Role of near-infrared fluorescence imaging in the resection of metastatic lymph nodes in an optimized orthotopic animal model of HNSCC

Indocyanine green uptake by human tumor and non‑tumor cell lines and tissue

Indocyanine green (ICG) is a potential promising dye for a better intraoperative tumor border definition and an improved patient outcome by potentially improving tumor border visualization compared with traditional white light guided surgery. Here, the cellular uptake of ICG in human squamous cell carcinoma (SCC026) and immortalized non-cancer skin (HaCaT) cell lines was evaluated to study the tumor-specific cellular uptake of ICG. The spatial distribution of ICG inside tumor tissue was investigated in tissue sections of head and neck squamous cell carcinoma at a microscopic level. ICG uptake and internalization was observed in living cells after 2.5 h and in the nucleus after 24 h. In dead cells, higher and faster uptake was observed. In the tissue sections, higher ICG signal intensity could be detected in connective tissue and surrounding clusters and blood vessels. In conclusion, no distinct ICG uptake by tumor cells was detected in cancer cell lines and tumor tissue. ICG localization in certain regions of tumor tissue appears to be a result of enhanced tissue permeability and retention, but not specific to tumor cells.

Comparison of indocyanine green-near-infrared fluorescence guided and traditional mediastinal lymphadenectomy during radical esophagectomy: A randomized controlled trial

BACKGROUND

The extent of lymph node dissection during radical esophagectomy remains a controversial topic. Thus, this study mainly aimed to explore the location of sentinel lymph nodes in esophageal squamous cell carcinoma and the application value of the indocyanine green-near-infrared fluorescence system in lymphadenectomy.

METHODS

This randomized controlled clinical trial (ClinicalTrials.gov, NCT04615806) included 42 participants without neoadjuvant therapy who were lymph node negative based on positron emission tomography/computed tomography findings. Traditional esophagectomy with indocyanine green-near-infrared fluorescence imaging was performed after injecting 0.5 mL indocyanine green (1.25 mg/mL) into the esophageal submucosa in the 4 peritumoral quadrants. The primary endpoint was to determine the location of the sentinel lymph node in esophageal squamous cell carcinoma based on postoperative pathologic reports.

RESULTS

A total of 40 patients, with 20 in each group, were included in the final analysis. In the indocyanine green group, indocyanine green-near-infrared fluorescence imaging was successful in all subjects. Seven cases (cases 2, 3, 9, 11, 17, 18, and 20) in the indocyanine green group exhibited lymph node metastases, all of which were near-infrared positive. The detection rate, positive predictive value, negative predictive value, sensitivity, and specificity were 100% (20 of 20 cases), 8.7% (13/150), 100% (265/265), 100% (13/13), and 65.9% (265/402), respectively. All near-infrared-negative lymph nodes were nonmetastatic lymph nodes. In addition, the number of mediastinal lymph nodes resected in the indocyanine green group was significantly higher than in the non-indocyanine green group.

CONCLUSION

Indocyanine green-near-infrared might be an important and promising technique in predicting sentinel lymph nodes of esophageal squamous cell carcinoma and could significantly improve the detection rate of lymph nodes of esophageal squamous cell carcinoma.

Lymph node metastasis in cancer progression: molecular mechanisms, clinical significance and therapeutic interventions

Lymph nodes (LNs) are important hubs for metastatic cell arrest and growth, immune modulation, and secondary dissemination to distant sites through a series of mechanisms, and it has been proved that lymph node metastasis (LNM) is an essential prognostic indicator in many different types of cancer. Therefore, it is important for oncologists to understand the mechanisms of tumor cells to metastasize to LNs, as well as how LNM affects the prognosis and therapy of patients with cancer in order to provide patients with accurate disease assessment and effective treatment strategies. In recent years, with the updates in both basic and clinical studies on LNM and the application of advanced medical technologies, much progress has been made in the understanding of the mechanisms of LNM and the strategies for diagnosis and treatment of LNM. In this review, current knowledge of the anatomical and physiological characteristics of LNs, as well as the molecular mechanisms of LNM, are described. The clinical significance of LNM in different anatomical sites is summarized, including the roles of LNM playing in staging, prognostic prediction, and treatment selection for patients with various types of cancers. And the novel exploration and academic disputes of strategies for recognition, diagnosis, and therapeutic interventions of metastatic LNs are also discussed.

