Real-time surveillance of surgical margins via ICG-based near-infrared fluorescence imaging in patients with OSCC

Intraoperative fluorescence in solid head and neck cancer: A scoping review

PURPOSE

Obtaining negative margins in primary tumor resection is essential to decreasing recurrence and mortality. Fluorescence imaging may aid in complete tumor removal. As fluorescent agents are still under clinical trial investigation for use in head and neck cancer (HNC), their effectiveness in intraoperative margin assessment (IMA) remains unclear. This scoping review examines the use of fluorescent-guided surgery (FGS) in the treatment of HNC, highlighting significant opportunities in this nascent field.

METHODS

PubMed, Scopus, CINAHL, and Cochrane Library were searched from inception through March 22, 2024. This study was conducted under PRISMA-ScR guidelines. Data on study characteristics, fluorescence and imaging techniques, imaging efficacy, and diagnostic accuracy were extracted.

RESULTS

Twenty-seven prospective studies from 2013 to 2024 on intraoperative FGS in HNC, involving 455 patients from six countries, were included. Studies ranged from preclinical to phase II trials, applying various fluorescent techniques, predominantly indocyanine green and IRDye800CW, to enhance surgical precision. Imaging assessments were conducted in-vivo, ex-vivo, or both, using a wide range of devices and taking an additional 0 to 30 min intraoperatively. Quantitative measures like signal-to-background ratio and mean fluorescent intensity suggested variable diagnostic accuracy across studies. FGS shows great potential in improving IMA, although standardization in methodologies and reporting is needed.

CONCLUSION

This scoping review highlights the potential of intraoperative FGS to enhance treatment accuracy in solid HNC, though variability in diagnostic efficacy and a lack of standardized methodologies persist. Advancements in fluorophore technology and uniform procedural protocols are essential to optimize surgical outcomes and move towards personalized HNC interventions.

Fluorescence Imaging-Assessed Surgical Margin Detection in Head and Neck Oncology by Passive and Active Targeting

Surgery remains the gold standard in the management of head and neck squamous cell carcinoma (HNSCC). However, the anatomical complexity of these cancers, combined with the difficulty in discriminating between healthy and cancerous tissue and the detection of microlesions, complicates tumor resection, resulting in positive surgical margins, which are associated with a poor patient prognosis. Fluorescence-guided surgery (FGS) has emerged as a promising technique in the management of HNSCC, improving tumor resection and margin assessment. FGS strategies can be roughly divided into three approaches; namely, natural tissue autofluorescence, passive delivery of fluorescent contrast agents, and active targeting. This review provides a comprehensive overview of the advances made in FGS of head and neck cancers, particularly aiming to improve surgical margin assessment. Recently, the field has shown promising results by addressing contrast agents targeted to the overexpressed epidermal growth factor receptor (EGFR), both in preclinical and clinical settings. The identification of new targets such as αVβ6 integrin, uPAR, PARP1, and so on, as well as the development of contrast agents, are key steps in the further development of FGS of head and neck cancers, making it an essential tool in precision oncology. Among these, as was demonstrated in preclinical studies, the αVβ6 integrin is emerging as a promising target due to its high and specific expression in tumor and tumor margins.

The Use of Fluorescent Markers to Detect and Delineate Head and Neck Cancer: A Scoping Review

OBJECTIVES

The aim of surgery for head and neck squamous cell carcinoma (HNSCC) is to achieve clear resection margins, whilst preserving function and cosmesis. Fluorescent markers have demonstrated potential in the intraoperative visualisation and delineation of tumours, such as glioma, with consequent improvements in resection. The purpose of this scoping review was to identify and compare the fluorescent markers that have been used to detect and delineate HNSCC to date.

METHODS

A literature search was performed using the Ovid MEDLINE, Ovid Embase, Cochrane CENTRAL, ClinicalTrials.gov and ICTRP databases. Primary human studies published through September 2023 demonstrating the use of fluorescent markers to visualise HNSCC were selected and reviewed independently by two authors.

RESULTS

The search strategy identified 5776 records. Two hundred and forty-four full texts were reviewed, and sixty-five eligible reports were included. The most used fluorescent markers in the included studies were indocyanine green (ICG) (n = 14), toluidine blue (n = 11), antibodies labelled with IRDye800CW (n = 10) and 5-aminolevulinic acid (5-ALA) (n = 8). Toluidine blue and ICG both have limited specificity, although novel targeted options derived from ICG may be more effective. 5-ALA has been demonstrated as a topical marker and, recently, via enteral administration but it is associated with photosensitivity reactions. The fluorescently labelled antibodies cetuximab-IRDye800CW and panitumumab-IRDye800CW are promising options being investigated by ongoing trials.

CONCLUSION

Multiple safe fluorescent markers have emerged which may aid the surgical resection of HNSCC. Further research in larger cohorts is required to identify which marker should be considered gold standard.

Recent advances of photodiagnosis and treatment for head and neck squamous cell carcinoma

Head and neck squamous cell carcinoma (HNSCC) are the most common type of head and neck tumor that severely threatens human health due to its highly aggressive nature and susceptibility to distant metastasis. The diagnosis of HNSCC currently relies on biopsy and histopathological examination of suspicious lesions. However, the early mucosal changes are subtle and difficult to detect by conventional oral examination. As for treatment, surgery is still the primary treatment modality. Due to the complex anatomy and the lack of intraoperative modalities to accurately determine the incision margins, surgeons are in a dilemma between extensive tumor removal and improving the quality of patient survival. As more knowledge is gained about HNSCC, the increasing recognition of the value of optical imaging has been emphasized. Optical technology offers distinctive possibilities for early preoperative diagnosis, intraoperative real-time visualization of tumor margins, sentinel lymph node biopsies, phototherapy. Fluorescence imaging, narrow-band imaging, Raman spectroscopy, optical coherence tomography, hyperspectral imaging, and photoacoustic imaging have been reported for imaging HNSCC. This article provides a comprehensive overview of the fundamental principles and clinical applications of optical imaging in the diagnosis and treatment of HNSCC, focusing on identifying its strengths and limitations to facilitate advancements in this field.

Cutting-edge insights: near-infrared imaging for surgical margin assessment in head and neck tumor resection: a systematic review and meta-analysis

BACKGROUND

In head and neck cancer (HNC), real-time evaluation of tumor margin status following surgical excision of the tumor is of critical importance. This systematic review aimed to assess the effectiveness of near-infrared fluorescence (NIRF) imaging for the real-time delineation of tumor margins in HNC resections.

METHODS

Two investigators independently conducted a comprehensive search following the Preferred Reporting Items for a Systematic Review and Meta-analysis of Diagnostic Test Accuracy Studies (PRISMA-DTA) guidelines across the PubMed, Scopus, Embase, and China National Knowledge Infrastructure (CNKI) databases until August 1st, 2023. Observational studies were included, while other studies with inappropriate study design were excluded. The primary outcomes included the specificity, sensitivity, and area under the summary receiver operating characteristic (SROC) curve when using NIRF imaging to assess surgical margins. We compared fluorescence in the resection specimen margins and residual fluorescence in the surgical cavity margins as methods of utilizing NIRF to evaluate surgical margins. Diagnostic trial quality was assessed, and statistical heterogeneity was determined.

