WOLVERINE
ForOligometastatic prostate cancer, up to 5 mets, mostly castration-sensitive
TL;DRIPD meta-analysis of 6 randomised phase 2 trials, 472 pts: MDT improved PFS (HR 0.44, 0.35-0.56), OS non-significant (HR 0.63, 0.39-1.00, p=0.051).
Surfaced from a review's discussed trials
The endpoint that survives every sensitivity cut is PFS (HR 0.44, and 0.46 excluding the observation-SOC trials), while OS stops at HR 0.63 (0.39-1.00, p=0.051). CRFS 0.58 in CSPC is the more decision-relevant signal, since delaying castration resistance is what MDT is being asked to buy. Nothing here resolves dose, target, or which oligo burden benefits.
In castration-sensitive oligometastatic prostate cancer with up to five lesions and a treated primary, this supports adding MDT for progression-free and castration resistance-free benefit; it does not establish an OS benefit, and the CRPC-only and untreated-primary populations are thinly represented.
The endpoint that survives every sensitivity cut is PFS (HR 0.44, and 0.46 excluding the observation-SOC trials), and CRFS 0.58 in CSPC is what MDT is being asked to buy. None of the constituent trials' dose, fractionation or target-selection choices are resolved by pooling, and rPFS carried I²=50% heterogeneity, so how to deliver MDT stays a local decision.
MDT deferred castration resistance (CRFS HR 0.58) in the castration-sensitive subset (n=257), which is the sequencing-relevant read: the question is whether local therapy buys time before ARPI escalation. Note the SOC arm actually got MORE second-generation ARPI (59.8% vs 50.4%), so the systemic backbone was not favouring MDT.
10 details 5 trials watching
Systematic review and individual patient data meta-analysis (X-MET collaboration), PROSPERO CRD42023479078. Searched Embase, PubMed, CENTRAL, MEDLINE and ClinicalTrials.gov to Nov 3 2023, updated May 4 2025; dual independent screening in Covidence, Cochrane RoB 2.0. Of 2975 studies screened, 7 phase 2 trials randomising 574 men were included.
Published randomised prospective trials in oligometastatic (up to five metastases) prostate cancer with data sufficient for PFS and OS. Most patients were castration-sensitive (n=375, 65%); ARTO enrolled entirely CRPC and the two EXTEND baskets a CRPC subset. The primary tumour had received prior definitive local therapy in 491 patients (85.5%), required in every trial except the EXTEND baskets and ARTO.
Co-primary: progression-free survival and overall survival. Secondary: radiographic PFS and castration resistance-free survival. Primary analysis restricted to the six trials randomising MDT plus SOC versus SOC, with both a random-effects trial-level analysis and a patient-level analysis stratified by trial.
Effect sizes are in the endpoint table. Trial- and patient-level estimates agreed closely on all four endpoints, and OS showed HR<1 in every individual trial without reaching significance in aggregate.
The constituent trials are the ones that currently drive MDT practice: STOMP and ORIOLE (small randomised phase 2, ADT-free intervals and progression), ARTO (MDT added to abiraterone in CRPC), the two EXTEND hormone baskets, and the prostate subgroup of SABR-COMET (16 men). Pooling them raises precision on PFS but cannot add the phase 3 evidence none of them supply, and the ongoing randomised phase 3 programmes remain the gate.
The SOC arm was not one thing: observation in all or part of STOMP, ORIOLE and COMET-SABR, and second-generation ARPI use differed between arms (59.8%, n=134 in SOC vs 50.4%, n=125 in MDT), which cuts against MDT rather than for it. Four abstract-only randomised primary analyses could not supply IPD and were excluded, and the prostate contribution from SABR-COMET is 16 men.
PFS is where the estimate is tight and consistent; OS is where the question stays open, and at p=0.051 the honest read is an underpowered signal, not a negative result. The endpoint most likely to matter to practice is CRFS (HR 0.58) in castration-sensitive disease, because deferring castration resistance is the outcome MDT is being asked to deliver.
Pools only phase 2 trials with non-blinded randomisation and mixed SOC; co-primary OS missed (p=0.051). Supports existing MDT practice rather than establishing level 1 evidence.
