Comparison of 1.1 GBq and 2.2 GBq Activities in Patients with Low-Risk Differentiated Thyroid Cancer Requiring Postoperative 131I Administration: A Real Life Study.

OBJECTIVES: To compare the efficacy of low and moderate 131I activities in low-risk differentiated thyroid carcinoma (DTC) patients requiring postoperative thyroid remnant ablation in a real-world clinical setting. METHODS: We retrospectively reviewed the records of 299 low-risk DTC patients (pT1-T2, Nx(0) Mx) who had undergone (near)-total thyroidectomy followed by 131I therapy, using either low (1.1 GBq) or moderate (2.2 GBq) radioiodine activities. The response to initial treatments was evaluated after 8-12 months, and patient responses were classified according to the 2015 American Thyroid Association guidelines. RESULTS: An excellent response was observed in 274/299 (91.6%) patients, specifically, in 119/139 (85.6%) and 155/160 (96.9%) patients treated with low and moderate 131I activities, respectively (p = 0.029). A biochemically indeterminate or incomplete response was observed in seventeen (22.2%) patients treated with low 131I activities and three (1.8%) patients treated with moderate 131I activities (p = 0.001). Finally, five patients showed an incomplete structural response, among which three and two received low and moderate 131I activities, respectively (p = 0.654). CONCLUSIONS: When 131I ablation is indicated, we encourage the use of moderate instead of low activities, in order to reach an excellent response in a significantly larger proportion of patients, including patients with the unexpected persistence of the disease.

Preliminary Findings of the Role of FAPi in Prostate Cancer Theranostics.

Prostate cancer (PCa) is the most frequently diagnosed cancer worldwide and the second most common cause of cancer-related deaths among men. Progress in molecular imaging has magnified its clinical management; however, an unmet clinical need involves the identification of new imaging biomarkers that complement the gold standard of prostate-specific membrane antigen (PSMA) positron emission tomography (PET) in cases of clinically significant PCa that do not express PSMA. Fibroblast activation protein (FAP) is a type II transmembrane serine overexpressed in many solid cancers that can be imaged through quinoline-based PET tracers derived from an FAP inhibitor (FAPi). Preliminary results of FAPi application in PCa (in PSMA-negative lesions, and in comparison with fluorodeoxyglucose-FDG) are now available in the literature. FAP-targeting ligands for PCa are not limited to detection, but could also include therapeutic applications. In this preliminary review, we provide an overview of the clinical applications of FAPi ligands in PCa, summarising the main results and highlighting contemporary strengths and limitations.