The clinical signification and application value of [Ga]Ga-PSMA imaging in thyroid malignancy.

[PURPOSE] Approximately 5% of differentiated thyroid cancers lose the ability to uptake iodine, leading to limited treatment options and poor prognosis due to invasion and distant metastasis. PSMA imaging probes have been proposed as a potential diagnostic and therapeutic tool for iodine-refractory thyroid cancer. However, there are limited reports and significant heterogeneity in patient selection, warranting further exploration of the application value of PSMA in thyroid cancer.

[METHODS] We performed Western Blot, PCR, and [Ga]Ga-PSMA uptake experiments on cell lines and conducted in vivo small animal imaging. Clinical and radiological results of included differentiated thyroid cancer patients were collected. (Trial registration number: 2021-669, Trial registration date: December 30, 2021).

[RESULTS] PSMA expression levels were significantly higher in poorly differentiated thyroid cancer (7.86 ± 1.90 vs. 1.00 ± 0, P < 0.01; 7.86 ± 1.90 vs. 0.03 ± 0.02, P < 0.01), but [Ga]Ga-PSMA imaging correlated with tumor burden, such as 18F-FDG (8.08 ± 7.74 and 5.67 ± 4.23, P = 0.01) and Tg levels (307.1 ± 183.4 vs. 118.0 ± 116.1, P = 0.002).

[CONCLUSION] Our results showed that PSMA expression increased with the decrease of thyroid cancer differentiation. However, the level of [Ga]Ga-PSMA uptake in thyroid cancer patients was not significantly associated with the degree of thyroid cancer differentiation, but also with the metabolism and burden of tumors such as 2-[F]FDG and Tg levels. These findings provide additional clinical significance and application value for PSMA in thyroid cancer.