Sentinel lymph node mapping by indocyanin green fluorescence imaging in oropharyngeal cancer - preliminary experience

Multispectral fluorescence imaging of EGFR and PD-L1 for precision detection of oral squamous cell carcinoma: a preclinical and clinical study

BACKGROUND

Early detection and treatment are effective methods for the management of oral squamous cell carcinoma (OSCC), which can be facilitated by the detection of tumor-specific OSCC biomarkers. The epidermal growth factor receptor (EGFR) and programmed death-ligand 1 (PD-L1) are important therapeutic targets for OSCC. Multispectral fluorescence molecular imaging (FMI) can facilitate the detection of tumor multitarget expression with high sensitivity and safety. Hence, we developed Nimotuzumab-ICG and Atezolizumab-Cy5.5 imaging probes, in combination with multispectral FMI, to sensitively and noninvasively identify EGFR and PD-L1 expression for the detection and comprehensive treatment of OSCC.

METHODS

The expression of EGFR and PD-L1 was analyzed using bioinformatics data sources and specimens. Nimotuzumab-ICG and Atezolizumab-Cy5.5 imaging probes were developed and tested on preclinical OSCC cell line and orthotopic OSCC mouse model, fresh OSCC patients' biopsied samples, and further clinical mouthwash trials were conducted in OSCC patients.

RESULTS

EGFR and PD-L1 were specifically expressed in human OSCC cell lines and tumor xenografts. Nimotuzumab-ICG and Atezolizumab-Cy5.5 imaging probes can specifically target to the tumor sites in an in situ human OSCC mouse model with good safety. The detection sensitivity and specificity of Nimotuzumab-ICG in patients were 96.4% and 100%, and 95.2% and 88.9% for Atezolizumab-Cy5.5.

CONCLUSIONS

EGFR and PD-L1 are highly expressed in OSCC, the combination of which is important for a precise prognosis of OSCC. EGFR and PD-L1 expression can be sensitively detected using the newly synthesized multispectral fluorescence imaging probes Nimotuzumab-ICG and Atezolizumab-Cy5.5, which can facilitate the sensitive and specific detection of OSCC and improve treatment outcomes.

TRIAL REGISTRATION

Chinese Clinical Trial Registry, ChiCTR2100045738. Registered 23 April 2021, https://www.chictr.org.cn/bin/project/edit?pid=125220.

Sentinel Lymph Node Biopsy (SLNB) for Early-Stage Head and Neck Squamous-Cell Carcinoma of the Tongue: Twenty Years of Experience at I.N.T. "G.Pascale"

Oral tongue squamous-cell carcinoma (OTSCC) is the most prevalent malignancy in the head and neck region. Lymphatic spread, particularly to cervical lymph nodes, significantly impacts 5-year survival rates, emphasizing the criticality of precise staging. Metastatic cervical lymph nodes can decrease survival rates by 50%. Yet, elective neck dissection (END) in T1-2 cN0 patients proves to be an overtreatment in around 80% of cases. To address this, sentinel lymph node biopsy (SLNB) was introduced, aiming to minimize postoperative morbidity. This study, conducted at the ENT and Maxillofacial Surgery department of the Istituto Nazionale Tumori in Naples, explores SLNB's efficacy in early-stage oral tongue squamous-cell carcinoma (OTSCC). From January 2020 to January 2022, 122 T1/T2 cN0 HNSCC patients were enrolled. Radioactive tracers and lymphoscintigraphy identified sentinel lymph nodes, aided by a gamma probe during surgery. Results revealed 24.6% SLN biopsy positivity, with 169 SLNs resected and a 21.9% positivity ratio. The study suggests SLNB's reliability for T1-2 cN0 OTSCC patient staging and early micrometastasis detection.

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.

Radioactive nanosized colloids and indocyanine green identify the same sentinel lymph nodes in oral squamous cell carcinoma

PURPOSE

Near-infrared fluorescence imaging using indocyanine green (ICG) combined with radioactive markers has the potential to improve sentinel lymph-node (SLN) mapping in oral squamous cell carcinoma (OSCC). This study aimed to evaluate the ability of 99mTc and ICG in identifying the sentinel lymph nodes in patients with early stage OSCC.

METHODS

Data were collected prospectively, and a retrospective analysis of 15 patients with early stage OSCC and a cN0 neck was performed. All patients received peritumoral injection of 99mTc the day before surgery and ICG was administered intraoperatively. Intentionally, the application of the two different tracers were done by two different physicians with varying degrees of experience. The number of identified lymph nodes positive for 99mTc and ICG, the overlap or possible discrepancies of both methods, and the time until fluorescence signals of ICG were detected were noted.

RESULTS

In all patients, a 100% agreement in sentinel lymph-node identification was achieved, regardless of both the exact location of the peritumoral injection and the experience of the injecting surgeon. Time until ICG accumulation in the sentinel lymph node was consistently found to be between 1 and 3 min.

CONCLUSION

ICG constitutes a viable and useful addition to 99mTc for intraoperative sentinel lymph-node detection in this study.

Development of novel tracers for sentinel node identification in cervical cancer

Indocyanine green (ICG) with near-infrared (NIR) fluorescence imaging is used for lymphatic mapping. However, binding of ICG to blood proteins like serum albumin can shorten its retention time in sentinel lymph nodes (SLNs). Here, we investigated the efficacy and safety of a new fluorescence tracer comprising phytate and liposome (LP)-encapsulated ICG. Coadministration of phytate with LP containing phosphatidic acid promotes chelation mediated by Ca2+ in bodily fluids to enhance SLN retention. Uniformly sized LPs (100 nm) encapsulating ICG under conditions that minimized fluorescence self-quenching during storage were produced. We analyzed the behavior of the new tracer (ICG-phytate-LP) and control tracers (ICG and ICG-LP) in the lymphatic flow of mice in terms of lymph node retention time. We also tested lymphatic flow and safety in pigs that have a more human-like lymphatic system. LPs encapsulating stabilized ICG were successfully prepared. Mixing LP with phytate in the presence of Ca2+ increased both the particle size and negative surface charge. In mice, ICG-phytate-LP had the best lymph node retention, with a fluorescence intensity ratio that increased over 6 h and then decreased slowly over the next 24 h. In pigs, administration of ICG and ICG-phytate-LP resulted in no death or weight loss. There were no obvious differences between blood test results for the ICG and ICG-phytate-LP groups, and the overall safety was good. ICG-phytate-LP may be a useful new tracer for gynecological cancers that require time for lymph node identification due to a retroperitoneal approach.

