Abstract
1505
Purpose: The purpose of this prospective study was to determine the test characteristics of 68Ga-PSMA-11 PET for disease detection in prostate cancer patients with biochemically recurrent disease after radiation therapy and/or prostatectomy. Materials and >Methods: 150 patients underwent 68Ga-PSMA-11 PET/CT or PET/MRI and were evaluated for the presence of disease by two blinded board-certified radiologists. Each rater evaluated for the presence or absence of PSMA-avid disease within the prostate bed, pelvic lymph nodes, bones, and soft tissues (extrapelvic lymph nodes and visceral structures). The presence or absence of disease was confirmed via histopathology if available. In patients without pathology, a composite of imaging and clinical follow-up were used as a gold standard.
Results: Prior to PSMA PET imaging, 63% of patients had undergone prostatectomy, 57% had undergone radiation therapy (brachytherapy and/or pelvic external beam radiation therapy), and 41% had undergone androgen deprivation therapy. 43 patients had pathology correlation, which was considered the gold standard for disease detection. Of those without pathology, follow-up imaging and clinical information such as interval therapy and PSA change were used in 27 patients to determine the presence or absence of disease. With high-moderate to strong inter-rater reliability (Kappa by region = 0.78-0.87), 68Ga-PSMA-11 PET demonstrated high sensitivity per region (up to 92.9%) and per patient (up to 85.5%), as well as high positive predictive value per region (up to 100%) and per patient (up to 91.5%). Sensitivity was highest for bone metastases and lowest for soft tissue metastases. Positive predictive value was highest for bone metastases and lowest for prostate bed metastases.
Conclusions: 68Ga-PSMA-11 PET is sensitive for prostate cancer metastases in patients with biochemically recurrent prostate cancer, with high positive predictive value and excellent inter-rater reliability.