University of California San Francisco Helen Diller Family Comprehensive Cancer Center, San Francisco, CA
Tom Hope , Rahul Raj Aggarwal , Kirsten L Greene , Bryant Chee , Dora Tao , Felix Yi-Chung Feng , Albert Chang , Matthew R. Cooperberg , Charles J. Ryan , Eric Jay Small , Peter Carroll
Background: PET imaging of prostate specific membrane antigen (PSMA) has been shown to have a higher sensitivity and specificity compared to conventional imaging. The objective was to evaluate the impact of PSMA PET on the management of prostate cancer patients with biochemical recurrence following local therapy. Methods: In our initial Ga-68-PSMA-11 PET protocol (NCT02611882), 150 patients with biochemical recurrence were imaged. 63 patients were imaged using PET/CT (GE Discovery VCT) and 63 patients using PET/MRI (GE Signa 3.0T PET/MRI). 110 patients received Lasix injections. Referring clinicians filled out a pretreatment management form and a management form based on the imaging results. Changes in management were graded as major, minor, no change or unknown based upon the responses. Results: We received both pre and post imaging forms in 126 patients, for an 84% response rate. The average PSA in the population was 5.9 ± 5.4 ng/mL with an average doubling time of 9.7 ± 11.0 months, and 60 patients had a PSA of less than 2.0 at the time of imaging. The average time between prior treatment and imaging (RP and/or radiation) was 5.3 ± 5.4 years, with 46 patients imaged within two years of their most recent treatment. 43 patients had a prior prostatectomy, 41 prior radiation, and 33 patients had both. 103 patients (82%) had disease localized on PSMA imaging. Of the 126 patients, 67 (53%) of the imaging studies resulted in a major change in management. The most common major change was converting from active surveillance to radiation therapy (15 patients, 12%), changing from ADT to radiation therapy (16 patients, 13%), and converting from radiation therapy to either active surveillance (6 patients, 5%) or to ADT alone (3 patients, 2%). 10 patients (8%) had a minor change, 42 patients (33%) had no change, and 7 patients (6%) had an unknown change in management. Conclusions: The results of our surveys demonstrate a substantial impact of PSMA PET on the intended patient management. The majority of changes involved converting a targeted therapy to systemic treatment or systemic treatment to a targeted therapy. Prospective studies are warranted to determine whether directed treatment towards PSMA-avid lesions affects long-term disease outcomes. Clinical trial information: NCT02611882
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