Lutetium-PSMA before SBRT held off progression in oligorecurrent prostate cancer

Design

Randomised phase 2 trial, extended follow-up

Population

92 men with PSMA-detected oligorecurrent (1–5 lesions) hormone-sensitive prostate cancer

Primary outcome

Progression-free survival

Effect

Median 17.6 vs 7.4 months, HR 0.38 (95% CI 0.23 to 0.61)

LUNAR is a randomised phase 2 trial in men with hormone-sensitive prostate cancer recurring as one to five lesions on PSMA PET/CT, all suitable for stereotactic body radiotherapy. Ninety-two men were randomised to SBRT alone (47) or two cycles of lutetium-177 PSMA radioligand followed by SBRT (45). Extended results appear in European Urology.

At a median follow-up of 31.9 months, progression-free survival — new lesions on PSMA PET, starting hormone therapy, or death — was a median 17.6 months with the radioligand against 7.4 months with SBRT alone (HR 0.38, 95% CI 0.23 to 0.61). Hormone therapy-free survival also improved (HR 0.57, 0.34 to 0.95). Exploratory endpoints, including progression to polymetastatic and castration-resistant disease, pointed the same way but with wide intervals. No new safety signals emerged.

This is a single phase 2 trial with a PSMA-PET-defined endpoint, which is sensitive to small recurrences. It supports a phase 3 trial rather than routine use, but it is the strongest signal yet that systemic radioligand can extend the benefit of metastasis-directed therapy.

• Lutetium-PSMA before SBRT more than doubled median progression-free survival in this phase 2 trial.
• Time to starting hormone therapy was also extended, a meaningful outcome for patients.
• Overall survival and castration resistance were exploratory and are not established.
• Offer this approach only within a trial or a specialist multidisciplinary setting for now.
• Lutetium-PSMA is not yet a standard option in oligorecurrent disease in current guidelines.

Why it matters

Adding systemic radioligand may turn metastasis-directed radiotherapy from a delay into a longer hormone-free interval.

Don't overread it

Phase 2 results with a PSMA-PET-defined endpoint do not establish a survival benefit.

The statistics, in plain English

A hazard ratio of 0.38 means progression occurred at about 38% of the rate with SBRT alone. The exploratory hazard ratios have confidence intervals crossing or near 1, so they are uncertain.

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