Sentinel node mapping guided by indocyanine green fluorescence imaging in gastric cancer. Ann Surg. 2009;249:58-62. [PMID: 19106676 DOI: 10.1097/sla.0b013e3181927267]

Bright and Specific Targeting of Metastatic Lymph Nodes in Orthotopic Mouse Models of Gastric Cancer with a Fluorescent Anti-CEA Antibody

BACKGROUND

Gastric cancer poses a major diagnostic and therapeutic challenge. Improved visualization of tumor margins and lymph node metastases with tumor-specific fluorescent markers could improve outcomes.

METHODS

To establish orthotopic models of gastric cancer, one million cells of the human gastric cancer cell line, MKN45, were suspended in 50 μl of equal parts PBS and Matrigel and injected into the nude mouse stomach with a 29-gauge needle. Tumors were allowed to grow for 8-12 weeks before performing imaging studies. For tumor labeling, M5A (humanized anti-CEA mAb) and IgG as a control, were conjugated with the near-infrared dye IRDye800CW. Mice were randomized to receive 50 μg of M5A-IR800 (n = 14) or 50 μg of IgG-IR800 (n = 14) intravenously and were imaged 72 hours later. Fluorescence imaging was performed using the LI-COR Pearl Imaging System.

RESULTS

Forty-two lymph nodes were collected from 28 mice, of which 59.5% were found to contain metastatic gastric cancer cells on pathologic examination. In mice that received M5A-IR800, there was a statistically significant difference in the mean fluorescence signal for cancer-positive lymph nodes at 0.431 (SE ± 0.224) compared with 0.105 (SE ± 0.009) for cancer-negative nodes (p: 0.002). For IgG-IR800, there was no significant difference in the mean fluorescence signal for cancer-positive nodes (0.057) compared with cancer-negative nodes (0.064), p-value 0.677.

CONCLUSIONS

Humanized anti-CEA (M5A) antibodies conjugated to fluorescent dyes provide bright labeling of lymph nodes containing metastatic gastric cancer. This tumor-specific fluorescent antibody is a promising clinical tool for identifying lymph nodes containing metastatic gastric cancer.

Advances in molecular imaging and targeted therapeutics for lymph node metastasis in cancer: a comprehensive review

Lymph node metastasis is a critical indicator of cancer progression, profoundly affecting diagnosis, staging, and treatment decisions. This review article delves into the recent advancements in molecular imaging techniques for lymph nodes, which are pivotal for the early detection and staging of cancer. It provides detailed insights into how these techniques are used to visualize and quantify metastatic cancer cells, resident immune cells, and other molecular markers within lymph nodes. Furthermore, the review highlights the development of innovative, lymph node-targeted therapeutic strategies, which represent a significant shift towards more precise and effective cancer treatments. By examining cutting-edge research and emerging technologies, this review offers a comprehensive overview of the current and potential impact of lymph node-centric approaches on cancer diagnosis, staging, and therapy. Through its exploration of these topics, the review aims to illuminate the increasingly sophisticated landscape of cancer management strategies focused on lymph node assessment and intervention.

Indocyanine green and near-infrared fluorescence-guided surgery for gastric cancer: a narrative review

In recent years, indocyanine green (ICG) and near-infrared (NIR) fluorescence-guided surgery has become a versatile and well-researched tool for gastric cancer treatment. Our narrative review aims to explore the applications, benefits, and challenges that are associated with this technique. Initially used to detect sentinel lymph nodes in early gastric cancer, its scope has broadened to include several clinical applications. Its most notable advantages are the ability to guide standard lymphadenectomy, intraoperatively localize tumors and define tumor margins. Despite these advantages, there are still ongoing discussions regarding its accuracy, lack of standardized administration, and oncologic safety in sentinel node navigation surgery. The limited tumor specificity of ICG has been especially put into question, hindering its ability to accurately differentiate between malignant and healthy tissue. With ongoing innovations and its integration into newer endoscopic and robotic systems, ICG-NIR fluorescence imaging shows promise in becoming a standard tool in the surgical treatment of gastric cancer.

Opportunities and challenges of indocyanine green in gastrointestinal cancers for intraoperative and nano-medicine application

The morbidity and mortality of gastrointestinal tumours remain high worldwide. Surgical resection is currently the most critical radical therapeutic schedule, while postoperative complications and sentinel lymph node (SLN) identification are closely related to the outcome. Indocyanine green (ICG)-mediated fluorescence imaging is increasingly being used in gastrointestinal surgery. It has been embraced by various surgical disciplines as a potential method to improve lymph node detection and enhance surgical field visualization. ICG can passively concentrate in SLN because of enhanced permeation and retention effects. After excitation by near-infrared light devices, SLN can display higher intensity fluorescence, helping visualization for better lymph node dissection. In addition, visual assessment of intestinal blood flow through ICG may reduce the incidence of anastomotic leakage. Although it has good clinical application, ICG-imaging still faces some problems, such as a higher false-negative rate, poorly targeted biodistribution, and lower fluorescence contrast, due to the lack of active tumour targeting. Thus, different ICG-coupled nanoparticles with inherent characteristics or functional modification-enhanced SLN identification features for gastrointestinal cancers bring benefit through active tumour targeting, superior tumour-background ratio, and high resolution. Nano-ICG combined with potential substances, including enhanced imaging contrast and/or combination therapy (chemotherapy, targeted therapy, immunotherapy, etc.), have been packaged and accumulated in the tumour area through active targeting for multimodal imaging and treatment. In this review, we outline the intraoperative application and possible future nanodirections of ICG in gastrointestinal cancer. The prospects and challenges of nano-ICG diagnostic and therapeutic methods in clinical applications are also discussed.

Graphical Abstract

Fluorescence and tracers in surgery: the coming future

The revolution that we are seeing in the world of surgery will determine the way we understand surgical approaches in coming years. Since the implementation of minimally invasive surgery, innovations have constantly been developed to allow the laparoscopic approach to go further and be applied to more and more procedures. In recent years, we have been in the middle of another revolutionary era, with robotic surgery, the application of artificial intelligence and image-guided surgery. The latter includes 3D reconstructions for surgical planning, virtual reality, holograms or tracer-guided surgery, where ICG-guided fluorescence has provided a different perspective on surgery. ICG has been used to identify anatomical structures, assess tissue perfusion, and identify tumors or tumor lymphatic drainage. But the most important thing is that this technology has come hand in hand with the potential to develop other types of tracers that will facilitate the identification of tumor cells and ureters, as well as different light beams to identify anatomical structures. These will lead to other types of systems to assess tissue perfusion without the use of tracers, such as hyperspectral imaging. Combined with the upcoming introduction of ICG quantification, these developments represent a real revolution in the surgical world. With the imminent implementation of these technological advances, a review of their clinical application in general surgery is timely, and this review serves that aim.

Application value of indocyanine green fluorescence imaging in guiding sentinel lymph node biopsy diagnosis of gastric cancer: Meta-analysis

BACKGROUND

Gastric cancer is a common malignant tumor of the digestive system worldwide, and its early diagnosis is crucial to improve the survival rate of patients. Indocyanine green fluorescence imaging (ICG-FI), as a new imaging technology, has shown potential application prospects in oncology surgery. The meta-analysis to study the application value of ICG-FI in the diagnosis of gastric cancer sentinel lymph node biopsy is helpful to comprehensively evaluate the clinical effect of this technology and provide more reliable guidance for clinical practice.

AIM

To assess the diagnostic efficacy of optical imaging in conjunction with indocyanine green (ICG)-guided sentinel lymph node (SLN) biopsy for gastric cancer.

METHODS

Electronic databases such as PubMed, Embase, Medline, Web of Science, and the Cochrane Library were searched for prospective diagnostic tests of optical imaging combined with ICG-guided SLN biopsy. Stata 12.0 software was used for analysis by combining the "bivariable mixed effect model" with the "midas" command. The true positive value, false positive value, false negative value, true negative value, and other information from the included literature were extracted. A literature quality assessment map was drawn to describe the overall quality of the included literature. A forest plot was used for heterogeneity analysis, and P < 0.01 was considered to indicate statistical significance. A funnel plot was used to assess publication bias, and P < 0.1 was considered to indicate statistical significance. The summary receiver operating characteristic (SROC) curve was used to calculate the area under the curve (AUC) to determine the diagnostic accuracy. If there was interstudy heterogeneity (I 2 > 50%), meta-regression analysis and subgroup analysis were performed.

