Endocrine, Breast, and Cancer Surgeon, Bombay Hospital, New Marine Lines, Mumbai, India.
Clin Nucl Med. 2018 Aug;43(8):e265-e268. doi: 10.1097/RLU.0000000000002161.
Prostate-specific membrane antigen (PSMA) overexpression is not restricted to prostate cancer, but it has also been demonstrated in gliomas, lung cancer, and in tumor neovasculature. Systematic studies exploring PSMA uptake in thyroid tumors are lacking. The aim of this pilot study was to assess PSMA expression in patients with metastatic differentiated thyroid cancer (mDTC).
Ten patients of mDTC harboring 32 lesions (5 men; age range, 38-65 years; mean age, 50 years) underwent prospective evaluation with radioiodine (I), F-FDG PET, and Ga-PSMA-HBED-CC PET scans as per the institution protocol. PSMA expression (SUVmax) was compared with F-FDG and I scan findings in all patients.
Lesions were radioiodine avid in 8 patients, whereas 2 were classified as thyroglobulin elevation with negative iodide scintigraphy (TENIS) patients. All patients with iodine-avid metastatic disease showed substantial PSMA uptake. PSMA PET detected 30/32 total lesions (93.75%; SUVmax ranging from 4.86 to 101.81 with median SUVmax of 31.35), whereas FDG PET/CT was positive in 23/32 lesions (81.85%). Twenty-one (70%) of 30 lesions that showed PSMA expression were localized to the bones. PSMA localized a lesion in each of the 2 TENIS patients similar to FDG PET scan.
Ga-PSMA-HBED-CC PET/CT is a potentially useful imaging modality in patients of mDTC with most (70%) of PSMA expressing metastasis being localized to the bones. PSMA PET/CT could be useful for identifying patients with limited therapeutic options (eg, TENIS) who might benefit from PSMA-targeted radionuclide therapy.
前列腺特异性膜抗原（PSMA）的过度表达不仅局限于前列腺癌，也在神经胶质瘤、肺癌和肿瘤新生血管中得到证实。缺乏对甲状腺肿瘤中 PSMA 摄取进行系统研究的报道。本研究的目的是评估转移性分化型甲状腺癌（mDTC）患者 PSMA 的表达情况。
10 例 mDTC 患者共 32 个病灶（5 例男性；年龄 38-65 岁；平均年龄 50 岁），根据机构方案行放射性碘（I）、F-FDG PET 和 Ga-PSMA-HBED-CC PET 扫描的前瞻性评估。所有患者均比较了 PSMA 表达（SUVmax）与 F-FDG 和 I 扫描结果。
8 例患者的病灶对碘有放射性摄取，2 例患者被归类为甲状腺球蛋白升高但碘扫描阴性（TENIS）患者。所有碘摄取转移性疾病患者均有大量 PSMA 摄取。PSMA PET 检测到 32 个病灶中的 30 个（93.75%；SUVmax 范围为 4.86-101.81，中位数 SUVmax 为 31.35），而 FDG PET/CT 阳性 23 个（81.85%）。30 个表达 PSMA 的病灶中有 21 个（70%）定位于骨骼。PSMA 在 2 例 TENIS 患者中均定位到与 FDG PET 扫描相似的病灶。
Ga-PSMA-HBED-CC PET/CT 是 mDTC 患者的一种潜在有用的成像方式，大多数（70%）表达 PSMA 的转移灶定位于骨骼。PSMA PET/CT 可用于识别可能受益于 PSMA 靶向放射性核素治疗的治疗选择有限（如 TENIS）的患者。