Pericancerous lymph node imaging with indocyanine green-guided near-infrared fluorescence in radical esophagectomy: Protocol for a single-center, prospective, randomized controlled clinical trial

INTRODUCTION

The incidence and mortality rates of esophageal carcinoma are higher than those of most malignancies in humans. Radical esophagectomy is the preferred treatment for early-stage esophageal cancer. However, the extent of lymphadenectomy during radical esophagectomy remains controversial. Indocyanine green (ICG) is the most commonly used imaging agent for the diagnosis of tumors and metastatic lymph nodes in clinical settings. Thus, the main aim of this study was to evaluate pericancerous lymph nodes imaging in video-assisted thoracoscopic surgery radical esophagectomy using a near-infrared (NIR) ICG imaging system and to improve the detection rate of sentinel lymph nodes (SLNs) and overall survival of patients with esophageal cancer.

METHODS

This was a single-center, prospective, randomized controlled clinical trial (allocation rate = 1:1). Forty treatment-naive esophageal cancer patients were recruited and divided into two groups: the ICG and control groups. The inclusion criteria were age, absence of preoperative neoadjuvant therapy, elective surgery, and signed informed consent. Data of participants at four different time points (preoperation, intraoperation, postoperative 1 week and 3 months) were collected and recorded. The main endpoint of this study was to explore the accuracy and false-negative rate of lymphadenectomy using NIR-ICG fluorescence imaging and to identify the location of esophageal cancer SLN combined with postoperative pathological reports.

DISCUSSION

This trial will provide more evidence on the extent of lymph node dissection for esophageal cancer and contribute to the development of treatment guidelines for esophageal cancer.

TRIAL REGISTRATION NUMBER

NCT04615806.

Tumor-Specific Imaging with Angiostamp800 or Bevacizumab-IRDye 800CW Improves Fluorescence-Guided Surgery over Indocyanine Green in Peritoneal Carcinomatosis

Complete surgical removal of lesions improves survival of peritoneal carcinomatosis and can be enhanced by intraoperative near-infrared fluorescence imaging. Indocyanine green (ICG) is the only near-infrared fluorescent dye approved for clinical use, but it lacks specificity for tumor cells, highlighting the need for tumor-selective targeting agents. We compared the tumor-specific near-infrared fluorescent probes Bevacizumab-IRDye 800CW and Angiostamp800, which target tumor angiogenesis and cancer cells, to ICG for fluorescence-guided surgery in peritoneal carcinomatosis of ovarian origin. The probes were administered to mice with orthotopic peritoneal carcinomatosis prior to conventional and fluorescence-guided surgery. The influence of neoadjuvant chemotherapy was also assessed. Conventional surgery removed 88.0 ± 1.2% of the total tumor load in mice. Fluorescence-guided surgery allowed the resection of additional nodules, enhancing the total tumor burden resection by 9.8 ± 0.7%, 8.5 ± 0.8%, and 3.9 ± 1.2% with Angiostamp800, Bevacizumab-IRDye 800CW and ICG, respectively. Interestingly, among the resected nodules, 15% were false-positive with ICG, compared to only 1.4% with Angiostamp800 and 3.5% with Bevacizumab-IRDye 800CW. Furthermore, conventional surgery removed only 69.0 ± 3.9% of the total tumor burden after neoadjuvant chemotherapy. Fluorescence-guided surgery with Angiostamp800 and Bevacizumab-IRDye 800CW increased the total tumor burden resection to 88.7 ± 4.3%, whereas ICG did not improve surgery at all. Bevacizumab-IRDye 800CW and Angiostamp800 better detect ovarian tumors and metastases than the clinically used fluorescent tracer ICG, and can help surgeons completely remove tumors, especially after surgery neoadjuvant chemotherapy.

The feasibility of folate receptor alpha- and HER2-targeted intraoperative fluorescence-guided cytoreductive surgery in women with epithelial ovarian cancer: A systematic review

BACKGROUND

Epithelial ovarian cancer (EOC) is often diagnosed late, with a 5-year relative survival of 30.2% for patients with metastatic disease. Residual disease following cytoreductive surgery is an important predictor for poor survival. EOC is characterized by diffuse peritoneal metastases and depositions of small size, challenging a complete resection. Targeted fluorescence imaging is a technique to enhance tumor visualization and can be performed intraoperatively. Folate receptor alpha (FRα) and human epidermal growth factor receptor 2 (HER2) are overexpressed in EOC in 80% and 20% of the cases, respectively, and have been previously studied as a target for intraoperative imaging.