RESULTS

The initial search yielded 1,607 articles. After reviewing the full texts, seven articles with 103 patients were included, among which five were incorporated for quantitative analysis. The selected studies had an average score of 10.1 of quality. Heterogeneity analysis revealed I2 values of 26% [95% confidence interval (CI): 0-100%] and 78% (95% CI: 52-100%) for NIRF specimen imaging with close margin considered positive or negative. Comparing NIRF imaging to the gold standard of pathology for surgical margin diagnosis, with close margin considered positive, sensitivity and specificity in excised specimens were 0.84 (95% CI: 0.39-0.98) and 0.96 (95% CI: 0.80-0.99), respectively. When a close margin was considered negative, sensitivity and specificity were 0.98 (95% CI: 0.10-1.00) and 0.96 (95% CI: 0.45-1.00), respectively. The areas under the SROC curves were 0.97 (95% CI: 0.95-0.98) and 0.99 (95% CI: 0.98-1.00), respectively. A quantitative analysis of residual fluorescence at surgical cavity margins was not performed due to an insufficient number of studies.

CONCLUSIONS

NIRF imaging is a promising method for real-time surgical margin assessment of HNC. With its robust diagnostic capabilities in excised tumor specimens, it is also an effective technique for detecting residual tumor fluorescence in the surgical cavity for supplementary assessment. But the results should be interpreted with caution.

Illuminating the future of precision cancer surgery with fluorescence imaging and artificial intelligence convergence

Real-time and accurate guidance for tumor resection has long been anticipated by surgeons. In the past decade, the flourishing material science has made impressive progress in near-infrared fluorophores that may fulfill this purpose. Fluorescence imaging-guided surgery shows great promise for clinical application and has undergone widespread evaluations, though it still requires continuous improvements to transition this technique from bench to bedside. Concurrently, the rapid progress of artificial intelligence (AI) has revolutionized medicine, aiding in the screening, diagnosis, and treatment of human doctors. Incorporating AI helps enhance fluorescence imaging and is poised to bring major innovations to surgical guidance, thereby realizing precision cancer surgery. This review provides an overview of the principles and clinical evaluations of fluorescence-guided surgery. Furthermore, recent endeavors to synergize AI with fluorescence imaging were presented, and the benefits of this interdisciplinary convergence were discussed. Finally, several implementation strategies to overcome technical hurdles were proposed to encourage and inspire future research to expedite the clinical application of these revolutionary technologies.

Nucleolin-targeted doxorubicin and ICG co-loaded theranostic lipopolymersome for photothermal-chemotherapy of melanoma in vitro and in vivo

Combination therapy using chemo-photothermal therapy (chemo-PTT) shows great efficacy toward tumor ablation in preclinical studies. Besides, lipopolymersomes as a hybrid nanocarriers, integrate advantages of liposomes and polymersomes in a single platform in order to provide tremendous biocompatibility, biodegradability, noteworthy loading efficacy for both hydrophobic and hydrophilic drugs with adjustable drug release and high stability. In this study, a multipurpose lipopolymersome was fabricated for guided chemotherapy-PTT and NIR-imaging of melanoma. A lipopolymerosomal hybrid nanovesicle consisting of equal molar ratio of 1,2-dioleoyl-3-trimethylammonium propane (DOTAP) and poly (ethylene glycol)-poly (lactic acid) (PEG-PLA) diblock copolymer (molar ratio 1:1) was fabricated. The nanoparticulate system was prepared through film rehydration technique for encapsulation of doxorubicin (DOX) and indocyanine green (ICG) to form DOX-ICG-LP platform. At the next stage, AS1411 DNA aptamer was conjugated to the surface of lipopolymersome (Apt-DOX-ICG-LP) for selective delivery. The sizes of DOX-ICG-LP and Apt-DOX-ICG-LP were obtained through DLS analysis (61.0 ± 6 and 74 ± 5, respectively). Near Infrared-responsive release pattern of the prepared lipopolymersome was verified in vitro. The formulated platform showed efficient photothermal conversion, and superior stability with acceptable encapsulation efficiency. Consistent with the in vitro studies, NIR-responsive lipopolymersome exhibited significantly higher cellular toxicity for Chemo-PTT versus single anti-cancer treatment. Moreover, superlative tumor shrinkage with favorable survival profile were attained in B16F10 tumor-bearing mice received Apt-DOX-ICG-LP and irradiated with 808 nm laser compared to those treated with either DOX-ICG-LP or Apt-DOX-ICG-LP without laser irradiation. The diagnostic capability of Apt-DOX-ICG-LP was addressed using in vivo NIR imaging, 6 and 24 h post-intravenous administration. The results indicated desirable feature of an established targeted theranostic capability of Apt-DOX-ICG-LP for both diagnostics and dual chemo-PTT of melanoma.

Repurposing GnRH-A as a Near-Infrared Fluorescent Probe for Diagnosis and Surgical Navigation of Breast Cancer Tumors and Metastases

Breast cancer, globally the most common cancer in women, presents significant challenges in treatment. Breast-conserving surgery (BCS), a less traumatic and painful alternative to radical mastectomy, not only preserves the breast's appearance but also supports postsurgical functional recovery. However, accurately identifying tumors, precisely delineating margins, and thoroughly removing metastases remain complex surgical challenges, exacerbated by the limitations of current imaging techniques, including poor tumor uptake and low signal contrast. Addressing these challenges, our study developed a series of GnRHR-targeted probes (YQGN-n) for fluorescence imaging and surgical navigation of breast cancer through a drug repositioning strategy. Notably, YQGN-7, with its high cellular affinity (Kd of 217.8 nM), demonstrates exceptional selectivity and specificity for breast cancer tumors, surpassing traditional imaging agents like ICG in tumor uptake and pharmacokinetic properties. Furthermore, YQGN-7's effectiveness in surgical navigation, both for primary breast tumors and metastases, highlights its potential as a revolutionary tool in BCS.

Targeting of 3D oral cancer spheroids by αVβ6 integrin using near-infrared peptide-conjugated IRDye 680

BACKGROUND

In the treatment of oral cavity cancer, margin status is one of the most critical prognostic factors. Positive margins are associated with higher local recurrence and lower survival rates. Therefore, the universal goal of oral surgical oncology is to achieve microscopically clear margins. Near-infrared fluorescence guided surgery (FGS) could improve surgical resection using fluorescent probes. αVβ6 integrin has shown great potential for cancer targeting due to its overexpression in oral cancers. Red fluorescent contrast agent IRDye 680 coupled with anti-αVβ6 peptide (IRDye-A20) represents an asset to improve FGS of oral cancer. This study investigates the potential of IRDye-A20 as a selective imaging agent in 3D three-dimensional tongue cancer cells.

METHODS

αVβ6 integrin expression was evaluated by RT-qPCR and Western Blotting in 2D HSC-3 human tongue cancer cells and MRC-5 human fibroblasts. Targeting ability of IRDye-A20 was studied in both cell lines by flow cytometry technique. 3D tumor spheroid models, homotypic (HSC-3) and stroma-enriched heterotypic (HSC-3/MRC-5) spheroids were produced by liquid overlay procedure and further characterized using (immuno)histological and fluorescence-based techniques. IRDye-A20 selectivity was evaluated in each type of spheroids and each cell population.

