Infrared ray electronic endoscopy combined with indocyanine green injection for detection of sentinel nodes of patients with gastric cancer

Comparative study of ICG and non-ICG-guided laparoscopic gastrectomy for gastric cancer: a propensity score-matched analysis at a single center

ABSTRACT

Objectives

To investigate the effectiveness of indocyanine green (ICG) lymphography in improving lymph nodes (LNs) harvesting during laparoscopic radical distal gastrectomy for gastric cancer.

Design

Non-randomized trial, prospective study compared ICG and non-ICG group using 1:1 propensity score matching (PSM) method.

Setting

Preoperative clinical characteristics, operative outcomes, and follow-up results.

Participants

242 patients who underwent laparoscopic distal gastrectomy with D2 lymphadenectomy for gastric cancer between 2019 and 2023. After exclusion and PSM, 160 patients (Pts) were included, paired in two groups: ICG (80 Pts) and non-ICG (80 Pts).

Interventions

Patients in the ICG group underwent ICG injection submucosal via endoscopy 1 day before surgery.

Main outcome measures

Comparison of the number of retrieved LNs and complications between the ICG and non-ICG group.

Results

There were no significant differences in age, sex, height, tumor size, pathological Tumor-stage, histological differentiation, and complications between the two groups. There was a shorter operative time in the ICG group compared with the non-ICG group (median: 118 mins (IQR, 105-135) vs 146 mins (IQR, 120-180), respectively). Regarding the effectiveness of LN dissection: the ICG group had a higher median of retrieved LNs than the non-ICG group (36 LNs (IQR, 29-46) vs 27 LNs (IQR, 21-31); p<0.001). The mean number of metastatic LNs in the ICG group was significantly higher than in the non-ICG group, with 2.6±5.4 LNs compared with 0.9±3.1 LNs, respectively (p=0.018). The proportion of patients with more than 25 and 30 retrieved LNs was higher in the ICG group compared with the non-ICG group, with rates of 86% and 71% versus 64% and 31%, respectively (p<0.001).

Conclusions

Using ICG fluorescence-guided LNs dissection has increased both the number of total LNs and metastatic LNs dissection without increasing complications in laparoscopic distal gastrectomy for 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

Progress of fluorescence imaging in lymph node dissection surgery for prostate and bladder cancer

Fluorescence imaging is a relatively new imaging method used to visualize different tissue structures to help guide intraoperative operations, which has potential advantages with high sensitivity and contrast compared to conventional imaging. In this work, we review fluorescent contrast agents and devices used for lymphatic system imaging. Indocyanine green is the most widely utilized due to its high sensitivity, specificity, low background fluorescence, and safety profile. In prostate and bladder cancer lymph node dissection, the complex lymphatic drainage can result in missed metastatic nodes and extensive dissection increases the risk of complications like lymphocele, presenting a significant challenge for urologists. Fluorescence-guided sentinel lymph node dissection facilitates precise tumor staging. The combination of fluorescence and radiographic imaging improves the accuracy of lymph node staging. Multimodal imaging presents new potential for precisely identifying metastatic pelvic lymph nodes.

How to objectively evaluate the impact of image-guided surgery technologies

PURPOSE

This manuscript aims to provide a better understanding of methods and techniques with which one can better quantify the impact of image-guided surgical technologies.

METHODS

A literature review was conducted with regard to economic and technical methods of medical device evaluation in various countries. Attention was focused on applications related to image-guided interventions that have enabled procedures to be performed in a minimally invasive manner, produced superior clinical outcomes, or have become standard of care.

RESULTS

The review provides examples of successful implementations and adoption of image-guided surgical techniques, mostly in the field of neurosurgery. Failures as well as newly developed technologies still undergoing cost-efficacy analysis are discussed.

CONCLUSION

The field of image-guided surgery has evolved from solely using preoperative images to utilizing highly specific tools and software to provide more information to the interventionalist in real time. While deformations in soft tissue often preclude the use of such instruments outside of neurosurgery, recent developments in optical and radioactive guidance have enabled surgeons to better account for organ motion and provide feedback to the surgeon as tissue is cut. These technologies are currently undergoing value assessments in many countries and hold promise to improve outcomes for patients, surgeons, care teams, payors, and society in general.

Appropriate concentration setting for the intraoperative administration of indocyanine green for fluorescence imaging to identify the sentinel lymph node in early gastric cancer: a clinical pilot study

PURPOSE

Some prospective trials have demonstrated the feasibility of sentinel node (SN) biopsy in gastric cancer (GC) surgery. This study aimed to identify the appropriate concentration settings for the intraoperative injection of indocyanine green (ICG) for SN biopsy.

METHODS

Before the clinical studies, porcine model experiments explored the optimal concentration of ICG injected intraoperatively. Next, nine GC patients were enrolled in the clinical research. ICG (0.5 ml) was injected intraoperatively into four quadrants of the submucosa around the tumor at various concentrations (0.5, 0.25, and 0.1 mg/ml). The lymphatic basin dissection method was applied to the ICG-positive lymphatic areas. The number and location of the lymphatic basins and positive nodes were recorded intraoperatively.

RESULTS

In the porcine model, the visibility gradually became clear at an ICG concentration higher than 0.1 mg/ml. In the clinical study, the average number of detected lymphatic basins was 3.3, 1.7, and 1.7, respectively. The mean number of detected SNs was 14.7, 6.7, and 4.0, respectively.

CONCLUSION

To improve the reproducibility of SN biopsy, it is essential to prepare the correct concentration setting of ICG. Under current conditions in which ICG is injected intraoperatively, a 0.1 mg/ml concentration setting of ICG may be necessary and sufficient for SN identification.

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.

