Baudin E, Do Cao C, Cailleux A F, Leboulleux S, Travagli J P, Schlumberger M
Department of Nuclear Medicine and Endocrine Tumors, Institut Gustave Roussy, Villejuif, France 94805.
J Clin Endocrinol Metab. 2003 Mar;88(3):1107-11. doi: 10.1210/jc.2002-021365.
The follow-up of patients with papillary and follicular thyroid carcinoma after thyroidectomy and radioiodine ablation is mainly based on serum thyroglobulin (Tg) level deter-mination. The positive predictive value (PPV) of serum Tg level after thyroid hormone withdrawal, measured during the first 6-12 months of follow-up (initial off L-T(4) Tg), was studied in 256 consecutive differentiated thyroid cancer patients. All underwent a total thyroidectomy and 3.7 GBq (131)I ablation; 37 patients had an elevated initial off L-T(4) Tg level. This study focuses on these 37 patients, 9 of whom had a clinical recurrence. The present data confirm that in this selected cohort of patients, 74-185 MBq (131)I-total body scan (TBS) has no clinical interest in the initial work-up and during the subsequent follow-up because it was negative in all patients, except in one with recurrent disease. The PPV of initial serum off L-T(4) Tg level above 5 ng/ml and 10 ng/ml was 42% and 53%, respectively; this PPV was only 50% at the time of recurrence or subsequent control. This relatively low PPV is related to the low recurrence rate in this series of patients, despite a prolonged follow-up, and to the subsequent decrease of serum Tg level in 14 of 37 (38%) patients in the absence of any further treatment. In contrast, the PPV of the increasing slope of serum Tg levels obtained after thyroid hormone withdrawal (83%) was excellent. In conclusion, we confirm that (131)I-TBS has a limited interest for the follow-up of thyroid cancer patients. Follow-up should rely on serum Tg level and prognostic parameters; however, initial serum Tg may be produced by thyroid tissues of various significance, an increase at two consecutive determinations indicating disease progression and a decrease being related to late effects of therapy. The best PPV is brought by the slope of serum Tg levels.
甲状腺乳头状癌和滤泡状癌患者甲状腺切除及放射性碘消融术后的随访主要基于血清甲状腺球蛋白（Tg）水平测定。对256例连续的分化型甲状腺癌患者研究了甲状腺激素撤药后（首次随访6 - 12个月期间测定，即初始停用左甲状腺素钠后的Tg）血清Tg水平的阳性预测值（PPV）。所有患者均接受了甲状腺全切术及3.7 GBq的碘-131消融；37例患者初始停用左甲状腺素钠后的Tg水平升高。本研究聚焦于这37例患者，其中9例有临床复发。目前的数据证实，在这个选定的患者队列中，74 - 185 MBq的碘-131全身扫描（TBS）在初始检查及后续随访中无临床意义，因为除1例复发患者外，所有患者的扫描结果均为阴性。初始血清停用左甲状腺素钠后的Tg水平高于5 ng/ml和10 ng/ml时的PPV分别为42%和53%；在复发或后续复查时，该PPV仅为50%。尽管随访时间延长，但该系列患者的复发率较低，且37例患者中有14例（38%）在未进行任何进一步治疗的情况下血清Tg水平随后下降，这导致了相对较低的PPV。相比之下，甲状腺激素撤药后血清Tg水平上升斜率的PPV（83%）极佳。总之，我们证实碘-131全身扫描对甲状腺癌患者的随访意义有限。随访应依赖血清Tg水平和预后参数；然而，初始血清Tg可能由具有不同意义的甲状腺组织产生，连续两次测定升高表明疾病进展，下降则与治疗的晚期效应有关。血清Tg水平的斜率具有最佳的PPV。