RESULTS

αVβ6 integrin was overexpressed in 2D HSC-3 cancer cells but not in MRC-5 fibroblasts and consistently, only HSC-3 were labelled with IRDye-A20. Round shaped spheroids with an average diameter of 400 μm were produced with a final ratio of 55%/45% between HSC-3 and MRC-5 cells, respectively. Immunofluorescence experiments demonstrated an uniform expression of αVβ6 integrin in homotypic spheroid, while its expression was restricted to cancer cells only in heterotypic spheroid. In stroma-enriched 3D model, Cytokeratin 19 and E-cadherin were expressed only by cancer cells while vimentin and fibronectin were expressed by fibroblasts. Using flow cytometry, we demonstrated that IRDye-A20 labeled the whole homotypic spheroid, while in the heterotypic model all cancer cells were highly fluorescent, with a negligible fluorescence in fibroblasts.

CONCLUSIONS

The present study demonstrated an efficient selective targeting of A20FMDV2-conjugated IRDye 680 in 3D tongue cancer cells stroma-enriched spheroids. Thus, IRDye-A20 could be a promising candidate for the future development of the fluorescence-guided surgery of oral cancers.

An Indocyanine Green-Based Nanoprobe for In Vivo Detection of Cellular Senescence

There is an urgent need to improve conventional cancer-treatments by preventing detrimental side effects, cancer recurrence and metastases. Recent studies have shown that presence of senescent cells in tissues treated with chemo- or radiotherapy can be used to predict the effectiveness of cancer treatment. However, although the accumulation of senescent cells is one of the hallmarks of cancer, surprisingly little progress has been made in development of strategies for their detection in vivo. To address a lack of detection tools, we developed a biocompatible, injectable organic nanoprobe (NanoJagg), which is selectively taken up by senescent cells and accumulates in the lysosomes. The NanoJagg probe is obtained by self-assembly of indocyanine green (ICG) dimers using a scalable manufacturing process and characterized by a unique spectral signature suitable for both photoacoustic tomography (PAT) and fluorescence imaging. In vitro, ex vivo and in vivo studies all indicate that NanoJaggs are a clinically translatable probe for detection of senescence and their PAT signal makes them suitable for longitudinal monitoring of the senescence burden in solid tumors after chemotherapy or radiotherapy.

Beneath the surface: A systematic review on intraoperative imaging techniques for deep margin assessment in oral squamous cell carcinoma

Resection margins of oral squamous cell carcinoma (SCC) are often inadequate. A systematic review on clinical intraoperative whole-specimen imaging techniques to obtain adequate deep resection margins in oral SCC is lacking. Such a review may render better alternatives for the current insufficient intraoperative techniques: palpation and frozen section analyses (FSA). This review resulted in ten publications investigating ultrasound (US), four investigating fluorescence, and three investigating MRI. Both US and fluorescence were able to image the tumor intraorally and perform ex-vivo imaging of the resection specimen. Fluorescence was also able to image residual tumor tissue in the wound bed. MRI could only be used on the ex-vivo specimen. The 95 % confidence intervals for sensitivity and specificity were large, due to the small sample sizes for all three techniques. The sensitivity and specificity of US for identifying < 5 mm margins ranged from 0 % to 100 % and 60 % to 100 %, respectively. For fluorescence, this ranged from 0 % to 100 % and 76 % to 100 %, respectively. For MRI, this ranged from 7 % to 100 % and 81 % to 100 %, respectively. US, MRI and fluorescence are the currently available imaging techniques that can potentially be used intraoperatively and which can image the entire tumor-free margin, although they have insufficient sensitivity for identifying < 5 mm margins. Further research on larger cohorts is needed to improve the sensitivity by determining cut-off points on imaging for inadequate margins. This improves the number of adequate resections of oral SCC's and pave the way for routine clinical implementation of these techniques.

Intratumor injected gold molecular clusters for NIR-II imaging and cancer therapy

Surgical resections of solid tumors guided by visual inspection of tumor margins have been performed for over a century to treat cancer. Near-infrared (NIR) fluorescence labeling/imaging of tumor in the NIR-I (800 to 900 nm) range with systemically administrated fluorophore/tumor-targeting antibody conjugates have been introduced to improve tumor margin delineation, tumor removal accuracy, and patient survival. Here, we show Au25 molecular clusters functionalized with phosphorylcholine ligands (AuPC, ~2 nm in size) as a preclinical intratumorally injectable agent for NIR-II/SWIR (1,000 to 3,000 nm) fluorescence imaging-guided tumor resection. The AuPC clusters were found to be uniformly distributed in the 4T1 murine breast cancer tumor upon intratumor (i.t.) injection. The phosphocholine coating afforded highly stealth clusters, allowing a high percentage of AuPC to fill the tumor interstitial fluid space homogeneously. Intra-operative surgical navigation guided by imaging of the NIR-II fluorescence of AuPC allowed for complete and non-excessive tumor resection. The AuPC in tumors were also employed as a photothermal therapy (PTT) agent to uniformly heat up and eradicate tumors. Further, we performed in vivo NIR-IIb (1,500 to 1,700 nm) molecular imaging of the treated tumor using a quantum dot-Annexin V (QD-P3-Anx V) conjugate, revealing cancer cell apoptosis following PTT. The therapeutic functionalities of AuPC clusters combined with rapid renal excretion, high biocompatibility, and safety make them promising for clinical translation.

Intraoperative Assessment of Resection Margin in Oral Cancer: The Potential Role of Spectroscopy

In parallel with the increasing number of oncological cases, the need for faster and more efficient diagnostic tools has also appeared. Different diagnostic approaches are available, such as radiological imaging or histological staining methods, but these do not provide adequate information regarding the resection margin, intraoperatively, or are time consuming. The purpose of this review is to summarize the current knowledge on spectrometric diagnostic modalities suitable for intraoperative use, with an emphasis on their relevance in the management of oral cancer. The literature agrees on the sensitivity, specificity, and accuracy of spectrometric diagnostic modalities, but further long-term prospective, multicentric clinical studies are needed, which may standardize the intraoperative assessment of the resection margin and the use of real-time spectroscopic approaches.

Improving oral squamous cell carcinoma diagnosis and treatment with fluorescence molecular imaging

Timely identification and complete removal of oral squamous cell carcinoma (OSCC) through surgery is crucial for effective treatment. However, current diagnostic methods that rely on physical abnormalities are not very informative and practical in clinical settings, leading to the late detection of oral cancer. Furthermore, no dependable intraoperative tools available for assessing surgical margins in real-time. Fluorescence imaging allows the visualization of biological processes occurring in the early stages of cancer, and as a result, small tumors can be detected at an early stage. Fluorescence imaging can effectively aid in assessing excised edges during surgery for OSCC as it possesses high sensitivity and spatial resolution. This review focuses on tongue cancer as a representation of OSCC and delves into various fluorescence techniques that can aid in early diagnosis and surgical guidance. The review also discusses the potential clinical applications of these techniques in the future.

