Postgraduate Program, Santa Casa de Belo Horizonte, Belo Horizonte, Brazil.
Thyroid. 2012 Nov;22(11):1165-9. doi: 10.1089/thy.2012.0026. Epub 2012 Oct 10.
Diagnostic radioiodine whole-body scanning (DxWBS) in combination with stimulated thyroglobulin (Tg) (i.e., measurement after levothyroxine [L-T4] withdrawal or recombinant human TSH administration) continues to be recommended for patients with differentiated thyroid carcinoma (DTC) at high or intermediate risk for recurrence with negative basal Tg and ultrasonography (US) after ablation. However, the value of DxWBS has been questioned, even in these cases. The objective of this prospective study was to evaluate the value of DxWBS in these patients.
The study consisted of 318 patients who had total thyroidectomy with apparent complete tumor resection for DTC. Further, per inclusion criteria, they had the following characteristics (i) a post-therapy radioiodine whole-body scan (RxWBS) showing no metastases and uptake in the thyroid bed of ≤2%, (ii) classification as high or intermediate risk for recurrence based on the large tumor size, tumor extension beyond the thyroid capsule, and lymph node metastases, (iii) Tg during L-T4 therapy (TgT4) of <1 ng/mL, (iv) negative anti-Tg antibodies (TgAb), and (v) normal US performed 8-12 months after ablation. Tg stimulation combined with DxWBS was performed in all patients. Patients without apparent disease in the initial assessment were followed up for 24 to 96 months.
In the initial assessment, stimulated Tg continued to be <1 ng/mL in 253 (79.5%) patients and converted to levels >1 ng/mL in 65 (20.4%). None of the patients had metastases on DxWBS, and 46 (14.4%) had discrete uptake (<0.5%) only in the thyroid bed. (18)F-fluorodeoxyglucose positron-emission tomography and computed tomography (FDG-PET/CT) revealed metastases in three patients with elevated stimulated Tg. Fourteen (4.4%) patients without initially apparent disease relapsed during follow-up, including five (2%) with initial stimulated Tg < 1 ng/mL. There was no disease-related death. Thyroid bed uptake on DxWBS had no prognostic value for recurrence, irrespective of stimulated Tg levels.
DxWBS can be avoided in patients with large tumors or extensions beyond the thyroid capsule or lymph node metastases, but who show no apparent disease upon initial RxWBS and US and whose serum TgT4 of <1 ng/mL and negative TgAb after thyroidectomy and ablation.
对于分化型甲状腺癌（DTC）患者，在甲状腺切除术后，若基础甲状腺球蛋白（Tg）水平正常且联合超声检查（US）未见异常，在停服左甲状腺素（L-T4）或给予重组人促甲状腺激素（rhTSH）刺激后，诊断性放射性碘全身扫描（DxWBS）联合血清 Tg 检测（即 Tg 水平在 L-T4 抑制治疗后下降或给予 rhTSH 刺激后）仍然是推荐的随访方法，尤其是对于复发风险较高或中度的患者。然而，即使在这些情况下，DxWBS 的价值也受到了质疑。本前瞻性研究旨在评估 DxWBS 在这些患者中的价值。
本研究纳入了 318 例在甲状腺全切术后因 DTC 接受治疗的患者。所有患者均满足以下纳入标准：（i）术后放射性碘全身扫描（RxWBS）未见转移灶且甲状腺床摄取率≤2%；（ii）根据肿瘤大小、甲状腺外侵犯和淋巴结转移等因素，复发风险被归类为高或中度；（iii）L-T4 抑制治疗期间 Tg（TgT4）<1ng/mL；（iv）抗 Tg 抗体（TgAb）阴性；（v）消融治疗后 8-12 个月行 US 检查未见异常。所有患者均进行了 Tg 刺激后的 DxWBS 检查。初始评估未见明显疾病的患者接受了 24-96 个月的随访。
在初始评估时，253 例（79.5%）患者的刺激 Tg 持续<1ng/mL，65 例（20.4%）患者的 Tg 转为>1ng/mL。所有患者的 DxWBS 均未见转移灶，46 例（14.4%）患者仅在甲状腺床有<0.5%的离散摄取。（18）F-氟代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）显示，3 例 Tg 升高的患者有转移灶。在随访期间，14 例（4.4%）无初始明显疾病的患者复发，其中 5 例（2%）患者的初始刺激 Tg<1ng/mL。无疾病相关死亡。DxWBS 检查显示甲状腺床摄取率与复发无关，无论刺激 Tg 水平如何。
对于 RxWBS 未见异常且血清 TgT4<1ng/mL、TgAb 阴性的大肿瘤或甲状腺外侵犯或淋巴结转移患者，可以避免进行 DxWBS。
