Changes in Treatment After Gallium-68 Prostate-Specific Membrane Antigen-11 Positron Emission Tomography/Computed Tomography in Patients With Prostate Cancer: A Retrospective Case Series Study

Abstract

Purpose The use of gallium-68 prostate-specific membrane antigen-11 positron emission tomography/computed tomography (Ga-68 PSMA-11 PET/CT) is becoming increasingly common among men with prostate cancer (PCa). However, it remains uncertain which patients will derive the most benefit, and there is a scarcity of real-world data regarding its impact on altering treatment plans. This study investigated which patients would most benefit from Ga-68 PSMA-11 PET/CT, focusing on detection rates and changes in treatment strategies, drawing from a single-center experience. Materials and Methods In total, 230 men with PCa who underwent Ga-68 PSMA-11 PET/CT between November 2021 and August 2022 were included in this retrospective study. The patients were classified into 5 groups based on their disease status: group 1, further work-up for high-risk localized PCa; group 2, de novo metastatic PCa; group 3, biochemical recurrence after definitive treatment; group 4, castration-resistant PCa; group 5, others. The positivity rate, positive lesions, predictive value of lymph node metastases, comparison with conventional images, and treatment changes after Ga-68 PSMA-11 PET/CT were analyzed in each group. Results Of the 230 patients, 40 (17.4%), 20 (8.7%), 77 (33.5%), 76 (33.0%), and 17 (7.4%) were classified into groups 1-5, respectively. Ga-68 PSMA-11 PET/CT showed lesions in 74.8% of patients, and the optimal cutoff value for PSA was 1.99 ng/mL. Lesions not observed on conventional imaging were found in 62 patients (33.2%). In 38 patients (13.5%), treatment was changed due to Ga-68 PSMA-11 PET/CT. Conclusions These real-world data suggest that Ga-68 PSMA-11 PET/CT may be clinically useful for various disease conditions, as substantial stage migration and subsequent treatment changes occur in men with PCa. However, the prognostic impact of this modality remains unclear; thus, a well-designed prospective study is needed to address this issue.