Development of a fibroblast activation protein-targeted PET/NIR dual-modality probe and its application in head and neck cancer

Purpose: The combination of near-infrared (NIR) and positron emission tomography (PET) imaging presents an opportunity to utilize the benefits of dual-modality imaging for tumor visualization. Based on the observation that fibroblast activation protein (FAP) is upregulated in cancer-associated fibroblasts (CAFs) infiltrating all solid tumors, including head and neck squamous cell carcinoma (HNSCC), we developed the novel PET/NIR probe [68Ga]Ga-FAP-2286-ICG. Preclinically, the specificity, biodistribution and diagnostic properties were evaluated. Methods: Cell uptake assays were completed with the U87MG cell to evaluate the specificity of the [68Ga]Ga-FAP-2286-ICG. The tumor-targeting efficiency, biodistribution and optimal imaging time window of the [68Ga]Ga-FAP-2286-ICG were studied in mice bearing U87MG xenografts. HNSCC tumor-bearing mice were used to evaluate the feasibility of [68Ga]Ga-FAP-2286-ICG for tumor localization and guided surgical resection of HNSCC tumors. Results: The in vitro experiments confirmed that [68Ga]Ga-FAP-2286-ICG showed good stability, specific targeting of the probe to FAP, and the durable retention effect in high-expressing FAP tumors U87MG cell. Good imaging properties such as good tumor uptake, high tumor-to-background ratios (5.44 ± 0.74) and specificity, and tumor contouring were confirmed in studies with mice bearing the U87MG xenograft. PET/CT imaging of the probe in head and neck cancer-bearing mice demonstrated specific uptake of the probe in the tumor with a clear background. Fluorescence imaging further validated the value of the probe in guiding surgical resection and achieving precise removal of the tumor and residual lesions. Conclusion: In a preclinical model, these attractive [68Ga]Ga-FAP-2286-ICG PET/NIR imaging acquired in head and neck cancer make it a promising FAP-targeted multimodal probe for clinical translation.

Clinical Experience with Autofluorescence Guided Oral Squamous Cell Carcinoma Surgery

In our study, the effect of the use of autofluorescence (Visually Enhanced Lesion Scope-VELscope) on increasing the success rate of surgical treatment in oral squamous carcinoma (OSCC) was investigated. Our hypothesis was tested on a group of 122 patients suffering from OSCC, randomized into a study and a control group enrolled in our study after meeting the inclusion criteria. The preoperative checkup via VELscope, accompanied by the marking of the range of a loss of fluorescence in the study group, was performed before the surgery. We developed a unique mucosal tattoo marking technique for this purpose. The histopathological results after surgical treatment, i.e., the margin status, were then compared. In the study group, we achieved pathological free margin (pFM) in 55 patients, pathological close margin (pCM) in 6 cases, and we encountered no cases of pathological positive margin (pPM) in the mucosal layer. In comparison, the control group results revealed pPM in 7 cases, pCM in 14 cases, and pFM in 40 of all cases in the mucosal layer. This study demonstrated that preoperative autofluorescence assessment of the mucosal surroundings of OSCC increased the ability to achieve pFM resection 4.8 times in terms of lateral margins.

Near infrared conjugated polymer nanoparticles (CPN™) for tracking cells using fluorescence and optoacoustic imaging

Tracking the biodistribution of cell therapies is crucial for understanding their safety and efficacy. Optical imaging techniques are particularly useful for tracking cells due to their clinical translatability and potential for intra-operative use to validate cell delivery. However, there is a lack of appropriate optical probes for cell tracking. The only FDA-approved material for clinical use is indocyanine green (ICG). ICG can be used for both fluorescence and photoacoustic imaging, but is prone to photodegradation, and at higher concentrations, undergoes quenching and can adversely affect cell health. We have developed novel near-infrared imaging probes comprising conjugated polymer nanoparticles (CPNs™) that can be fine-tuned to absorb and emit light at specific wavelengths. To compare the performance of the CPNs™ with ICG for in vivo cell tracking, labelled mesenchymal stromal cells (MSCs) were injected subcutaneously in mice and detected using fluorescence imaging (FI) and a form of photoacoustic imaging called multispectral optoacoustic tomography (MSOT). MSCs labelled with either ICG or CPN™ 770 could be detected with FI, but only CPN™ 770-labelled MSCs could be detected with MSOT. These results show that CPNs™ show great promise for tracking cells in vivo using optical imaging techniques, and for some applications, out-perform ICG.

A novel near-infrared EGFR targeting probe for metastatic lymph node imaging in preclinical mouse models

For the treatment of patients with oral squamous cell carcinoma (OSCC), the imaging of cervical lymph nodes and the evaluation of metastastic progression are of great significance. In recent years, the development of new non-radioactive lymph node tracers has been an area of intense research. Here, we report the synthesis, good biocompatibility, and in vivo evaluation of a new small molecule near-infrared (NIR) fluorescence probe by the conjugation of Lapatinib to S0456 (LP-S). We show that like Lapatinib, LP-S binds to the epidermal growth factor receptor (EGFR) resulting in high quality fluorescence imaging of metastatic lymph nodes in OSCC mouse models. After local injection of LP-S into the tumor, the lymphatic drainage pathway and lymph nodes can be clearly identified by NIR fluorescence imaging. Further, the LP-S probe shows higher contrast and longer retention in metastatic lymph nodes, allowing them to be differentiated from normal lymph nodes, and affording a new choice for fluorescence-guided surgery. Scheme. Chemical synthesis and application of EGFR targeting probe LP-S for imaging of metastatic lymph nodes (mLNs) in OSCC.

Cell-Membrane Coated Nanoparticles for Tumor Delineation and Qualitative Estimation of Cancer Biomarkers at Single Wavelength Excitation in Murine and Phantom Models

Real-time guidance through fluorescence imaging improves the surgical outcomes of tumor resections, reducing the chances of leaving positive margins behind. As tumors are heterogeneous, it is imperative to interrogate multiple overexpressed cancer biomarkers with high sensitivity and specificity to improve surgical outcomes. However, for accurate tumor delineation and ratiometric detection of tumor biomarkers, current methods require multiple excitation wavelengths to image multiple biomarkers, which is impractical in a clinical setting. Here, we have developed a biomimetic platform comprising near-infrared fluorescent semiconducting polymer nanoparticles (SPNs) with red blood cell membrane (RBC) coating, capable of targeting two representative cell-surface biomarkers (folate, αυβ3 integrins) using a single excitation wavelength for tumor delineation during surgical interventions. We evaluate our single excitation ratiometric nanoparticles in in vitro tumor cells, ex vivo tumor-mimicking phantoms, and in vivo mouse xenograft tumor models. Favorable biological properties (improved biocompatibility, prolonged blood circulation, reduced liver uptake) are complemented by superior spectral features: (i) specific fluorescence enhancement in tumor regions with high tumor-to-normal tissue (T/NT) ratios in ex vivo samples and (ii) estimation of cell-surface tumor biomarkers with single wavelength excitation providing insights about cancer progression (metastases). Our single excitation, dual output approach has the potential to differentiate between the tumor and healthy regions and simultaneously provide a qualitative indicator of cancer progression, thereby guiding surgeons in the operating room with the resection process.