RESULTS

Optical imaging involves two methods: Near-infrared (NIR) imaging and fluorescence imaging. A combination of optical imaging and ICG-guided SLN biopsy was useful for diagnosis. The positive likelihood ratio was 30.39 (95%CI: 0.92-1.00), the sensitivity was 0.95 (95%CI: 0.82-0.99), and the specificity was 1.00 (95%CI: 0.92-1.00). The negative likelihood ratio was 0.05 (95%CI: 0.01-0.20), the diagnostic odds ratio was 225.54 (95%CI: 88.81-572.77), and the SROC AUC was 1.00 (95%CI: The crucial values were sensitivity = 0.95 (95%CI: 0.82-0.99) and specificity = 1.00 (95%CI: 0.92-1.00). The Deeks method revealed that the "diagnostic odds ratio" funnel plot of SLN biopsy for gastric cancer was significantly asymmetrical (P = 0.01), suggesting significant publication bias. Further meta-subgroup analysis revealed that, compared with fluorescence imaging, NIR imaging had greater sensitivity (0.98 vs 0.73). Compared with optical imaging immediately after ICG injection, optical imaging after 20 minutes obtained greater sensitivity (0.98 vs 0.70). Compared with that of patients with an average SLN detection number < 4, the sensitivity of patients with a SLN detection number ≥ 4 was greater (0.96 vs 0.68). Compared with hematoxylin-eosin (HE) staining, immunohistochemical (+ HE) staining showed greater sensitivity (0.99 vs 0.84). Compared with subserous injection of ICG, submucosal injection achieved greater sensitivity (0.98 vs 0.40). Compared with 5 g/L ICG, 0.5 and 0.05 g/L ICG had greater sensitivity (0.98 vs 0.83), and cT1 stage had greater sensitivity (0.96 vs 0.72) than cT2 to cT3 clinical stage. Compared with that of patients ≤ 26, the sensitivity of patients > 26 was greater (0.96 vs 0.65). Compared with the literature published before 2010, the sensitivity of the literature published after 2010 was greater (0.97 vs 0.81), and the differences were statistically significant (all P < 0.05).

CONCLUSION

For the diagnosis of stomach cancer, optical imaging in conjunction with ICG-guided SLN biopsy is a therapeutically viable approach, especially for early gastric cancer. The concentration of ICG used in the SLN biopsy of gastric cancer may be too high. Moreover, NIR imaging is better than fluorescence imaging and may obtain higher sensitivity.

Endoscopic resection and laparoscopic lymph node dissection for early gastric cancer beyond conventional endoscopic treatment indications: a 10-year outcome study

BACKGROUND

Endoscopic full-thickness gastric resection (EFTGR) with laparoscopic regional lymph node dissection (LLND) and endoscopic submucosal dissection (ESD) with LLND have been investigated as treatment options for early gastric cancer beyond the absolute indications for ESD. However, comparative studies on the long-term outcomes of these procedures are lacking. This study aimed to analyze and compare the 10-year outcomes of both procedures in a real clinical setting.

METHODS

Between January 2009 and December 2013, 28 and 37 patients diagnosed with EGC beyond the absolute indications for ESD were treated with EFTGR with LLND and ESD with LLND, respectively. In both procedures, the dye was injected into the tumor. However, after injection and LLND, EFTGR was performed immediately in the EFTGR with LLND group, whereas LLND was followed by ESD in the ESD with LLND group. The primary endpoint was the 10-year survival rate.

RESULTS

The EFTGR with LLND group had one case of local recurrence (3.6%) and mortality (3.6%) each, while the ESD with LLND group had none (0.0% for both); however, the differences were not statistically significant (P = 0.247 for each). Furthermore, there was no significant difference in complications such as ischemia and anastomosis leakage between the groups (P = 0.247).

CONCLUSIONS

When the procedures were properly applied, EFTGR with LLND and ESD with LLND did not increase the 10-year mortality in patients with EGC beyond the absolute ESD indications compared with conventional radical gastrectomy.

Da Vinci robot-assisted endoscopic full-thickness gastric resection with regional lymph node dissection using a 3D near-infrared video system: a single-center 5-year clinical outcome

BACKGROUND

Endoscopic full-thickness gastric resection (EFTGR) with regional lymph node dissection (LND) has been used for early gastric cancer (EGC) exceeding the indications for endoscopic submucosal dissection (ESD). The extent of the dissected lymph nodes is crucial. A 3D near-infrared (NIR) video robot system significantly enhances visualization of the lymphatic system. However, this system has not been used in EFTGR with LND. Thus, this study assessed the benefits of the 3D NIR video robot system in a clinical setting.

METHODS

Between February 2015 and September 2018, 24 patients with EGC exceeding the indications for ESD were treated with EFTGR and LND using a 3D NIR video system with the da Vinci surgical robot. Indocyanine green (ICG) was injected endoscopically around the tumor, and basin node (BN) dissection around the nodes was examined using the 3D NIR video system of the da Vinci Si surgical robot. Subsequently, robot-assisted EFTGR was performed. The primary outcome was the 5-year survival rate.

RESULT

During a 5-year follow-up of all 24 patients, an 80-year-old patient with an ulcer and T2 invasion was lost to follow-up. Among the remaining 23 patients, no mortality or recurrence was observed.

CONCLUSION

No metastasis or mortality occurred using the da Vinci robot-assisted EFTGR with LLND and a 3D NIR video system for patients who required radical gastrectomy for EGC in over 5 years. Hence, this may be a safe and effective method for radical gastrectomy; further studies are required confirming its effectiveness.

Accuracy of ICG compared with technetium-99 m for sentinel lymph node biopsy in vulvar cancer

PURPOSE

Sentinel lymph node biopsy with radioactive tracer is the standard-of-care in lymph node status assessment in vulvar cancer. Indocyanine green fluorescence-ICG is a promising detection method, due to its advantages over technetium-99 m. In vulvar cancer, the procedure is controversial due to study heterogeneity and the small sample size in previous studies. This study evaluates ICG sentinel lymph node detection compared with the criterion-standard with technetium (dual modality method).

METHODS

Preoperative technetium and intraoperative ICG for sentinel lymph node have been prospectively evaluated in early-stage vulvar cancer. The primary endpoint was to determine accuracy in the detection rate for ICG compared with technetium. Secondary objectives included tracer modality relationship with obesity, tumor size and location.

RESULTS

In total, 75 patients participated at 8 centers; 38 had lateral and 37 had midline vulvar tumors. The overall sentinel lymph node detection rate was 85.3 % for technetium and 82.7 % for ICG. For lateral tumors, the detection rate was 84.2 % vs. 89.5 %, while it was 86.5 % vs. 75.7 % for middle tumors, using technetium and ICG, respectively. The median sentinel node harvest was 1.7 (range 1-4), with 24 % metastatic involvement. The sensitivity and positive predictive value for ICG based on the standard technique with technetium was 91.08 % (95 % CI, 83.76-95.84) and 94.8 % (95 % CI, 84.84-96.48), respectively. No significant differences were found comparing the two tracers in patients with midline lesions, obesity (body mass index ≥ 30) and tumor size ≥ 2-4 cm.

CONCLUSION(S)

ICG shows comparable performance parameters to the gold-standard of radioisotope localization.

Factors Affecting the Efficiency of Near-Infrared Indocyanine Green (NIR/ICG) in Lymphatic Mapping for Colorectal Cancer: A Systematic Review

As laparoscopy gained global popularity in oncologic surgery, the challenge of detecting lymph nodes spurred researchers to explore innovative techniques and approach the situation from a fresh perspective. While many proposed methods have faded into obscurity, the utilization of indocyanine green (ICG) in the surgical treatment of oncologic patients has continued to advance. The immense potential of this dye is widely acknowledged, yet its full extent and limitations in lymphatic mapping for colorectal cancer remain to be precisely determined. This article aims to assess the magnitude of its potential and explore the constraints based on insights from clinical studies published by pioneering researchers. A systematic review of the existing literature, comprising articles in English, was conducted using the Scopus, PubMed, and Springer Link databases. The search employed keywords such as "colorectal cancer" AND/OR "indocyanine green," "fluorescence" AND/OR "lymphatic mapping" AND/OR "lymph nodes." Initially identifying 129 articles, the application of selection criteria narrowed down the pool to 10 articles, which served as the primary sources of data for our review. Despite the absence of a standardized protocol for the application of ICG in colorectal cancer, particularly in the context of lymphatic mapping, the detection rates have exhibited considerable variation across studies. Nevertheless, all authors unanimously regarded this technique as beneficial and promising. Additionally, it is advocated as an adjunctive tool to enhance the accuracy of cancer staging. Near-infrared (NIR)-enhanced surgery holds the promise of transforming the landscape of oncologic surgery, emerging as a valuable tool for surgeons. However, the absence of a standardized technique and the subjective nature of result assessment impose limitations on the potential of this method. Consequently, it can be inferred that the establishment of a universally accepted protocol, encompassing parameters such as dose, concentration, technique, and site of administration of ICG, along with the optimal time needed for fluorescence visualization, would enhance the outcomes. Emphasizing the accurate selection of patients is crucial to prevent the occurrence of false-negative results.