[Application of methylene blue near-infrared fluorescence imaging for oral sentinel lymph node mapping in rats]

OBJECTIVE

To explore the concentration range and penetration depth of methylene blue near-infrared fluorescence imaging, and to clarify the role of methylene blue in oral lymphatic drainage and sentinel lymph node localization, so as to lay a foundation for the potential research and application of sentinel lymph node in oral cancer.

METHODS

10% (mass fraction) methylene blue injection was diluted into 29 different concentrations with 0.9% (mass fraction) normal saline, and the concentration range of methylene blue near-infrared fluorescence imaging was determined by near-infrared fluorescence imager. The maximum penetration depth of methylene blue near-infrared fluorescence was determined by covering pigskin with different thicknesses (1, 2, 3, 4 and 5 mm) in methylene blue solution. 0.2 mL methylene blue solution was injected into the submucosal 0.5 cm at the lateral margin of tongue on one side of the rats. The near-infrared fluorescence imager was used for continuously monitoring for 3 hours. The first near-infrared fluorescence hotspot was identified as sentinel lymph node and labeled by percutaneous observation. The rats were then sacrificed and dissected in the head and neck. Near-infrared fluorescence imaging was performed again to observe whether the fluorescent tissue was consistent with the labeled fluorescent hotspot in vitro, and the presence of lymphoid tissue was confirmed by pathological examination after resection.

RESULTS

Except that no fluorescence signals were detected in the blank control groups, the fluorescence intensity of methylene blue increased first and then decreased with its solution concentration decreased. When the concentration of methylene blue was diluted to the picomole level, the fluorescence signal could still be detected. The maximum penetration depth of methylene blue fluorescence was 4 mm. Methylene blue near-infrared fluorescence could be localized in oral lymphatic drainage and sentinel lymph node. The fluorescence was sustained for more than 3 hours after methylene blue injection. Methylene blue solution concentrations of 3.34 mmol/L, 6.68 mmol/L, 13.37 mmol/L and 26.74 mmol/L were selected in the rats to map sentinel lymph node by near-infrared fluorescence.

CONCLUSION

Methylene blue near-infrared fluorescence has a certain penetrating ability and can transcuta-neously map the sentinel lymph node and their associated lymphatic vessels in rats, which is expected to be further applied in the study of sentinel lymph node in oral cancer.

Diagnostic accuracy of combined optical- and radio-guided SNB for neck staging of oral squamous cell carcinoma lesions in the anterior oral cavity

PURPOSE

The purpose was to investigate the diagnostic performance of bimodal optical and radio-guided sentinel node biopsy (SNB) for oral squamous cell carcinoma (OSCC) sub-sites in the anterior oral cavity.

METHODS

Prospective study of 50 consecutive patients with cN0 OSCC scheduled for SNB was injected with the tracer complex Tc99m:ICG:Nacocoll. A near-infrared camera was applied for optical SN detection. Endpoints were modality for intraoperative SN detection and false omission rate at follow-up.

RESULTS

In all patients, a SN could be detected. In 12/50 (24%) of cases, the SPECT/CT showed no focus in level 1, but intraoperatively a SN in level 1 was optically detected. In 22/50 cases (44%), an additional SN was identified only due to the optical imaging. At follow-up, the false omission rate was 0%.

CONCLUSION

Optical imaging appears to be an effective tool to allow real-time SN identification comprising level 1 unaffected by possible interference of radiation site from the injection.

Novel color fluorescence imaging for sentinel lymph node detection in oral and oropharyngeal cancer

AIM

Fluorescence imaging (FI) using indocyanine green (ICG) is a noteworthy alternative technique for sentinel lymph node (SLN) detection without radiation exposure in oral cavity and oropharynx cancer. However, conventional FI is monochrome, so the visibility is limited. This study assessed whether color FI using the HyperEye Medical System (HEMS) is feasible as an alternative for SLN detection.

METHODS

Patients with previously untreated cT1-2N0 oral or oropharyngeal cancer who were to undergo primary tumor resection and elective neck dissection (END) in our hospital were enrolled from November 2012 to March 2016. The patients underwent SLN detection for biopsy via the HEMS following the injection of ICG solution around the primary lesion before neck dissection. The visibility and the diagnostic accuracy of the imaging were evaluated.

RESULTS

SLNs were visualized in all eight cases; however, transcutaneous fluorescence detection was not observed in all cases. Utilizing color mode imaging simplified harvest by clearly discriminating SLNs from surrounding structures, while the monochrome mode proved to be more sensitive for detection. Two cases showed occult metastases on both sentinel and regional nodes. The identification and false negative rates were 100% and 0%, respectively. There were no complications incurred due to this method.

CONCLUSION

Our results suggest that color FI with the HEMS allows for the accurate and safe harvest of SLNs with a preparatory skin incision. Although there is room for improvement of sensitivity, this easy-to-handle procedure might provide the potential to expand the role of the ICG method for SLN detection in head and neck cancer.

