Background:Cancer of unknown primary (CUP) is difficult to diagnose and classify clinically, and the disease develops rapidly. Therefore, the primary tumor detected in patients with CUP plays a profound role in the diagnosis and treatment of patients. The search for the primary tumor of CUP is also one of the indications for 18F-fluoro-2-deoxyglucose-positron emission tomography and computed tomography (FDG-PET/CT). Our objective was to evaluate the role of 18F-FDG PET/CT imaging in primary tumor detection and treatment formulation in patients with CUP.Methods:Sixty-two patients with CUP were selected from a database consisting of 18 802 cases in the Jiangsu Cancer Hospital PET/CT center from May 18, 2016 to November 18, 2022. Clinical data and changes in treatment strategies before and after PET/CT were collected.Results:A total of 42 primary tumors (42/62, 67.7%) were identified by PET/CT examination. The tumor staging of patients before conventional PET/CT imaging (such as CT/magnetic resonance imaging [MRI]/US) and after PET/CT did not change in 28 patients (28/62, 45.2%), whereas for 34 patients (34/62, 54.8%), tumor staging changed. Forty-five patients (45/62, 72.6%) had not developed treatment plans before PET/CT examination, but treatment plans were clarified after PET/CT examination. Thirteen patients (13/62, 21.0%) underwent changes in treatments before and after PET/CT examination. Among the 20 patients (20/62, 32.3%) whose primary tumors were not detected, 16 patients (16/20, 80.0%) had no treatment plans before PET/CT and the treatment plans were defined after PET/CT, 3 patients (3/20, 15.0%) changed the treatment plans before and after PET/CT, and 1 patient (1/20, 5.0%) did not change the treatment plan.Conclusions:The 18F-FDG PET/CT plays an important role in the detection and staging of primary tumors in patients with CUP. The PET/CT findings can not only help clinicians develop appropriate treatment plans for patients with CUP but also serve as an effective approach to improve real-life treatment strategies for these patients.

中文翻译：

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18F-FDG PET/CT 在原发性不明癌症患者治疗策略中的应用：一项单中心、回顾性管理变更研究

背景：原发灶不明的癌症（CUP）临床诊断和分类困难，且病情发展迅速。因此，CUP患者原发肿瘤的检测对于患者的诊断和治疗具有深远的作用。寻找CUP原发肿瘤也是18F-氟-2-脱氧葡萄糖-正电子发射断层扫描和计算机断层扫描（FDG-PET/CT）的适应症之一。我们的目标是评估18F-FDG PET/CT显像在CUP患者原发肿瘤检测及治疗制定中的应用方法收集2016年至2022年11月18日PET/CT前后的临床资料及治疗策略的变化。结果：PET/CT检查共确诊原发肿瘤42个（42/62，67.7%）。常规 PET/CT 成像（如 CT/磁共振成像 [MRI]/US）前和 PET/CT 后患者的肿瘤分期在 28 名患者（28/62，45.2%）中没有变化，而 34 名患者（ 34/62, 54.8%)，肿瘤分期改变。 45例患者（45/62，72.6%）在PET/CT检查前未制定治疗计划，但在PET/CT检查后明确了治疗计划。 13名患者（13/62，21.0%）在PET/CT检查前后治疗发生变化。未检出原发肿瘤的20例患者（20/62，32.3%）中，16例患者（16/20，80.0%）在PET/CT前没有治疗计划，在PET/CT后确定治疗计划，3例患者(3/20, 15.0%)在PET/CT前后改变治疗计划，1例患者(1/20, 5.0%)没有改变治疗计划。结论：18F-FDG PET/CT 在 CUP 患者原发肿瘤的检测和分期中发挥着重要作用。 PET/CT结果不仅可以帮助临床医生为CUP患者制定适当的治疗计划，而且可以作为改善这些患者现实生活中治疗策略的有效方法。