Retrospective studies have shown that 68Ga-labelled prostate-specific membrane antigen PET (68Ga-PSMA-11 PET) imaging improves metastasis detection compared with conventional imaging (CT, MRI and bone scintigraphy) in biochemically recurrent prostate cancer. Findings from the first prospective trial in this setting have now been reported.

The single-arm multicentre trial enrolled 635 men with biochemically recurrent prostate cancer to undergo 68Ga-PSMA-11 PET imaging. The final efficacy analysis included patients with adequate follow-up for lesion validation via histopathological analysis (n = 93) or a composite reference standard (n = 223; comprising conventional imaging and serum PSA follow-up).

The overall detection rate was 75%, and detection significantly increased with rising PSA, although PSA doubling time and nadir were not associated with detection rate. Both per-patient and per-region positive predictive values (PPVs) were 0.84 (95% CI 0.75–0.90 and 0.76–0.91, respectively) by histopathological validation (the primary end point) and 0.92 (both 95% CI 0.88–0.95) by composite validation. The per-patient and per-region sensitivity by histopathological validation was 0.92 (95% CI 0.84–0.96) and 0.9 (95% CI 0.82–0.95), respectively. Regarding secondary end points, inter-reader agreement was substantial across regions and no grade ≥2 adverse events occurred.

These data illustrate the promise of 68Ga-PSMA-11 PET for localization of recurrent disease, and data from an ongoing study (NCT03515577) comparing 68Ga-PSMA-11 PET with the FDA-approved 18F-fluciclovine PET modality are eagerly awaited.