In Vivo Oral Sentinel Lymph Node Mapping by Near-Infrared Fluorescent Methylene Blue in Rats

This study aimed to demonstrate the feasibility of near-infrared (NIR) fluorescence imaging using methylene blue (MB) for detecting oral sentinel lymph nodes (SLNs) in rats and compared MB’s tracer effects with those of indocyanine green (ICG) in SLN mapping. Different concentrations of MB were injected into the rats’ left lingual submucosa to determine the optimal concentration by using a continuous (1 h) MI-1 fluorescence imaging system. To compare the tracer effects of the optimal MB concentration with ICG in oral SLN mapping, MI-1 imaging was continuously monitored for 12 h. The mean signal-to-background ratio (SBR) of the SLNs and SLN fluorescence area fraction were analyzed. SLNs and lymphatic vessels were clearly visible in all rats. The optimal injection dose of MB infected into lingual submucosa for NIR fluorescence imaging was 0.2 mL of 6.68 mM MB. During continuous monitoring for 12 h, the mean SBR of the SLNs was significantly higher in the ICG groups than in the MB groups (p < 0.001). However, the area fraction of SLN fluorescence in the ICG groups increased continuously, owing to strong fluorescent contamination. This study examined the feasibility of detection of draining lymph nodes in the oral cavity of rats using MB NIR fluorescence imaging. MB causes less fluorescent contamination than does ICG, which shows promise for clinical research and application.

Application of near-infrared fluorescence imaging in lingual lymph node screening and drainage pattern observation for tongue cancer

Objective: Lingual lymph node (LLN) metastasis is regarded as an indicator of unfavorable prognosis and a crucial sign of the high degree of primary tumor aggressiveness. However, detecting LLN metastasis is an important but frequently overlooked aspect of diagnosis and surgical treatment planning. The study aims to identify LLNs by intraoperative near-infrared (NIR) fluorescence imaging with indocyanine green absorbed into human serum albumin (ICG: HSA) and describe the presence of lymphatic drainage channels from the floor of the mouth in patients with tongue carcinoma.

Materials and Methods: 21 patients diagnosed with cT1-T4 squamous cell carcinoma (SCC) of the tongue margin and scheduled to undergo tumor resection and unilateral neck dissection were enrolled. After exposing the neck, the patients were injected with 0.3 ml of ICG: HSA (500 μM) in three quadrants around the tumor, excluding the mucous membrane of the basal region cavity. Employing a near-infrared fluorescence imaging system, the fluorescence of levels I, II, III, and IV was measured during neck dissection.

Results: LLNs were detected in four patients and were identified as metastatic LLNs in all 21 patients. The near-infrared fluorescence imaging system showed the existence of lymphatic drainage channels in the floor of the mouth. In patients receiving peritumoral injection of ICG: HSA, the mean fluorescence intensity (MFI)of metastatic lymph nodes (LNs) (178.4 ± 64.39, mean ± SD) was higher than that in non-metastatic LNs (132.0 ± 76.5, mean ± SD) (p &lt; 0.05).

Conclusion: NIR fluorescence imaging with ICG: HSA could be used for intraoperative identification of LLNs and assist in the determination of metastatic lymph nodes for tongue carcinoma patients. Additionally, this finding demonstrates the feasibility of near-infrared fluorescence imaging in defining lymphatic drainage channels in the head and neck.

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.

Sentinel lymph node biopsy with a handheld cordless magnetic probe following preoperative MR lymphography using superparamagnetic iron oxide for clinically N0 early oral cancer: A feasibility study

PURPOSE

Radioisotope (RI) tracers are generally used for preoperative mapping of sentinel lymph node (SLN) and intraoperative detection with a portable γ probe. However, the use of RI has several limitations. Therefore, a method without RI is required for the widespread application of SLN biopsy. The purpose of this study was to evaluate the feasibility of SLN biopsy with a handheld cordless magnetic probe following magnetic resonance lymphography (MRL) using superparamagnetic iron oxide (SPIO) and for clinically N0 early oral cancer.

MATERIALS AND METHODS

MRL using SPIO and SLNB with the handheld cordless magnetic probe were performed for 27 patients with clinically N0 early oral cancer.

RESULTS

In all 27 patients (100%), SLNs were detected by MRL, and the total and mean number of SLNs were 73 and 2.7, respectively. All SLNs identified by MRL were detectable using the magnetic probe in all patients.

CONCLUSIONS

SLNB with handheld cordless magnetic probe following preoperative SLN mapping by MRL using SPIO is feasible, without RI use, for neck management in cases of clinically N0 early oral cancer.

Methods for sentinel lymph node mapping in oral cancer: a literature review

Oral cancers, excluding non-melanoma skin cancer, are the most common cancers of the head and neck. Of these, 90% are squamous cell carcinomas (SCC). Surgery, which consists of dissection of the primary tumor and lymphadenectomy, is considered a radical method of treatment. There are several ranges of cervical lymphadenectomy: selective neck dissection (SND), modified radical neck dissection (MRND), and radical neck dissection (RND). The extension of surgery depends on the stage of clinical advancement, which can be determined by TNM classification, among other methods. The greatest controversy is related to SND in patients with cN0 (no evidence of regional lymph node metastasis), which is currently standard procedure. This approach is dictated by the possibility of hidden or subclinical metastases. The use of the sentinel lymph node (SLN) concept in patients with early stage of oral cancer and appropriate methods of its mapping may lead to a reduction in the extent of the lymphadenectomy procedure, thus reducing postoperative mortality and maintaining the patient’s function and quality of life, with correct oncological results. So far, available methods for SLN mapping are based on use of markers: methylene blue dye (MBD), metastable radioactive isotope Technetium (99mTc), or the fluorescent substance indocyanine green (ICG).

Activatable molecular probes for fluorescence-guided surgery, endoscopy and tissue biopsy

The real-time, dynamic optical visualization of lesions and margins ensures not only complete resection of the malignant tissues but also better preservation of the vital organs/tissues during surgical procedures. Most imaging probes with an "always-on" signal encounter high background noise due to their non-specific accumulation in normal tissues. By contrast, activatable molecular probes only "turn on" their signals upon reaction with the targeted biomolecules that are overexpressed in malignant cells, offering high target-to-background ratios with high specificity and sensitivity. This review summarizes the recent progress of activatable molecular probes in surgical imaging and diagnosis. The design principle and mechanism of activatable molecular probes are discussed, followed by specific emphasis on applications ranging from fluorescence-guided surgery to endoscopy and tissue biopsy. Finally, potential challenges and perspectives in the field of activatable molecular probe-enabled surgical imaging are discussed.

