Differential Tumor Biology Between Locoregional and Distant Metastasis in a TENIS Patient with Tyrosine Kinase Inhibitor–Resistant Recurrent Disease: Comparative Evaluation with¹⁸F-FDG,⁶⁸Ga-DOTATATE, and⁶⁸Ga-PSMA-11 PET/CT

Abstract

The molecular PET-CT imaging profile of an interesting case of differentiated thyroid carcinoma, later transformed into with thyroglobulin elevation and negative iodine scintigraphy (TENIS) with tyrosine kinase inhibitor (TKI) resistant recurrent aggressive disease, is presented. The patient was evaluated to assess SSTR-2 or PSMA expression to explore the possibility of any effective targeted nuclear therapy. 18 F-FDG, 68 Ga-DOTATATE and 68 Ga-PSMA-11 PET/CT was performed, which revealed tracer avidity in all 3 scans in the extensive loco-regional disease of large ill-defined retropharyngeal and retro-tracheal soft tissue eroding cricoid cartilage, extending into tracheal lumen and left sided strap muscles. On the contrary, there was no definite uptake in the multiple bilateral lung nodules, the scan findings indicating a differential tumor biology between loco-regional and distant metastasis.

Assessing Krenning’s score on 68Ga-DOTATATE PET-CT and miPSMA score on 68Ga-PSMA-11 PET-CT in TENIS: a comparison with FDG PET/CT and examining the feasibility of targeted radionuclide therapy

“…Specifically, the patients 70, 45, and 36 (Figs. 3–5, respectively), as well as patient 2 [8], demonstrated such findings. Discordant findings between 68 Ga-DOTATATE and 68 Ga-PSMA-11 scans were observed in eight out of 14 patients (57.14%).…”

“…3-5, Ga-PSMA-617, Gallium-68 prostate-specific membrane antigen-617; miPSMA, molecular imaging prostate-specific membrane antigen; PSMA, prostate-specific membrane antigen. respectively), as well as patient 2 [8], demonstrated such findings. Discordant findings between 68 Ga-DOTATATE and 68 Ga-PSMA-11 scans were observed in eight out of 14 patients (57.14%).…”