OBJECTIVE

To systematically review the literature on the feasibility of FRα and HER2 targeted fluorescence-guided cytoreductive surgery (FGCS) in women with EOC.

METHODS

PubMed and Embase were searched for human and animal studies on FGCS targeting either HER2 or FRα in either women with EOC or animal models of EOC. Risk of bias and methodological quality were assessed with the SYRCLE and MINORS tool, respectively.

RESULTS

All animal studies targeting either FRα or HER2 were able to detect tumor deposits using intraoperative fluorescence imaging. One animal study targeting HER2 compared conventional cytoreductive surgery (CCS) to FGCS and concluded that FGCS, either without or following CCS, resulted in statistically significant less residual disease compared to CCS alone. Human studies on FGCS showed an increased detection rate of tumor deposits. True positives ranged between 75%-77% and false positives between 10%-25%. Lymph nodes were the main source of false positive results. Sensitivity was 85.9%, though only reported by one human study.

CONCLUSION

FGCS targeting either HER2 or FRα appears to be feasible in both EOC animal models and patients with EOC. FGCS is a promising technique, but further research is warranted to validate these results and particularly study the survival benefit.

NIR fluorescence-guided tumor surgery: new strategies for the use of indocyanine green

Surgery is the frontline treatment for a large number of cancers. The objective of these excisional surgeries is the complete removal of the primary tumor with sufficient safety margins. Removal of the entire tumor is essential to improve the chances of a full recovery. To help surgeons achieve this objective, near-infrared fluorescence-guided surgical techniques are of great interest. The concomitant use of fluorescence and indocyanine green (ICG) has proved effective in the identification and characterization of tumors. Moreover, ICG is authorized by the Food and Drug Administration and the European Medicines Agency and is therefore the subject of a large number of studies. ICG is one of the most commonly used fluorophores in near-infrared fluorescence-guided techniques. However, it also has some disadvantages, such as limited photostability, a moderate fluorescence quantum yield, a high plasma protein binding rate, and undesired aggregation in aqueous solution. In addition, ICG does not specifically target tumor cells. One way to exploit the capabilities of ICG while offsetting these drawbacks is to develop high-performance near-infrared nanocomplexes formulated with ICG (with high selectivity for tumors, high tumor-to-background ratios, and minimal toxicity). In this review article, we focus on recent developments in ICG complexation strategies to improve near-infrared fluorescence-guided tumor surgery. We describe targeted and nontargeted ICG nanoparticle models and ICG complexation with targeting agents.

Gold nanoclusters as a contrast agent for image-guided surgery of head and neck tumors

With the objective to evaluate the potential of ultra-small gold (Au) nanoclusters (NCs) for optical image-guided surgery, we synthesized and characterized AuNCs shelled by zwitterionic or pegylated ligands. The toxicity of the different AuNCs was evaluated on the Head and Neck Squamous Cell Carcinoma (HNSCC) CAL-33 and SQ20B cell lines in vitro. The safer AuNCs were administrated intravenously to mice for the determination of the pharmacokinetic properties. Biodistributions were performed on orthotopic CAL-33 HNSCC-bearing mice. Finally, the AuNCs were used for image-guided surgery, allowing the increase of the survival time vs. control animals, and the number of animals without any local recurrence.

RGD-Binding Integrins in Head and Neck Cancers

Alterations in integrin expression and function promote tumour growth, invasion, metastasis and neoangiogenesis. Head and neck cancers are highly vascular tumours with a tendency to metastasise. They express a wide range of integrin receptors. Expression of the αv and β1 subunits has been explored relatively extensively and linked to tumour progression and metastasis. Individual receptors αvβ3 and αvβ5 have proved popular targets for diagnostic and therapeutic agents but lesser studied receptors, such as αvβ6, αvβ8, and β1 subfamily members, also show promise. This review presents the current knowledge of integrin expression and function in squamous cell carcinoma of the head and neck (HNSCC), with a particular focus on the arginine-glycine-aspartate (RGD)-binding integrins, in order to highlight the potential of integrins as targets for personalised tumour-specific identification and therapy.