[68Ga]Ga-PSMA-11 PET/CT and [18F]Fluorocholine PET/CT in Assessment and Clinical Decision Making of Recurrent Prostate Cancer: A Prospective Crossover Trial

Abstract

Purpose: There are few prospective studies addressed toward the role of 68Gallium-labelled prostate-specific membrane antigen-11 ([68Ga]Ga-PSMA-11) compared to [18F]Fluorocholine ([18F]FCH) PET/CT in clinical decision-making as prostate-specific PET-tracers. This study aims to evaluate the impact of PET/CT using [68Ga]Ga-PSMA-11 and [18F]FCH in clinical management of recurrent prostate cancer (PCa) and correlates imaging findings with clinical characteristics of PCa. Procedures: Forty-six patients with PCa (mean age 68.3 ± 6.3 years) with biochemical recurrence were enrolled in this prospective crossover trial. All patients underwent both [68Ga]Ga-PSMA-11 and [18F]FCH PET/CT within a maximum interval of 12 days (median 7d). A standard randomization tool randomized the sequence of PET/CT imaging. Clinical decision-making occurred in an interdisciplinary meeting considering PET/CT findings. PET/CT-blinded readings were performed 3 months after imaging followed by a consensus meeting for final interpretation of detected lesions. Results: Both imaging modalities detected 136 total malignant lesions. [68Ga]Ga-PSMA-11 and [18F]FCH PET/CT detected 125 and 60 lesions with a sensitivity of 96% and 48%, respectively. Tumor-to-background ratios and semi-quantitative PET parameters on [68Ga]Ga-PSMA-11 were significantly higher in 54 (41.2%) tracer-avid congruent lesions detected on both imaging modalities. [68Ga]Ga-PSMA-11 PET/CT exclusively detected 71 (52.2%) lesions, while 6 (4.4%) lesions were solely seen on [18F]FCH PET/CT. [68Ga]Ga-PSMA-11 and [18F]FCH PET/CT were positive in 35/46 (76%) and 26/46 (57%) patients, respectively. PET/CT imaging led to a major treatment change in 4 (8.7%) patients, of which [18F]FCH PET/CT had superior impact in one patient. Conclusions: [68Ga]Ga-PSMA-11 PET/CT revealed superior diagnostic performance to [18F]FCH PET/CT in patients with recurrent PCa, specifically with very low PSA levels ≤ 1 ng/ml. Moreover, it led to more accurate staging and clinical management of the disease. [18F]FCH PET/CT may play a complementary role in rare, select high-risk cases with negative [68Ga]Ga-PSMA-11 PET/CT and ongoing ADT.