甲状腺球蛋白检测诊断分化型甲状腺癌的临床意义

Clinical significance of the determination of thyroglobulin in diagnosis of differentiated thyroid carcinoma

目的通过检测颈部可疑淋巴结细针穿刺（FNA）洗脱液中甲状腺球蛋白（Tg）的变化,为判断淋巴结是否有分化型甲状腺癌（DTC）转移提供依据。方法收集DTC术后颈部可疑淋巴结B超引导下的FNA洗脱液标本145例,以颈部反应性增生淋巴结洗脱液标本16例作为对照组。采用免疫化学发光法检测洗脱液标本的FNA-Tg值,结合组织病理结果回顾性分析FNA-Tg测定值在阴性反应性淋巴结（27例）与转移性淋巴结（118例）之间的差异。评价细胞学分析联合不同FNA-Tg临界值判定DTC淋巴结转移的诊断性能。结果转移性淋巴结FNA-Tg测定值[中位数（M）（P25-P75）]为4 163（273-13 138）ng/m L,明显高于阴性反应性淋巴结[0.1（0.1-0.2）ng/m L,P〈0.01]。细胞学方法单独诊断DTC淋巴结转移的敏感性为83.1%、特异性为100%。FNA-Tg的临界值取4.7、47.1 ng/m L时,单独诊断DTC淋巴结转移的敏感性分别为96.6%、91.5%,特异性分别为92.6%、100%。FNA-Tg临界值分别取1、5、10、50及100 ng/m L,与细胞学联合诊断DTC淋巴结转移的敏感性分别为97.5%、97.5%、96.6%、96.6%、96.6%,特异性分别为88.9%、92.6%、92.6%、100%、100%。结论 FNA-Tg检测可作为诊断DTC淋巴结转移的辅助方法。当细胞学诊断为阳性时,FNA-Tg临界值取〉5 ng/m L,可用于提示组织来源（即转移灶为DTC来源）;当细胞学诊断为阴性时,FNA-Tg临界值取〉50 ng/m L,可用于明确诊断,提示病灶为DTC转移性淋巴结。

Objective To provide a reference for the diagnosis of metastatic differentiated thyroid carcinoma（DTC）,through determining the level of thyroglobulin（Tg） in washout fluid of fine needle aspirate（FNA） for suspicious cervical lymph nodes. Methods A total of 145 FNA washout fluid samples were collected from suspicious cervical lymph nodes of patients with DTC after surgery by B ultrasound,and 16 FNA washout fluid samples of cervical reactive proliferation lymph nodes were used as control group. The FNA-Tg levels were determined by chemiluminescence immunoassay. Combined with pathological analysis,the difference of FNA-Tg levels between negative lymph nodes（27 cases）and metastasis lymph nodes（118 cases）was analyzed retrospectively. Combined with cytological analysis,the diagnosis efficiencies for different FNA-Tg cut-off values were evaluated. Results The FNA-Tg level in metastasis lymph node group [median（P25-P75）] was 4 163（273-13 138）ng/m L,which was higher than that in negative lymph node group [0.1（0.1-0.2）ng/m L]（P〈0.01）. The diagnosis sensitivity of cytological analysis was 83.1%,and the specificity was 100%. For cytological analysis,the diagnosis sensitivities were 96.6% and 91.5%,when the cut-off values were 4.7 and 47.1 ng/L,and the specificities were 92.6% and 100%. Combined with cytological analysis,when the cut-off values were 1,5,10,50 and 100 ng/m L,the sensitivities were 97.5%,97.5%,96.6%,96.6% and 96.6%,and the specificities were 88.9%,92.6%,92.6%,100% and 100%. Conclusions FNATg method is an auxiliary method for the determination of lymph node metastasis in the diagnosis of DTC. When the result of cytological analysis is positive,and FNA-Tg cut-off value is 5 ng/m L,metastasis is from DTC. When the result of cytological analysis is negative,and FNA-Tg cut-off value is 50 ng/m L,lymph node has DTC metastasis.