ASCO guideline: imaging for advanced prostate cancer
TL;DRNGI should be offered when salvage RT is contemplated after RP (evidence high, strong). Withhold it when no salvage local therapy is planned.
The only high-evidence, strong recommendation is NGI before contemplated salvage RT after RP (4.4), and Habl et al reported 59% of RT plans changed by 68Ga-PSMA PET/CT. Post-RT rising PSA without salvage intent gets the opposite call (4.5), so imaging should follow the salvage decision, not precede it.
In post-RP rising PSA with negative conventional imaging where salvage RT is on the table, this supports NGI first; it does not support NGI for men not candidates for, or unwilling to receive, salvage therapy.
Rec 4.4 (high evidence, strong) backs NGI before salvage RT after RP, with 59% RT plan changes and 43% stage changes in Habl et al. For post-RT BCR, NGI is supported only when salvage local or regional therapy is contemplated (4.6, moderate).
In metastatic CRPC, PSA progression alone should not drive a therapy switch, and conventional imaging stays the serial comparator (4.9, strong). In nonmetastatic CRPC, NGI is reserved for when a care change is contemplated (4.8), and evidence is weak.
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ASCO expert panel with ASTRO, AUA, SNMMI, ACR, SAR and SUO. Systematic review 2013 to Aug 2018, 35 studies: 17 systematic reviews ± meta-analysis and 18 primary articles.
Men with advanced prostate cancer: newly diagnosed clinical high-risk, suspected or confirmed metastatic, recurrent, or progressive on treatment, including nonmetastatic CRPC and metastatic CRPC.
For men in whom salvage radiotherapy is contemplated, NGI should be offered (Rec 4.4; evidence high, strength strong). Habl et al reported 59% RT plan changes from 68Ga-PSMA PET/CT.
Conventional imaging (CT, bone scan, prostate MRI) and/or NGI per scenario. NGI is not offered absent salvage intent after RP (4.3) or RT (4.5), and not routinely offered for radiographic progression in mCRPC (4.11).
| Scenario | NGI recommendation | Evidence quality | Strength |
|---|---|---|---|
| Rising PSA post-RP, neg conventional imaging, no salvage planned (4.3) | Should not be offered | Low | Moderate |
| Rising PSA post-RP, salvage RT contemplated (4.4) | Should be offered | High | Strong |
| Rising PSA post-RT, salvage not planned (4.5) | Should not be offered, except IRB trial | Intermediate | Moderate |
| Rising PSA post-RT, salvage local/regional therapy contemplated (4.6) | Supported; may guide management | Intermediate | Moderate |
| Hormone-sensitive, metastatic on conventional imaging (4.7) | Potential role to clarify burden | Intermediate | Moderate |
| Nonmetastatic CRPC (4.8) | Only if care change contemplated | Weak | Moderate |
| Metastatic CRPC, PSA progression (4.9) | Conventional imaging; PSA alone not reason to switch | Intermediate | Strong |
| Metastatic CRPC, high suspicion, neg conventional imaging (4.10) | Could be contemplated, ideally trial | Insufficient | Weak |
| Metastatic CRPC, radiographic progression on conventional imaging (4.11) | Not routinely offered | Insufficient | Moderate |
Evidence is drawn from detection-rate and diagnostic-accuracy meta-analyses of choline, fluciclovine, acetate and 68Ga-PSMA PET. It contains no randomized trial of NGI-guided treatment with clinical outcome endpoints.
Literature closes Aug 2018, before the prospective PSMA PET era matured. Much of the recommendation set is informal consensus with benefits/harms ratio uncertain.
The guideline makes imaging conditional on a salvage or care-change decision, not a reflex to rising PSA. It does not settle whether NGI-driven stage migration improves outcomes, especially for oligometastatic MDT selection (4.7).
- Does NGI-guided salvage RT improve outcomes beyond plan change? recruiting Comparing "Salvage" Radiotherapy and Individualized PSMA PET/CT Targeted Treatment in With Relapsing Prostate Cancer Phase 3n=450 · primary completion 2027-10 · phase 3 PSMA-individualized vs standard SRT post-RP
- Do PSMA-defined oligometastatic thresholds transfer MDT benefit? n=60 · primary completion 2030-12 · IADT ± SBRT, PSMA+ but CI-negative oligomet HSPC
- Role of NGI in nmCRPC management
📚 Sources · 📄 1 paper
Abstract
The longer read
The organizing principle here is that next-generation imaging earns its place only when the result can change what happens next. Nearly every recommendation is gated on intent: offer NGI when salvage radiotherapy or another salvage local therapy is contemplated, and withhold it when no such therapy is planned. That framing is sensible because the evidence base cannot support anything more ambitious. The 35 included studies measure detection rates, sensitivity and specificity, and the proportion of plans changed. None measures whether patients imaged with NGI live longer or stay progression-free longer than those imaged conventionally. A management change is not a benefit until a downstream trial shows it.
For the radiation oncologist, the load-bearing recommendation is 4.4. It is the only one rated high evidence quality with strong strength, and it covers the most common referral: rising PSA after prostatectomy with negative conventional imaging and salvage RT under consideration. The primary data in the review make clear why the panel was confident here: Habl et al reported a changed RT plan in 59% of patients and a changed stage in 43% after 68Ga-PSMA PET/CT. Changing the plan is a statement about target volume and possibly about intent. Whether the extra nodal or distant findings justify extending fields, boosting, or abandoning salvage is exactly what the guideline does not settle.
The asymmetry between the post-prostatectomy and post-radiotherapy scenarios deserves attention. After RT, NGI is supported only when salvage local or regional therapy is contemplated (4.6, intermediate evidence, moderate strength), and is actively discouraged outside a trial when it is not (4.5). That is coherent with the gating principle. It also places the burden on the clinician to decide salvage candidacy before imaging, which in practice often runs in the other direction.
Recommendation 4.7 is the one most likely to age poorly. For hormone-sensitive disease already metastatic on conventional imaging, the panel acknowledges NGI may move a patient from multimodality oligometastatic management to systemic therapy alone. That is stage migration with direct consequences for metastasis-directed RT eligibility, yet the trials defining oligometastatic benefit selected patients on conventional imaging. Applying PSMA-defined burden to thresholds validated on bone scan and CT is a translation the guideline flags only as 'prospective data are limited'.
Vintage is the main reason to read this guideline as a floor rather than a ceiling. The search closes in August 2018, and PSMA ligands appear 'where available', listed alongside choline and fluciclovine rather than above them. A reader applying it now should treat the scenario gating as durable and the tracer hierarchy as superseded. The castration-resistant recommendations (4.8 to 4.11) rest on weak or insufficient evidence and largely defer to conventional imaging and the PCWG3 principle that PSA progression alone should not drive a therapy change.