In advanced prostate cancer with few options, clinicians retreat patients with radioligand therapy after an initial response, despite a lack of formal data. The rationale is practical: for a patient who previously responded well and has no better alternatives, reusing an effective therapy is a logical clinical decision.

While PSMA PET scans are more sensitive, they create a clinical dilemma because pivotal trials defining treatment efficacy were based on conventional imaging (CT/bone scans). This forces oncologists to either re-image patients with older technology to match trial criteria or make treatment decisions based on PET data that lacks a clear evidence-based framework for response assessment.

Despite two positive Phase 3 trials showing an overall survival benefit, Radium-223 is not widely used. A key reason is its failure to produce dramatic PSA declines or clear scan improvements. This lack of a satisfying, immediate feedback signal, or "firework display," makes clinicians less likely to prescribe it, even with proven efficacy.

Even if radioligand therapies like Lutetium-PSMA are approved for first-line metastatic prostate cancer, their real-world adoption will be significantly hampered by logistics. Most U.S. patients are treated in community practices that lack the infrastructure for these therapies, creating a major access and bandwidth problem that will temper uptake.

Intensive treatments like ADT plus an ARPI can suppress a patient's PSA so effectively that it becomes an unreliable marker of disease status. Patients may show radiographic progression on scans even while their PSA remains low and they feel clinically well. This discordance necessitates periodic imaging to avoid missing actual disease progression.

If lutetium-PSMA is approved and used upfront in hormone-sensitive disease, clinicians may become more comfortable with radioligands generally. This could lead them to use the enzalutamide-radium combination more frequently later on, paradoxically increasing radium's use by flipping the current treatment sequence.

Clinicians may be biased towards lutetium-PSMA because it causes significant PSA drops, which radium-223 does not. This observable metric may not reflect superior overall efficacy, as radium's survival benefit is proven and it may even have unique synergistic potential with drugs like enzalutamide through different biological pathways.

In metastatic hormone-sensitive prostate cancer (mHSPC), radiographic progression-free survival (rPFS) is no longer seen as a convincing primary endpoint on its own. Clinicians demand a clear signal for overall survival (OS) improvement, citing historical data where early treatment intensification showed significant OS gains.

Clinical Complete Response (cCR), assessed by imaging and biopsy, is the primary endpoint for avoiding surgery in new trials. However, these tools are known to be unreliable, potentially missing up to 25% of residual post-mucosal tumors and leading to undertreatment.