Revolutionizing lymph node metastasis imaging: the role of drug delivery systems and future perspectives

The deployment of imaging examinations has evolved into a robust approach for the diagnosis of lymph node metastasis (LNM). The advancement of technology, coupled with the introduction of innovative imaging drugs, has led to the incorporation of an increasingly diverse array of imaging techniques into clinical practice. Nonetheless, conventional methods of administering imaging agents persist in presenting certain drawbacks and side effects. The employment of controlled drug delivery systems (DDSs) as a conduit for transporting imaging agents offers a promising solution to ameliorate these limitations intrinsic to metastatic lymph node (LN) imaging, thereby augmenting diagnostic precision. Within the scope of this review, we elucidate the historical context of LN imaging and encapsulate the frequently employed DDSs in conjunction with a variety of imaging techniques, specifically for metastatic LN imaging. Moreover, we engage in a discourse on the conceptualization and practical application of fusing diagnosis and treatment by employing DDSs. Finally, we venture into prospective applications of DDSs in the realm of LNM imaging and share our perspective on the potential trajectory of DDS development.

Treatment strategy for lymph node metastasis of hepatocellular carcinoma using an ICG navigation system: a case report

BACKGROUND

Since indocyanine green (ICG) accumulates selectively in hepatocellular carcinoma (HCC) cells, it can be used to detect metastatic lesions. Lymph node metastasis of HCC is rarely observed, both simultaneously and metachronously. Therefore, it is sometimes difficult to identify metachronous lymph nodes during salvage surgery because of prior surgery. Herein, we report a case in which lymph node metastasis of HCC was successfully resected using an ICG navigation system.

CASE PRESENTATION

The patient was a 62-year-old man who had undergone radical liver resection for HCC 8 years ago. During surveillance, contrast-enhanced computed tomography (CT) revealed a mass in the hepatic hilum. Various diagnostic modalities suggested that the patient had a solitary metastatic lymph node of HCC, and extirpation of the tumor was planned. Intraoperative ICG fluorescence imaging allowed surgeons to clearly identify the target lesion. Histopathologically, the tumor was confirmed to be a lymph node metastasis of HCC. The patient's postoperative course was uneventful, and he remains alive without recurrence 2 years after the second surgery.

CONCLUSION

Intraoperative navigation surgery by ICG fluorescence imaging was useful for the safe resection of extrahepatic metastasis of HCC in a complicated situation.

Use of Indocyanine Green Fluorescence Imaging in Thoracic and Esophageal Surgery

BACKGROUND

Fluorescence imaging using indocyanine green in thoracic and esophageal surgery is gaining popularity because of the potential to facilitate surgical planning, to stage disease, and to reduce postoperative complications. To optimize use of fluorescence imaging in thoracic and esophageal surgery, an expert panel sought to establish a set of recommendations at a consensus meeting.

METHODS

The panel included 12 experts in thoracic and upper gastrointestinal surgery from Asia-Pacific countries. Before meeting, 7 focus areas were defined: intersegmental plane identification for sublobar resections; pulmonary nodule localization; lung tumor detection; bullous lesion detection; lymphatic mapping of lung tumors; evaluation of gastric conduit perfusion; and lymphatic mapping in esophageal surgical procedures. A literature search of the PubMed database was conducted using keywords indocyanine green, fluorescence, thoracic, surgery, and esophagectomy. At the meeting, panelists addressed each focus area by discussing the most relevant evidence and their clinical experiences. Consensus statements were derived from the proceedings, followed by further discussions, revisions, finalization, and unanimous agreement. Each statement was assigned a level of evidence and a grade of recommendation.

RESULTS

A total of 9 consensus recommendations were established. Identification of the intersegmental plane for sublobar resections, localization of pulmonary nodules, lymphatic mapping in lung tumors, and assessment of gastric conduit perfusion were applications of fluorescence imaging that have the most robust current evidence.

CONCLUSIONS

Based on best available evidence and expert opinions, these consensus recommendations may facilitate thoracic and esophageal surgery using fluorescence imaging.

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.

Impact of near-infrared fluorescence imaging with indocyanine green on the surgical treatment of pulmonary masses in dogs

Objectives

To investigate the intraoperative identification and complete resection of pulmonary masses, and to evaluate lymph node metastasis of pulmonary malignant tumors in dogs using indocyanine green (ICG) fluorescence imaging.

Methods

Forty dogs with pulmonary masses were included, all of which underwent surgical treatment. ICG fluorescence imaging was performed on pulmonary masses before lobectomy and the resection margins after lobectomy. In addition, ICG fluorescence of the excised masses and lymph nodes was evaluated in the shaded box. The fluorescence findings were compared with the histopathological diagnosis.

Results

Of 44 nodules resected from 40 dogs, 32 nodules were histopathologically diagnosed as lung adenocarcinoma, five were histiocytic sarcoma, three were undifferentiated sarcoma, two were malignant epithelial tumor metastases, one was carcinosarcoma, and one was a non-neoplastic lesion. Fluorescence was observed in all nodules. In addition to the main lesion, other fluorescent nodules were found in four dogs. Regarding the diagnostic accuracy of complete resection based on ICG fluorescence, the sensitivity was 67.7% and the specificity was 60.0%. The sensitivity and specificity of ICG fluorescence for the diagnosis of lymph node metastasis were 100 and 75.0%, respectively.

Conclusions

ICG fluorescence imaging might be a useful intraoperative diagnostic method to identify the location of tumors and lymph node metastasis, but not to evaluate complete tumor resection, in dogs with pulmonary malignant tumors.

Real-time vessel navigation using indocyanine green fluorescence during robotic-assisted gastrectomy for gastric cancer after coronary artery bypass grafting using the right gastroepiploic artery

Injury to the right gastroepiploic artery (RGEA) graft during gastrectomy after coronary artery bypass grafting (CABG) can cause critical coronary failure. A man in his 60s with advanced gastric cancer and a history of CABG was admitted to our hospital. His cardiac blood flow was dependent on RGEA, and a gastrectomy with RGEA preservation was necessary. Robot-assisted distal gastrectomy with real-time vessel navigation using indocyanine green (ICG) fluorescence imaging and Da Vinci Firefly technology was planned. Intraperitoneal observation revealed severe adhesions around the graft. Two milliliters ICG (2.5 mg/mL) was injected intravenously, and RGEA was visualized. An RGEA-preserving robot-assisted distal gastrectomy was successfully performed. The operation time was 279 minutes, and the blood loss was 5 mL. The postoperative course was good and there were no complications.