Indocyanine green fluorescence imaging-guided versus conventional laparoscopic lymphadenectomy for gastric cancer: long-term outcomes of a phase 3 randomised clinical trial

Indocyanine green (ICG) fluorescence imaging-guided lymphadenectomy has been demonstrated to be effective in increasing the number of lymph nodes (LNs) retrieved in laparoscopic gastrectomy for gastric cancer (GC). Previously, we reported the primary outcomes and short-term secondary outcomes of a phase 3, open-label, randomized clinical trial (NCT03050879) investigating the use of ICG for image-guided lymphadenectomy in patients with potentially resectable GC. Patients were randomly (1:1 ratio) assigned to either the ICG or non-ICG group. The primary outcome was the number of LNs retrieved and has been reported. Here, we report the primary outcome and long-term secondary outcomes including three-year overall survival (OS), three-year disease-free survival (DFS), and recurrence patterns. The per-protocol analysis set population is used for all analyses (258 patients, ICG [n = 129] vs. non-ICG group [n = 129]). The mean total LNs retrieved in the ICG group significantly exceeds that in the non-ICG group (50.5 ± 15.9 vs 42.0 ± 10.3, P < 0.001). Both OS and DFS in the ICG group are significantly better than that in the non-ICG group (log-rank P = 0.015; log-rank P = 0.012, respectively). There is a difference in the overall recurrence rates between the ICG and non-ICG groups (17.8% vs 31.0%). Compared with conventional lymphadenectomy, ICG guided laparoscopic lymphadenectomy is safe and effective in prolonging survival among patients with resectable GC.

Dual tracer navigation for lymph node dissection in laparoscopic radical gastrectomy (DANCE trial): a protocol for a prospective, randomized clinical trial

BACKGROUND

Lymph node (LN) metastasis is the most common metastasis route in gastric cancer. Extensive dissection of LNs can significantly improve the prognosis of patients with gastric cancer. Recently, multiple clinical studies have demonstrated that either indocyanine green (ICG) or carbon nanoparticles (CNs) can assist to promote the dissection of LNs during laparoscopic radical gastrectomy. Considering the pros and cons of the two tracers, this study proposed a novel method of dual tracer (ICG combined with CNs) for lymphatic tracing in laparoscopic gastric cancer surgery.

METHODS

This trial is a prospective, randomized controlled trial (RCT) with an estimation of 516 participants that randomize into 4 groups (1:1:1:1), namely control group, ICG group, CNs group, and dual tracer group. The primary outcome is the number of dissected LNs. The secondary outcomes include positive rate, false positive rate, negative rate, false negative rate, number of metastatic LNs, relationship between LN metastasis and tracer stained, operation duration, blood loss, incision length, morbidity and mortality rate, 3-year DFS (disease free survival), PFS (progression-free survival), and OS (overall survival).

DISCUSSION

This study will investigate the efficacy and safety of a novel strategy using dual tracers for laparoscopic gastrectomy. The protocol has been approved by the Ethics Committee of Nanjing Drum Tower Hospital (2021-361-02). The trial findings will be published in peer-reviewed journals.

TRIAL REGISTRATION

Chinese Clinical Trial Registry (ChiCTR2100051309). Registered 18 September 2021, https://www.chictr.org.cn/showproj.html?proj=133764 .

Quantification of Indocyanine Green Fluorescence Imaging in General, Visceral and Transplant Surgery

Near-infrared (NIR) imaging with indocyanine green (ICG) has proven to be useful in general, visceral, and transplant surgery. However, most studies have performed only qualitative assessments. Therefore, a systematic overview of all studies performing quantitative indocyanine green evaluation in general, visceral, and transplant surgeries should be conducted. Free term and medical subject heading (MeSH) term searches were performed in the Medline and Cochrane databases until October 2022. The main categories of ICG quantification were esophageal surgery (24.6%), reconstructive surgery (24.6%), and colorectal surgery (21.3%). Concordantly, anastomotic leak (41%) was the main endpoint, followed by the assessment of flap perfusion (23%) and the identification of structures and organs (14.8%). Most studies examined open surgery (67.6%) or laparoscopic surgery (23.1%). The analysis was mainly carried out using manufacturer software (44.3%) and open-source software (15.6%). The most frequently analyzed parameter was intensity over time for blood flow assessment, followed by intensity alone or intensity-to-background ratios for structure and organ identification. Intraoperative ICG quantification could become more important with the increasing impact of robotic surgery and machine learning algorithms for image and video analysis.

A TMVP1-modified near-infrared nanoprobe: molecular imaging for tumor metastasis in sentinel lymph node and targeted enhanced photothermal therapy

BACKGROUND

TMVP1 is a novel tumor targeting polypeptide screened by our laboratory with a core sequence of five amino acids LARGR. It specially binds to vascular endothelial growth factor receptor-3 (VEGFR-3), which is mainly expressed on neo-lymphatic vessels in sentinel lymph node (SLN) with tumor metastasis in adults. Here, we prepared a targeted nanoprobe using TMVP1-modified nanomaterials for tumor metastasis SLN imaging.

RESULTS

In this study, TMVP1-modified polymer nanomaterials were loaded with the near-infrared (NIR) fluorescent dye, indocyanine green (ICG), to prepare a molecular imaging TMVP1-ICG nanoparticles (NPs) to identify tumor metastasis in SLN at molecular level. TMVP1-ICG-NPs were successfully prepared using the nano-precipitation method. The particle diameter, morphology, drug encapsulation efficiency, UV absorption spectrum, cytotoxicity, safety, and pharmacokinetic properties were determined. The TMVP1-ICG-NPs had a diameter of approximately 130 nm and an ICG loading rate of 70%. In vitro cell experiments and in vivo mouse experiments confirmed that TMVP1-ICG-NPs have good targeting ability to tumors in situ and to SLN with tumor metastasis by binding to VEGFR-3. Effective photothermal therapy (PTT) with TMVP1-ICG-NPs was confirmed in vitro and in vivo. As expected, TMVP1-ICG-NPs improved ICG blood stability, targeted tumor metastasis to SLN, and enhanced PTT/photodynamic (PDT) therapy, without obvious cytotoxicity, making it a promising theranostic nanomedicine.

CONCLUSION

TMVP1-ICG-NPs identified SLN with tumor metastasis and were used to perform imaging-guided PTT, which makes it a promising strategy for providing real-time NIR fluorescence imaging and intraoperative PTT for patients with SLN metastasis.

Endoscopic fluorescent lymphography for gastric cancer

Lymphography by radioisotope or dye is a well-known technique for visualizing the lymphatic drainage pattern in a neoplastic lesion and it is in use in gastric cancer. Indocyanine green (ICG) more recently has been validated in fluorescent lymphography studies and is under evaluation as a novel tracer agent in gastric cancer. The amount and dilution of ICG injected as well as the site and the time of the injection are not standardized. In our unit, endoscopic submucosal injections of ICG are made as 0.5 mg in 0.5 mL at four peritumoral sites the day before surgery (for a total of 2.0 mg in 2.0 mL). Detection instruments for ICG fluorescence are evolving. Near-infrared systems integrated into laparoscopic or robotic instruments (near-infrared fluorescence imaging) have shown the most promising results. ICG fluorescence recognizes the node that receives lymphatic flow directly from a primary tumor. This is defined as the sentinel lymph node, and it has a high predictive negative value at the cT1 stage, able to reduce the extent of gastrectomy and lymph node dissection. ICG also enhances the number of lymph nodes detected during extended lymphadenectomy for advanced gastric cancer. Nevertheless, the practical effects of ICG use in a single patient are not yet clear. Standardization of the technique and further studies are needed before fluorescent lymphography can be used extensively worldwide. Until then, current guidelines recommend an extensive lymphadenectomy as the standard approach for gastric cancer with suspected metastasis.

Recent Advances in Sentinel Node Navigation Surgery for Early Gastric Cancer

Maintaining the postoperative quality of life (QOL) while ensuring curability without overtreatment is important in the treatment of early gastric cancer. Postoperative QOL is anticipated to be maintained through minimally invasive function-preserving gastrectomy in early gastric cancer. The concept of the sentinel lymph node (SN) basin is essential to maintain the curability of early gastric cancer using minimally invasive function-preserving gastrectomy. However, additional resection after surgery is difficult to perform in gastric cancer. Thus, the SN basin theory is important. Recently, a multicenter randomized phase III trial in South Korea (SENORITA trial) proved that laparoscopic sentinel node navigation surgery (LSNNS) for stomach preservation results in better postoperative QOL compared with standard gastrectomy in patients with early gastric cancer. LSNNS contributes to patients' QOL based on the concept that curability is not impaired. A multicenter nonrandomized phase III trial is ongoing in Japan, and oncologic safety is expected to be demonstrated. LSNNS has been established as a treatment option for selected patients with early gastric cancer, and its application will become widespread in the future.

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.

