Prostate
Two threads: when radical RT/surgery can be safely deferred (ProtecT cribriform), and how to deliver primary SBRT when it is chosen (ESTRO consensus).
ESTRO Prostate SBRT Consensus Recommendations
TL;DR15-expert ESTRO Delphi consensus on optimising primary prostate SBRT: patient selection, contouring, dose/fractionation, follow-up, and delivery technique.
HYPO-RT-PCPACE-B
For a department standardising primary prostate SBRT, this is the implementation reference: an ESTRO Delphi panel settles the controversy points (patient selection, contouring, dose, fractionation, follow-up, delivery technique). Planning is anchored to the PACE-B protocol (Fig 1, isodose 8 to 46 Gy).
Sets the RT technical playbook for primary prostate SBRT: patient selection, contouring, dose, fractionation, follow-up, and minimal vs optimal delivery technique, resolved by a 15-expert Delphi. Figure 1 anchors planning to the PACE-B protocol (isodose 8 to 46 Gy), useful for benchmarking or standing up a program.
4 details 5 trials watching
ESTRO clinical practice consensus, 15-expert panel, Delphi process answering a 10-item questionnaire on areas of controversy. Covers selection, contouring, dose, fractionation, follow-up, and minimal-vs-optimal delivery technique for primary prostate SBRT.
- Optimal dose and fractionation for prostate SBRT active Prostate Radiotherapy Comparing Moderate and Extreme Hypo-fractionation (PRIME Trial) Phase NAn=526 · primary completion 2024-09 · extreme vs moderate hypofx, non-inferiorityrecruiting Two-fraction Versus Five-fraction Stereotactic Radiotherapy for Localized Prostate Cancer Phase NAn=562 · primary completion 2027-12 · 2-fraction vs 5-fraction SBRT, localized
- Role of focal ablative microboost n=124 · primary completion 2022-06 · SBRT focal ablative microboost, hypo-FLAME 2.0recruiting Image-guided Focal Dose Escalation- Primary pc Treated With Primary External Beam Hypofract.Stereotactic rt Phase NAn=374 · primary completion 2025-08 · randomized focal dose escalation vs no boostactive Standard Moderately Hypofractionated RT vs. Ultra-hypofractionated Focal Lesion Ablative Microboost in Prostate Cancer Phase NAn=484 · primary completion 2032-01 · randomized standard RT vs focal microboost
📚 Sources · 📄 1 paper
ProtecT (secondary analysis: cribriform morphology)
ForPSA-screened clinically localized prostate cancer, GG1-2 predominant
TL;DRCribriform-negative pts (87%): radical Rx gave no significant 15yr metastasis reduction vs active monitoring; cribriform-negative GG2 matched GG1 risk.
Reported via UroToday →
Selection, not technique, is the RT read: cribriform-negative GG2 matched GG1 on 15yr metastasis risk and gained no significant benefit from radical treatment, so definitive RT is deferrable there. Cribriform-positive (~13%) is where local treatment changed metastasis outcomes, moving the surveillance-vs-treat decision at biopsy.
Selection, not technique: cribriform-negative GG2 matched GG1 on 15yr metastasis risk and got no significant benefit from radical treatment, so definitive RT is deferrable there. Cribriform-positive (~13%) marks the group where local treatment changed metastasis outcomes, sharpening who to irradiate versus monitor at biopsy.
First trial-level backing for EAU's advice against active surveillance in any cribriform disease, which previously rested on no prospective data. Cribriform-negative GG2 behaved like GG1, supporting continued surveillance; cribriform-positive (~13%) flags pts for radical prostatectomy or RT despite a localized presentation.
8 details
Secondary analysis of the ProtecT RCT. Cribriform status was not a randomization characteristic; biopsy slides from 712 of 1,643 randomized pts were centrally reviewed, with centralization still ongoing.
PSA-detected clinically localized prostate cancer. ~13% cribriform-positive on biopsy, 87% cribriform-negative. Gleason re-graded to 2019 ISUP from the original 2005 criteria, which did not change the result.
The radical-treatment options were surgery or EBRT with 3-6mo neoadjuvant ADT. The RT+ADT arm carried a higher cribriform prevalence, attributed to chance since cribriform was not randomized.
Primary outcome was metastases at 15yr median follow-up, analyzed by both intention-to-treat and per-protocol (accounting for crossover between assigned and received treatment).
In cribriform-negative pts (87%), early radical Rx gave no significant 15yr metastasis reduction vs active monitoring, in ITT and per-protocol. Cribriform-negative GG2 matched GG1 metastasis risk on multivariable Cox.
The cribriform-positive group carrying the clinical message is small (~13% of the 712 reviewed), and its metastasis effect size is not reported in source. The 20yr ProtecT follow-up (census just reached) is not yet available.
Post-hoc analysis of a non-randomized histologic feature; only 712 of 1,643 randomized pts had slides reviewed. Cribriform-positive effect size not reported in source.
In cribriform-negative GG2 localized prostate cancer, this supports active surveillance as reasonable (same 15yr metastasis risk as GG1); it does not extend to cribriform-positive disease, which the data marks as higher-risk.
- Magnitude of radical-treatment benefit in cribriform-positive pts
- Should cribriform status formally gate active surveillance eligibility
- Does 20yr ProtecT follow-up confirm the cribriform signal