Diagnostic value of indocyanine green for sentinel lymph node mapping and lymph node metastasis in oral/oropharyngeal carcinoma

Indocyanine green (ICG) fluorescence-based sentinel lymph node (SLN) biopsy has been promoted to detect early metastasis of oral/oropharyngeal carcinoma, but its diagnostic value still remains unclear. In this letter, we identified 6 studies on ICG fluorescence based SLN in the detection of lymph node metastasis in oral/oropharyngeal carcinoma. For detection of metastatic lymph node, the overall sensitivity and specificity of the studies were 0.86 and 0.91, respectively. SROC curve was determined according to the combined sensitivity and specificity, and the overall area under the curve AUC was 0.93. On the whole, ICG fluorescence-based SLN biopsy showed promising effect for earlier detection and staging.

A Scoping Review of Ongoing Fluorescence-Guided Surgery Clinical Trials in Otolaryngology

OBJECTIVE

Fluorescence-guided surgery (FGS) is a rapidly developing intraoperative technology, and many contrast agents are currently under investigation. We sought to provide a review of the current state of FGS clinical trials in Otolaryngology, emphasizing its oncologic applications.

METHODS

According to the preferred reporting Items for systematic reviews and meta-analyses (PRISMA) workflow for scoping reviews, a clinical trial search was performed across multiple international clinical trials registries, searching for permutations of "fluorescence," "tumor," "surgery," and "nerve" to identify all relevant studies. Studies that were active, enrolling, or soon to be enrolling patients undergoing head and neck surgery were included.

RESULTS

Nineteen studies were eligible for inclusion. Seventeen studies are focused on FGS for oncologic resection and lymph node detection. One study assesses peripheral nerve fluorescence, and one evaluates normal parathyroid function after thyroidectomy. Contrast agents under development are conjugated to fluorophores that excite in the 800 nm (indocyanine green), 410 nm (5-aminolevulinic acid), 700 nm (Cyanine 5.5), and 525 nm ranges (fluorescein derivatives).

CONCLUSION

Presently, there are 19 ongoing trials investigating novel FGS contrast agents for their safety, efficacy, and utility in Otolaryngology-Head and Neck Surgery. These agents rely on unique fluorophores and absorption ranges in the near-infrared and visible light spectra. FGS studies are expanding within Otolaryngology-Head and Neck Surgery with profound implications in oncologic surgery, lymph node detection, and anatomic and functional assessment. Laryngoscope, 2021.

An overview of the current clinical status of optical imaging in head and neck cancer with a focus on Narrow Band imaging and fluorescence optical imaging

Early and accurate identification of head and neck squamous cell carcinoma (HNSCC) is important to improve treatment outcomes and prognosis. New optical imaging techniques may assist in both the diagnostic process as well as in the operative setting by real-time visualization and delineation of tumor. Narrow Band Imaging (NBI) is an endoscopic technique that uses blue and green light to enhance mucosal and submucosal blood vessels, leading to better detection of (pre)malignant lesions showing aberrant blood vessel patterns. Fluorescence optical imaging makes use of near-infrared fluorescent agents to visualize and delineate HNSCC, resulting in fewer positive surgical margins. Targeted fluorescent agents, such as fluorophores conjugated to antibodies, show the most promising results. The aim of this review is: (1) to provide the clinical head and neck surgeon an overview of the current clinical status of various optical imaging techniques in head and neck cancer; (2) to provide an in-depth review of NBI and fluorescence optical imaging, as these techniques have the highest potential for clinical implementation; and (3) to describe future improvements and developments within the field of these two techniques.

Role of indocyanine green combined with radiotracer-Technetium 99 m in neck surgery for primary and recurrent head and neck cancer: preliminary results of a tertiary cancer center

PURPOSE

Neck dissection (ND), whether therapeutic or elective, is an essential component of the treatment of head and neck squamous cell carcinoma (HNSCC). Due to altered anatomy and fibrosis caused by initial treatments, surgeons face challenges during salvage ND. A combination of Technetium-99 m and indocyanine green (ICG) previously used in the sentinel lymph node (SLN) biopsy for oral cavity cancers, may be useful in different types of neck surgeries. We aimed to show the additional advantage of this combination in detecting HNSCC and thyroid cancer recurrences, as well as individual lymphatic drainage in elective ND.

METHODS

We retrospectively reviewed medical records of patients, underwent neck surgery guided with ICG and Tc-99 m, in Hacettepe University Hospital between June 2018 and December 2020. In a total of 28 patients, intraoperative gamma probes were paired with near infrared (NIR) cameras. Patients are divided into two groups: neck surgery with recurrent occult lesion localization (NS- ROLL) (n: 14) and ND with SLN screening (ND-SLNS) (n: 14).

RESULTS

Among all 14 patients in NS-ROLL group, recurrent diseases, hidden behind tissues were 100% successfully localized. In ND-SLNS group, 238 lymph nodes were harvested, metastasis rate was 31.3% (10/32) in sentinel nodes. SLNS revealed 100% accuracy in detecting metastasis in clinically N0 neck (10/238). Contralateral lymphatic drainage was observed in three patients (lateral-sided oral cavity SCC). In two patients (floor of mouth), three sentinel nodes were detected by NIR only.

CONCLUSION

The use of ICG-radiotracer provides additional value in disease removal for both primary and recurrent tumors of the head and neck.

[Near-infrared sentinel diagnostics in head and neck squamous cell carcinoma: a systematic review]

BACKGROUND

 Near-infrared fluorescence (NIR) imaging is a new technique for intraoperative identification of sentinel lymph nodes (SLN). It has shown promising results in several surgical specialties. This article reviews the current study situation of NIR SLN diagnosis of head and neck malignancy.

MATERIAL AND METHODS

 systematic literature search in the following online databases: PubMed, MEDLINE, Thompson Reuters Web of Science, SPIE for the search terms: sentinel node, sentinel node biopsy, head and neck squamous cell carcinoma, near-infrared imaging, indocyanine green, icg. Evaluation of scientific relevance of papers according to established criteria.