Mapping Lymph Node during Indocyanine Green Fluorescence-Imaging Guided Gastric Oncologic Surgery: Current Applications and Future Directions

Huge strides have been made in the navigation of gastric cancer surgery thanks to the improvement of intraoperative techniques. For now, the use of indocyanine green (ICG) enhanced fluorescence imaging has received promising results in detecting sentinel lymph nodes (SLNs) and tracing lymphatic drainages, which make it applicable for limited and precise lymphadenectomy. Nevertheless, issues of the lack of specificity and unpredictable false-negative lymph nodes were encountered in gastric oncologic surgery practice using ICG-enhanced fluorescence imaging (ICG-FI), which restrict its application. Here, we reviewed the current application of ICG-FI and assessed potential approaches to improving ICG-FI.

[ICG lymph node mapping in cancer surgery of the upper gastrointestinal tract]

The importance of the assessment of the N‑status in gastric carcinoma, tumors of the gastroesophageal junction and esophageal cancer is undisputed; however, there is currently no internationally validated method for lymph node mapping in esophageal and gastric cancer. Near-infrared fluorescence imaging (NIR) is an innovative technique from the field of vibrational spectroscopy, which in combination with the fluorescent dye indocyanine green (ICG) enables intraoperative real-time visualization of anatomical structures. The ICG currently has four fields of application in oncological surgery: intraoperative real-time angiography for visualization of perfusion, lymphography for visualization of lymphatic vessels, visualization of solid tumors, and (sentinel) lymph node mapping. For imaging of the lymph drainage area and therefore the consecutive lymph nodes, peritumoral injection of ICG must be performed. Several studies have demonstrated the feasibility of peritumoral injection of ICG administered 15 min to 3 days preoperatively with subsequent intraoperative visualization of the lymph nodes. So far prospective randomized studies on the validation of the method are still lacking. In contrast, the use of ICG for lymph node mapping and visualization of sentinel lymph nodes in gastric cancer has been performed in large cohorts as well as in prospective randomized settings. Up to now, multicenter studies for ICG-guided lymph node mapping during oncological surgery of the upper gastrointestinal tract are lacking. Artificial intelligence methods can help to evaluate these techniques in an automated manner in the future as well as to support intraoperative decision making and therefore to improve the quality of oncological surgery.

Indocyanine Green Fluorescence-Guided Surgery for Gastrointestinal Tumors: A Systematic Review

Objective

To conduct a systematic review of the currently available literature on the use of ICG to guide surgical dissection in gastrointestinal (GI) cancer surgery.

Background

Real-time indocyanine green (ICG) fluorescence-guided surgery has the potential to enhance surgical outcomes by increasing patient-tailored oncological precision.

Methods

MEDLINE, PubMed, EMBASE, and Google Scholar were searched for publications on the use of ICG as a contrast agent in GI cancer surgery until December 2020. Perfusion studies were excluded. Quality of the studies was assessed with the Methodological Index for nonrandomized Studies or Jadad scale for randomized controlled trials. A narrative synthesis of the results was provided, with descriptive statistics when appropriate.

Results

Seventy-eight studies were included. ICG was used for primary tumor and metastases localization, for sentinel lymph node detection, and for lymph flow mapping. The detection rate for primary colorectal and gastric tumors was 100% after preoperative ICG endoscopic injection. For liver lesions, the detection rate after intravenous ICG infusion was 80% and up to 100% for lesions less than 8 mm from the liver surface. The detection rate for sentinel lymph nodes was 89.8% for esophageal, 98.6% for gastric, 87.4% for colorectal, and 83.3% for anal tumors, respectively. In comparative studies, ICG significantly increases the quality of D2 lymphadenectomy in oncological gastrectomy.

Conclusion

The use of ICG as a guiding tool for dissection in GI surgery is promising. Further evidence from high-quality studies on larger sample sizes is needed to assess whether ICG-guided surgery may become standard of care.

Indocyanine green (ICG) fluorescence guide for the use and indications in general surgery: recommendations based on the descriptive review of the literature and the analysis of experience

Indocyanine Green is a fluorescent substance visible in near-infrared light. It is useful for the identification of anatomical structures (biliary tract, ureters, parathyroid, thoracic duct), the tissues vascularization (anastomosis in colorectal, esophageal, gastric, bariatric surgery, for plasties and flaps in abdominal wall surgery, liver resection, in strangulated hernias and in intestinal ischemia), for tumor identification (liver, pancreas, adrenal glands, implants of peritoneal carcinomatosis, retroperitoneal tumors and lymphomas) and sentinel node identification and lymphatic mapping in malignant tumors (stomach, breast, colon, rectum, esophagus and skin cancer). The evidence is very encouraging, although standardization of its use and randomized studies with higher number of patients are required to obtain definitive conclusions on its use in general surgery. The aim of this literature review is to provide a guide for the use of ICG fluorescence in general surgery procedures.

Water-soluble near-infrared fluorescent heptamethine dye for lymphatic mapping applications

The identification of sentinel lymph node (SLN) is an important method for prognostic evaluation and minimally invasive staging of metastatic tumors. Here, we report a series of near-infrared fluorescent heptamethylamine dyes (series A, B and C) with central cycloalkene ring modified by tyrosine or N-Boc tyrosine via ether linkage. N-Boc tyrosine/tyrosine modification provided enhanced absorption coefficient and fluorescence quantum yield in DMSO, however with slight hypsochromic shift compared to the mother dyes in DMSO. In PBS, series A and B were found to be more fluorescent than ICG and showed brighter images. Compound A1 was found to exhibit the most favorable imaging performance among all the dyes investigated and was selected for in vivo sentinel lymph node mapping experiments in mice. A1 showed faster response and stronger fluorescence emission than FDA-approved ICG. The lymph node tracing with A1 could be assisted by MB staining. Ex vivo imaging of harvested organs indicated that similar metabolic characteristics of A1 and ICG. Overall, A1 is advantageous over ICG and is very promising for non-invasive lymph node imaging.

The Use of Indocyanine Green (ICG) and Near-Infrared (NIR) Fluorescence-Guided Imaging in Gastric Cancer Surgery: A Narrative Review

Near-infrared fluorescence imaging with indocyanine green is an emerging technology gaining clinical relevance in the field of oncosurgery. In recent decades, it has also been applied in gastric cancer surgery, spreading among surgeons thanks to the diffusion of minimally invasive approaches and the related development of new optic tools. Its most relevant uses in gastric cancer surgery are sentinel node navigation surgery, lymph node mapping during lymphadenectomy, assessment of vascular anatomy, and assessment of anastomotic perfusion. There is still debate regarding the most effective application, but with relatively no collateral effects and without compromising the operative time, indocyanine green fluorescence imaging carved out a role for itself in gastric resections. This review aims to summarize the current indications and evidence for the use of this tool, including the relevant practical details such as dosages and times of administration.

Applicative Limitations of Indocyanine Green Fluorescence Assistance to Laparoscopic Lymph Node Dissection in Total Gastrectomy for Cancer

BACKGROUND

Indocyanine green (ICG) fluorescence has been recently introduced as a novel imaging technique improving the accuracy of lymph node (LN) dissection in gastric cancer (GC) surgery, although procedure standardization and achievements have not been clearly defined. This study analyzed the feasibility and effectiveness of ICG-guidance for laparoscopic D2-lymphadenectomy during total gastrectomy for cancer.

METHODS

This study retrospectively analyzed a single-center series of patients who underwent laparoscopic total gastrectomy for cancer between April 2015 and August 2021. All patients underwent surgery with standard D2 LN dissection. Intraoperative ICG-fluorescence was institutionally implemented in April 2018 and was performed routinely afterward. Primary outcomes were LN harvest and ratio. Secondary endpoints included operative time and subgroup analysis to assess variables potentially affecting LN retrieval.

RESULTS

The study population included 102 patients, and ICG-fluorescence was applied in 38 (37.3%). ICG and no-ICG groups presented similar median age, gender proportions, ASA score and comorbidities (age-adjusted Charlson Comorbidity Index), body mass index, and advanced pathological stage. The median of LNs retrieved was significantly higher after the intraoperative ICG-guidance (44 vs. 32; p = 0.004), although this association was not significant after neoadjuvant therapy or among patients with positive LNs. Lymph node ratio and operative time were not significantly impacted by ICG fluorescence. Multivariate analysis identified the ICG-assistance as the only independent determinant for LN harvest (p = 0.029).

CONCLUSIONS

ICG-guidance contributes to a significantly wider LN retrieval after laparoscopic D2-lymphadenectomy during total gastrectomy for cancer. However, neoadjuvant therapy and positive LN stage appeared to limit the procedural effectiveness to ICG-assisted LN identification.

Clinical Application of Indocyanine Green Fluorescence Technology in Laparoscopic Radical Gastrectomy

Background

This study aimed to observe the application and evaluate the feasibility and safety of indocyanine green (ICG) fluorescence technology in laparoscopic radical gastrectomy (LRG).