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.

Clinical impact of near-infrared fluorescence imaging with indocyanine green on surgical treatment for hepatic masses in dogs

BACKGROUND

Near-infrared fluorescence imaging using indocyanine green (ICG) is clinically applied to intraoperatively identify hepatic masses in humans. In addition, it is reported to be effective for assessing complete resection in human hepatocellular carcinoma (HCC). However, there is limited information on ICG fluorescence imaging for canine HCC, and its clinical usefulness is still unclear. Therefore, the purpose of this study was to evaluate the intraoperative identification and status of surgical margin for canine hepatic masses using near-infrared ICG fluorescence imaging. This clinical study included 104 dogs with hepatic masses. Between 12 and 24 h prior to surgery, ICG solution was injected intravenously at a dose of 0.5 mg/kg. The fluorescence intensity and pattern of each hepatic mass was investigated using an infrared camera before resection. After resection, the fluorescence intensity of the resection margin was also investigated. The resected masses were histopathologically diagnosed and compared using ICG fluorescence imaging.

RESULTS

One hundred and twenty-two masses obtained from 104 dogs included 76 HCCs, 16 hepatocellular adenomas, 12 focal nodular hyperplasias, and 18 other lesions. Of the 122 masses, 106 (94 partial, 9 whole, and 3 ring fluorescence patterns), 7, and 9 masses showed increased, the same, or decreased fluorescence compared to the normal liver tissue, respectively. The fluorescence intensity and pattern were not significantly related to the histopathological diagnosis. The sensitivity and specificity of the margin evaluation in the 47 dogs were 100% and 77.3%, respectively. The median survival times in cases of HCC with complete and incomplete resection were 914 and 254 days, respectively. The median survival time of patients with a complete resection was significantly longer than that of patients with a incomplete resection (p = 0.043).

CONCLUSION

ICG fluorescence imaging has potential clinical value for the identification and margin evaluation of canine hepatic masses. Although it is difficult to use fluorescence imaging for the differential diagnosis of liver tumours, it may be useful for assessing complete resection in cases of hepatic masses demonstrating increased fluorescence in dogs, and complete resection of HCC could have a survival benefit.

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.

Efficacy and safety of indocyanine green tracer-guided lymph node dissection in minimally invasive radical gastrectomy for gastric cancer: A systematic review and meta-analysis

Background

The implementation of indocyanine green (ICG) tracer-guided lymph node dissection is still in the preliminary stages of laparoscopic surgery, and its safety and efficacy for gastric cancer remain unclear.

Methods

A systematic review was conducted in PubMed, Embase, Web of Science, the Cochrane Library, and Scopus to identify relevant subjects from inception to June 2022. The core indicators were the total number of harvested lymph nodes and the safety of the laparoscopic gastrectomy with ICG. A meta-analysis was performed to estimate the pooled weighted mean difference (WMD) and 95% confidence interval (CI).

Results

Thirteen studies and 2,027 participants were included (642 for the ICG-group and 1,385 for the non-ICG group). The mean number of lymph nodes dissected in the ICG group was significantly greater than that in the non-ICG group (WMD = 6.24, 95% CI: 4.26 to 8.22, P <0.001). However, there was no significant difference in the mean number of positive lymph nodes dissected between the ICG and the non-ICG groups (WMD = 0.18, 95% CI: −0.70 to 1.07, P = 0.879). Additionally, ICG gastrectomy did not increase the risk in terms of the operative time, estimated blood loss, and postoperative complications.

Conclusion

ICG tracer with favorable safety increases the number of harvested lymph nodes but not the number of positive lymph nodes in laparoscopic gastrectomy. More high-quality, large-sample-size randomized controlled trials are still needed to enhance this evidence.

Near-Infrared Fluorescence Image-Guided Surgery in Esophageal and Gastric Cancer Operations

BACKGROUND

Near-infrared fluorescence image-guided surgery helps surgeons to see beyond the classical eye vision. Over the last few years, we have witnessed a revolution which has begun in the field of image-guided surgery.

PURPOSE, AND RESEARCH DESIGN

Fluorescence technology using indocyanine green (ICG) has shown promising results in many organs, and in this review article, we wanted to discuss the 6 main domains where fluorescence image-guided surgery is currently used for esophageal and gastric cancer surgery.

STUDY SAMPLE AND DATA COLLECTION

Visualization of lymphatic vessels, tumor localization, fluorescence angiography for anastomotic evaluation, thoracic duct visualization, tracheal blood flow analysis, and sentinel node biopsy are discussed.

CONCLUSIONS

It seems that this technology has already found its place in surgery. However, new possibilities and research avenues in this area will probably make it even more important in the near future.

Optimization and use of near infrared imaging to guide lymph node collection in rhesus macaques (Macaca mulatta)

Background

Identification of lymph nodes (LNs) draining a specific site or in obese macaques can be challenging.

Methods

Indocyanine Green (ICG) was administered intradermal (ID), intramuscular, in the oral mucosa, or subserosal in the colon followed by Near Infrared (NIR) imaging.

Results

After optimization to maximize LN identification, intradermal ICG was successful in identifying 50–100% of the axillary/inguinal LN at a site. Using NIR, collection of peripheral and mesenteric LNs in obese macaques was 100% successful after traditional methods failed. Additionally, guided collection of LNs draining the site of intraepithelial or intramuscular immunization demonstrated significantly increased numbers of T follicular helper (Tfh) cells in germinal centers of draining compared to nondraining LNs.

Conclusion

These imaging techniques optimize our ability to evaluate immune changes within LNs over time, even in obese macaques. This approach allows for targeted serial biopsies that permit confidence that draining LNs are being harvested throughout the study.

