Pelizzo M R, Merante Boschin I, Toniato A, Piotto A, Bernante P, Paggetta C, De Salvo G L, Carpi A, Rubello D, Casara D
Department of Surgical Science, University of Padova, Via Giustiniani, 2, 35100, Padova, Italy.
Biomed Pharmacother. 2006 Sep;60(8):405-8. doi: 10.1016/j.biopha.2006.08.001. Epub 2006 Sep 1.
The clinical role of sentinel node biopsy (SNB) in thyroid cancer remains an open matter in literature. The main reason of this fact is that nodal disease is considered a non-relevant prognostic factor by some authors in differentiated thyroid cancer (DTC). Aim of this study was to investigate the efficacy of radiocolloid lymphoscintigraphy and of hand held gamma probe procedure for SNB in patients with DTC and its potential clinical role. Forty-one consecutive pts with a small thyroid nodule highly suspected for malignancy at fine-needle aspiration cytology (FNAC) and without clinical and ultrasonographic (US) evidence of lymph node involvement entered the study. All patients underwent lymphoscintigraphy 3 hours before intervention using a 99mTc-nanocolloid solution. One single intratumoral injection of 4-9 MBq in 0.1-02 ml normal saline was obtained under US-guidance followed by a dynamic lymphoscintigraphy. After total thyroidectomy central and lateral compartments of the neck were scanned with a hand held gamma probe. The hottest node and any lymph node with a count rate of more than 10% of the hottest node were removed. SLNs were sent to frozen section analysis and a surgical enlargement of corresponding compartment was performed when at least one SLN was positive at histology. Preoperative lymphoscintigraphy was able to identify one node in six cases, two nodes in five cases, three nodes in 14 cases, four or more nodes in 16 cases. A papillary thyroid carcinoma (PTC) was diagnosed in 39 cases, a mixed papillary-medullary carcinoma in one case and a micro-follicular adenoma in one case. In 21/40 patients (pts) positive lymph nodes were found: in 16/21 patient one node showed micrometastasis only, in 5/21 patients more nodes were metastatic. In particular in 11 cases the first hottest node was involved (true SLN), in 10 cases a second or third hot lymph node was involved. In our preliminary experience lymphoscintigraphy with 99mTc-nanocolloid resulted highly sensitive: in fact at least one lymph node was visualized in all cases and the surgeon was able to detect by means of hand held probe during intervention al least one hot SLN in all cases. In 21/40 pts (more than 50% of cases) metastatic lymph nodes were found despite preoperative clinical and US examination negative for lymph node involvement. In prospective SLN technique might be proposed as a relevant tool in lymphoadenectomy decision in DTC patients with a small tumor.
前哨淋巴结活检（SNB）在甲状腺癌中的临床作用在文献中仍是一个有待探讨的问题。这一情况的主要原因是，一些作者认为在分化型甲状腺癌（DTC）中，淋巴结病变并非重要的预后因素。本研究旨在探讨放射性胶体淋巴闪烁显像及手持γ探测仪在前哨淋巴结活检中的有效性，及其在DTC患者中的潜在临床作用。41例经细针穿刺细胞学检查（FNAC）高度怀疑为恶性的甲状腺小结节患者，且无临床及超声（US）淋巴结受累证据，纳入本研究。所有患者在干预前3小时接受淋巴闪烁显像，使用99mTc-纳米胶体溶液。在超声引导下，于瘤内单次注射4-9MBq于0.1-0.2ml生理盐水中，随后进行动态淋巴闪烁显像。甲状腺全切除术后，用手持γ探测仪对颈部中央和外侧区进行扫描。切除最热点的淋巴结以及计数率超过最热点淋巴结10%的任何淋巴结。前哨淋巴结送冰冻切片分析，当至少一个前哨淋巴结组织学检查为阳性时，对相应区域进行手术扩大清扫。术前淋巴闪烁显像在6例中发现1个淋巴结，5例中发现2个淋巴结，14例中发现3个淋巴结，16例中发现4个或更多淋巴结。39例诊断为乳头状甲状腺癌（PTC），1例为混合性乳头状-髓样癌，1例为微滤泡性腺瘤。在40例患者中有21例发现阳性淋巴结：21例中的16例仅有1个淋巴结显示微转移，5例有多个淋巴结转移。特别是11例中第一个最热点的淋巴结受累（真正的前哨淋巴结），10例中第二个或第三个热点淋巴结受累。根据我们的初步经验，99mTc-纳米胶体淋巴闪烁显像具有高度敏感性：事实上所有病例中至少有一个淋巴结显影，并且在所有病例中外科医生在干预过程中都能够通过手持探测仪检测到至少一个热点前哨淋巴结。在40例患者中有21例（超过50%的病例）尽管术前临床及超声检查未发现淋巴结受累，但仍发现有转移淋巴结。在前瞻性研究中，对于小肿瘤的DTC患者，前哨淋巴结技术可能是淋巴结清扫决策中的一个重要工具。