Methods

Patients who underwent LRG & D2 lymphadenectomy at Qilu Hospital of Shandong University were included between January 2018 and August 2019. According to whether endoscopic injection of ICG was performed, patients were assigned to the ICG group (n=107) and the control group (n=88). The clinicopathologic features, retrieved lymph nodes, postoperative recovery, and follow-up data were compared between the two groups.

Results

Baseline characteristics are comparable. The ICG group had a significantly larger number of lymph nodes retrieved (49.55 ± 12.72 vs. 44.44 ± 10.20, P<0.05), shorter total operation time (min) (198.22 ± 13.14 vs. 202.50 ± 9.91, P<0.05), shorter dissection time (min) (90.90 ± 5.34 vs. 93.74 ± 5.35, P<0.05) and less blood loss (ml) (27.51 ± 12.83 vs. 32.02 ± 17.99, P<0.05). The median follow-up time was 29.0 months (range 1.5-43.8 months), and there was no significant difference between the ICG group and the control group in 2-year OS (87.8% vs. 82.9%, P>0.05) or DFS (86.0% vs. 80.7%, P>0.05).

Conclusions

ICG fluorescence technology in laparoscopic radical gastrectomy has advantages in LN dissection, operation time, and intraoperative blood loss. The 2-year OS and 2-year DFS rates between the two groups were comparable. In conclusion, ICG fluorescence technology is feasible and safe.

Assessment of indocyanine green fluorescence lymphography on lymphadenectomy during minimally invasive gastric cancer surgery: a systematic review and meta-analysis

BACKGROUND

In recent years, indocyanine green fluorescence lymphography has been introduced for lymphatic mapping in gastric cancer surgery. The aim of this study was to investigate the efficacy of ICGFL in lymph node dissection during minimally invasive surgery for gastric cancer.

METHODS

A systematic review of electronic databases including PubMed, Embase, Web of Science, the Cochrane Library, and China National Knowledge Infrastructure was performed from the inception to January 2021 for all studies comparing ICGFL with non-ICGFL in GC patients undergoing minimal access gastrectomy. The primary outcome was the total number of harvested lymph nodes. The secondary endpoints were the number of metastatic LNs, operative time, estimated blood loss, and postoperative complications. The registration number of this protocol is PROSPERO CRD42020203443.

RESULTS

A total of 13 studies including 1882 participants were included. In this meta-analysis, the use of ICGFL was associated with a higher number of harvested LNs (40.33 vs. 33.40; MD = 6.93; 95%CI: 4.28 to 9.58; P < 0.0001; I2 = 86%). No significant difference was found between the ICGFL and control groups in terms of metastatic LNs (2.63 vs. 2.42; MD = 0.21; 95%CI: -0.46 to 0.87; P = 0.54; I2 = 0%). In addition, the use of ICGFL could be safely performed without increasing the operative time (P = 0.49), estimated blood loss (P = 0.26) and postoperative complications (P = 0.54).

CONCLUSION

The use of ICGFL may be a useful tool facilitating complete lymph node dissection during minimally invasive GC resection. However, more high-quality RCTs with large sample size are needed to validate this issue.

ICG-Guided Lymphadenectomy during Surgery for Colon and Rectal Cancer-Interim Analysis of the GREENLIGHT Trial

Lymphadenectomy is crucial for an optimal oncologic resection of colon and rectal cancers. However, without a direct visualization, an aberrant route of lymph node (LN) diffusion might remain unresected. Indocyanine-green (ICG) lymphatic mapping permits a real-time LNs visualization. We designed the GREENLIGHT trial to explore in 100 patients undergoing robotic colorectal resection the clinical significance of a D3 ICG-guided lymphadenectomy. The primary endpoint was the number of patients in whom ICG changed the extent of lymphadenectomy. We report herein the interim analysis on the first 70 patients. After endoscopic ICG injection 24 h (n = 49) or 72 h (n = 21) ahead, 19, 20, and 31 patients underwent right colectomy, left colectomy, and anterior rectal resection. The extent of lymphadenectomy changed in 35 (50%) patients, mostly (29 (41.4%)) for the identification of LNs (median two) outside the standard draining basin. Identification of such LNs was less frequent in rectal tumors that had undergone chemoradiotherapy (26.3%) (p > 0.05). A non-significant correlation between time-to-ICG injection and identification of aberrant LNs was observed (48.9% at 24 h vs. 23.8% at 72 h). The presence of LN metastases did not affect a proper fluorescent mapping. These data indicate that ICG lymphatic mapping provides relevant information in 50% of patients, thus increasing the accuracy of potentially curative resections.

Intraoperative reperfusion assessment of human pancreas allografts using hyperspectral imaging (HSI)

Background

The most common causes of early graft loss in pancreas transplantation are insufficient blood supply and leakage of the intestinal anastomosis. Therefore, it is critical to monitor graft perfusion and oxygenation during the early post-transplant period. The goal of our pilot study was to evaluate the utility of hyperspectral imaging (HSI) in monitoring the microcirculation of the graft and adequate perfusion of the intestinal anastomosis during pancreatic allotransplantation.

Methods

We imaged pancreatic grafts and intestinal anastomosis in real-time in three consecutive, simultaneous pancreas-kidney transplantations using the TIVITA^® HSI system. Further, the intraoperative oxygen saturation (StO₂), tissue perfusion (near-infrared perfusion index, NIR), organ hemoglobin index (OHI), and tissue water index (TWI) were measured 15 minutes after reperfusion by HSI.

Results

All pancreas grafts showed a high and homogeneous StO₂ (92.6%±10.45%). Intraoperative HSI analysis of the intestinal anastomosis displayed significant differences of StO₂ (graft duodenum 67.46%±5.60% vs. recipient jejunum: 75.93%±4.71%, P<0.001) and TWI {graft duodenum: 0.63±0.09 [I (Index)] vs. recipient jejunum: 0.72±0.09 [I], P<0.001}. NIR and OHI did not display remarkable differences {NIR duodenum: 0.68±0.06 [I] vs. NIR jejunum: 0.69±0.04 [I], P=0.747; OHI duodenum: 0.70±0.12 [I] vs. OHI jejunum: 0.68±0.13 [I], P=0.449}. All 3 patients had an uneventful postoperative course with one displaying a Banff 1a rejection which was responsive to steroid treatment.

Conclusions

Our study shows that contact-free HSI has potential utility as a novel tool for real-time monitoring of human pancreatic grafts after reperfusion, which could improve the outcome of pancreas transplantation. Further investigations are required to determine the predictive value of intraoperative HSI imaging.

Mapping of the perigastric lymphatic network using indocyanine green fluorescence imaging and tissue marking dye in clinically advanced gastric cancer

BACKGROUND

Using indocyanine green (ICG) fluorescence imaging and tissue marking dyes (TMDs), perigastric lymphatic mapping and their pathological correlation were examined to see whether ICG staining covers all metastatic lymph nodes (LNs) in advanced gastric cancer (AGC).

METHODS

Patients with AGC who underwent open distal or total gastrectomy were enrolled. ICG was serially injected intraoperatively into the subserosa along the greater and lesser curvatures. Stomach specimens were examined under a near-infrared camera. ICG-stained LNs were named, excised, and tattooed with different colored TMDs to retrace the exact location after pathological examinations.

RESULTS

A total of 687 LNs and 69 LN stations were examined from 11 patients. The map of the perigastric lymphatic network showing the topography of ICG-stained and ICG-unstained LNs, including metastatic information, was successfully reconstructed. The average number of ICG-stained and ICG-unstained LNs were 23.6 ± 12.3 (37.8%) and 38.8 ± 17.1 (62.2%), respectively. LN metastases were present in 28 LN stations of 8 patients. Of 8 cases with LN metastases, 40% (11.1-75% per case) of metastatic LNs were stained by ICG. Of 28 metastatic LN stations, 21 (75.0%) were covered by ICG, and actual metastatic LNs were stained in 16 LN stations (57.1%). In 4/8 cases (50%), all metastatic LN stations showed ICG signals.

CONCLUSIONS

ICG fluorescence imaging and TMD are useful tools for visualizing the perigastric lymphatic network and retracing the exact location of ICG-stained LNs in AGC. However, ICG imaging is still not recommended for selective LN dissection in AGC because of the limited staining of perigastric LNs.

Safety and efficacy of indocyanine green fluorescence imaging-guided radical gastrectomy: a systematic review and meta-analysis

BACKGROUND

The clinical value of indocyanine green (ICG) in laparoscopic radical gastrectomy remains controversial. We performed this meta-analysis to investigate the safety and efficacy of ICG fluorescence imaging-guided radical gastrectomy.