NIRDye 812: A molecular platform tailored for multimodal bioimaging applications of targeted fluorescence- and photoacoustic-guided surgery

The primary treatment for malignant tumors remains to be surgical removal of the diseased tissue. The presence or absence of residual diseased tissue at the tumor margin is the strongest predictor of postoperative prognosis and recurrence. Accordingly, reliance on the ability of surgeons to visually distinguish diseased tissue from healthy tissue unambiguously in real time is crucial. Near infrared-I (NIRI) fluorescence-emitting targeting biomolecular constructs such as anticancer antibody-fluorophore conjugates, namely cetuximab-IRDye® 800CW (CTB-IRDye® 800CW), are FDA-approved for clinical trial usage in the fluorescence-guided resection of diseased tissue due to affording improved direct visualization of tumor tissue when compared to the use of either the unaided eye under standard white light illumination (WLI) surgical techniques or non-targeting fluorophores. Unfortunately, though helpful, CTB-IRDye® 800CW affords limited (i) identification of diseased tissue and (ii) tumor margin delineation, because the immunoconjugate generates suboptimal tumor-to-background ratios (TBRs) as a result of its spectral/photophysical profiles poorly aligning with the fixed optical windows of pre-/clinical setups. As such, CTB-IRDye® 800CW is more prone to affording incomplete resection compared to if TBRs were higher due to otherwise. To aid in accurately identifying deep-seated diseased tissue, photoacoustic (PA) tomography has been implemented alongside CTB-IRDye® 800CW to achieve PA signals that could result in higher TBRs. However, in clinical trial practice, using IRDye® 800CW for PA imaging also yields subpar TBRs due to it affording low PA signals. To overcome such limitations, we developed NIRDye 812, a structurally-modified topological equivalent of IRDye® 800CW, to confer it the capability to yield both higher TBRs and superior PA signal than that of the equivalent CTB-conjugate and fluorophore IRDye® 800CW itself, respectively. To do so, we substituted the oxygen atom at its meso-position with a sulfur atom. CTB-NIRDye 812 demonstrated a red-shifted absorption wavelength at 796 nm and a peak NIR-I fluorescence emission wavelength at 820 nm, which better dovetails with the fixed windows of preinstalled fixed emission filters within commercial pre-/clinical NIR-I fluorescence imaging instruments. Overall, CTB-NIRDye 812 provided a ∼ 2-fold increase in TBRs compared to those of CTB-IRDye® 800CW in vivo. Also, NIRDye 812 displayed an ∼60% higher PA signal than that of IRDye® 800CW. Collectively, we achieved our goal of improving upon the spectral/photophysical and PA properties of IRDye® 800CW via introducing a subtle modification to its electronic core such that its CTB immunoconjugate could potentially allow for fast track or breakthrough designation by the FDA due to its near-identical structure displaying considerably improved efficacy.

Applicability of autofluorescence and fluorescent probes in the trans-surgical of oral carcinomas: A systematic review

Oral cancer represents an important health problem, as it is the sixth most common type of cancer in the world and is associated with high rates of morbidity and mortality. The treatment considered the gold standard for this type of tumor is surgical resection with negative margins, with a distance of at least 5 mm from the tumor. This procedure is strongly associated with local control and disease-specific survival, however, in many cases, large amounts of healthy tissue are removed, resulting in surgical defects, compromising various functions and directly affecting the individual's quality of life. From this perspective, this systematic review aimed to evaluate the use of autofluorescence and fluorescent probes as potential adjuvant techniques to facilitate the delineation of surgical margins for oral cancers. A comprehensive search was performed in Pubmed, Scopus, Web of Science, LIVIVO, Embase, ProQuest Open Access Dissertations & Theses, Open Access Theses and Dissertations, and DART Europe databases, where 1948 articles were found. After the different stages of critical evaluation, 15 articles were selected, eligible for the inclusion criteria. Of these, 7 articles used autofluorescence, 7 used fluorescent probes and 1 article used both methods. As for autofluorescence, the most used device was the VELScope, and indocyanine green was the most used probe. Compared to histopathology, autofluorescence did not obtain significant and/or superiors results. In contrast to fluorescent probes that, most articles showed a good performance of margins during surgical resection, making them a promising alternative. However, it is still necessary to carry out the analysis of more articles, with more significant samples and sensitivity and specificity data to qualify the results.

Application of near-infrared fluorescence imaging in the accurate assessment of surgical margins during breast-conserving surgery

Objective

To evaluate the feasibility and accuracy of near-infrared fluorescence imaging technology for assessing margins during breast-conserving surgery for breast cancer.

Methods

Forty-three breast cancer patients who received surgical treatment at Yijishan Hospital of Wannan Medical College were selected. Before the operation, the patients were administered with an indocyanine green injection of 0.5 mg/kg intravenously 2 h before operation. During and after the operation, all patients underwent surgical margin monitoring with the near-infrared fluorescence imaging system for fluorescence imaging and acquisition of images and quantitative fluorescence intensity. During the operation, the patients’ tissue specimens were collected on the upper, lower, inner, outer, apical, and basal sides of the fluorescence boundary of the isolated lesions for pathological examination.

Results

Fluorescence was detected in the primary tumor in all patients. The average fluorescence intensities of tumor tissue, peritumoral tissue, and normal tissue were 219.41 ± 32.81, 143.35 ± 17.37, and 105.77 ± 17.79 arbitrary units, respectively (P < 0.05, t test). The signal-to-background ratio of tumor to peritumor tissue and normal tissue was 1.54 ± 0.20 and 2.14 ± 0.60, respectively (P < 0.05, t test). Abnormal indocyanine green fluorescence was detected in 11.6% patients (5/43), including 3 patients with residual infiltrating carcinoma and 2 patients with adenosis with ductal dilatation.

Conclusion

This study confirms the high sensitivity and specificity of near-infrared fluorescence imaging technology for breast-conserving surgery margin assessment. Near-infrared fluorescence imaging technology can be used as an intraoperative diagnosis and treatment tool to accurately determine the surgical margin and is of important guiding value in breast-conserving surgery for breast cancer.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12957-022-02827-4.

Phosphorylcholine-conjugated gold-molecular clusters improve signal for Lymph Node NIR-II fluorescence imaging in preclinical cancer models

Sentinel lymph node imaging and biopsy is important to clinical assessment of cancer metastasis, and novel non-radioactive lymphographic tracers have been actively pursued over the years. Here, we develop gold molecular clusters (Au₂₅) functionalized by phosphorylcholine (PC) ligands for NIR-II (1000–3000 nm) fluorescence imaging of draining lymph nodes in 4T1 murine breast cancer and CT26 colon cancer tumor mouse models. The Au-phosphorylcholine (Au-PC) probes exhibit ‘super-stealth’ behavior with little interactions with serum proteins, cells and tissues in vivo, which differs from the indocyanine green (ICG) dye. Subcutaneous injection of Au-PC allows lymph node mapping by NIR-II fluorescence imaging at an optimal time of ~ 0.5 − 1 hour postinjection followed by rapid renal clearance. Preclinical NIR-II fluorescence LN imaging with Au-PC affords high signal to background ratios and high safety and biocompatibility, promising for future clinical translation.

