Interventional Molecular Imaging Laboratory, Department of Radiology, Leiden University Medical Center, Leiden, The Netherlands.
Department of Urology, The Netherlands Cancer Institute-Antoni van Leeuwenhoek Hospital, Amsterdam, The Netherlands.
Eur J Nucl Med Mol Imaging. 2019 Nov;46(12):2558-2568. doi: 10.1007/s00259-019-04443-z. Epub 2019 Aug 3.
Diagnostic imaging modalities have moderate sensitivity for the identification of lymph node (LN) metastases in prostate cancer (PCa) patients. Mapping the lymphatic drainage from the prostate can help to identify the LNs directly draining from the tumour (sentinel nodes (SNs)); the LNs stated to have the highest chance of containing metastatic cancer cells. Although the lymphatic drainage may differ between segments within the prostate, the location of the primary tumour is not routinely taken into account during peripheral zone-aimed tracer administration. This study evaluates whether linking the SN procedure to the primary cancer deposits increases the identification accuracy of lymphatic metastases.
Sixty-seven PCa patients, scheduled for robot-assisted laparoscopic prostatectomy (RALP) and extended lymph node dissection (ePLND) with subsequent SN biopsy, were included in this retrospective study. After injection of the hybrid tracer ICG-Tc-nanocolloid in the prostate, SN mapping was performed based on lymphoscintigraphy and SPECT/CT. SNs were resected using a combination of radio- and fluorescence guidance. Pathology was used to determine the primary tumour location and metastatic spread. Fluorescence imaging of paraffin-embedded prostate tissue was used to determine the location of the tracer deposits in the prostate. This deposition was related to the primary tumour location, the lymphatic drainage pattern of the injected tracer, and the metastatic spread.
In total 265 radioactive LNs (211 SNs and 54 higher-echelon nodes in 64 patients; 4.3 LNs per patient; IQR: 2-6) were identified. In three patients (4%) preoperative imaging did not allow identification of SNs. Tumour-positive SN visualization within the pelvis was shown to be influenced by intraprostatic location of tracer administration. This could be concluded from (1) a clear correlation between lymphatic drainage to the right or left side of the body and tracer deposition on the right or left side of the prostate, (2) visualization of a higher number of LNs after dorsal tracer deposition compared with ventral tracer deposition, (3) different drainage patterns observed for tracer deposition into the base or apex of the prostate, and (4) the indication that intratumoural tracer deposition increases the chance of visualizing nodal metastases compared with extratumoural tracer deposition.
The correlation between the location of the tracer deposits, the location of the primary tumour, and the visualization of the (tumour-positive) SNs indicated that placement of tracer deposits is of influence on the visualized lymphatic drainage pattern. This suggests that tracer injection near or into the primary tumour site is beneficial for the identification of metastatic spread.
诊断成像方式对前列腺癌（PCa）患者淋巴结（LN）转移的识别具有中等敏感性。对前列腺的淋巴引流进行定位有助于识别直接来自肿瘤的LN（前哨淋巴结（SNs））；这些 LN 被认为具有最高的转移性癌细胞的可能性。尽管前列腺内的不同节段的淋巴引流可能不同，但在进行外周区靶向示踪剂给药时通常不考虑原发肿瘤的位置。本研究评估将 SN 手术与原发性肿瘤结合起来是否能提高对淋巴转移的识别准确性。
67 例 PCa 患者，计划接受机器人辅助腹腔镜前列腺切除术（RALP）和扩大淋巴结清扫术（ePLND），并随后进行 SN 活检，被纳入本回顾性研究。在前列腺内注射混合示踪剂 ICG-Tc-纳米胶体后，根据淋巴闪烁显像和 SPECT/CT 进行 SN 定位。使用放射性和荧光引导相结合的方法切除 SNs。病理检查用于确定原发肿瘤的位置和转移扩散情况。对石蜡包埋的前列腺组织进行荧光成像，以确定前列腺内示踪剂沉积的位置。该沉积与原发肿瘤的位置、注射示踪剂的淋巴引流模式和转移扩散情况相关。
共识别出 265 个放射性 LN（64 名患者中有 211 个 SNs 和 54 个高级别淋巴结，每个患者 4.3 个 LN；IQR：2-6）。在 3 名患者（4%）中，术前影像学无法识别 SNs。骨盆内肿瘤阳性 SN 的可视化受到示踪剂在前列腺内给药部位的影响。这可以从以下几个方面得出结论：（1）身体左右侧的淋巴引流与前列腺左右侧的示踪剂沉积之间存在明确的相关性；（2）与腹侧示踪剂沉积相比，背侧示踪剂沉积后可观察到更多的 LN；（3）观察到不同的示踪剂沉积到前列腺基底部或尖部的引流模式；（4）肿瘤内示踪剂沉积比肿瘤外示踪剂沉积增加了观察到淋巴结转移的机会。
示踪剂沉积的位置、原发肿瘤的位置和（肿瘤阳性）SN 的可视化之间的相关性表明，示踪剂的放置位置会影响可视化的淋巴引流模式。这表明在靠近或进入原发肿瘤部位注射示踪剂有助于识别转移扩散。
