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

OBJECTIVES

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.

METHODS

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.

RESULTS

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.

CONCLUSIONS

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.