Fluorescent tracers facilitate the identification and subsequent collection of tumour draining lymph node biopsies, enabling important clinical assessment. Here, the authors present a molecular gold nanocluster NIR-II fluorescent imaging probe and demonstrate its utility to visualise draining lymph nodes in breast and colon cancer mouse models.

Indocyanine green fluorescence-guided surgery in head and neck cancer: A systematic review

OBJECTIVE

To assess the feasibility and effectiveness of indocyanine green (ICG) for image-guided resection of head and neck cancer (HNC).

DATA SOURCES

PubMed, Embase, and Scopus databases.

REVIEW METHODS

Searches were conducted from database inception to February 2022. Patient and study characteristics, imaging parameters, and imaging efficacy data were extracted from each study.

RESULTS

Nine studies met inclusion criteria, representing 103 head and neck tumors. Weighted mean ICG dose and imaging time were 1.27 mg/kg and 11.77 h, respectively. Among the five studies that provided quantitative metrics of imaging efficacy, average ICG tumor-to-background ratio (TBR) was 1.56 and weighted mean ONM-100 TBR was 3.64. Pooled sensitivity and specificity across the five studies were 91.7 % and 71.9 %, respectively.

CONCLUSION

FGS with ICG may facilitate real-time tumor-margin delineation to improve margin clearance rates and progression-free survival. Future studies with validated, quantitative metrics of imaging success are necessary to further evaluate the prognostic benefit of these techniques.

Fluorescent Molecular Imaging Can Improve Intraoperative Sentinel Margin Detection in Oral Squamous Cell Carcinoma

In head and neck cancer, a major limitation of current intraoperative margin analysis is the ability to detect areas most likely to be positive based on specimen palpation, especially for larger specimens where sampling error limits detection of positive margins. This study aims to prospectively examine the clinical value of fluorescent molecular imaging to accurately identify "the sentinel margin," the point on a specimen at which the tumor lies closest to the resected edge in real-time during frozen section analysis. Methods: Eighteen patients with oral squamous cell carcinoma were enrolled into a prospective clinical trial and infused intravenously with 50 mg of panitumumab-IRDye800CW 1-5 d before surgery. Resected specimens were imaged in a closed-field near-infrared optical imaging system in near real-time, and custom-designed software was used to identify locations of highest fluorescence on deep and peripheral margins. The surgeon identified the sentinel margin masked to optical specimen mapping, and then the regions of highest fluorescence were identified and marked for frozen analysis. Final pathology based on specimen reconstruction was used as reference standard. Results: Resected specimens were imaged in the operating room, and fluorescence had a higher interobserver agreement with pathology (Cohen κ value 0.96) than the surgeon (Cohen κ value of 0.82) for the location of the closest margin. Plotting margin distance at the predicted sentinel margin location of each observer versus the actual closest margin distance at pathology demonstrated best correlation between fluorescence and pathology (R2 = 0.98) with surgeon (R2 = 0.75). Conclusion: Fluorescence imaging can improve identification of the sentinel margin in head and neck cancer resections, holding promise for rapid identification of positive margins and improved oncologic outcomes.

Label-free, real-time detection of perineural invasion and cancer margins in a murine model of head and neck cancer surgery

Surgical management of head and neck cancer requires a careful balance between complete resection of malignancy and preservation of function. Surgeons must also determine whether to resect important cranial nerves that harbor perineural invasion (PNI), as sacrificing nerves can result in significant morbidity including facial paralysis. Our group has previously reported that Dynamic Optical Contrast Imaging (DOCI), a novel non-invasive imaging system, can determine margins between malignant and healthy tissues. Herein, we use an in vivo murine model to demonstrate that DOCI can accurately identify cancer margins and perineural invasion, concordant with companion histology. Eight C3H/HeJ male mice were injected subcutaneously into the bilateral flanks with SCCVIISF, a murine head and neck cancer cell line. DOCI imaging was performed prior to resection to determine margins. Both tumor and margins were sent for histologic sectioning. After validating that DOCI can delineate HNSCC margins, we investigated whether DOCI can identify PNI. In six C3H/HeJ male mice, the left sciatic nerve was injected with PBS and the right with SCCVIISF. After DOCI imaging, the sciatic nerves were harvested for histologic analysis. All DOCI images were acquired intraoperatively and in real-time (10 s per channel), with an operatively relevant wide field of view. DOCI values distinguishing cancer from adjacent healthy tissue types were statistically significant (P < 0.05). DOCI imaging was also able to detect perineural invasion with 100% accuracy compared to control (P < 0.05). DOCI allows for intraoperative, real-time visualization of malignant and healthy tissue margins and perineural invasion to help guide tumor resection.

Intraoperative In Vivo Imaging Modalities in Head and Neck Cancer Surgical Margin Delineation: A Systematic Review

Surgical margin status is one of the strongest prognosticators in predicting patient outcomes in head and neck cancer, yet head and neck surgeons continue to face challenges in the accurate detection of these margins with the current standard of care. Novel intraoperative imaging modalities have demonstrated great promise for potentially increasing the accuracy and efficiency in surgical margin delineation. In this current study, we collated and analyzed various intraoperative imaging modalities utilized in head and neck cancer to evaluate their use in discriminating malignant from healthy tissues. The authors conducted a systematic database search through PubMed/Medline, Web of Science, and EBSCOhost (CINAHL). Study screening and data extraction were performed and verified by the authors, and more studies were added through handsearching. Here, intraoperative imaging modalities are described, including optical coherence tomography, narrow band imaging, autofluorescence, and fluorescent-tagged probe techniques. Available sensitivities and specificities in delineating cancerous from healthy tissues ranged from 83.0% to 100.0% and 79.2% to 100.0%, respectively, across the different imaging modalities. Many of these initial studies are in small sample sizes, with methodological differences that preclude more extensive quantitative comparison. Thus, there is impetus for future larger studies examining and comparing the efficacy of these intraoperative imaging technologies.

In vivo molecular and single cell imaging

Molecular imaging is used to improve the disease diagnosis, prognosis, monitoring of treatment in living subjects. Numerous molecular targets have been developed for various cellular and molecular processes in genetic, metabolic, proteomic, and cellular biologic level. Molecular imaging modalities such as Optical Imaging, Magnetic Resonance Imaging (MRI), Positron Emission Tomography (PET), Single Photon Emission Computed Tomography (SPECT), and Computed Tomography (CT) can be used to visualize anatomic, genetic, biochemical, and physiologic changes in vivo. For in vivo cell imaging, certain cells such as cancer cells, immune cells, stem cells could be labeled by direct and indirect labeling methods to monitor cell migration, cell activity, and cell effects in cell-based therapy. In case of cancer, it could be used to investigate biological processes such as cancer metastasis and to analyze the drug treatment process. In addition, transplanted stem cells and immune cells in cell-based therapy could be visualized and tracked to confirm the fate, activity, and function of cells. In conventional molecular imaging, cells can be monitored in vivo in bulk non-invasively with optical imaging, MRI, PET, and SPECT imaging. However, single cell imaging in vivo has been a great challenge due to an extremely high sensitive detection of single cell. Recently, there has been great attention for in vivo single cell imaging due to the development of single cell study. In vivo single imaging could analyze the survival or death, movement direction, and characteristics of a single cell in live subjects. In this article, we reviewed basic principle of in vivo molecular imaging and introduced recent studies for in vivo single cell imaging based on the concept of in vivo molecular imaging.