METHODS

All relevant studies published until 30 October 2020 were retrieved from several databases. Fixed- and random-effects models were used to analyze the results based on different heterogeneity levels. Data were expressed as odds ratios or weighted mean differences along with 95% confidence intervals. The Grading of Recommendations, Assessment, Development, and Evaluation system scale was used for quality of evidence evaluation.

RESULTS

This meta-analysis included six cohort studies that investigated 622 patients. Compared with conventional radical gastrectomy, ICG fluorescence imaging-guided gastrectomy facilitates complete lymph node dissection, reduces intraoperative blood loss, and shortens the length of postoperative hospitalization. Moreover, we observed no significant intergroup differences in the operative time, first exhaust time, and postoperative complications.

CONCLUSION

ICG fluorescence imaging-guided radical gastrectomy scores over conventional gastrectomy and appears to be a promising approach in patients who require radical gastrectomy. However, further research is warranted to explore the potential long-term survival benefit of ICG fluorescence imaging in patients with gastric cancer.

Comparison of submucosal and subserosal approaches toward optimized indocyanine green tracer-guided laparoscopic lymphadenectomy for patients with gastric cancer (FUGES-019): a randomized controlled trial

BACKGROUND

Application of indocyanine green (ICG) fluorescence imaging is effective in guiding laparoscopic radical lymphadenectomy for gastric cancer. However, the optimal approach for indocyanine green injection is controversial. Therefore, the objective of this study was aimed to compare the efficacy and ICG injection between the preoperative submucosal and intraoperative subserosal approaches for lymph node (LN) tracing during laparoscopic gastrectomy.

METHOD

This randomized controlled trial (ClinicalTrials.gov, NCT04219332) included 266 patients with potentially resectable gastric cancer (cT1-T4a, N0/+, M0) enrolled from a tertiary teaching center between December 2019 and October 2020. The primary endpoint was total number of retrieved LNs.

RESULTS

In total, 259 patients (n = 130 and n = 129 in the submucosal and subserosal groups, respectively) were included in the per-protocol analysis. There are no significant differences in total number of retrieved LNs between the two groups (49.8 vs. 49.2, P = 0.713). The rate of LN noncompliance in the submucosal group was comparable to that in the subserosal group (32.3% vs. 33.3%, P = 0.860). No significant difference was found between the submucosal and subserosal groups in terms of the incidence (17.7% vs. 16.3%; P = 0.762) or severity of postoperative complications. The mean fluorescence cost in the submucosal group was higher than that in the subserosal group ($335.3 vs. $182.4; P < 0.001). The overall treatment satisfaction score was lower in the submucosal group than in the subserosal group (70.5 vs. 76.1%, P = 0.048).

CONCLUSION

ICG administered by subserosal injection was comparable to that administered by submucosal injection for lymph node tracing in gastric cancer. However, the former approach imposed a lower economic and mental burden on patients undergoing laparoscopic D2 lymphadenectomy.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT04219332 .

Clinical implications of Indocyanine Green Fluorescence Imaging-Guided laparoscopic lymphadenectomy for patients with gastric cancer: A cohort study from two randomized, controlled trials using individual patient data

BACKGROUND

The value of indocyanine green (ICG) fluorescence imaging in tracing metastatic lymph nodes (LNs) has rarely been reported. We aimed to evaluate the clinical implications of fluorescence imaging-guided lymphadenectomy and the sensitivity of fluorescent lymphography to detect metastatic LN stations in gastric cancer (GC).

MATERIALS AND METHODS

This analysis pooled data from two randomized controlled trials (FUGES-012 and FUGES-019 studies) on laparoscopic ICG tracer-guided lymphadenectomy for GC between November 2018 and October 2020. Patients who received ICG injection using either the intraoperative subserosal or preoperative submucosal approaches 1 day before surgery and underwent fluorescence imaging-guided lymphadenectomy were defined as the ICG group. Patients who underwent conventional lymphadenectomy without ICG injection and intraoperative imaging were defined as the non-ICG group.

RESULTS

Among 514 enrolled patients, the ICG and non-ICG groups included 385 and 129, respectively. A significantly higher mean number of LNs was retrieved in the ICG group than in the non-ICG group (49.9 vs. 42.0, P < 0.001). The ICG group showed a lower LN noncompliance rate than that in the non-ICG group (31.9% vs. 57.4%, P < 0.001). The sensitivity of fluorescence imaging for detecting all metastatic LN stations was 86.8%. The negative predictive value was 92.2% for nonfluorescent stations. For detecting all metastatic stations, subgroup analysis revealed 97.7%, 91.7%, 86.2%, and 84.3% sensitivities for pT1, pT2, pT3, and pT4a tumors, respectively. Regardless of gastrectomy type, the diagnostic accuracy for detecting all metastatic stations in the D1+ and D2 stations for cT1-cT2 disease reached 100%.

CONCLUSION

ICG fluorescence imaging, using either the subserosal or submucosal approaches, assisted in the thorough dissection of potentially metastatic LNs, as recommended for individualized laparoscopic lymphadenectomy for GC.

Real-time fluorescence image-guided gastrointestinal oncologic surgery: Towards a new era

Technological improvements are crucial in the evolution of surgery. Real-time fluorescence-guided surgery (FGS) has spread worldwide, mainly because of its usefulness during the intraoperative decision-making processes. The success of any gastrointestinal oncologic resection is based on the anatomical identification of the primary tumor and its regional lymph nodes. FGS allows also to evaluate the blood perfusion at the gastrointestinal stumps after colorectal or esophageal resections. Therefore, a reduction on the anastomotic leak rates has been postulated as one of the foreseeable benefits provided by the use of FGS in these procedures. Although the use of fluorescence in lymph node detection was initially described in breast cancer surgery, the technique is currently applied in gastric or splenic flexure cancers, as they both present complex and variable lymphatic drainages. FGS allows also to perform intraoperative lymphograms or sentinel lymph node biopsies. New applications of FGS are being developed to assist in the detection of peritoneal metastases or in the evaluation of the tumor resection margins. The present review aims to provide a general overview of the current status of real-time FGS in gastrointestinal oncologic surgery. We put a special focus on the different applications of FGS, discussing the main findings and limitations found in the contemporary literature and also the promising near future applications.

The short-term and long-term outcomes of indocyanine green tracer-guided laparoscopic radical gastrectomy in patients with gastric cancer

Background

The safety and efficacy of indocyanine green (ICG) imaging navigational laparoscopic gastrectomy remain controversial. This study is to evaluate the short-term and long-term outcomes of ICG-guided laparoscopic radial gastrectomy in patients with gastric cancer.

Methods

Consecutive patients with definitive diagnosis of gastric cancer that underwent laparoscopic radical gastrectomy were collected retrospectively. Propensity score matching (PSM) at 1:1 ratio was performed to compare the outcomes of two groups.

Results

A total of 122 qualified patients were divided into ICG group (n = 34) and non-ICG group (n = 88). PSM yielded 28 patients with comparable baseline characteristics into each group. The number of retrieved lymph node in ICG group was significantly higher than that in non-ICG group (P = 0.0196). There was no statistical difference of perioperative, short-term, and long-term complications between the two groups.

Conclusion

ICG-guided laparoscopic radical gastrectomy is safe and effective, and ICG-navigated lymphadenectomy improves the number of retrieved lymph nodes for patients with gastric cancer.

Optimal Lymphadenectomy of the Mesopancreas Based on Fluorescence Imaging During Pancreaticoduodenectomy

BACKGROUND

Excision of the mesopancreas with lymphadenectomy is an important component of pancreatoduodenectomy. However, the optimal extent of lymphadenectomy remains unclear. Furthermore, accurate description of the mesopancreatic lymphatic pathways is difficult, probably because of the complex anatomy. Intestinal derotation simplifies the anatomy and facilitates both examination of lymphatic flow and the surgical procedure. The aim of this study was to evaluate lymphatic flow in the mesopancreas using indocyanine green fluorescence imaging with an intestinal derotation technique, and to clarify the optimal extent of mesopancreas excision and lymphadenectomy in pancreatoduodenectomy.

METHODS

Indocyanine green solution (2.5 × 10^-3 mg) was injected into the pancreatic head parenchyma. After intestinal derotation, the spread of indocyanine green was observed using near-infrared imaging.

RESULTS

Participants comprised 10 patients who underwent pancreatoduodenectomy for periampullary neoplasms. With indocyanine green fluorescence imaging, 9 of the 10 patients showed lymphatic flow from the pancreatic head to the superior mesenteric artery via the inferior pancreaticoduodenal artery and first jejunal artery (but not via the second and more distant arteries), with eventual drainage into the paraaortic region.

CONCLUSIONS

Lymphatic pathways from the pancreatic head were connected to the superior mesenteric artery via the inferior pancreaticoduodenal artery and first jejunal artery. Excision of the mesopancreas with the inferior pancreaticoduodenal artery and first jejunal artery while preserving the second or more distant arteries appears optimal in pancreatoduodenectomy for periampullary malignancies.