RESULTS

 Studies were analyzed in terms of clinical application, clinical reporting, identification rate, and false-negative rate. The identification rate of SLN is 97-100 %, with an average of 1.2-3.4 fluorescence positive lymph nodes per examination. The overall false-negative rate varies between 0 and 20 %.

CONCLUSIONS

 In the synopsis of the currently published results, NIR imaging promises the great potential to improve the diagnosis of SLN in carcinomas of the oral cavity and pharynx. A simple and fast procedure with high spatial resolution and without radiation exposure is beneficial.

Recent Developments of ICG-Guided Sentinel Lymph Node Mapping in Oral Cancer

Sentinel lymph node (SLN) biopsy has gained attention as a method of minimizing the extent of neck dissection with a similar survival rate as elective neck dissection in oral cancer. Indocyanine green (ICG) imaging is widely used in the field of surgical oncology. Real-time ICG-guided SLN imaging has been widely used in minimally invasive surgeries for various types of cancers. Here, we provide an overview of conventional SLN biopsy and ICG-guided SLN mapping techniques for oral cancer. Although ICG has many strengths, it still has limitations regarding its potential use as an ideal compound for SLN mapping. The development of novel fluorophores and imaging technology is needed for accurate identification of SLNs, which will allow precision surgery that would reduce morbidities and increase patient survival.

MR lymphography with superparamagnetic iron oxide for sentinel lymph node mapping of N0 early oral cancer: A pilot study

OBJECTIVES

The purpose of this pilot study was to evaluate the usefulness of magnetic resonance lymphography (MRL) with superparamagnetic iron oxide (SPIO) in sentinel lymph node (SLN) mapping of clinically N0 early oral cancer, and to conduct a comparative study of this MRL with CT lymphography (CTL).

METHODS

CTL and MRL were performed for SLN mapping before surgery for 20 patients with clinically N0 early oral cancer. The detection rate, number, and location of SLNs in CTL and MRL were evaluated. Furthermore, optimal scanning/imaging timing in MRL was examined.

RESULTS

SLNs were detected by CTL in 18 (90%) patients, and the total and mean number of SLN were 35 and 1.8, respectively. All SLNs could be detected 2 min and 3.5-5 min after contrast medium injection. In all patients, SLNs were detected by MRL at 10 min after SPIO injection, and the total and mean number of SLN was 53 and 2.7, respectively. MRL at 30 min after the injection showed additional 18 secondary lymph nodes.

CONCLUSION

MRL with SPIO is safe and useful imaging for the detection of SLNs in clinically N0 early oral cancer, and the optimal imaging timing is 10 min after SPIO injection.

Novel Experience in Hybrid Tracers: Clinical Evaluation of Feasibility and Efficacy in Using ICG-99mTc Nanotop for Sentinel Node Procedure in Breast Cancer Patients

PURPOSE

The clinical introduction of a radioactive and fluorescent hybrid tracer allowed for preoperative lymphatic mapping and intraoperative real-time fluorescence tracing of the sentinel lymph node (SLN) by a single injection. The aim of this feasibility study is to evaluate the first-in-human use of the hybrid tracer by combining indocyanine green (ICG) and radiocolloid based on Nanotop compound (99mTc Nanotop) for SLN biopsy (SLNB) in breast cancer patients.

METHODS

The day before surgery, ICG-99mTc Nanotop was injected periareolarly in breast cancer patients scheduled for SLNB. Planar lymphoscintigraphic (PL) and SPECT/CT images were then acquired. An intraoperative optonuclear probe was used to detect SLN gamma and fluorescent signals. The harvested SLNs were examined by hematoxylin-eosin staining, and patients were clinically evaluated 1 month after surgery.

RESULTS

Twenty-one consecutive patients were enrolled. The PL and SPECT/CT techniques identified at least 1 SLN in all patients for a preoperative sentinel detection rate of 100%. SPECT/CT revealed 3 additional lymph nodes in the same nodal basin, which had not been visualized on conventional PL (κ = 0.747; P < 0.005). All 30 preoperative SLNs were localized and excised up to 16 hours after injection. The counts measured via gamma tracing showed a very strong correlation with those measured via near-infrared fluorescent tracing (P < 0.005, r = 0.964). No adverse reactions were observed.

CONCLUSIONS

The SLNB technique used with the ICG-99mTc Nanotop tracer resulted to be feasible, reliable, and safe. This hybrid compound allowed us to obtain excellent performance in terms of both preoperative lymphatic mapping and intraoperative SLN detection in breast cancer patients.

Comparative study on the diagnostic value of intravenous/peritumoral injection of indocyanine green for metastatic lymph node location in patients with head and neck squamous cell carcinoma (HNSCC)

Background

Accurate assessment of regional lymph node (LN) status is essential for the treatment of head and neck squamous cell carcinoma (HNSCC) patients. In this study, we aimed to compare the difference between intravenous injection of indocyanine green (ICG) and peritumoral injection of ICG in the location of metastatic LNs.

Methods

Twenty-nine patients were enrolled in this study with 13 patients receiving intravenous injection of ICG and 16 patients receiving peritumoral injection of ICG. During the surgery, the fluorescence-positive LNs in vivo were sent to undergo frozen section after fluorescence intensity was recorded. After the cervical LN dissection, all LNs were sorted by region, and the fluorescence intensity was recorded before the LNs were sent for paraffin section.

Results

During the surgery, both intravenous or peritumoral injections with near-infrared (NIR) fluorescence imaging of ICG had their respective pros and cons in vivo, with the sensitivity and specificity being 62.5%/75% and 98.1%/89.1% respectively. After the surgery, both methods could reduce the pathological workload by preselecting the LNs at-risk in the premise of accurate assessing the cervical LN stage. However, intravenous ICG administration was more valuable in determining all types of LN status according to the fluorescence intensity [area under the curve (AUC): 0.91 vs. 0.78, P<0.001].

Conclusions

With the assistance of NIR fluorescence imaging using ICG, both administration methods could reduce the postoperative complication and the pathological workload, whereas the intravenous mode of ICG administration is superior in application value.

