Leijte Joost A P, van der Ploeg Iris M C, Valdés Olmos Renato A, Nieweg Omgo E, Horenblas Simon
Department of Urology, The Netherlands Cancer Institute-Antoni van Leeuwenhoek Hospital, Amsterdam, The Netherlands.
J Nucl Med. 2009 Mar;50(3):364-7. doi: 10.2967/jnumed.108.059733. Epub 2009 Feb 17.
The reliability of sentinel node biopsy is dependent on the accurate visualization and identification of the sentinel node(s). It has been suggested that extensive metastatic involvement of a sentinel node can lead to blocked inflow and rerouting of lymph fluid to a "neo-sentinel node" that may not yet contain tumor cells, causing a false-negative result. However, there is little evidence to support this hypothesis. Recently introduced hybrid SPECT/CT scanners provide both tomographic lymphoscintigraphy and anatomic detail. Such a scanner enabled the present study of the concept of tumor blockage and rerouting of lymphatic drainage in patients with palpable groin metastases.
Seventeen patients with unilateral palpable and cytologically proven metastases in the groin underwent bilateral conventional lymphoscintigraphy and SPECT/CT before sentinel node biopsy of the contralateral groin. The pattern of lymphatic drainage in the 17 palpable groin metastases was evaluated for signs of tumor blockage or rerouting.
On the CT images, the palpable node metastases could be identified in all 17 groins. Four of the 17 palpable node metastases (24%) showed uptake of radioactivity on the SPECT/CT images. In 10 groins, rerouting of lymphatic drainage to a neo-sentinel node was seen; one neo-sentinel node was located in the contralateral groin. A complete absence of lymphatic drainage was seen in the remaining 3 groins.
The concept of tumor blockage and rerouting was visualized in 76% of the groins with palpable metastases. Precise physical examination and preoperative ultrasound with fine-needle aspiration cytology may identify nodes with considerable tumor invasion at an earlier stage and thereby reduce the incidence of false-negative results.
前哨淋巴结活检的可靠性取决于前哨淋巴结的准确可视化和识别。有人提出，前哨淋巴结广泛转移受累可导致淋巴液流入受阻，并使其改道至可能尚未含有肿瘤细胞的“新前哨淋巴结”，从而导致假阴性结果。然而，几乎没有证据支持这一假说。最近推出的混合型SPECT/CT扫描仪可同时提供断层淋巴闪烁显像和解剖细节。这种扫描仪使本研究能够探讨腹股沟可触及转移瘤患者肿瘤阻塞和淋巴引流改道的概念。
17例单侧腹股沟可触及且经细胞学证实有转移的患者，在对侧腹股沟前哨淋巴结活检前接受了双侧传统淋巴闪烁显像和SPECT/CT检查。评估17例腹股沟可触及转移瘤的淋巴引流模式，以寻找肿瘤阻塞或改道的迹象。
在CT图像上，所有17个腹股沟均可识别出可触及的淋巴结转移灶。17个可触及的淋巴结转移灶中有4个（24%）在SPECT/CT图像上显示有放射性摄取。在10个腹股沟中，可见淋巴引流改道至新前哨淋巴结；1个新前哨淋巴结位于对侧腹股沟。其余3个腹股沟未见淋巴引流。
在76%有可触及转移瘤的腹股沟中观察到了肿瘤阻塞和改道的概念。精确的体格检查和术前超声引导下细针穿刺细胞学检查可能在更早阶段识别出有大量肿瘤浸润的淋巴结，从而降低假阴性结果的发生率。