Application of Indocyanine Green Enhanced Fluorescence in Esophageal Surgery: A Mini Review

Despite recent technological innovations and the development of minimally invasive surgery, esophagectomy remains an operation burdened with severe postoperative complications. Fluorescence imaging, particularly using indocyanine green (ICG), offers the ability to address a number of issues faced during esophagectomy. The three main indications for the intraoperative use of ICG during esophagectomy are visualization of conduit vascular supply, allow identification of sentinel nodes and visualization of the thoracic duct. The purpose of this mini review is to present an overview of current practice in fluorescence imaging utilizing ICG during esophagectomy, as well as to demonstrate how this technology can guide lymphadenectomy and reduce surgical morbidity such as anastomotic leaking and chylothorax.

A novel laparoscopic near-infrared fluorescence spectrum system with indocyanine green fluorescence overcomes limitations of near-infrared fluorescence image-guided surgery

BACKGROUND

Near-infrared (NIR) fluorescence image-guided surgery (FIGS) introduces a revolutionary new approach to address this basic challenge in minimally invasive surgery. However, current FIGS systems have some limitations - the infrared rays cannot detect and visualise thick tissues with low concentrations of the fluorescent agent. We established a novel laparoscopic fluorescence spectrum (LFS) system using indocyanine green (ICG) fluorescence to overcome these limitations.

MATERIALS AND METHODS

Bovine serum albumin (BSA) was conjugated to ICG, and the mixtures were serially diluted at 5 × 10-8-5 × 10-1 mg/mL. We used the LFS system and a NIR camera system (NLS; SHINKO OPTICAL CO., LTD Tokyo, Japan) to determine the optical dilution for the fluorescence detection. BSA was conjugated to ICG (5.0 × 10-2 mg/mL) and used to coat the clips. We attempted to identify the fluorescence-coated clip from the serosal side of the cadaveric porcine stomach tissues using the LFS system and the NIR camera system. We measured the depth of the cadaveric porcine stomach wall at the thickest part that could be confirmed.

RESULTS

We could not visualise fluorescence concentrations <2.5 × 10-3 mg/mL using the NIR camera system. The spectrum was detected at a concentration <2.5 × 10-3 mg/mL. We were able to identify the spectrum of ICG (829 nm) to a 13-mm depth of cadaveric porcine stomach wall by using the LFS system but could not identify the same with the NIR camera system regardless of wall thickness.

CONCLUSIONS

The novel LFS system with NIR fluorescence imaging in this ex vivo and cadaveric porcine model was confirmed useful at deeper depths and lower concentrations. Based on these findings, we anticipate that the LFS system can be integrated and routinely used in minimally invasive surgery.

Life prognosis of sentinel node navigation surgery for early-stage gastric cancer: Outcome of lymphatic basin dissection

BACKGROUND

Lymphatic basin dissection is a sentinel node biopsy method that is specific for gastric cancer. In this method, the dyed lymphatic system is dissected en bloc, and sentinel nodes are identified at the back table (ex vivo). Even with lymphatic basin dissection, blood flow to the residual stomach can be preserved, and function-preserving curative gastrectomy can be performed. The oncological safety of function-preserving curative gastrectomy combined with lymphatic basin dissection has not yet been fully investigated. We hypothesized that the oncological safety of sentinel node navigation surgery (SNNS) is not inferior to that of the guidelines.

AIM

To investigate the life prognosis of SNNS for gastric cancer in comparison with guidelines surgery.

METHODS

This was a retrospective cohort study. Patients were selected from gastric cancer patients who underwent sentinel node biopsy from April 1999 to March 2016. Patients from April 1999 to August 2008 were from the Department of Surgery II, Kanazawa University Hospital, and patients from August 2009 to March 2016 were from the Department of Surgical Oncology, Kanazawa Medical University Hospital. Patients who were diagnosed with gastric cancer, which was preoperatively diagnosed as superficial type (type 0), 5 cm or less in length, clinical T1-2 and node negative, and underwent various gastrectomies guided by sentinel node navigation were retrospectively collected. The overall survival (OS) and relapse-free survival (RFS) of these patients (SNNS group) were investigated. Patients with gastric cancer of the same stage and who underwent guidelines gastrectomy with standard nodal dissection were also selected as the control group.

RESULTS

A total of 239 patients in the SNNS group and 423 patients in the control group were included. Pathological nodal metastasis was observed in 10.5% and 10.4% of the SNNS and control groups, respectively. The diagnostic abilities of sentinel node biopsy were 84% and 98.6% for sensitivity and accuracy, respectively. In the SNNS group, 81.6% of patients underwent modified gastrectomy or function-preserving curative gastrectomy with lymphatic basin dissection, in which the extent of nodal dissection was further reduced compared to the guidelines. The OS rate in the SNNS group was 96.8% at 5 years and was significantly better than 91.3% in the control group (P = 0.0014). The RFS rates were equal in both groups. After propensity score matching, there were 231 patients in both groups, and the cumulative recurrence rate was 0.43% at 5 years in the SNNS group and 1.30% in the control group, which was not statistically different.

CONCLUSION

The oncological safety of patients who undergo gastrectomy guided by sentinel node navigation is not inferior to that of the guidelines surgery.

A narrative review of fluorescence imaging in robotic-assisted surgery

Objective

In this review, we provide examples of applications of fluorescence imaging in urologic, gynecologic, general, and endocrine surgeries.

Background

While robotic-assisted surgery has helped increase the availability of minimally invasive procedures across surgical specialties, there remains an opportunity to reduce adverse events associated with open, laparoscopic, and robotic-assisted methods. In 2011, fluorescence imaging was introduced as an option to the da Vinci Surgical System, and has been standard equipment since 2014. Without interfering with surgical workflow, this fluorescence technology named Firefly^® allows for acquisition and display of near-infrared fluorescent signals that are co-registered with white light endoscopic images. As a result, robotic surgeons of all specialties have been able to explore the clinical utility of fluorescence guided surgery.

Methods

Literature searches were performed using the PubMed and MEDLINE databases using the keywords "robotic-assisted fluorescence surgery", "ICG robotic surgery", and "fluorescence guided surgery" covering the years 2011-2020.