Sentinel lymph node mapping using ICG fluorescence and cone beam CT - a feasibility study in a rabbit model of oral cancer

BACKGROUND

Current sentinel lymph node biopsy (SLNB) techniques, including use of radioisotopes, have disadvantages including the use of a radioactive tracer. Indocyanine green (ICG) based near-infrared (NIR) fluorescence imaging and cone beam CT (CBCT) have advantages for intraoperative use. However, limited literature exists regarding their use in head and neck cancer SLNB.

METHODS

This was a prospective, non-randomized study using a rabbit oral cavity VX2 squamous cell carcinoma model (n = 10) which develops lymph node metastasis. Pre-operatively, images were acquired by MicroCT. During surgery, CBCT and NIR fluorescence imaging of ICG was used to map and guide the SLNB resection.

RESULTS

Intraoperative use of ICG to guide fluorescence resection resulted in identification of all lymph nodes identified by pre-operative CT. CBCT was useful for near real time intraoperative imaging and 3D reconstruction.

CONCLUSIONS

This pre-clinical study further demonstrates the technical feasibility, limitations and advantages of intraoperative NIR-guided ICG imaging for SLN identification as a complementary method during head and neck surgery.

Sentinel lymph node mapping of clinically N0 early oral cancer: a diagnostic pitfall on CT lymphography

OBJECTIVE

The purpose of this study was to reevaluate preoperative computed tomography lymphography (CTL) and enhanced CT images during follow-up to clarify whether SLNs enhanced by CTL were identified accurately before primary surgery with sentinel lymph node biopsy (SLNB) for clinically N0 early oral cancer.

METHODS

Thirty two early oral cancer patients without cervical lymph node metastasis were enrolled in this study. To clarify whether SLNs enhanced by CTL were identified accurately before primary surgery with SLNB, we reevaluated preoperative CTL and enhanced CT images during follow-up in all patients.

RESULTS

SLNs were detected by CTL in 31 of 32 patients (96.9%). During follow-up after primary surgery with SLNB, 4 of 27 patients without SLN metastasis had occult neck metastasis. Of the 4 patients, only 1 patient with cancer of floor of the mouth had overlooking of SLN, and the overlooking rate of SLN was 3.1%. The overlooked small SLN (2.9 × 3.3 × 3.1 mm) was located at contralateral level IB. The CT numbers before, 2, 5, 10 min after iopamidol injection, were 33 HU, 37 HU, 62 HU, 52 HU, respectively. The CT numbers of overlooked SLN 5 and 10 min after the injection was higher than CT images scanned before the iopamidol injection.

CONCLUSIONS

The enhancement of SLNs in CTL images after iopamidol injection should be compared sufficiently with CT images before iopamidol injection to avoid overlooking of SLNs in N0 early oral cancer.

Advances in image enhancement for sarcoma surgery

The recurrence rate of soft tissue and bone sarcomas strongly correlates to the status of the surgical margin after excision, yet excessive removal of tissue may lead to distinct, otherwise avoidable morbidity. Therefore, adequate margination of sarcomas both pre- and intra-operatively is a clinical necessity that has not yet fully been met. Current guidance for soft-tissue sarcomas recommends an ultrasound scan followed by magnetic resonance imaging (MRI). For bone sarcomas, two plane radiographs are required, followed similarly by an MRI scan. The introduction of more precise imaging modalities may reduce the morbidity associated with sarcoma surgery; the PET-CT and PET-MRI approaches in particular demonstrating high clinical efficacy. Despite advancements in the accuracy in pre-operative imaging, translation of an image to surgical margins is difficult, regularly resulting in wider resection margins than required. For soft tissue sarcomas there is currently no standard technique for image guided resections, while for bone sarcomas fluoroscopy may be used, however margins are not easily discernible during the surgical procedure. Near infra-red (NIR) fluorescence guided surgery offers an intra-operative modality through which complete tumour resection with adequate tumour-free margins may be achieved, while simultaneously minimising surgical morbidity. NIR imaging presents a potentially valuable adjunct to sarcoma surgery. Early reports indicate that it may be able to provide the surgeon with helpful information on anatomy, perfusion, lymphatic drainage, tumour margins and metastases. The use of NIR fluorochromes have also been demonstrated to be well tolerated by patients. However, prior to widespread implementation, studies related to cost-effectiveness and the development of protocols are essential. Nevertheless, NIR imaging may become ubiquitous in the future, carrying the potential to transform the surgical management of sarcoma.

CT lymphography for sentinel lymph node mapping of clinically N0 early oral cancer

BACKGROUND

The objectives of this retrospective study were to evaluate the usefulness of computed tomography lymphography (CTL) and to clarify the optimal timing of CTL in sentinel lymph node (SLN) mapping of clinically N0 early oral cancer.

METHODS

Twenty patients with clinically N0 early oral cancer underwent CTL with a 128 multi-detector row CT scanner to detect SLN the day before resection of primary tumor and SLN biopsy with indocyanine green (ICG) fluorescence guidance. CT scanning was performed in the first 10 patients at 2, 5, and 10 min after submucosal injection of iopamidol and in the remaining 10 patients at 2, 3.5, 5, and 10 min after the injection of contrast medium. We evaluated the SLN detection rate at each scan timing and the number and location of SLNs. We evaluated whether CTL-enhanced SLNs could be identified intraoperatively as ICG fluorescent lymph nodes.

RESULTS

SLNs were detected by CTL in 19 of the 20 patients (95.0%), and the mean number of SLNs was 2 (range, 1-4). All SLNs were located on the ipsilateral side; 35 of 37 SLNs were located at level I and II, and 2 SLNs were lingual lymph nodes. All SLNs could be detected 2 min and 3.5-5 min after contrast medium injection, and CTL-enhanced SLNs could be identified intraoperatively as fluorescent lymph nodes.

CONCLUSIONS

CTL could facilitate the detection of SLNs in early oral cancer, and the optimal timing of CT scanning was at 2 and 5 min after injection of contrast medium.

