Diagnostic value of 18F-FDG PET/CT and MRI in patients suspected of cancer of unknown primary in the head and neck

Cancer of unknown primary (CUP) is diagnostically challenging. Diagnostic strategy remains controversial.
The aim of this retrospective study was to evaluate the diagnostic value of FDG-PET/CT and MRI in detecting primary tumours in patients presenting with suspected CUP.
Patients referred to FDG-PET/CT for suspected CUP were included retrospectively. Data on demographics, diagnostic tests and imaging was collected. Sensitivity and specificity for FDG-PET/CT and MRI were compared using McNemar’s test.
In a four year period a total of 329 patients were included, 226 (68.7%) with malignant and 103 (31.3%) with benign pathology. Of the 226 with malignant tumours, 150 (66.4%) had head and neck cancer, the majority of which were with oropharyngeal origin 114 (76.0%).
In a subgroup of 80 patients who had both FDG-PET/CT and MRI scans (53.3%), MRI did not significantly increase sensitivity (p = 0.092) in identifying tumour site
There was no significant difference in the sensitivity between FDG-PET/CT and MRI in patients with head and neck cancer or CUP. Adding MRI to the diagnostic workup in occult cancer did not significantly improve detection of primary tumours. In case of malignant tumours, 50% were oropharyngeal cancer and required MRI for preoperative planning.
原发灶不明癌（CUP）的诊断极具挑战性。诊断策略仍存在争议。
本回顾性研究旨在评估PET/CT和MRI在疑有CUP患者原发肿瘤检测中的诊断价值。
回顾性纳入因疑有CUP而接受PET/CT检查的患者。收集患者的人口统计学资料、诊断性检查和影像学资料。采用McNemar检验比较PET/CT和MRI的敏感性和特异性。
四年期间共纳入329例患者, 其中226例（68.7%）为恶性肿瘤, 103例（31.3%）为良性肿瘤。在226例恶性肿瘤患者中, 150例（66.4%）为头颈部肿瘤, 其中大多数起源于口咽部, 共114例（76.0%）。在接受PET/CT和MRI扫描的80例患者亚组（53.3%）中, MRI并未显著提高肿瘤部位的识别敏感性（p=0.092）。
在头颈部肿瘤或原发灶不明癌（CUP）患者中, PET/CT和MRI之间的敏感性无显著差异。在隐匿性肿瘤的诊断流程中加入MRI并未显著提高原发肿瘤的检出率。在恶性肿瘤病例中, 50%为口咽癌, 需要进行MRI检查以进行术前规划。