Conclusions

Real-time intraoperative fluorescence guidance has shown great potential in helping guide surgeons in both simple and complex surgical interventions. Indocyanine green is one of the most widely-used imaging agents in fluorescence guided surgery, and other targeted, near-infrared imaging agents are in various stages of development. Fluorescence is becoming a reliable tool that can help surgeons in their decision-making process in some specialties, while explorations continue in others.

Consensus Guidelines for the Use of Fluorescence Imaging in Hepatobiliary Surgery

OBJECTIVE

To establish consensus recommendations for the use of fluorescence imaging with indocyanine green (ICG) in hepatobiliary surgery.

BACKGROUND

ICG fluorescence imaging has gained popularity in hepatobiliary surgery in recent years. However, there is varied evidence on the use, dosage, and timing of administration of ICG in clinical practice. To standardize the use of this imaging modality in hepatobiliary surgery, a panel of pioneering experts from the Asia-Pacific region sought to establish a set of consensus recommendations by consolidating the available evidence and clinical experiences.

METHODS

A total of 13 surgeons experienced in hepatobiliary surgery and/or minimally invasive surgery formed an expert consensus panel in Shanghai, China in October 2018. By the modified Delphi method, they presented the relevant evidence, discussed clinical experiences, and derived consensus statements on the use of ICG in hepatobiliary surgery. Each statement was discussed and modified until a unanimous consensus was achieved.

RESULTS

A total of 7 recommendations for the clinical applications of ICG in hepatobiliary surgery were formulated.

CONCLUSIONS

The Shanghai consensus recommendations offer practical tips and techniques to augment the safety and technical feasibility of ICG fluorescence-guided hepatobiliary surgery, including laparoscopic cholecystectomy, liver segmentectomy, and liver transplantation.

Preliminary application of indocyanine green fluorescence imaging in postoperative gastrointestinal fistula

We describe a case using indocyanine green (ICG) fluorescence imaging for diagnosis of postoperative gastrointestinal fistula. When the fistula is very large, both indocyanine green and methylene blue can be found in the postoperative drainage. After treatment, when the leak became small, only ICG fluorescence imaging continued to be demonstrated. ICG fluorescence imaging is likely to prove to be a safe and effective method of examination, and one that is very practical and easy to execute for the diagnosis of postoperative gastrointestinal fistula.

Near-Infrared Fluorescence Imaging of Breast Cancer and Axillary Lymph Nodes After Intravenous Injection of Free Indocyanine Green

Background

Near-infrared fluorescence imaging (NIRFI) of breast cancer (BC) after the intravenous (IV) injection of free indocyanine green (fICG) has been reported to be feasible. However, some questions remained unclarified.

Objective

To evaluate the distribution of fICG in BC and the axillary lymph nodes (LNs) of women undergoing surgery with complete axillary LN dissection (CALND) and/or selective lymphadenectomy (SLN) of sentinel LNs (NCT no. 01993576 and NCT no. 02027818).

Methods

An intravenous injection of fICG (0.25 mg/kg) was administered to one series of 20 women undergoing treatment with mastectomy, the day before surgery in 5 (group 1) and immediately before surgery in 15 (group 2: tumor localization, 25; and pN+ CALND, 4) as well as to another series of 20 women undergoing treatment with tumorectomy (group 3). A dedicated NIR camera was used for ex vivo fluorescence imaging of the 45 BC lesions and the LNs.

Results

In group 1, two of the four BC lesions and one large pN+ LN exhibited fluorescence. In contrast, 24 of the 25 tumors in group 2 and all of the tumors in group 3 were fluorescent. The sentinel LNs were all fluorescent, as well as some of the LNs in all CALND specimens. Metastatic cells were found in the fluorescent LNs of the pN+ cases. Fluorescent BC lesions could be identified ex vivo on the surface of the lumpectomy specimen in 14 of 19 cases.

Conclusions

When fICG is injected intravenously just before surgery, BC can be detected using NIRFI with high sensitivity, with metastatic axillary LNs also showing fluorescence. Such a technical approach seems promising in the management of BC and merits further investigation.

Performance of Indocyanine-Green Imaging for Sentinel Lymph Node Mapping and Lymph Node Metastasis in Esophageal Cancer: Systematic Review and Meta-Analysis

BACKGROUND AND OBJECTIVES

Lymphatic mapping with indocyanine-green (ICG) and near-infrared light fluorescent imaging is widely used for sentinel lymph node staging in different types of cancer but is not fully accepted for all procedures because studies have reported heterogeneous results. This study aimed to assess the detection rate (DR) of ICG imaging for sentinel lymph node mapping (SLNM) and lymph node metastases (LNMs) in esophageal cancer.

METHODS

A systematic search was performed to identify relevant studies examining the use of ICG imaging for SLNM in patients with esophageal cancer. Extracted results were pooled in a single-proportion meta-analysis, with a random-effects model, presented as forest plots.

RESULTS

Six studies were included in the analysis. The ICG DR for SLNM was 89% [95% confidence interval (CI) 71%-96%]. The pooled sensitivity and specificity values for the detection of LNMs were 84% (95% CI 64%-94%) and 15% (95% CI 3%-45%), respectively. A trend towards a lower DR was found with increasing mean latency time between ICG injection and SLNM.

CONCLUSIONS

ICG imaging is a technique that potentially could improve lymph node yield excision and, as a consequence, improve the detection of lymph node metastases.

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.

Clinical role of fluorescence imaging in colorectal surgery - an updated review

INTRODUCTION

Colorectal surgery has markedly advanced due to the introduction of laparoscopic and robotic surgery. During the past 20 years, these two modalities have been further enhanced by fluorescence imaging.

AREAS COVERED

This article will review the common and novel uses for fluorophores in colorectal surgery, including tissue perfusion for anastomotic creation, ureter identification, lymphatic mapping, and tumor localization.