Nanotechnology in Oral Cavity Carcinoma: Recent Trends and Treatment Opportunities

Oral cavity carcinoma (OCC) remains an ongoing public health problem. Emerging nanotechnology provides alternative treatment approaches. This review covers the up-to-date literature in the human OCC treatment field. We explored the growing body of evidence to reveal novel and highly promising diagnostic and therapeutic applications of nanotechnology in this field. Various types of nanoparticles have been tested for applications in OCC. Imaging modalities in addition to nanocarriers are discussed. The encouraging contribution of lymphotropic nanoparticles contrast in the diagnosis of metastatic cervical lymph nodes needs to be confirmed. The development of the sentinel lymph node procedure and photodynamic therapy may lead to breakthrough therapies in order improve clinical outcomes and quality of life. In this perspective, cancer nanotechnology has the potential to revolutionize the treatment of OCC patients.

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.

Near-infrared fluorescence imaging improves the nodal yield in neck dissection in oral cavity cancer - A randomized study

INTRODUCTION

Lymph node yield (LNY) in neck dissection has been identified as a prognostic factor in oral cavity cancer. The purpose of this study was to investigate the impact of additional use of optical imaging on LNY in therapeutic ND in oral cancer.

METHODS

Consecutive patients with oral squamous cell carcinoma with clinical neck metastasis planned for primary tumor resection were randomized to conventional neck dissection or near-infrared fluorescence (NIRF)-guided neck dissection, respectively. In the intervention group, patients were injected with ICG-Nanocoll prior to surgery. Intraoperatively, an optical hand-held camera system was used for lymph node identification. Also, NIRF imaging of the neck specimen was performed, and optical signals were pinned with needle markings to guide the pathological examination. The endpoint of the study was LNY per neck side in levels Ib-III.

RESULTS

31 patients were included with 18 neck sides in the control group and 18 neck sides in the intervention group for evaluation. During NIRF-guided ND, individual lymph nodes could be identified by a bright fluorescent signal and individual tumor-related drainage patterns could be observed in the neck. The LNY in the intervention group was significantly higher compared to the control group (p = 0.032) with a mean of 24 LN (range: 12-33 LN in levels Ib-III compared to 18 LN (range: 10-36 LN) in the control group, respectively.

CONCLUSIONS

NIRF-guided ND significantly improved the nodal yield compared to the control group. Intraoperative real-time optical imaging enabled direct visualization of tumor-related drainage patterns within the neck lymphatics.

Intraoperative Imaging with Second Window Indocyanine Green for Head and Neck Lesions and Regional Metastasis

While optical imaging with near-infrared (NIR) fluorescent dye has been used in oncologic surgery, its use in the head and neck has not been established. We aimed to evaluate the feasibility of using NIR to visualize primary tumor and regional metastasis in head and neck malignancy. Patients undergoing resection of primary head and neck tumors were included in this pilot study. Each patient was injected with indocyanine green dye (ICG) the day prior to surgery. The VisionSense Iridium camera system was used to visualize the primary lesion, its margins, and neck dissection specimen intraoperatively. Fourteen patients were enrolled. Eighty-six percent of primary tumors showed fluorescence as compared with surrounding tissues. ICG positivity showed 100% sensitivity for pathologic nodes in 7 neck dissection specimens; however, for 3 patients, nonpathologic nodes also showed ICG positivity. NIR imaging with ICG dye can be considered for intraoperative imaging of head and neck lesions.

Detection of Sentinel Lymph Nodes with Near-Infrared Imaging in Malignancies

Optical molecular imaging, a highly sensitive and noninvasive technique which is simple to operate, inexpensive, and has the real-time capability, is increasingly being used in the diagnosis and treatment of carcinomas. The near-infrared fluorescence dye indocyanine green (ICG) is widely used in optical imaging for the dynamic detection of sentinel lymph nodes (SLNs) in real time improving the detection rate and accuracy. ICG has the advantages of low scattering in tissue absorbance, low auto-fluorescence, and high signal-to-background ratio. The detection rate of axillary sentinel lymph nodes biopsy (SLNB) in breast cancers with ICG was more than 95 %, the false-negative rate was lower than 10 %, and the average detected number ranged from 1.75 to 3.8. The combined use of ICG with nuclein or blue dye resulted in a lower false-negative rate. ICG is also being used for the sentinel node detection in other malignant cancers such as head and neck, gastrointestinal, and gynecological carcinomas. In this article, we provide an overview of numerous studies that used the near-infrared fluorescence imaging to detect the sentinel lymph nodes in breast carcinoma and other malignant cancers. It is expected that with improvements in the optical imaging systems together with the use of a combination of multiple dyes and verification in large clinical trials, optical molecular imaging will become an essential tool for SLN detection and image-guided precise resection.

Sensitivity and specificity of sentinel lymph node biopsy in patients with oral squamous cell carcinomas using indocyanine green fluorescence imaging

PURPOSE

The purpose of this clinical study was to evaluate the sensitivity and specificity of cervical sentinel lymph node biopsy after mapping with indocyanine green fluorescence (ICG) for imaging early-stage oral cancer.

PATIENTS AND METHODS

A sentinel lymph node biopsy (SLNB) was performed during a selective neck dissection (SND) in 20 patients with oral squamous cell carcinoma (OSCC, cT1 or cT2, N0 status). The sentinel lymph nodes (SLN) were identified using an infrared video camera after ICG injection. Lymph nodes were examined histologically. The endpoint of this study was to investigate the rate of false-negative results in SLNB.

RESULTS

Sentinel lymph nodes could be detected after 8.1 min (range 1-22 min). In eight out of 20 cases, lymph node metastases were found during histopathological evaluation of the neck dissection specimen. In four cases a metastasis could be found in the detected SLN (sensitivity 50%). In the other four cases metastases were found in different lymph nodes. Specificity was 100%, positive predictive value 100%, and negative predictive value 75%.

CONCLUSION

In this study, reliability of sentinel lymph node biopsy after ICG imaging could not be verified, as there were false-negative results in 50% of the cases. Therefore, SND can still be recommended as for patients with cT1 or cT2 OSCC, and a N0 neck status.

