (95% CI 0.16-1.46; p=0.18). BCF-free at 5 years 94.8% (84.6, 98.3) SBRT vs 94.1% (82.6, 98.1) prostatectomy; at 8 years 91.2% (80.1, 96.2) vs 83.7% (68.4, 92.0). Seven deaths, none from prostate cancer.
| Endpoint | SBRT | Prostatectomy |
|---|---|---|
| ≥1 urinary pad at 5 yrs (EPIC-26) | 3/36 (8.3%) | 14/29 (48%) |
| Moderate/big bowel problem (EPIC-26) | 0 | 1/28 (3.6%) |
| CTCAE G≥2 GI | 1/54 (2%) | 0 |
| CTCAE G≥2 GU | 2/53 (3.8%) | 1/40 (2.5%) |
At 5 years, ≥1 urinary pad in 3/36 (8.3%) SBRT vs 14/29 (48%) prostatectomy. Moderate/big bowel problem in 0 SBRT vs 1/28 (3.6%) prostatectomy. Clinician-reported G≥2 GI 1/54 (2%) vs 0 and G≥2 GU 2/53 (3.8%) vs 1/40 (2.5%), SBRT vs prostatectomy. Sexual function is not reported in source.
ProtecT is the randomised reference for surgery against radiotherapy in localised disease, using conventionally fractionated RT rather than SBRT. PACE-B, a sibling cohort of the same trial, compared SBRT with longer-course RT in men not headed for surgery. This is the direct randomised SBRT against prostatectomy efficacy comparison that the abstract describes as lacking.
Failure thresholds differ by arm, so PSA failure is detectable earlier after surgery than after SBRT. The 5-year pad figures rest on 36 and 29 respondents of 63 and 60 randomised. The tweet reports 10 centres against the abstract's 8, and the slide labels the absolute-difference interval 90% CI where the abstract says 95%.
The 5-year rates are near identical and the 8-year gap rests on few men at risk, so the defensible read is no detectable difference, not SBRT superiority. The continence contrast is the largest effect in the dataset and the bowel penalty usually set against RT is not visible here. It does not settle metastasis or mortality outcomes.
CONSORT flow
Randomised phase III supporting an already-listed SBRT option, but only 13 events, a CI spanning both directions, no non-inferiority margin, and arm-specific failure definitions. Supports, does not prove, equivalence.
- Metastasis and prostate cancer mortality by arm with more events
- SBRT vs prostatectomy above Gleason 3+4 or with ADT
- Sexual function by arm, not reported in source
📚 Sources · 🐦 1 tweet · 📄 1 paper
#ASTRO26 Plenary -- PACE-A: 5-yr Outcomes of RP vs SBRT for GG1-2 PCa @nickva1 @urotoday
— Zach Klaassen (@zklaassen_md) September 28, 2026
📍n=123 (60 RP, 63 SBRT), mFU 8 yrs, 10 🇬🇧 centers
📍13 BCF events: HR 0.48, 95% CI 0:16-1.46
📍7 deaths (no PCa): HR 0.55, 95% CI 0.12, 2.46
📍EPIC-26 >=1 urinary pad: 14/29 (48%) RP vs… pic.twitter.com/tSYdMxDayT
Abstract
The longer read
Men choosing between surgery and radiotherapy for localised prostate cancer have long been counselled on the assumption that cancer control is equivalent and that function is the tiebreaker. ProtecT gave that assumption randomised support for conventionally delivered radiotherapy, and PACE-B placed SBRT alongside longer-course RT. What had not been done was to randomise SBRT directly against prostatectomy for efficacy, and the abstract is explicit that such evidence was lacking. That is the gap this dataset fills, and it is also why the size of the trial matters so much to how it should be read.
The efficacy result is 13 events among 123 men. A hazard ratio of 0.48 with an interval running from 0.16 to 1.46 is compatible with SBRT being considerably better and with it being meaningfully worse. No non-inferiority margin appears in the source, so "comparable" is the investigators' description of overlapping estimates, not a tested claim. The 5-year figures, 94.8% and 94.1%, are the honest summary. The 8-year figures of 91.2% and 83.7% look like late divergence in favour of SBRT, but they sit on a shrinking number at risk and should not be read as a durable advantage.
The endpoint definition deserves more weight than the headline gives it. Failure after SBRT required a rise to nadir+2 ng/ml, while failure after prostatectomy was triggered at >0.2 ng/ml. Those thresholds are not equally sensitive. A surgical recurrence is declared early and at low disease burden; a post-radiotherapy recurrence is declared later by construction. Any comparison of biochemical failure across these two modalities therefore leans toward radiotherapy, and a trial with this few events cannot absorb that lean. The salvage data are a partial check: radiotherapy in 5 prostatectomy pts, surgery in 1 SBRT pt, with ADT in 3 and 2. These point the same way, but they are not symmetric either, since salvage RT after surgery is a routine, low-threshold step and salvage after SBRT is not. With 7 deaths and none from prostate cancer, the hard endpoints are silent.
The functional data carry the clearest signal. Pad use at 5 years in 3/36 (8.3%) after SBRT against 14/29 (48%) after prostatectomy is a large contrast, and the bowel penalty normally set against radiotherapy does not appear: no SBRT pt reported a moderate or big bowel problem, and clinician-graded G≥2 GI toxicity was 1/54. The caution is the denominators. Responses came from 36 and 29 men of 63 and 60 randomised, and nothing in the source says whether non-responders differed. Sexual function, the third leg of this counselling conversation, is not in the source.
Generalisability is narrow in a specific way. Recruiting 123 men between August 2012 and February 2022 shows how few accept randomisation between an operation and radiotherapy, so those who did are a selected group. The cohort was 94.3% intermediate risk, capped at Gleason 3+4, and treated without ADT. The result informs the counselling of a surgical candidate in that band who is weighing SBRT. It leaves untouched higher-grade disease, RT combined with ADT, and nodal treatment. It would be overturned by longer follow-up showing divergence in metastasis or in salvage burden once more events accrue.