EXPERT OPINION

The versatility of this technology permeates through many aspects of colorectal procedures. The white light spectrum has historically been the only available modality to visualize tissue perfusion, tumor implants, and structures including the ureters and lymph nodes. The ability of the near-infrared spectrum to penetrate biologic tissues allows the identification of these structures with injection of fluorophores. The two most common intravenously utilized fluorophores are methylene blue and indocyanine green. Additionally, novel tumor marker-specific fluorophores are being investigated for purposes of cancer detection.

Lymph Node Mapping in Gastric Cancer Surgery: Current Status and New Horizons

Gastric cancer (GC) remains one of the most important malignant diseases with significant geographical, ethnic, and socioeconomic differences in distribution. Sentinel lymph node (SLN) mapping is an accepted way to assess lymphatic spread in several solid tumors; however, the complexity of gastric lymphatic drainage may discourage use of this procedure, and the estimated accuracy rate is, in general, reasonably good. This study aimed at reviewing the current status of SLN mapping and navigation surgery in GC. SLN mapping should be limited to tumors clinically T1 and less than 4 cm in diameter. Combination SLN mapping with radioactive colloid and blue dye is used as the standard. Despite its notable limitations, SLN mapping and SLN navigation surgery present a novelty individualizing the extent of lymphadenectomy.

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.

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

•

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.

•

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®.

Near-infrared fluorescent clip guided gastrectomy: Report of 2 cases (Case reports)

INTRODUCTION

This is the first report on near-infrared fluorescent (NIRF) clip-guided gastrectomy. The NIRF clip, ZEOCLIP FS, emits NIRF signals when excited. We hypothesized that preoperative placement of the ZEOCLIP FS near a gastric lesion would allow fluorescence laparoscopic localization of the clip, and hence, the lesion, during surgery. We report this technique in two cases.

CASE PRESENTATION

Case 1: An 81-year-old female was diagnosed with early gastric cancer and a pedunculated 4 cm large hyperplastic polyp that had prolapsed into the duodenum, and was scheduled for laparoscopy-assisted distal gastrectomy, due to the potential risk of dissection of the polyp with the duodenal wall. On the day before surgery, ZEOCLIP FS clips were endoscopically placed at the cancer site and the polyp. The locations of the fluorescent clips were confirmed intraoperatively using a full-color fluorescence laparoscope.

CASE 2

An 81-year-old male was scheduled for laparoscopy-assisted total gastrectomy for gastric cancer under fluorescent clip-guidance. Clip locations could not be confirmed during initial intraoperative observation. However, when the stomach wall was raised using forceps during a second observation attempt, the fluorescent clip locations were confirmed.

DISCUSSION

In case 1, it was easy to confirm clip location, facilitating complete resection of early gastric cancer without dissecting the polyp. In case 2, the fluorescent clip was located by raising the stomach and adjusting the angle between the stomach wall and the fluorescence laparoscope.

CONCLUSION

The positive results of these two cases warrant conducting feasibility studies for use of this method.

Effectiveness and safety of tumor site marking with near-infrared fluorescent clips in colorectal laparoscopic surgery: A case series study

BACKGROUND

In colorectal laparoscopic surgery, accuracy of tumor marking has been an important but not fully resolved issue. The tattoo marking technique or intraoperative endoscopy have been used but they either carry the risk of accidental intestinal puncture or require either longer operation times, a skilled endoscopist and/or intraoperative colon insufflation. We supposed that tumor site marking with the near-infrared fluorescent clips, ZEOCLIP FS clips (Zeon Medical Co., Ltd., Tokyo, Japan) might overcome disadvantages of both tattoo marking and intraoperative endoscopy-based tumor localization methods. This is the first report on the case series using near-infrared fluorescent marking clip. We summarize the early results in 30 patients, who underwent colorectal laparoscopic surgery; we focus particularly on effectiveness and safety of the method.

MATERIALS AND METHODS

Thirty consecutive patients, who underwent laparoscopic surgery for colorectal cancer after previous endoscopic ZEOCLIP FS placement were enrolled from May 2019 till October 2019. The primary endpoint was the rate of intraoperative clip detection and the secondary endpoints were: the rate of adverse effects, percentage of slipped clips and usefulness of plain abdominal radiography to preoperatively confirm the clip retention. Locations of fluorescent clips were identified with a full-color fluorescence laparoscope. All operations and clip placements were performed by the same senior surgeon with sufficient experience in both procedures.

RESULTS

Fluorescent clips could be detected in 94.1% of tumor lesions. Three (2.1%) clips dropped before surgery. Plain abdominal radiography was sufficient to assess clip retention in all cases. No adverse effects related to either clip placement or clip detection were observed.

CONCLUSION

The ZEOCLIP FS could be easily detected from the serosal side of the intestinal tract when placed 1-2 days before surgery. Fluorescent clip-guided laparoscopy may be considered a safe and effective method for localization of colorectal tumor sites. The Research Registry UIN: researchregistry5400.

Sentinel lymph node detection for gastric cancer: Promise or pitfall?

At present, optimal surgery for gastric cancer is still under debate, especially the extent of lymph node dissection. Gastrectomy with D1/D2 lymphadenectomy is standard treatment for resectable advanced gastric cancer. However, in early gastric cancer without lymph node metastasis, gastrectomy with D1/D2 lymphadenectomy may not be unnecessary, which could increases morbidity and mortality and reduces the quality of life (QOL). Therefore, the concept of sentinel lymph node could be applied in gastric cancer. But due to the complexity of gastric lymphatic drainage, there are still many issues under debate, such as suitable tracers, the method of mapping and collecting and the oncologic safety of sentinel node navigation surgery (SNNS). In addition, skip metastasis and unreliability of intraoperative pathological diagnosis are two main reasons for false negative cases. In this review, we summarize the current status and controversy of sentinel lymph node detection in gastric cancer, attempting to help with practical application. Further, we hold opinion that we should be cautious about performing sentinel lymph node detection in gastric cancer before an accurate and effective method occurs.

