Distribution of prostate specific membrane antigen (PSMA) on PET-MRI in patients with and without ovarian cancer.

Abstract

Ovarian cancer is the most lethal cancer and future research needs to focus on the early detection and exploration of new therapeutic agents. The objectives of this proof-of-concept study are to assess the feasibility of PSMA 18F-DCFPyl PET/MR imaging for detecting ovarian cancer and to evaluate the PSMA distribution in patients with and without ovarian cancer. This prospective pilot proof-of-concept study in patients with and without ovarian cancers occurred between October 2017 and January 2020. Patients were recruited from gynecologic oncology or hereditary ovarian cancer clinics, and underwent surgical removal of the uterus and ovaries for gynecologic indications. PSMA 18F-DCFPyl PET/MRI was obtained prior to standard of care surgery. Fourteen patients were scanned: four patients with normal ovaries, six patients with benign ovarian lesions, and four patients with malignant ovarian lesions. Tracer uptake in normal ovaries (SUVmax = 2.8±0.4) was greater than blood pool (SUVmax = 1.8±0.5, p < 0.0001). Tracer uptake in benign ovarian lesions (2.2±1.0) did not differ significantly from blood pool (p=0.331). Tracer uptake in ovarian cancer (SUVmax = 7.8±3.8) was greater than blood pool (p<0.0001), normal ovaries (p=0.0014), and benign ovarian lesions (p=0.005). PET/MR imaging detected PSMA uptake in ovarian cancer, with little to no uptake in benign ovarian findings. These results are encouraging and further studies in a larger patient cohort would be useful to help determine the extent and heterogeneity of PSMA uptake in ovarian cancer patients.