Evidence of Prostate-Specific Membrane Antigen Expression in Metastatic Differentiated Thyroid Cancer Using...

Area of Science:

• Oncology
• Nuclear Medicine
• Radiology

Background:

• Prostate-specific membrane antigen (PSMA) is overexpressed in various cancers, including prostate cancer, gliomas, and lung cancer.
• PSMA expression is also noted in tumor neovasculature.
• Systematic studies on PSMA uptake in thyroid tumors are limited.

Purpose of the Study:

• To assess PSMA expression in patients with metastatic differentiated thyroid cancer (mDTC).
• To evaluate the utility of Gallium-68 (Ga)-PSMA-HBED-CC PET/CT in mDTC.
• To compare PSMA uptake with radioiodine (I) and Fluorodeoxyglucose (FDG) PET findings.

Main Methods:

• Prospective evaluation of 10 mDTC patients with 32 lesions.
• Patients underwent radioiodine (I), F-FDG PET, and Ga-PSMA-HBED-CC PET scans.
• Comparison of PSMA expression (SUVmax) with I and F-FDG scan findings.

Main Results:

• All iodine-avid metastatic lesions showed substantial PSMA uptake.
• Ga-PSMA-HBED-CC PET detected 93.75% of lesions, compared to 81.85% for FDG PET/CT.
• 70% of PSMA-expressing lesions were located in the bones.
• PSMA PET identified a lesion in each of the two thyroglobulin elevation with negative iodide scintigraphy (TENIS) patients.

Conclusions:

• Ga-PSMA-HBED-CC PET/CT is a promising imaging modality for mDTC.
• Most PSMA-expressing metastases (70%) are found in the bones.
• PSMA PET/CT can identify patients with limited treatment options, such as TENIS patients, who may benefit from PSMA-targeted radionuclide therapy.