Performance of Indocyanine green for sentinel lymph node mapping and lymph node metastasis in colorectal cancer: a diagnostic test accuracy meta-analysis

BACKGROUND

Indocyanine green has been widely employed as a secure and easy technique for sentinel lymph node mapping in different types of cancer. Nonetheless, the usage of Indocyanine green has not been fully implemented due to the heterogeneous results found in published studies. Thus, the objective of this meta-analysis is to evaluate the overall performance of Indocyanine green for sentinel lymph node mapping and node metastasis in patients undergoing colorectal cancer surgery.

METHODS

An extensive systematic search was performed to identify relevant studies in English and Spanish with no time limit restrictions. For the meta-analysis, a hierarchical summary receiver operating characteristic curve (HSROCs) was constructed, and quantitative data synthesis was performed using random effects models. Specificity, sensitivity, positive, and negative likelihood ratios were obtained from the corresponding HSROC. Between-study heterogeneity was visually evaluated using Galbraith plot, and publication bias was quantified using Deeks' method.

RESULTS

A total of 11 studies were included for analysis. The pooled detection rate for sentinel lymph node mapping was 91% (80-98%). Covariates significantly influencing the pooled detection rate were having colon cancer (estimate: 1.3001; 1.114 to 1.486; p < 0.001) and the usage of a laparoscopic approach (estimate: 1.3495; 1.1029 to 1.5961; p < 0.001). The performance of Indocyanine green for the detection of metastatic lymph nodes yielded an area under the roc curve of 66.5%, sensitivity of 64.3% (51-76%), and specificity of 65% (36-85%).

CONCLUSIONS

Indocyanine green for the detection of sentinel lymph node mapping demonstrates better accuracy when used in colonic cancer and by a laparoscopic approach. Nevertheless, its overall performance for the detection of lymph node metastasis is poor.

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

BACKGROUND

Early gastric cancer (EGC) is more common nowadays and is related a to low percentage of lymph node metastasis. For this reason, there is enormous interest to implicate minimally invasive approaches. Recently, special efforts have been made towards a potential intraoperative (real-time) lymph node metastasis (LNM) assessment, as nodal disease status could not be identified with precision before or during surgery. In this direction, accurate prediction of the LNM status through sentinel LN mapping has been attempted, as an approach to the intraoperative detection of sentinel lymph nodes (SLNs). A careful literature search was conducted in order to clarify the potential clinical application of SN biopsy in the gastric cancer field.

CONCLUSION

The real clinical application of SN biopsy in gastric cancer treatment has been more than challenging due to the "complicated" nature of gastric lymphatic drainage and the high possibility of "skip" metastasis phenomenon. Notably, sophisticated technical aspects, such as the preferred tracer used and the potential "ideal" method to verify the presence of metastases in the resected SLNs, made SN biopsy application in gastric cancer field extremely demanding. Assessing the potential role of SN navigation for gastric cancer treatment in the era of advanced technology, where the minimally invasive surgical approaches are in the top of the scientific interest, it has to be highlighted that SN navigation for gastric cancer is a topic that remains highly controversial, and the need for future clinical trials on this topic is obvious.

Prospective feasibility study for single-tracer sentinel node mapping by ICG (indocyanine green) fluorescence and OSNA (one-step nucleic acid amplification) assay in laparoscopic gastric cancer surgery

BACKGROUND

The double-tracer method has been established for sentinel node (SN) mapping in gastric cancer surgery. However, there remain several unresolved issues that prevent its widespread use in clinical practice. In this study, we aimed to demonstrate the feasibility of single-tracer SN mapping in laparoscopic surgery for gastric cancer, using indocyanine green (ICG) fluorescence imaging with a one-step nucleic acid amplification (OSNA) assay intraoperatively.

METHODS

Patients with clinical T1N0M0 gastric adenocarcinoma preoperatively were considered for inclusion if they had a single primary lesion 4 cm or less in maximal diameter. Immunohistochemical staining with the anti-cytokeratin 19 antibody was performed on preoperative biopsy specimens, and patients with faint positive reactions were excluded. Intraoperatively, single-tracer SN biopsy with ICG fluorescence imaging was performed, followed by laparoscopic gastrectomy with modified D1+ or D2 lymph node dissection.

RESULTS

Twenty eligible patients underwent SN biopsy and laparoscopic gastrectomy. SNs were identified in 17 cases (85%), with a median number of three SNs per patient. The median times for SN mapping and OSNA assay were 19 and 35 min, respectively. OSNA assay detected one metastatic lymph node, but all other nodes were negative. No adverse effects were observed in relation to SN mapping.

CONCLUSIONS

Single-tracer SN mapping by ICG fluorescence imaging with intraoperative diagnosis by OSNA assay is feasible and safe. SNs can be identified in most patients, without producing false-negative results. Further clinical trial to demonstrate the sensitivity is ongoing.

Residual cancerous lesion and vein tumour thrombus identified intraoperatively using a fluorescence navigation system in liver surgery

AIM

The main aims of this study are to investigate the clinical application value of using indocyanine green fluorescence imaging for ensuring complete resection of tumour tissue during hepatectomy and to evaluate the diagnostic efficacy of near-infrared (NIR) fluorescence imaging system using indocyanine green in hepatectomy.

METHODS

After undergoing liver resection at the Affiliated Hospital of Southwest Medical University from July 2017 to May 2018, 35 eligible patients were included in this study. The liver surface and resection margin were intraoperatively assessed by intraoperative ultrasonography and NIR fluorescence imaging, after intravenous administration of indocyanine green (0.5 mg/kg) 72-96 h prior to surgery. The intraoperative observations were compared with the pathological findings in the liver.

RESULTS

In the 35 patients, a total of 53 lesions were found, of which 42 were malignant lesions. The analysis results showed that the sensitivity and accuracy of detection using NIR fluorescence imaging were significantly higher than with intraoperative ultrasonography (P < 0.05). However, there was no difference between contrast-enhanced helical computed tomography and NIR fluorescence imaging in finding lesions (P > 0.05). In addition, 11 new suspicious lesions were detected only by NIR fluorescence imaging in the liver surface and resection margin during surgery, four of which were hepatocellular carcinoma. We also detected four vein tumour thrombi using the NIR fluorescence navigation system.