Intraoperative guidance using ICG fluorescence imaging system for safe and precise laparoscopic liver resection

BACKGROUND

Laparoscopic liver resection (LLR) has been spread as minimally invasive surgery for liver disease. Advances in surgical technique and devices enabled us to perform various procedures of LLR. Indocyanine green (ICG) fluorescence imaging has been suggested as useful tool to identify liver tumors, anatomical territory of liver parenchyma, and cholangiography in open liver surgery. Due to recent development, this technology can be applied in LLR. we describe safe and effective using of the ICG fluorescence imaging during LLR.

METHODS

From September 2013 to August 2019, 34 patients were performed LLR using a total of 46 procedures by ICG fluorescence imaging system for purposes including identification of anatomic domain of the liver in 12 LLRs, detection of liver tumors in 30 nodules, or intraoperative cholangiography in 4 LLRs.

RESULTS

During the detection of liver tumors, 25 nodules in 30 malignant to benign tumors were positively detected (83.3%). Although there has been no publication regarding information on ICG fluorescence imaging of low grade malignant or benign tumors, we found positive emission in focal nodular hyperplasia, an angiomyolipoma, and an intraductal papillary neoplasm of the bile duct. The identification of anatomic domain in the liver was successful in all 12 LLRs with negative and positive staining techniques. In the intraoperative cholangiography, all 4 tests were successfully performed. One of 4 patients were found to have biliary leakage which was repaired intraoperatively.

CONCLUSIONS

The ICG fluorescence imaging could be useful in safe and precise performance of LLR.

ICG-NIR-guided lymph node dissection during robotic subtotal gastrectomy for gastric cancer. A single-centre experience

BACKGROUND

Near-infrared (NIR) fluorescence imaging with indocyanine green (ICG) allows intraoperative visualisation of the lymph nodes (LNs) draining the tumour.

METHODS

We included in our study 20 patients who underwent robotic subtotal gastrectomy + D2 lymphadenectomy for gastric cancer. In 10 cases, intraoperative ICG-guided lymphography has been used (Group A). We compared the number of LNs retrieved with the use of NIR imaging and the number of LNs retrieved without the use of this technique (Group B, historical group).

RESULTS

No complications related to ICG injection or near-infrared imaging were observed. The mean number of overall LNs retrieved was significantly greater in Group A than in group B (40 vs. 24). No statistically significant difference in operative time was observed.

CONCLUSIONS

ICG-guided fluorescent lymphography can help in performing a more accurate locoregional lymphadenectomy during robotic subtotal gastrectomy for gastric cancer. This technique represents a precious contribution to gastric cancer surgery.

How useful is sentinel lymph node biopsy for the status of lymph node metastasis in cT1N0M0 gastric cancer? A systematic review and meta-analysis

Sentinel lymph node biopsy (SLNB) is intriguing because it is expected to further expand the indication of endoscopic resection (ER) for cT1N0M0 gastric cancer and as an additional operation for post-ER gastric cancer. The aim of our study was to perform a systematic review and meta-analysis on the feasibility and diagnostic value of SLNB technique in patients with cT1N0M0 gastric cancer. Eligible studies were systematically searched in PubMed, Embase, and Cochrane Library databases from inception to April 2020. A random-effect model was used to pool the data, and subgroup analysis was used to explain the heterogeneities. A total of 22 clinical studies (1993 patients with cT1N0M0 gastric cancer) were included. The pooled SLN identification rate, sensitivity, specificity, and diagnostic odds ratio with 95% confidence intervals were 0.99 (0.99-1.00), 0.92 (0.88-0.95), 1.00 (1.00-1.00), and 832.8 (395.5-1753.6), respectively. The summary receiver operator characteristic displayed a test accuracy of 99.3%. Subgroup analysis found an improved SLN sensitivity for studies with the mean number of SLNs > 4 and studies stained with a combination of hematoxylin-eosin with immunohistochemistry (HE + IHC). Further, studies using the basin dissection were associated with a higher SLN identification rate. The current meta-analysis provides data that favors the use of SLNB for predicting the status of lymph node metastasis in patients with cT1N0M0 gastric cancer. However, establishing standard procedure and suitable criteria for further application and optimization of SLNB is urgently needed.

Assessment of diagnostic value of fluorescent lymphography-guided lymphadenectomy for gastric cancer

BACKGROUND

Indocyanine green fluorescent lymphography helps visualize the lymphatic drainage pattern in gastric cancer; however, it is unknown whether fluorescent lymphography visualizes all metastatic lymph nodes. This study aimed to evaluate the sensitivity of fluorescent lymphography to detect metastatic lymph node stations and lymph nodes and the risk of false-negative findings.

METHODS

Patients with clinical T1-4a gastric cancer were included. Indocyanine green was peritumorally injected the day prior to surgery by endoscopy. Gastrectomy with systematic D1+ or D2 lymphadenectomy was performed. Stations and lymph nodes were retrieved at the back-table using near-infrared imaging and classified as "fluorescent" or "non-fluorescent" and later matched with histopathological findings.

RESULTS

Among 592 patients who underwent minimally invasive gastrectomy from September 2013 until December 2016, lymph node metastases were present in 150. The sensitivity of fluorescent lymphography in detecting all metastatic lymph node stations was 95.3% (143/150 patients), with a false-negative rate of 4.7% (7/150 patients) and the sensitivity in detecting all metastatic lymph nodes was 81.3% (122/150 patients). The negative predictive value was 99.3% for non-fluorescent stations and 99.2% for non-fluorescent LNs. For detecting all metastatic LN stations, subgroup analysis revealed 100% sensitivity for pT1a, 96.8% for pT1b, 100% for pT2, 91.3% for pT3, and 93.6% for pT4a tumors.

CONCLUSIONS

Fluorescent lymphography-guided lymphadenectomy can be a useful method for radical lymphadenectomy by facilitating the complete dissection of all potentially positive LN stations. Fluorescent lymphography-guided lymphadenectomy appears to be a reasonable alternative to conventional systematic lymphadenectomy for gastric cancer.

Diagnostic value of indocyanine green fluorescence guided sentinel lymph node biopsy in vulvar cancer: A systematic review

INTRODUCTION

Sentinel lymph node biopsy (SLN) helps define lymph node status, a major prognostic factor in vulvar cancer. The aim of the current systematic review was to assess the use of indocyanine green (ICG) coupled with near-infrared (NIR) fluorescence imaging in SLN mapping in vulvar cancer in terms of technique used, feasibility and accuracy.

DATA SOURCES

We performed a systematic review using bibliographic citations from PubMed, Clinical Trials.gov, Embase, Cochrane Library, and Web of Science databases. MeSH terms for SLN, ICG and vulvar cancer were combined and restricted to the English language. The final search was performed on May 28, 2020. The primary outcome was to determine if the use of ICG alone in detecting SLN in women with vulvar cancer is as accurate as the gold standard dual labeling technique.

RESULTS

Of the 34 studies initially identified, 13 were included for analysis. The SLN detection rate with ICG and NIR fluorescence ranged from 89.7 to 100%. No studies demonstrated the superiority of other detection techniques compared to ICG and NIR imaging. Lower SLN detection rates were found in studies with the most metastatic lymph nodes. No consensus was reached concerning the optimal use of ICG in terms of: injection timing or site; concentrations or volume of ICG; or use of human serum albumin or hybrid tracer. No adverse events were reported.

CONCLUSION

ICG for SLN mapping appears to be safe in women with vulvar cancer with a detection rate similar to the current techniques. A large prospective randomized controlled study with optimization of the technique is necessary to homogenize current practice and determine the true value of ICG in vulvar cancer.

PROSPERO ID

CRD42020178261.

SiPM-based gamma detector with a central GRIN lens for a visible/NIRF/gamma multi-modal laparoscope

Intraoperative imaging has been studied using conventional devices such as near infrared (NIR) optical probes and gamma probes. However, these devices have limited depth penetration and spatial resolution. In a previous study, we realized a multi-modal endoscopic system. However, charge-coupled device (CCD)-based gamma imaging required long acquisition times and lacked gamma energy information. A silicon photomultiplier (SiPM)-based gamma detector is implemented in a multi-modal laparoscope herein. A gradient index (GRIN) lens and CCD are used to transfer and readout visible and NIR photons. The feasibility of in-vivo sentinel lymph node (SLN) mapping was successfully performed with the proposed system.

A Systematic Review and Meta-Analysis of Sentinel Lymph Node Biopsy in Gastric Cancer, an Optimization of Imaging Protocol for Tracer Mapping

BACKGROUND

Sentinel lymph node biopsy (SLNB) plays an essential role in the evaluation of lymph node (LN) metastasis status and the extent of LN dissection in gastric cancer. The aim of our study was to perform a systematic review and meta-analysis for corresponding identification rate and sensitivity of different SLNB techniques.

