To evaluate the impact of staging 68Ga-PSMA-11 PET imaging on radiotherapy (RT) dose and volumes in patients with prostate cancer.
Forty-five patients (89% high or very high-risk by NCCN criteria) who underwent 68Ga-PSMA-11 PET imaging prior to definitive treatment for prostate cancer between December 2015 and December 2016 were included. Locations of 68Ga-PSMA-11-avid lesions were compared to RTOG consensus pelvic nodal volumes (clinical target volume, CTV); coverage of lesions outside the consensus CTV was considered a major change, while dose-escalation to lesions within the consensus CTV was considered a minor change.
All patients had 68Ga-PSMA-11 PET uptake in the prostate. 25 patients (56%) had N1/M1a disease on 68Ga-PSMA-11 PET scan, of whom 21 (47%) were previously N0. Six patients (13%) had bone metastases on 68Ga-PSMA-11 PET scan, of whom four had prior negative bone scans. 8 patients (18%) had lymph node metastases outside the consensus CTV. 12 patients (27%) received a RT boost to nodes within the consensus CTV. 6 patients (13%) had limited bone metastases treated with focal RT. Overall PSMA PET imaging resulted in major and/or minor changes to RT plans in 24 patients (53%).
68Ga-PSMA-11 PET imaging resulted in RT changes in 53% of patients. Prospective investigation is needed to evaluate the clinical benefit of RT changes based on staging 68Ga-PSMA-11 PET imaging.
Urology. 2018 Dec 20 [Epub ahead of print]
Susan Y Wu, Lauren Boreta, Katsuto Shinohara, Hao Nguyen, Alexander R Gottschalk, I-Chow Hsu, Mack Roach Iii, Antonio C Westphalen, Felix Y Feng, Peter R Carroll, Albert J Chang, Thomas A Hope
Department of Radiation Oncology, University of California, San Francisco., Department of Urology, University of California, San Francisco; University of California San Francisco Helen Diller Family Comprehensive Cancer Center., Department of Urology, University of California, San Francisco., Department of Radiation Oncology, University of California, San Francisco; University of California San Francisco Helen Diller Family Comprehensive Cancer Center., Department of Radiology and Biomedical Imaging, University of California, San Francisco., Department of Radiation Oncology, University of California, San Francisco; Department of Urology, University of California, San Francisco; University of California San Francisco Helen Diller Family Comprehensive Cancer Center; Department of Medicine, University of California, San Francisco., Department of Radiation Oncology, David Geffen School of Medicine, University of California, Los Angeles., University of California San Francisco Helen Diller Family Comprehensive Cancer Center; Department of Radiology and Biomedical Imaging, University of California, San Francisco; Department of Radiology, San Francisco VA Medical Center. Electronic address: .