[¹⁸F]PSMA-1007 PET-Based Recurrence Site Distribution and Predictors of Metastatic Disease in Patients With...

Prostate-specific membrane antigen positron emission tomography (PSMA-PET) is a sensitive imaging modality for detecting recurrent prostate cancer following definitive local therapy. However, evidence on ¹⁸F-labeled PSMA tracers in Japanese patients with biochemical recurrence (BCR) remains limited. The aim of this study was to examine the recurrence site distribution by [¹⁸F]PSMA-1007 PET in patients with BCR and identify factors associated with metastatic disease.

We retrospectively analyzed 129 patients with prostate cancer who developed BCR after definitive local therapy and underwent [¹⁸F]PSMA-1007 PET. The primary endpoint was the distribution of recurrence sites detected by PSMA-PET. Secondary endpoints included clinicopathological factors associated with metastatic disease. Exploratory endpoints involved outcomes of lesion-directed therapy following PSMA-PET.

PSMA-PET identified recurrent lesions in 83% (n = 107), including local recurrence in 40% (n = 51), lymph node metastasis in 43% (n = 55), and bone metastasis in 26% (n = 33); sites were not mutually exclusive. Metastatic lesions were detectable even at low prostate-specific antigen (PSA) levels (≤ 1.0 ng/mL). In multivariate analysis, Grade Group ≥ 4 was independently associated with metastatic disease (odds ratio [OR], 2.65; 95% confidence interval [CI], 1.06-6.77), whereas a PSA doubling time ≥ 8.7 months was independently associated with a lower likelihood of metastasis (OR, 0.12; 95% CI, 0.05-0.27). Among 55 patients who underwent lesion-directed therapy, PSA declines ≥ 90% were observed in 60% of cases.

In this Japanese cohort with BCR, [¹⁸F]PSMA-1007 PET delineated recurrence patterns and identified clinicopathological factors associated with metastatic disease. PSMA-PET may provide clinically relevant information to support individualized salvage treatment strategies.