Röhrich Manuel
, Im Neuenheimer Feld 400, 69120, Heidelberg, Deutschland.
Radiologie (Heidelb). 2023 May;63(5):354-357. doi: 10.1007/s00117-023-01144-5. Epub 2023 Apr 20.
CLINICAL/METHODOLOGICAL ISSUE: In approximately 2% of all cancers, no primary tumor can be detected and cancer of unknown primary (CUP) syndrome, a diagnosis of exclusion, is made.
In CUP syndrome, computed tomography (CT) and/or magnetic resonance imaging (MRI) do not lead to the detection of primary tumors.
In the advanced diagnostic workup of CUP syndrome, F‑fluordeoxyglucose positron emission tomography/computed tomography (F‑FDG PET/CT) can be used. In addition, Ga-fibroblast activation protein inhibitor (FAPI) PET/CT as a novel, experimental imaging technique may be considered.
F‑FDG PET/CT is clinically established for the detection of primary tumors of cervical CUP syndrome. High detection rates have also been reported for F‑FDG-PET/CT in extracervical CUP syndrome. Ga-FAPI PET/CT has not yet been clinically established, but remarkably high detection rates have been shown for F‑FDG-negative cervical CUP syndrome due to its low background activity.
The benefit of F‑FDG PET in CUP syndrome has been documented in several meta-analyses. To date, the evidence for the use of Ga-FAPI PET/CT in CUP syndrome is still rudimentary.
F‑FDG PET should be applied regularly in cervical CUP syndrome and can be individually considered in extracervical CUP syndrome.
临床/方法学问题：在所有癌症中，约2%的病例无法检测到原发性肿瘤，从而诊断为原发性不明癌症（CUP）综合征，这是一种排除性诊断。
在CUP综合征中，计算机断层扫描（CT）和/或磁共振成像（MRI）无法检测到原发性肿瘤。
在CUP综合征的高级诊断检查中，可使用氟脱氧葡萄糖正电子发射断层扫描/计算机断层扫描（F-FDG PET/CT）。此外，可考虑使用镓成纤维细胞激活蛋白抑制剂（FAPI）PET/CT作为一种新型的实验性成像技术。
F-FDG PET/CT在临床上已被用于检测宫颈CUP综合征的原发性肿瘤。F-FDG PET/CT在宫颈外CUP综合征中的检测率也有报道。Ga-FAPI PET/CT尚未在临床上得到确立，但由于其背景活性低，对于F-FDG阴性的宫颈CUP综合征显示出极高的检测率。
F-FDG PET在CUP综合征中的益处已在多项荟萃分析中得到证实。迄今为止，关于在CUP综合征中使用Ga-FAPI PET/CT的证据仍然初步。
F-FDG PET应定期应用于宫颈CUP综合征，在宫颈外CUP综合征中可个别考虑使用。