Intraoperative uses of near-infrared fluorescence spectroscopy in pediatric surgery: A systematic review

BACKGROUND

The application of near infrared spectroscopy (NIRS) imaging in surgery is growing. This study aimed to systematically review the literature to summarize the intraoperative uses of NIRS in pediatric surgery.

METHODS

A PRISMA-compliant literature search was conducted in PubMed, Embase, Scopus, and Web of Science from inception to February 2020. Title/abstract and then full-text screening were performed. The Oxford centre for Evidence Based Medicine tool (OCEBM) was used to evaluate the level of evidence of included studies.

RESULTS

Reviewers identified 53 articles. Of which, 34 studies (64.2%) were case-series and 11 (20.8%) were case reports. Most of the studies (n = 45, 84.9%) were level 4 on the OCEBM tool. The most common uses of NIRS were to visualize the biliary tree and to identify primary and metastatic malignant tissues. Other applications include assessment of perfusion of tissues including bowel anastomoses, and lymphatic surgery. Several advantages of the introduction of NIRS in pediatric surgery exist including having the potential to reduce operative time and intra/post-operative complications. Moreover, NIRS helps in detecting malignant tissues that can be missed by conventional imaging. However, NIRS has important limitations such as difficulty in identification of the biliary tree in obese patients or inflamed gallbladder, detection of small deeply localized malignant tissues, as well as the high cost.

CONCLUSIONS

NIRS is a promising modality that can be used intraoperatively to augment different pediatric surgical procedures. NIRS has important advantages and limitations compared to conventional surgery, however, more studies are required to evaluate its outcomes and cost-effectiveness.

LEVEL OF EVIDENCE

IV.

In vivo molecular and single cell imaging

Molecular imaging is used to improve the disease diagnosis, prognosis, monitoring of treatment in living subjects. Numerous molecular targets have been developed for various cellular and molecular processes in genetic, metabolic, proteomic, and cellular biologic level. Molecular imaging modalities such as Optical Imaging, Magnetic Resonance Imaging (MRI), Positron Emission Tomography (PET), Single Photon Emission Computed Tomography (SPECT), and Computed Tomography (CT) can be used to visualize anatomic, genetic, biochemical, and physiologic changes in vivo. For in vivo cell imaging, certain cells such as cancer cells, immune cells, stem cells could be labeled by direct and indirect labeling methods to monitor cell migration, cell activity, and cell effects in cell-based therapy. In case of cancer, it could be used to investigate biological processes such as cancer metastasis and to analyze the drug treatment process. In addition, transplanted stem cells and immune cells in cell-based therapy could be visualized and tracked to confirm the fate, activity, and function of cells. In conventional molecular imaging, cells can be monitored in vivo in bulk non-invasively with optical imaging, MRI, PET, and SPECT imaging. However, single cell imaging in vivo has been a great challenge due to an extremely high sensitive detection of single cell. Recently, there has been great attention for in vivo single cell imaging due to the development of single cell study. In vivo single imaging could analyze the survival or death, movement direction, and characteristics of a single cell in live subjects. In this article, we reviewed basic principle of in vivo molecular imaging and introduced recent studies for in vivo single cell imaging based on the concept of in vivo molecular imaging. [BMB Reports 2022; 55(6): 267-274].

Pathologic correlation with near infrared-indocyanine green guided surgery for pediatric liver cancer

PURPOSE

Hepatoblastoma (HB) and hepatocellular carcinoma (HCC) are the most common primary malignant tumors of childhood. Intraoperative indocyanine green (ICG) administration with near-infrared imaging (NIR) has emerged as a surgical technology that can be used to assist with localization of pulmonary metastases secondary to HB; however, there has been limited application as an adjunct for resection of the primary liver tumor and assessment of extrahepatic disease.

METHODS

We present 14 patients treated for HB, HCC, and malignant rhabdoid tumor at our institution with the use of intraoperative NIR-ICG guidance. All patients were treated with 0.2-0.75 mg/kg IV ICG, 48-96 h prior to surgery. Intraoperative NIR-ICG guided imaging was performed with several commercial devices.

RESULTS

Intraoperative NIR-ICG guidance allowed pulmonary metastasectomy in five patients using thoracoscopy or thoracotomy allowing for visualization of multiple nodules not seen on preoperative imaging most of which were positive for malignancy. NIR-ICG guidance allowed for assessment of extrahepatic extension in three patients; an HCC patient with extrahepatic lymph node extension of disease, an HB patient with extrapulmonary thoracic recurrence in the diaphragm and chest wall, and a patient with tumor rupture at diagnosis with peritoneal nodules at the time of surgery. This technique was used to guide partial hepatectomy in 11 patients for which the technique enabled successful identification of tumor and tumor margins. Three patients had nonspecific staining of the liver secondary to decreased timing from ICG injection to surgery or biliary obstruction. NIR-ICG enabled resection of satellite HB lesions in three multifocal patients and confirmed a benign satellite lesion in two additional patients.

CONCLUSIONS

Intraoperative use of NIR-ICG imaging during partial hepatectomy enabled enhanced identification and guidance for surgical resection of extrahepatic disease and multifocal liver tumors for the treatment of children with primary liver cancer.

The oncologic safety and accuracy of indocyanine green fluorescent dye marking in securing the proximal resection margin during totally laparoscopic distal gastrectomy for gastric cancer: a retrospective comparative study

Background

Securing the proximal resection margin in totally laparoscopic distal gastrectomy for gastric cancer is related to curability and recurrence, while reducing the operation time is related to patient safety. This study aimed to investigate the role of indocyanine green (ICG) fluorescent dye marking in totally laparoscopic distal gastrectomy, whether it is an oncologically safe and accurate procedure that can be conducted in a single centre.

Methods

The data of 93 patients who underwent laparoscopic-assisted distal gastrectomy (non-ICG group) or totally laparoscopic distal gastrectomy using ICG (ICG group) between 2010 and 2020 were retrospectively reviewed. To correct for confounding factors, a propensity score matching was performed.

Results

Proximal resection margin did not vary with the ICG injection site after the propensity score matching (lower ICG, 3.84 cm vs. lower non-ICG, 4.42 cm, p = 0.581; middle ICG, 3.34 cm vs. middle non-ICG, 3.20 cm; p = 0.917), while the operation time was reduced by a mean of 34 min in the ICG group (ICG, 239.3 [95% confidence interval, 220.1–258.5 min]; non-ICG, 273.0 [95% confidence interval, 261.6–284.4] min; p = 0.006).

Conclusions

ICG injection for securing the proximal resection margin in totally laparoscopic distal gastrectomy is an oncologically safe and accurate procedure, with the advantage of reducing the operation time of gastric cancer surgery while it has the benefit of locating the tumour or clips when it is impossible to locate the tumour during surgery due to the inability to perform an endoscopic examination or when it is hard to directly palpate the tumour or clips in the operating theatre; this can be performed at a single centre.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12957-022-02494-5.