CONCLUSIONS

The NIR fluorescence navigation system enables the identification of small tumours, residual cancer tissues in resection margin and venous tumour embolies in real time and enhances the accuracy and integrity of liver resection.

The Feasibility and Safety of Preoperative Fluorescence Marking with Indocyanine Green (ICG) in Laparoscopic Gastrectomy for Gastric Cancer

BACKGROUND

Securing the surgical margin is the most essential and important task in curative surgery. However, it is difficult to accurately identify the tumor location during laparoscopic surgery for gastric cancer, and existing methods, such as preoperative endoscopic marking with tattooing and clipping, have multiple disadvantages.

AIMS

We investigated the feasibility and safety of indocyanine green (ICG) fluorescence marking for determining the tumor location during laparoscopic gastrectomy.

METHODS

We retrospectively analyzed preoperative and perioperative data from consecutive patients with gastric cancer undergoing planned laparoscopic distal gastrectomy. Data was maintained in a prospectively compiled surgical database, and patients were categorized into ICG (n = 84) or non-ICG (n = 174) groups based on whether they underwent preoperative endoscopic mucosal ICG injection. One-to-one propensity score matching (PSM) was performed to compare outcomes between the two groups.

RESULTS

We included 84 patient pairs after PSM, and there were no significant differences in preoperative patient characteristics. The ICG group had shorter procedure time (p < 0.001), lower estimated blood loss (p = 0.005), and significantly shorter postoperative hospital stay (p < 0.001). Positive resection margins were confirmed in five cases (6.0%) in the non-ICG group, whereas there were none in the ICG group (p = 0.008). Real-time confirmation was possible during laparoscopy, and the injected ICG did not affect the surgical procedure or result in adverse events.

CONCLUSION

ICG fluorescence imaging is feasible and safe and can potentially be used as a tumor-marking agent for determining the surgical resection line.

Techniques and Current Role of Sentinel Lymph Node (SLN) Concept in Gastric Cancer Surgery

Gastric cancer patients represent a rather divergent patient group and in certain carefully selected cases of early forms of gastric cancer the D2 gastrectomy could be considered a more radical procedure than the biological and oncological characteristics of the primary tumor on the gastric wall would require. As any unnecessary dissection increases morbidity without always respective survival benefits, an approach that could accurately predict and actually dictate the exact extent of lymph node dissection would be ideal. It is more than logical the assumption that the standard D2 lymphadenectomy could represent an overtreatment in distinct patients groups such as patients with early gastric cancer with favorable pathological characteristics and clinically negative nodes not suitable for endoscopic treatment because this early stage disease shows limited lymph node metastasis incidence and excellent overall survival. Considering that the D2 gastrectomy has a negative impact on the quality of life of gastric cancer patients due to the post-gastrectomy functional results, a concept of a more targeted lymph node dissection, when appropriate, is certainly appealing. It is yet to be proven whether sentinel lymph node navigation surgery can fulfill such expectations providing the appropriate balance between morbidity and oncological safety in selected gastric cancer patients.

Indocyanine green fluorescence-navigated laparoscopic metastasectomy for peritoneal metastasis of hepatocellular carcinoma: a case report

Background

Indocyanine green (ICG) can selectively accumulate in primary hepatocellular carcinoma (HCC) and its extrahepatic metastases. ICG fluorescence imaging is an extremely sensitive intraoperative tool for detecting HCC foci and can be used to detect impalpable tumors in laparoscopic surgery. Here, we report a case of a 75-year-old man who underwent peritoneal metastasis resection of HCC using a laparoscopic near-infrared imaging system and ICG fluorescence-navigated surgery.

Case presentation

A 75-year-old man was referred to our department for peritoneal metastasis resection of HCC. Two years before admission, he had undergone transarterial embolization and segmentectomy of segment 6 with open surgery for ruptured HCC. Computed tomography revealed a 12-mm peritoneal metastatic lesion on the abdominal wall near the cut surface of the liver. No other metastases were observed; resection of the solitary metastasis was scheduled. ICG (0.5 mg/kg body weight) was intravenously injected, 72 h preoperatively. An endoscopic, ICG near-infrared fluorescence imaging system revealed clear green fluorescence, indicating peritoneal metastasis of HCC on the abdominal wall. The tumor was resected with adequate surgical margin by partially resecting the liver and diaphragm, followed by histological confirmation as peritoneal metastasis of HCC. No recurrence was observed after 12 months of follow-up.

Conclusions

ICG fluorescence can be useful in laparoscopic surgery for identifying peritoneal metastasis.

Quantitative assessment of fluorescence intensity of ICG in sentinel nodes in early gastric cancer

BACKGROUND

The sentinel node (SN) detection by dual tracer method using indocyanine green (ICG) and a radioisotope (RI) has been recommended for early gastric cancer. However, institutions are limited due to radioactivity in the RI method. The greatest advantage of the RI method is that it objectively assesses RI uptake as a numerical value. The aim of the present study was to verify the usefulness of ICG fluorescence intensity in SN.

METHODS

Seventeen patients with early gastric cancer were enrolled in this study. RI uptake by each lymph node was measured using Navigator GPS and fluorescence nodes were identified using the hyper eye medical system (HEMS). Fluorescence intensity in fluorescence nodes was evaluated using ICG intensity imaging software (Mizuho, Japan) of the HEMS.

RESULTS

The total number of dissected lymph nodes was 227, with an average of 13.3 per patient. The numbers of HN, FN-S, and FN-B were 64, 77, and 34. RI uptake was significantly greater by FN-S than by non-FN-S (P = 0.0016). The median fluorescence intensity value was higher in HN than in non-HN (P < 0.001). A correlation was observed between RI uptake and fluorescence intensity. Dissecting FNs with fluorescence intensity levels of 1-6 resulted in 92.1% dissection of HNs.

CONCLUSION

It is possible that the evaluation of fluorescence intensity is useful for selected SNs instead of RI tracer. If fluorescence intensity is measurable in surgery, an infrared fluorescence method using ICG may be useful and safe for the detection of SN in early gastric cancer.