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

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.

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.

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.

The Evolution of Fluorescence-Guided Surgery

There has been continual development of fluorescent agents, imaging systems, and their applications over the past several decades. With the recent FDA approvals of 5-aminolevulinic acid, hexaminolevulinate, and pafolacianine, much of the potential that fluorescence offers for image-guided oncologic surgery is now being actualized. In this article, we review the evolution of fluorescence-guided surgery, highlight the milestones which have contributed to successful clinical translation, and examine the future of targeted fluorescence imaging.