- Does MDT extend overall survival in a phase 3 population active Prostate-cancer Treatment Using Stereotactic Radiotherapy for Oligometastases Ablation in Hormone-sensitive Patients Phase 3n=550 · primary completion 2026-06 · phase 3 SBRT to all oligomets, 550 pts, mHSPCrecruiting Veterans Affairs Seamless Phase II/III Randomized Trial of STAndard Systemic theRapy With or Without PET-directed Local Therapy for Oligometastatic pRosTate Cancer Phase 2/3n=464 · primary completion 2026-09 · seamless ph2/3, CRPC-free survival, PET-directedrecruiting Metastasis Directed Stereotactic Body Radiotherapy for Oligo Metastatic Hormone Sensitive Prostate Cancer Phase NAn=118 · primary completion 2031-12 · randomised ph3 MD-SBRT vs standard tx, 1-3 mets
- Optimal dose, fractionation and target selection for prostate MDT recruiting OligoCare TwiCs (Trials Within Cohorts) Trial Comparing Acute Toxicity in Single-fraction vs Multiple-fraction SBRT for Metastasis-directed Treatment (SPRINT) Phase NAn=302 · primary completion 2029-02 · single- vs multi-fraction SBRT, acute toxicity 1° EPrecruiting SBRT Versus Hypofractionated Radiotherapy for Biochemically Recurrent or Oligometastatic Prostate Adenocarcinoma Phase 3n=118 · primary completion 2030-01 · ph3 SBRT vs hypofx RT in oligomet/BCR prostate
- Upper bound on metastasis number that still benefits
📚 Sources · 📄 1 paper
Abstract
The longer read
The value of this analysis is not that it found a new effect but that it fixes the size of an old one. MDT in oligometastatic prostate cancer has been practised on the strength of small randomised phase 2 trials, each individually too small to do more than point in a direction. Pooling individual patient data from six of them puts a tight interval around the progression-free survival estimate, HR 0.44 (0.35-0.56), and the near-identical patient-level estimate of 0.45 says the pooling is not being driven by one trial's weighting. That is a real gain in precision. It is not a gain in evidence level, and the distinction matters: six phase 2 trials pooled remain six phase 2 trials, with the risk-of-bias assessment flagging non-blinded randomisation across most of them.
The overall survival result is where readers will disagree, and the disagreement is worth being explicit about. HR 0.63 with a confidence interval of 0.39 to 1.00 and p=0.051 is not a negative result; every individual trial showed HR<1, and the sensitivity analysis excluding the observation-controlled trials returned HR 0.65 in the same direction with a wider interval. What it is, is underpowered. Four hundred and seventy-two patients across trials designed to detect progression signals will not settle survival, and treating a p-value one thousandth above a threshold as evidence of absence would be as wrong as treating it as evidence of effect. The correct reading is that the survival question has not been answered here and the phase 3 programme still owns it.
Two features of the pooled population should move confidence in opposite directions. The one that strengthens the result is the imbalance in second-generation ARPI use: more patients in the standard-of-care arm received an ARPI, 59.8% versus 50.4%, and the standard-of-care patients were older. If anything that biases the comparison against MDT, so the observed benefit is unlikely to be an artefact of better systemic therapy in the intervention arm. The one that weakens generalisability is the heterogeneity of what standard of care meant. In STOMP, ORIOLE and SABR-COMET the control arm was observation in all or part of the population, which makes the progression-free survival comparison partly a comparison of treatment against no treatment rather than of local therapy added to systemic therapy. The sensitivity analysis excluding those three is the analysis that most closely matches how these patients are managed now, and it holds: PFS HR 0.46, rPFS 0.56, CRFS 0.46.
For a radiation oncologist the most useful number is castration resistance-free survival, HR 0.58 in the castration-sensitive subset, because that is the outcome MDT is implicitly being asked to buy. Deferring castration resistance is a plausible mechanism by which local ablation could translate into something patients feel, and it is measured here rather than assumed. What the analysis cannot tell you is how to deliver it. Dose, fractionation, target selection, whether all lesions or only progressing ones need treatment, and what upper bound on lesion number still benefits, are all invisible in a pooled analysis of trials that made these choices differently. The trial-level heterogeneity in radiographic PFS, I²=50%, is a hint that those choices are not interchangeable. This tightens the case for offering MDT in castration-sensitive oligometastatic disease with a treated primary; it does not standardise how.