de Geus-Oei Lioe-Fee, Pieters Gerlach F F M, Bonenkamp Johannes J, Mudde Aart H, Bleeker-Rovers Chantal P, Corstens Frans H M, Oyen Wim J G
Department of Nuclear Medicine, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands.
J Nucl Med. 2006 May;47(5):770-5.
Fine-needle aspiration biopsy (FNAB) is inconclusive in up to 20% of patients with solitary thyroid nodules. In these cases, hemithyroidectomy is necessary, but only 20% of the nodules prove to be thyroid carcinoma. The aim of this study was to explore the potential of (18)F-FDG PET to reduce the number of unnecessary hemithyroidectomies in the preoperative assessment of thyroid nodules with inconclusive FNAB results.
Forty-four consecutive patients, scheduled for hemithyroidectomy because of inconclusive FNAB findings, participated in this prospective study. (18)F-FDG PET of the thyroid region was performed before hemithyroidectomy, and standardized uptake values were calculated. The final histopathologic diagnosis served as a standard of reference.
Histopathologic examination of the surgical specimens revealed 7 well-differentiated thyroid carcinomas in 6 patients, all accumulating (18)F-FDG (negative predictive value, 100%). (18)F-FDG accumulated in 13 of 38 benign nodules. The pre-PET probability for cancer in this study population was 14% (6/44), and the post-PET probability increased to 32% (6/19). The percentage of unnecessary hemithyroidectomies in a hypothetical algorithm using (18)F-FDG PET was only 30% (13/44), compared with 86% (38/44) without (18)F-FDG PET. (18)F-FDG PET reduced the number of futile hemithyroidectomies by 66% (25/38) (95% confidence interval, 49%-80%; Fisher's exact test, P = 0.0038). Semiquantitative analysis using standardized uptake values did not help to further reduce this number.
In addition to data in the literature demonstrating accurate detection of thyroid cancer by (18)F-FDG PET, this study showed that (18)F-FDG PET should play an important role in the management of patients with inconclusive cytologic diagnosis of a thyroid nodule. (18)F-FDG PET reduced the number of futile hemithyroidectomies by 66%. Although PET is a relatively costly procedure, this cost outweighs the costs and risks associated with unnecessary thyroid surgery.
在高达20%的孤立性甲状腺结节患者中，细针穿刺活检（FNAB）结果不明确。在这些病例中，需要进行甲状腺半切术，但只有20%的结节被证实为甲状腺癌。本研究的目的是探讨（18）F-FDG PET在术前评估FNAB结果不明确的甲状腺结节时减少不必要甲状腺半切术数量的潜力。
44例因FNAB结果不明确而计划行甲状腺半切术的连续患者参与了这项前瞻性研究。在甲状腺半切术前进行甲状腺区域的（18）F-FDG PET检查，并计算标准化摄取值。最终的组织病理学诊断作为参考标准。
手术标本的组织病理学检查显示6例患者中有7例高分化甲状腺癌，所有病例均摄取（18）F-FDG（阴性预测值为100%）。38个良性结节中有13个摄取（18）F-FDG。本研究人群中术前PET检查时癌症的概率为14%（6/44），术后PET检查时概率增至32%（6/19）。在使用（18）F-FDG PET的假设算法中，不必要甲状腺半切术的比例仅为30%（13/44），而不使用（18）F-FDG PET时为86%（38/44）。（18）F-FDG PET使无效甲状腺半切术的数量减少了66%（25/38）（95%置信区间，49%-80%；Fisher精确检验，P = 0.0038）。使用标准化摄取值进行半定量分析无助于进一步减少这一数量。
除了文献中证明（18）F-FDG PET能准确检测甲状腺癌的数据外，本研究表明（18）F-FDG PET在甲状腺结节细胞学诊断不明确的患者管理中应发挥重要作用。（18）F-FDG PET使无效甲状腺半切术的数量减少了66%。虽然PET是一种相对昂贵的检查，但该成本超过了不必要甲状腺手术相关的成本和风险。
