Prospective evaluation of ⁶⁸Ga-PSMA-11 PET/CT in Chinese men with biochemical recurrence after radical prostatectomy for prostate cancer: relationships between location of recurrence, time after prostatectomy, and serum PSA level

The purpose of this study was to prospectively evaluate the distribution of PSMA-targeted, PET-avid lesions in prostate cancer (PCa) patients with biochemical recurrence in a Chinese cohort. The relationships between PSA levels, disease-free time after prostatectomy, and ⁶⁸Ga-PSMA-11 PET/computed tomography (CT) findings were investigated. Inclusion criteria included histopathologically proven prostate adenocarcinoma, two consecutive PSA levels > 0.20 ng/mL, and negative CT of the abdomen and pelvis or magnetic resonance imaging of the pelvis and whole-body bone scan. Exclusion criteria were non-prostate malignancy within 3 years and persistent PSA after radical prostatectomy. Patients with findings of recurrent disease on re-staging conventional imaging were excluded, as were patients previously treated with systemic therapy and/or salvage therapy. 51 patients were enrolled in this study. 34/51 (66.7%) patients had at least one site of ⁶⁸Ga-PSMA-11 uptake consistent with PCa. 23.5% of patients had recurrence in the prostate bed, 27.4% had pelvic lymph nodes, 15.7% had extrapelvic lymph node metastases, and 17.6% had bone metastases. For patients with lymph node involvement/metastasis, bone metastasis, and patients with both, their median serum PSA levels were 1.83 ng/mL, 2.54 ng/mL, and 4.03 ng/mL, respectively. They were diagnosed with recurrence with a median of 2.06 years, 2.54 years, and 1.15 years after radical prostatectomy, respectively. In this study of Chinese men with biochemical recurrence, added value for the detection of lesions compatible with sites of PCa was found with ⁶⁸Ga-PSMA-11 PET/CT over conventional imaging. The observed patterns of disease spread may have implications for understanding the biology of early prostate cancer metastasis.