Attempt of Real-Time Near-Infrared Fluorescence Imaging Using Indocyanine Green (ICG) in Radical Resection of Gallbladder Cancer: A Case Report

Surgery is the mainstay of treatment for resectable gallbladder cancer. Near-infrared fluorescence (NIRF) imaging using ICG is an innovation in laparoscopic surgery, which can provide real-time navigation during the whole operation. In this article, we present a 56-year older woman with gallbladder cancer, in which we evaluated the applicability of NIRF imaging using ICG for tumor and biliary tree visualization during the operative procedure of gallbladder cancer. The tumor and biliary tree were clearly visualized by utilizing a green fluorescence dye. The patient was successfully operated radical resection of gallbladder cancer under fluorescence laparoscope, without any complications. According to this case, the utilization of ICG based NIRF imaging is feasible and beneficial in identifying tumors and the biliary tree during radical resection. It can assist in the achievement of a negative margin and lymphatic clearance around the biliary tree. However, further studies are needed to corroborate the results of this case.

Fluorescence Guided Surgery

Fluorescence guided surgery (FGS) is an imaging technique that allows the surgeon to visualise different structures and types of tissue during a surgical procedure that may not be as visible under white light conditions. Due to the many potential advantages of fluorescence guided surgery compared to more traditional clinical imaging techniques such as its higher contrast and sensitivity, less subjective use, and ease of instrument operation, the research interest in fluorescence guided surgery continues to grow over various key aspects such as fluorescent probe development and surgical system development as well as its potential clinical applications. This review looks to summarise some of the emerging opportunities and developments that have already been made in fluorescence guided surgery in recent years while highlighting its advantages as well as limitations that need to be overcome in order to utilise the full potential of fluorescence within the surgical environment.

Evaluation of autofluorescence visualization system in the delineation of oral squamous cell carcinoma surgical margins

INTRODUCTION

Delineating the margins of Oral squamous cell carcinoma (OSCC) is a critical step for optimaltumor resection. The aim of this study was to evaluate the accuracy of lesion surgical margin identification using autofluorescence visualization.

MATERIALS AND METHODS

Thirty patients with OSCC were included in this study. For each lesion, the fluorescence loss boundary was determined using VELscope before ablative surgical resection (with a 1.5-2cm safety margin) was performed. A total of 126 samples were obtained from 30 surgical specimens, each containing the tissue from the fluorescence loss boundary to surgical margin. The status of each sample was determined by oral pathologists and the staining intensities of Ki-67, E-cadherin, and Vimentin at the fluorescence loss boundary and surgical margin were evaluated by immunohistochemistry.

RESULTS

Fluorescence loss regions were identified in all patients. Of the 126 samples collected, HE staining identified 77 normal epithelia (61.1%), 26 mild dysplasia (20.6%), 17 severe dysplasia (13.4%) and 6 carcinomas in situ (4.9%). A significant correlation was found between the differentiation grade of tumor cells and the pathological status of the surgical marginal specimens (P<0.05). Forty-two of the 126 samples were randomly selected for further immunohistochemical staining. No significant differences were seen in Ki-67, E-cadherin, or Vimentin expression at the fluorescence loss boundary or surgical margin, however, the proteins' expression level was positively correlated with the degree of dysplasia (P<0.01).

CONCLUSION

Autofluorescence visualization has potential as a simple surgical margin setting device for OSCC and may help delineate the superficial area of OSCC with acceptable accuracy. However, when considering the inherent limitations of this system, we suggest that the approach should only be applied under certain conditions, such as when dealing with superficial, well-differentiated lesions.

Assessment of the deep resection margin during oral cancer surgery: A systematic review

The main challenge for radical resection in oral cancer surgery is to obtain adequate resection margins. Especially the deep margin, which can only be estimated based on palpation during surgery, is often reported inadequate. To increase the percentage of radical resections, there is a need for a quick, easy, minimal invasive method, which assesses the deep resection margin without interrupting or prolonging surgery. This systematic review provides an overview of technologies that are currently being studied with the aim of fulfilling this demand. A literature search was conducted through the databases Medline, Embase and the Cochrane Library. A total of 62 studies were included. The results were categorized according to the type of technique: 'Frozen Section Analysis', 'Fluorescence', 'Optical Imaging', 'Conventional imaging techniques', and 'Cytological assessment'. This systematic review gives for each technique an overview of the reported performance (accuracy, sensitivity, specificity, positive predictive value, negative predictive value, or a different outcome measure), acquisition time, and sampling depth. At the moment, the most prevailing technique remains frozen section analysis. In the search for other assessment methods to evaluate the deep resection margin, some technologies are very promising for future use when effectiveness has been shown in larger trials, e.g., fluorescence (real-time, sampling depth up to 6 mm) or optical techniques such as hyperspectral imaging (real-time, sampling depth few mm) for microscopic margin assessment and ultrasound (less than 10 min, sampling depth several cm) for assessment on a macroscopic scale.

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.

Off-Peak Near-Infrared-II (NIR-II) Bioimaging of an Immunoconjugate Having Peak Fluorescence Emission in the NIR-I Spectral Region for Improving Tumor Margin Delineation

The primary treatment for malignant tumors remains to be resection. The strongest predictor of recurrence and postoperative prognosis is whether diseased tissue/cells remain(s) at the surgical margin. Cancer surgery entails surgeons having the capability to visually distinguish between subtle shades of color in attempts of differentiating between diseased tissue and healthy tissue under standard white-light illumination, as such tissue states appear identical at the meso-/macroscopic level. Accordingly, enhancing the capability of surgeons to do so such that they can accurately delineate the tumor margin is of paramount importance. Fluorescence-guided surgery facilitates in enhancing such capability by color-coding the surgical field with overlaid contrasting pseudo-colors from real-time intraoperative fluorescence emission via utilizing fluorescent constructs in tandem. Constructs undergoing clinical trials or that are FDA-approved provide peak fluorescence emission in the visible (405 - 700 nm) or near-infrared-I (NIR-I) spectral region (700-900 nm), whereby differentiation between tissue states progressively improves in sync with using constructs that emit longer wavelengths of light. Here, we repurpose the usage of such fluorescent constructs by establishing feasibility of a tumor-targeting immunoconjugate (cetuximab-IRDye800) having peak fluorescence emission at the NIR-I spectral region to provide improved tumor margin delineation by affording higher tumor-to-background ratios (TBRs) when measuring its off-peak fluorescence emission at the near-infrared-II (NIR-II) spectral region (1000-1700 nm) in in vivo applications. We prepared murine tumor models, administered such immunoconjugate, and imaged such models pre-/post-administration via utilizing imaging systems that separately afforded acquisition of fluorescence emission in the NIR-I or NIR-II spectral region. On doing so, we determined in vivo TBRs, ex vivo TBRs with/-out skin, and ex vivo biodistribution, all via measuring the fluorescence emission of the immunoconjugate at tumor site(s) at both spectral regions. Collectively, we established feasibility of using the immunoconjugate to afford improved tumor margin delineation by providing 2-fold higher TBRs via utilizing the NIR-II spectral region to capture off-peak fluorescence emission from a fluorescent construct having NIR-I peak fluorescence emission.