Sentinel Node Navigation in Gastric Cancer: Where Do We Stand?

Tracers in Gastric Cancer Surgery

The treatment of gastric cancer mainly depends on radical gastrectomy. Determination of appropriate surgical margins and adequate lymph node (LN) resection are two major surgical steps that directly correlate with prognosis in gastric cancer. Due to the expanding use of minimally invasive procedures, it is no longer possible to locate tumors and LNs through touch. As an alternative, tracers have begun to enter the field due to their capacities for intraoperative visualization. Herein, we summarize the application of contemporary tracers in gastric cancer surgery, including isosulfan blue, methylene blue, patent blue, indocyanine green, carbon particles, and radioactive tracers. Their mechanisms, administration methods, detection efficiency, and challenges, as well as perspectives on them, are also outlined.

Value of preoperative gastroscopic carbon nanoparticles labeling in patients undergoing laparoscopic radical gastric cancer surgery

BACKGROUND AND OBJECTIVES

Lymph node metastasis is crucial for gastric cancer. We aim to explore the value of preoperative gastroscopic carbon nanoparticles labeling in patients undergoing laparoscopic radical gastric cancer surgery.

METHODS

1199 cases undergoing laparoscopic radical gastric cancer surgery were retrospectively analyzed. 214 cases received preoperative gastroscopic carbon nanoparticles labeling. The number of total lymph nodes detected, positive lymph nodes, N staging, and operation time were analyzed.

RESULTS

The patients received carbon nanoparticles labeling had more total lymph nodes detected (27.9 ± 6.5 vs 22.2 ± 4.0; P ＜ 0.001) and shorter operation time (185.9 ± 27.8min vs 218.7 ± 69.2min; P ＜ 0.001) compared with the control group. In addition, preoperative endoscopic carbon nanoparticles labeling improved the diagnosis rate of synchronous multiple gastric cancer (2.8% vs 0.4%; P ＜ 0.001).

CONCLUSIONS

Preoperative endoscopic carbon nanoparticles tracer labeling is of great value in patients undergoing laparoscopic radical gastric cancer surgery. It shortens the operation time, increases the number of total lymph nodes detected for more accurate pathological TNM staging, and finds some cases of synchronous multiple gastric cancer.

Wnt/β-Catenin Signaling Axis Is Required for TFEB-Mediated Gastric Cancer Metastasis and Epithelial-Mesenchymal Transition

Gastric cancer remains the third leading cause of cancer-related death, and tumor metastasis is the main risk factor for poor prognosis of patients with gastric cancer. Transcription factor EB (TFEB) is a MiT family member and has been found to drive tumorigenesis in a number of tissues, whereas few studies were focused on investigating its prometastasis role and mechanism in gastric cancer. Here, we found TFEB was upregulated in gastric cancer tissues compared with adjacent normal gastric epithelial tissues. IHC analysis from gastric cancer tissue microarray revealed that TFEB in gastric cancer was correlated with depth of tumor invasion, lymph node or distant metastasis, tumor tumor-node-metastasis stage, and overall survival. Gastric cancer cells with TFEB overexpression presented an increased cell migration or invasion, and epithelial-mesenchymal transition (EMT). Furthermore, gene correlation analysis and gene set enrichment analysis enriched Wnt/β-catenin signaling pathway members in TFEB high-expression group, and the TOP/FOPflash assay verified the effect of TFEB on β-catenin transcription activity. Besides, we found that TFEB could trigger the aggregation of β-catenin in nucleus and activate its transcription, as well as facilitate the expression of Wnt/β-catenin target genes and EMT-related markers, which could be reversed by the Wnt/β-catenin inhibitor XAV-939. Collectively, TFEB enhances gastric cancer metastatic potential by activating Wnt/β-catenin signaling pathway and may become a promising therapeutic target for gastric cancer metastasis. IMPLICATIONS: Overexpressed TFEB predicts a higher rate of metastasis and worse survival in patients with gastric cancer. Mechanistically, TFEB activates Wnt/β-catenin signaling to fuel migratory and invasive activities of gastric cancer cells, as well as EMT.

