Vrachimis A, Schober O, Riemann B
Department of Nuclear Medicine, Muenster University, Albert-Schweitzer-Campus 1, Building A1, 48149 Muenster, Germany.
Nuklearmedizin. 2012;51(3):67-72. doi: 10.3413/Nukmed-0432-11-10. Epub 2012 Feb 1.
Radioiodine remnant ablation (RRA) after (near-)total thyroidectomy (TE) is a key element in patients with differentiated thyroid cancer (DTC). The use of exogenous TSH stimulation (rhTSH) prior to RRA has shown promising results as compared to conventional thyroid hormone withdrawal (THW). As yet, the efficacy of RRA after brief THW and single rhTSH administration has not been assessed.
PATIENTS, METHODS: The study sample comprised 147 patients with DTC referred to our center between May 2008 and September 2010. All patients received TE with subsequent RRA. None of these 147 patients had evidence of distant metastasis. 93 patients had endogenous TSH stimulation 4-5 weeks after surgery (group I) and twenty-six received two rhTSH injections (group II). 28 patients were treated with a single rhTSH injection after a brief THW (group III). RRA-Efficacy was assessed three months after therapy by diagnostic whole-body scan and measurement of the tumour marker thyroglobulin (Tg) under TSH stimulation.
Three categories of success were defined for remnant ablation. Based on the definition of successful remnant ablation no visible uptake and a Tg ≤ 2.0 ng/ml (category 1) was seen in 62/93 patients in group I, in 17/26 patients in group II (p = n.s.) and in 12/28 patients in group III (p < 0.05). Visible radioiodine uptake and a Tg ≤ 2.0 ng/ml (category 2) was seen in 16/28 patients of group III and thus significantly more frequent than in group I (28/93 patients) (p < 0.01). However, patients in group III (16/28 patients) and group II (8/26 patients) showed no significant difference in this category (p = n.s.). Visible radioiodine uptake and a Tg > 2.0 ng/ml (category 3) was found in 3/93 patients in group I and 1/26 patients in group II but in no patient in group III.
The third strategy of remnant ablation using a single injection of rhTSH after a brief THW period resulted in a significant higher rate of patients with residual uptake in the thyroid bed and a Tg level below 2 ng/ml three months after remnant ablation in comparison to THW. However, the overall efficacy of the third protocol was not significantly different as compared to two rhTSH injections. Under the aspect of the supply shortage of rhTSH the combined endogenous and exogenous TSH stimulation may be an attractive alternative for remnant ablation in differentiated thyroid cancer.
（近）全甲状腺切除术后进行放射性碘残留消融（RRA）是分化型甲状腺癌（DTC）患者治疗的关键环节。与传统的甲状腺激素撤停（THW）相比，RRA前使用外源性促甲状腺激素（rhTSH）刺激已显示出良好的效果。然而，短暂THW和单次注射rhTSH后RRA的疗效尚未得到评估。
研究样本包括2008年5月至2010年9月转诊至本中心的147例DTC患者。所有患者均接受了甲状腺全切术及后续的RRA。这147例患者均无远处转移证据。93例患者在术后4 - 5周接受内源性促甲状腺激素刺激（I组），26例接受两次rhTSH注射（II组）。28例患者在短暂THW后接受单次rhTSH注射（III组）。治疗三个月后，通过诊断性全身扫描和促甲状腺激素刺激下肿瘤标志物甲状腺球蛋白（Tg）的测量来评估RRA疗效。
残留消融成功分为三类。根据残留消融成功的定义，I组93例患者中有62例未见可见摄取且Tg≤2.0 ng/ml（1类），II组26例患者中有17例（p =无统计学差异），III组28例患者中有12例（p < 0.05）。III组28例患者中有16例可见放射性碘摄取且Tg≤2.0 ng/ml（2类），因此比I组（93例患者中的28例）更常见（p < 0.01）。然而，III组（28例患者中的16例）和II组（26例患者中的8例）在该类别中无显著差异（p =无统计学差异）。I组93例患者中有3例、II组26例患者中有1例可见放射性碘摄取且Tg > 2.0 ng/ml（3类），而III组无患者出现这种情况。
与THW相比，在短暂THW期后单次注射rhTSH的第三种残留消融策略，导致甲状腺床残留摄取且残留消融三个月后Tg水平低于2 ng/ml的患者比例显著更高。然而，与两次注射rhTSH相比，第三种方案的总体疗效无显著差异。鉴于rhTSH供应短缺，内源性和外源性促甲状腺激素联合刺激可能是分化型甲状腺癌残留消融的一个有吸引力的替代方案。
