Bombardieri Emilio, Seregni Ettore, Villano Carlo, Aliberti Gianluca, Mattavelli Franco
Nuclear Medicine Division, National Cancer Institute, Milan, Italy.
Tumori. 2003 Sep-Oct;89(5):533-6. doi: 10.1177/030089160308900515.
The follow-up of thyroid cancer is based on the detection of residual and recurrent thyroid carcinoma. This is traditionally done by means of measurements of serum thyroglobulin (Tg) combined with various imaging techniques (131I-whole body scan, ultrasound and other modalities). Tg serum levels and the uptake of 131I on a whole body scan (WBS) depend on TSH stimulation, which in thyroidectomized patients can be obtained either by withdrawal of thyroid hormone treatment (thyroxine) or by administration of exogenous TSH. At present exogenous human TSH is obtained by means of recombinant DNA technology, (recombinant human TSH (rhTSH), Thyrogen). Even if the administration of rhTSH and withdrawal of thyroid hormone are not completely equivalent, the use of rhTSH has already entered the clinical routine (rhTSH Tg test and rhTSH WBS) because with rhTSH the morbidity and discomfort associated with the withdrawal of thyroid hormone can be avoided. At a recent International Consensus Conference on the follow-up of differentiated thyroid carcinoma it was proposed to carry out only Tg measurement after rhTSH stimulation; moreover, it was stated that 131I whole body scan has to be discouraged in patients submitted to radical surgery and radioiodine ablation with no clinical evidence of residual tumor and with undetectable levels of Tg during hormonal suppression of TSH. Similar strategies in this respect tend to eliminate the 131I WBS and propose only the rhTSH Tg test combined with head and neck ultrasound (US). This is still a matter of debate, also because it is not valid for all risk groups and not all patients undergo the same clinical management (radical surgery or not, thyroid ablation with 131I or not). However, the availability of rhTSH will definitely change the management of papillary and follicular thyroid carcinoma, also with regard to iodine treatment. In fact, rhTSH can be used during radioiodine treatment to enhance the 131I uptake by the cancer cells in particular groups of patients. Patients who could benefit from this approach can be divided into three subgroups: 1) patients in whom thyroxine withdrawal may be dangerous because of the effects of long-term TSH stimulation on the tumor mass (brain metastases, vertebral metastases, presence of neurological signs, heart diseases); 2) patients affected by tumors with marked biological aggressiveness and a low iodine uptake (variants of follicular carcinoma, insular carcinoma, tall and columnar cell variants of papillary thyroid carcinoma, Hürthle cell carcinoma); 3) patients with hypothalamic-pituitary alterations. The potential efficiency of rhTSH in radiometabolic treatment is an important issue that has been studied in a limited number of patients, but is worthy of further investigations in large perspective. A recent clinical prospective trial has been proposed by the Thyroid Cancer Study Group of the Istituto Nazionale Tumori and is now ongoing.
甲状腺癌的随访基于对残余及复发性甲状腺癌的检测。传统上，这是通过检测血清甲状腺球蛋白（Tg）并结合各种成像技术（131I全身扫描、超声及其他方式）来完成的。Tg血清水平及131I在全身扫描（WBS）中的摄取取决于促甲状腺激素（TSH）刺激，对于甲状腺切除术后的患者，可通过停用甲状腺激素治疗（甲状腺素）或给予外源性TSH来实现TSH刺激。目前，外源性人TSH是通过重组DNA技术获得的（重组人TSH（rhTSH），商品名Thyrogen）。即使给予rhTSH和停用甲状腺激素并不完全等效，但rhTSH的使用已进入临床常规（rhTSH Tg检测和rhTSH WBS），因为使用rhTSH可避免与停用甲状腺激素相关的发病率和不适。在最近一次关于分化型甲状腺癌随访的国际共识会议上，提议在rhTSH刺激后仅进行Tg测量；此外，会议指出，对于接受根治性手术及放射性碘消融且无残留肿瘤临床证据、在TSH激素抑制期间Tg水平不可检测的患者，应不鼓励进行131I全身扫描。在这方面的类似策略倾向于取消131I WBS，仅提议将rhTSH Tg检测与头颈超声（US）相结合。这仍是一个有争议的问题，还因为它并非对所有风险组都有效，且并非所有患者都接受相同的临床管理（是否进行根治性手术、是否用131I进行甲状腺消融）。然而，rhTSH的可用性肯定会改变乳头状和滤泡状甲状腺癌的管理，在碘治疗方面也是如此。事实上，rhTSH可在放射性碘治疗期间用于增强特定患者组中癌细胞对131I的摄取。可能从这种方法中获益的患者可分为三个亚组：1）因长期TSH刺激对肿瘤块的影响（脑转移、脊柱转移（椎体转移）、存在神经体征、心脏病）而停用甲状腺素可能危险的患者；2）受具有明显生物学侵袭性且碘摄取低的肿瘤影响的患者（滤泡癌变体、岛状癌、乳头状甲状腺癌的高柱状细胞变体、许特莱细胞癌）；3）下丘脑 - 垂体改变的患者。rhTSH在放射性代谢治疗中的潜在疗效是一个重要问题，虽已在有限数量的患者中进行了研究，但值得从更广泛的角度进行进一步研究。国家肿瘤研究所甲状腺癌研究组最近提出了一项临床前瞻性试验，目前正在进行中。