A new method of sentinel node mapping for early gastric cancer using a fluorescent laparoscope that can adjust the intensity of excitation light and quantify the intensity of indocyanine green fluorescence: Report of a case

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VISION SENSE® is a new near-infrared fluorescence laparoscope, and allows adjustment of the intensity of excitation light and quantification of the intensity of ICG fluorescence during observation.

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Using VISION SENSE®, when many ICG-positive lymph nodes are observed, we can select lymph nodes by quantifying ICG fluorescence during surgery.

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This procedure might improve SN mapping for early gastric cancer.

Introduction

One of the drawbacks of indocyanine green (ICG) fluorescence sentinel node (SN) mapping is the impossibility of quantifying lymph node fluorescence during surgery. VISION SENSE® is a new near-infrared fluorescence laparoscope for bright-field full-color observation, and provides the ability to adjust the intensity of excitation light and quantify the intensity of ICG fluorescence during observation.

We report the case of a patient who underwent ICG SN mapping for early gastric cancer using VISION SENSE®.

Presentation of case

A woman in her 60 s was diagnosed with cType0-IIc early gastric cancer located in the anterior wall of the middle gastric body (25 mm in diameter, cT1b, cN0, cM0, cStage IA). Contrast-enhanced computed tomography showed no metastases. Laparoscopy assisted distal gastrectomy with D1+ lymph node dissection and SN mapping with ICG fluorescence using the VISION SENSE® were successfully performed. Using VISION SENSE®, we could select those lymph nodes objectively showing high intensity by quantifying ICG fluorescence during surgery.

The pathological diagnosis was well-differentiated adenocarcinoma, pT1a, N0, M0, pStage IA. No ICG-positive lymph nodes (8 nodes) contained metastases.

Postoperative course was good, with no complications.

Discussion

The use of VISION SENSE® allowing adjustment of excitation light and quantification of ICG fluorescence intensity might decreased the false-negative rate for SNs and increased the sensitivity of the ICG for detecting SNs.

Conclusion

We successfully performed ICG SN mapping for early gastric cancer using VISION SENSE®.

Burgeoning study of sentinel-node analysis on management of early gastric cancer after endoscopic submucosal dissection

Endoscopic submucosal dissection (ESD) represents an organ-preserving alternative to surgical resection of early gastric cancer. However, even with ESD yielding en-bloc resection specimens, there are concerns regarding tumor spread such as with larger lesions, ulcerated lesions, undifferentiated pathology and submucosal invasion. Sentinel node navigational surgery (SNNS) when combined with ESD offers a minimally invasive alternative to the traditional extended gastrectomy and lymphadenectomy if lack of lymph node spread can be confirmed. This would have a clear advantage in terms of potential complications and quality of life. However, SNNS, though useful in other malignancies such as breast cancer and melanoma, may not have a sufficient sensitivity for malignancy and negative predictive value in EGC to justify this as standard practice after ESD. The results of SNNS may improve with greater standardization and more involved dissection, technological innovations and more experience and validation such that the paradigm for post-ESD resection of EGC may change and include SNNS.

[Does sentinel lymph node identification has indication in digestive cancers?]

Despite being a standard of care in several cancers, sentinel lymph node (SLN) is not widespread in digestive cancers. European guidelines do not recommend its use for any digestive cancers. Particularity of the lymphatic vessel, intimately linked to blood vessel, may explain part of this phenomenon. Nevertheless, more indication could arise in the near future with the early diagnosis of tumor induced by cancer screening. Ruling out the lymphatic invasion could allow preserving the organ currently resected because of risk of lymph node positivity. This procedure is well studied in early gastric cancer in Korea and Japan. Several study have demonstrated that, a dual-tracer (isotopic and dye) allows to accurately identify the SLN. A randomized phase 3 trial is currently active in Korea to evaluate the oncological results of the procedure. Similar indication could arise for T1 tumor of the low-rectum, but currently available data are insufficient to recommend its use outside of a study. SLN may also be used to detect aberrant lymphatic drainage (rectum, ileum) but have been tested so far only in a few dozen of patients. Finally, SLN is disappointing in colon cancer, due to its low sensitivity and the absence of modification of the surgical procedure induced.