^18F-FDGPET／CT对原发灶不明颈部淋巴结转移癌的诊断及预后价值

Diagnostic and prognostic values of ^18F-FDG PET/CT in cervical nodal metastatic carcinoma of unknown primary site

目的评价^18F-FDGPET／CT显像对原发灶不明颈部淋巴结转移癌（CCUP）的诊断及预后价值。方法回顾性分析2010年3月至2015年6月137例病理学诊断为CCUP的患者[男95例、女42例，年龄24～84（55．77±11．71）岁]的PET／CT显像结果，将其与病理学和（或）临床长期随访（≥6个月）结果进行比较，计算PET／CT探寻CCUP原发灶的灵敏度、特异性、准确性、阳性预测值及阴性预测值，并应用Kaplan—Meier分析法对患者年龄、性别，是否有远隔转移灶，颈部淋巴结累及区域，颈部淋巴结单、双侧累及，组织学类型，PET／CT是否找到原发灶等因素进行生存分析。结果共96例患者找到原发灶，其中87例经PET／CT显像发现，PET／CT诊断原发灶的灵敏度、特异性、准确性、阳性预测值及阴性预测值分别为90．6％（87／96）、80．5％（33／41）、87．6％（120／137）、91．6％（87／95）和78．6％（33／42）。有远隔转移灶、累及颈部下组淋巴结为影响患者预后的因素（x。=20．990、12．277，均P〈0．01）；颈部SUVmax可能对患者预后有一定影响，ROC曲线显示SUVmax〉6．5患者死亡风险高于其余患者（x^2=7．120，P〈0．01）。结论^18F—FDGPET／CT显像对于探寻CCUP原发灶有十分重要的诊断价值；即使在原发灶不明确时其也能够根据有无远隔转移灶及颈部淋巴结累及范围对患者进行预后评估。

Objective To investigate the diagnostic and prognostic values of ^18F-FDG PET/CT in patients with cervical nodal metastases from carcinoma of unknown primary site （CCUP）. Methods A total of 137 consecutive patients （ 95 males, 42 females, age range 24- 84 （ 55.77 ± 11.71 ） years） with histological proven CCUP who underwent ^18F-FDG PET/CT imaging to find primary tumors from March 2010 to June 2015 were retrospectively analyzed. The gold standard was the final pathological diagnosis or clinical long-term fol- low-up （≥6 months） results. The diagnostic sensitivity, specificity, accuracy, positive predictive value and negative predictive value of PET/CT imaging in detecting primary tumors were calculated. Kaplan-Meier analysis was conducted for survival analysis and to identify the presence of any prognostic factors, such as age, gender, presence or absence of distant metastasis, region of involved cervical lymph nodes, left （right）-side/ both sides of lymph node involvement, histopathologic tumor type and primary site found or not by PET/CT imaging. Results Primary tumors were confirmed in 96 patients, of which 87 patients were diagnosed correctly by ^18F-FDG PET/CT imaging. The diagnostic sensitivity, specificity, accuracy, positive predictive value and negative predictive value were 90.6% （87/96）, 80.5% （33/41）, 87.6% （120/137）, 91.6% （87/95） and 78.6% （33/42） respectively. Primary tumors were found most commonly in the head, neck and lung. However, the false positive and negative lesions were also mainly seen in those sites. Distant metastasis and the inferior region of cervical lymph node metastasis were associated with the worst survival （x^2 = 20.990 and 12. 277, both P〈0.01）. The ROC curve revealed that patients with SUVmax 〉6.5 were of higher mortality risk than those with SUVmax≤6.5 （x^2=7.120, P〈0.01）. Conclusions Whole-body ^18F-FDG PET/CT scan is a significant and valuable tool in the identification of the primary tumor site in patients with CCUP. Furthermore, according to the distant metastasis and region of cervical lymph nodes metastasis, ^18F-FDG PET/CT scans are of value in prognostic evaluation even if without the need to identify the primary tumors.