de Vries Lisa H, Lodewijk Lutske, Braat Arthur J A T, Krijger Gerard C, Valk Gerlof D, Lam Marnix G E H, Borel Rinkes Inne H M, Vriens Menno R, de Keizer Bart
Department of Surgery, University Medical Centre Utrecht, Heidelberglaan 100, 3584, CX, Utrecht, The Netherlands.
Department of Radiology and Nuclear Medicine, University Medical Centre Utrecht, Heidelberglaan 100, 3584, CX, Utrecht, The Netherlands.
EJNMMI Res. 2020 Mar 6;10(1):18. doi: 10.1186/s13550-020-0610-x.
Differentiated thyroid carcinoma (DTC) is the most common type of thyroid cancer. Treatment with surgery, radioactive iodine (RAI), and TSH suppression is effective in most patients. Five to 15% of patients become RAI refractory and need alternative therapy; however, treatment options are limited. Ga-PSMA PET/CT, originally developed for prostate cancer, is also applicable to other malignancies, including thyroid carcinoma. The uptake of PSMA in thyroid carcinoma gives opportunities for imaging and therapy of RAI-refractory DTC. The aim of this study was to analyze imaging on Ga-PSMA PET/CT and evaluate the response to Lu-PSMA-617 therapy in patients with RAI-refractory DTC.
Five patients with RAI-refractory DTC underwent Ga-PSMA PET/CT to determine their eligibility for Lu-PSMA-617 therapy. Ga-PSMA PET/CTs were analyzed visually and quantitatively. Response to Lu-PSMA-617 therapy was evaluated using imaging and thyroglobulin (Tg) values.
Tracer uptake suspicious for distant metastases was depicted in all Ga-PSMA PET/CTs. Based on tracer uptake, three patients were eligible for Lu-PSMA-617 therapy, of whom two were treated. One patient showed disease progression on imaging 1 month later, while her Tg values gradually increased from 18 to 63 μg/L in the months after treatment. Another patient showed partial, temporary response of lung and liver metastases. Her Tg levels initially decreased from 17 to 9 μg/L. However, 7 months after treatment, there was disease progression on imaging and Tg levels had increased to 14 μg/L. Imaging with Ga-PSMA PET/CT could be compared to FDG PET/CT in three patients. Two patients showed additional lesions on Ga-PSMA PET/CT, and one patient showed concordant imaging.
Ga-PSMA PET/CT appears to have added value in patients with RAI-refractory DTC, as it is able to detect various types of lesions, some of which were not picked up by FDG PET/CT. Furthermore, Ga-PSMA PET/CT might be used to identify patients eligible for treatment with Lu-PSMA-617. One of the two patients who underwent Lu-PSMA-617 therapy showed a modest, temporary response. To draw conclusions about the effectiveness of this therapy, more research is needed.
分化型甲状腺癌（DTC）是最常见的甲状腺癌类型。手术、放射性碘（RAI）和促甲状腺激素（TSH）抑制治疗对大多数患者有效。5%至15%的患者对RAI难治，需要替代治疗；然而，治疗选择有限。镓-前列腺特异性膜抗原（Ga-PSMA）PET/CT最初是为前列腺癌开发的，也适用于包括甲状腺癌在内的其他恶性肿瘤。PSMA在甲状腺癌中的摄取为RAI难治性DTC的成像和治疗提供了机会。本研究的目的是分析Ga-PSMA PET/CT成像，并评估RAI难治性DTC患者对镥-PSMA-617治疗的反应。
5例RAI难治性DTC患者接受Ga-PSMA PET/CT检查，以确定其是否适合接受镥-PSMA-617治疗。对Ga-PSMA PET/CT进行视觉和定量分析。使用成像和甲状腺球蛋白（Tg）值评估对镥-PSMA-617治疗的反应。
所有Ga-PSMA PET/CT均显示有远处转移可疑的示踪剂摄取。根据示踪剂摄取情况，3例患者适合接受镥-PSMA-617治疗，其中2例接受了治疗。1例患者在1个月后的成像中显示疾病进展，而其Tg值在治疗后的几个月内从18μg/L逐渐升至63μg/L。另1例患者的肺和肝转移显示部分、暂时缓解。其Tg水平最初从17μg/L降至9μg/L。然而，治疗7个月后，成像显示疾病进展，Tg水平升至14μg/L。3例患者的Ga-PSMA PET/CT成像可与氟代脱氧葡萄糖（FDG）PET/CT进行比较。2例患者在Ga-PSMA PET/CT上显示有额外病变，1例患者成像结果一致。
Ga-PSMA PET/CT在RAI难治性DTC患者中似乎具有附加价值，因为它能够检测到各种类型的病变，其中一些病变FDG PET/CT未检测到。此外，Ga-PSMA PET/CT可用于识别适合接受镥-PSMA-617治疗的患者。接受镥-PSMA-617治疗的2例患者中有1例显示出适度的、暂时的缓解。为了得出该治疗有效性的结论，还需要更多研究。
