PSMA PET: A Potential Theranostic Agent in Thyroid Cancer?
Posted: Tuesday, February 2, 2021
Courtney Lawhn Heath, MD, of the University of California, San Francisco (UCSF), and colleagues conducted a feasibility study to investigate the use of gallium-68 (Ga-68) prostate‐specific membrane antigen–11 (PSMA-11) PET/MRI as a method to detect aggressive types of thyroid cancer. They found that fluorodeoxyglucose (FDG) PET detected metastatic thyroid cancer at a higher rate than PSMA PET. Their findings were published in EJNMMI Research.
“The exploration of PSMA PET as a possible theranostic agent in thyroid cancer is its infancy,” commented Dr. Lawhn Heath in a UCSF press release.
This single-center, prospective, open-label pilot study analyzed data from 11 patients with a history of thyroid cancer who had abnormal radiotracer uptake on a 2-[18F]-FDG PET and/or iodide-123/iodide-131 scintigraphy within 12 months prior to enrollment. PMSA PET images were compared with previous qualifying FDG PET and/or radioiodine scintigraphy for lesion locations and relative intensity. Differentiated thyroid cancer types included papillary thyroid cancer (n = 3), follicular thyroid cancer (n = 2), and Hurthle cell carcinoma (n = 2). There were four patients with dedifferentiated thyroid cancers: two with poorly differentiated papillary thyroid cancer and two with anaplastic thyroid cancer. All patients had metastatic disease.
Image comparisons showed that 8 of 11 patients had positive disease on PMSA PET compared with 9 of 11 patients on FDG PET. Of the 43 lesions detected, 95.3% were FDG-positive, and 65.1% were PSMA-positive. Detection rates for all differentiated thyroid cancer lesions were 93.8% and 53.1% for FDG PET and PSMA PET, respectively. The detection rate for dedifferentiated thyroid cancer was 100% for FDG PET and 72.7% for PSMA PET.
“[Ga]-68 PSMA-11 PET may be complementary to 2-[18F] FDG PET for lesion visualization and may be useful for determining patient eligibility for PSMA radioligand therapy,” explained the researchers.
Disclosure: The study authors reported no conflicts of interest.