METHODS

Systematic search using PubMed, Embase, and Cochrane library databases was conducted for studies on SLNB in patients with gastric cancer. Studies were stratified according to the sentinel lymph node (SLN) biopsy technique: blue dye (BD), radiocolloid tracer (RI), indocyanine green (ICG), a combination of radiocolloid with blue dye (RI + BD), and a combination of radiocolloid with ICG (RI + ICG). A random-effect model was used to pool the identification rate, sensitivity, and accuracy.

RESULTS

A total of 54 eligible studies (3767 patients) was included. The pooled identification rates of SLNB using BD, RI, ICG, RI + BD, RI + ICG were 95% (95%CI: 92-97%), 95% (95%CI: 93-97%), 99% (95%CI: 97-99%), 97% (95%CI: 96-98%), and 95% (95%CI: 87-99%), respectively. The pooled sensitivities were 82% (95%CI: 77-86%), 87% (95%CI: 81-92%), 90% (95%CI: 82-95%), 89% (95%CI: 84-93%), and 88% (95%CI: 79-94%), respectively. The pooled accuracies were 94% (95%CI: 91-96%), 95% (95%CI: 92-97%), 98% (95%CI: 95-99%), 97% (95%CI: 95-99%), and 98% (95%CI: 95-99%), respectively.

CONCLUSIONS

The current meta-analysis provides reliable evidence that favors the use of ICG and dual tracer method (RI + BD/ICG) for the identification of the SLN. Considering the high costs and potential biohazard of using radioactive substances in dual tracer method, performing SLNB with ICG is the technique of choice for experienced surgeons.

Recent updates and current issues of sentinel node navigation surgery for early gastric cancer

With the increase in the incidence of early gastric cancer (EGC), several endoscopic and laparoscopic approaches, such as endoscopic submucosal dissection and function-preserving gastrectomy, have been accepted as standard treatments. Sentinel node navigation surgery (SNNS) is an ideal surgical option for preservation of most parts of the stomach and consequent maintenance of normal gastric function to improve quality of life in patients with EGC. Although many previous studies and clinical trials have demonstrated the safety and feasibility of the sentinel node concept in gastric cancer, the clinical application of SNNS is debatable. Several issues regarding technical standardization and oncological safety need to be resolved. Recently several studies to resolve these problems are being actively performed, and SNNS might be an important surgical option in the treatment of gastric cancer in the future.

Intraoperative Molecular Imaging Utilizing a Folate Receptor-Targeted Near-Infrared Probe Can Identify Macroscopic Gastric Adenocarcinomas

PURPOSE

Current methods of assessing disease burden in gastric adenocarcinoma are imperfect. Improved visualization during surgery with intraoperative molecular imaging (IMI) could improve gastric adenocarcinoma staging and guide surgical decision-making. The goal of this study was to evaluate if IMI with a folate receptor-targeted near-infrared fluorescent agent, OTL38, could identify gastric adenocarcinomas during surgery.

PROCEDURES

Five patients were enrolled in an IMI clinical trial. Patients received a folate receptor-targeted near-infrared dye (OTL38) 1.5-6 h prior to surgery. During staging laparoscopy and gastric resection, IMI was utilized to identify the primary tumor and any fluorescent lymph nodes. Resected tumors were analyzed for folate receptor alpha (FRα) and CD68 expression using immunohistochemistry. Microscopic OTL38 accumulation was examined with immunofluorescence.

RESULTS

Four out of five patients underwent total or subtotal gastrectomy; one had a staging laparoscopy only. All four patients who underwent gastric resection had invasive gastric adenocarcinoma; three had fluorescent tumors, mean tumor to background ratio (TBR) 4.1 ± 2.9. The one patient with a non-fluorescent tumor had a T1a tumor with two 0.4 cm tumor foci within a larger polyp. In each case with a fluorescent tumor, the fluorescence was evident from the exterior of the stomach. Two of the fluorescent tumors had modest FRα expression and no CD68 expression. One fluorescent tumor had high CD68 expression and no FRα expression.

CONCLUSIONS

Intraoperative molecular imaging of gastric adenocarcinoma with OTL38 is feasible. Further studies should evaluate the clinical utility of this technique.

The Clinical Value of Fluorescent Lymphography with Indocyanine Green During Robotic Surgery for Gastric Cancer: a Matched Cohort Study

BACKGROUND

Near-infrared (NIR) fluorescence imaging with indocyanine green (ICG) has been recently introduced for lymphatic mapping in several tumors. We aimed at investigating whether this technology may improve the intraoperative visualization of lymph nodes during robotic gastrectomy for gastric cancer.

METHODS

Between June 2014 and June 2018, a total of 94 patients underwent robotic gastrectomy with D2 lymph node dissection for gastric cancer. In 37 patients, ICG was injected endoscopically into the submucosal layer around the tumor the day before surgery. After propensity score matching, the results of these 37 patients were compared with the results of 37 control patients who had undergone robotic gastrectomy without ICG injection.

RESULTS

Among the 37 patients within the ICG group, no adverse events related to ICG injection or intraoperative NIR imaging occurred. After completion of D2 lymph node dissection, no residual fluorescent lymph nodes were left in the surgical field. A mean of 19.4 ± 14.7 fluorescent lymph nodes was identified per patient. The mean total number of harvested lymph nodes was significantly higher in the ICG group than in the control group (50.8 vs 40.1, P = 0.03). In the ICG group, 23 patients had metastatic lymph nodes. The accuracy, sensitivity, and specificity of ICG fluorescence for metastatic lymph nodes were 62.2%, 52.6%, and 63.0%, respectively.

CONCLUSION

Our study indicates that NIR imaging with ICG may provide additional node detection during robotic surgery for gastric cancer. Unfortunately, this technique failed to show good selectivity for metastatic lymph nodes.

Advances in laparoscopic surgery for the treatment of advanced gastric cancer in China

Most gastric cancer (GC) cases are diagnosed at an advanced stage in China. Because of its high morbidity and mortality, GC remains a major health crisis in China. Surgical resection is the only potentially curative treatment for GC. Owing to being minimally invasive, laparoscopic radical gastrectomy has been widely used in various countries, especially in East Asia, since Kitano first reported the feasibility and safety of this technique. Although laparoscopic gastric surgery was introduced relatively late in China, Chinese surgeons have made unique contributions to the research and clinical practice of laparoscopic gastric surgery due to the large number of clinical cases. This review focuses on the progress in laparoscopic gastrectomy for advanced stage GC in China, including reasonable approaches in different areas and oncologic efficacy of laparoscopic surgery, and introduce advanced technology to facilitate surgeons to rapidly overcome the learning curve in clinical practice.

Fluorescence-guided lymphadenectomy in gastric cancer: a prospective western series

BACKGROUND

Indocyanine green (ICG) has been recently introduced in clinical practice as a fluorescent tracer. Lymphadenectomy is particularly challenging in gastric cancer surgery, owing to the complex anatomical drainage.

AIM

The primary outcomes of this study were the feasibility and usefulness of ICG-guided lymphadenectomy in gastric cancer surgery, considering both the success rate and improved understanding of the surgical anatomy of nodal basins. The secondary outcome was the diagnostic ability of ICG to predict the presence of nodal metastases.

PATIENTS AND METHODS

We conducted a single-center prospective trial comprising 13 patients with gastric cancer. ICG was injected the afternoon prior to surgery or intraoperatively via the submucosal or subserosal route. Standard lymphadenectomy was performed in all patients, according to patient age and tumor stage, as usual, but after standard lymphadenectomy the residual ICG + nodes were harvested and analyzed. Each nodal station and each dissected node was recorded and classified as ICG + or ICG- (both in vivo and back table evaluation was utilized for classification). After pathological analysis, each nodal station and each dissected node was recorded as metastatic or nonmetastatic (E&E staining).

RESULTS

The feasibility rate was 84.6% (11/13). The mean number of dissected lymph nodes per patient was 37.9. Focusing on the 11 patients in whom ICG-guided nodal navigation was successfully performed, 81 lymph node stations were removed, for a total of 417 lymph nodes. Sixty-six stations (81.48%), comprising a total of 336 lymph nodes, exhibited fluorescence. No IC- node was metastatic; all 54 metastatic nodes were ICG + . A total of 282 ICG + nodes were nonmetastatic. In two cases, some nodes outside D2 areas were harvested, being ICG + (1 case of metastatic node).

CONCLUSIONS

Fluorescence lymphography-guided lymphadenectomy is a promising new technique that combines a high feasibility rate with considerable ease of use. Regarding its diagnostic value, the key finding from this prospective series is that no metastatic nodes were found outside fluorescent lymph node stations. Further studies are needed to investigate whether this technique can help surgeons performing standard lymphadenectomy and selecting cases for D2 + lymphadenectomy.