Fluorescence-Guided Surgery

Surgical resection of cancer remains an important treatment modality. Despite advances in preoperative imaging, surgery itself is primarily guided by the surgeon’s ability to locate pathology with conventional white light imaging. Fluorescence-guided surgery (FGS) can be used to define tumor location and margins during the procedure. Intraoperative visualization of tumors may not only allow more complete resections but also improve safety by avoiding unnecessary damage to normal tissue which can also reduce operative time and decrease the need for second-look surgeries. A number of new FGS imaging probes have recently been developed, complementing a small but useful number of existing probes. In this review, we describe current and new fluorescent probes that may assist FGS.

Feasibility of Real-Time Near-Infrared Fluorescence Tracer Imaging in Sentinel Node Biopsy for Oral Cavity Cancer Patients

Background

Sentinel node biopsy (SNB) is an established method in oral squamous cell carcinoma (OSCC) for staging the cN0 neck and to select patients who will benefit from a neck dissection. Near-infrared fluorescence (NIRF) imaging has the potential to improve the SNB procedure by facilitating intraoperative visual identification of the sentinel lymph node (SN). The purpose of this study was to evaluate the feasibility of fluorescence tracer imaging for SN detection in conjunction with conventional radio-guided technique.

Methods

Prospective study of patients with primary OSCC planned for tumor resection and SNB. Thirty patients were injected peritumorally with a bimodal tracer (ICG-^99mTc-Nanocoll) followed by lymphoscintigraphy and SPECT/CT to define the SNs and their anatomical location preoperatively. SNs were detected intraoperatively with a hand-held gamma-probe and a hand-held NIRF camera.

Results

In 29 of 30 subjects (97%), all preoperatively defined SNs could be identified intraoperatively using a combination of radioactive and fluorescence guidance. A total of 94 SNs (mean 3, range 1–5) that were both radioactive and fluorescent ex vivo were harvested. Eleven of 94 SNs (12%) could only be identified in vivo using NIRF imaging, and the majority of those were located in level 1 close to the primary tumor.

Conclusions

A combined fluorescent and radioactive tracer for SNB is feasible, and the additional use of NIRF imaging may improve the accuracy of SN identification in oral cancer patients. Intraoperative fluorescence guidance seems of particular value when SNs are located in close proximity to the injection site.

Sentinel node biopsy using indocyanine green in oral/oropharyngeal cancer

BACKGROUNDS

Radioactive tracer-based detection has been proposed as a standard procedure in identifying sentinel nodes for cN0 oral/oropharyngeal carcinoma. However, access to radioactive isotopes may be limited in some surgical centers, and there is potential risk of the radioactive tracers to the operators. This study was designed to evaluate the feasibility of near-infrared fluorescence imaging with indocyanine green combined with blue dye mapping in sentinel node biopsy for cN0 oral/oropharyngeal carcinoma.

METHODS

Twenty-six cases of previously untreated oral/oropharyngeal carcinoma staged cT1-2N0M0 were enrolled in this study. One milliliter of indocyanine green (5 mg/ml) and 1.5 ml of methylene blue (1 mg/ml) were injected sequentially around the primary tumor in a four-quadrant pattern before skin incision. After elevation of the platysma flap and posterior retraction of the sternocleidomastoid muscle, fluorescence images were taken with a near-infrared detector, with special attention paid to any blue-dyed lymph nodes. Lymph nodes identified first with fluorescent hot spots with or without blue dye were defined as sentinel nodes, and they were harvested and sent for pathologic study.

RESULTS

Sentinel nodes were successfully harvested in all 26 cases. The number of sentinel nodes (SNs) per case varied from 1 to 9, with an average of 3.4. Routine pathology demonstrated occult metastasis exclusively in SNs in four cases (15.4 %). No tracer-associated side effects occurred in this series.

CONCLUSIONS

Near-infrared imaging using indocyanine green combined with methylene blue mapping is a feasible and reliable new method for SN biopsy in cN0 oral/oropharyngeal carcinoma.

Application of infrared-based molecular imaging to a mouse model with head and neck cancer

BACKGROUND

This study investigated whether near infrared (NIR) or visible fluorescent molecular imaging produced a better representation of a mouse model with head and neck squamous cell carcinoma (HNSCC). Additionally, the study explored whether epidermal growth factor receptor (EGFR)-targeted probes could play an important role in the diagnosis of HNSCC.

METHODS

An orthotopic mouse model of HNSCC labeled with the NIR fluorophore, infrared fluorescent protein (iRFP), was developed and monitored noninvasively in real time. The tumors were further evaluated using tumor-specific EGFR-targeted probes conjugated with an NIR dye (IRDye800), or a visible fluorescent protein.

RESULTS

The iRFP cell line produced better results than cells emitting visible light when studying local, distant, and deep tumors in the mouse model. The EGFR-targeted probe conjugated with IRDye800 accurately detected tumor perimeters.

CONCLUSION

This model has great potential as a unique tool in the study of HNSCC tumor development. © 2015 Wiley Periodicals, Inc. Head Neck 38: E1351-E1357, 2016.

A review of performance of near-infrared fluorescence imaging devices used in clinical studies

Near-infrared fluorescence (NIRF) molecular imaging holds great promise as a new "point-of-care" medical imaging modality that can potentially provide the sensitivity of nuclear medicine techniques, but without the radioactivity that can otherwise place limitations of usage. Recently, NIRF imaging devices of a variety of designs have emerged in the market and in investigational clinical studies using indocyanine green (ICG) as a non-targeting NIRF contrast agent to demark the blood and lymphatic vasculatures both non-invasively and intraoperatively. Approved in the USA since 1956 for intravenous administration, ICG has been more recently used off label in intradermal or subcutaneous administrations for fluorescence imaging of the lymphatic vasculature and lymph nodes. Herein, we summarize the devices of a variety of designs, summarize their performance in lymphatic imaging in a tabular format and comment on necessary efforts to develop standards for device performance to compare and use these emerging devices in future, NIRF molecular imaging studies.