Long term-follow-up multicenter feasibility study of ICG fluorescence-navigated sentinel node biopsy in oral cancer

Use of Indocyanine Green Near-Infrared Imaging for Sentinel Lymph Node Biopsy in Early Oral Squamous Cell Carcinoma: A Pilot Study

PURPOSE

The current established technique for sentinel lymph node (SLN) biopsy is preoperative injection of 99mtechnetium-labeled nanosized colloids (99mTc) followed by single photon emission computed tomography and standard computed tomography (SPECT/CT) with subsequent intraoperative gamma probe-guided excision of the SLN. It is however time and resource consuming, causes radiation exposure and morbidity for the patient as the injection is done in the awake patient. Recently near-infrared imaging with indocyanine green (ICG) gained importance in SLN biopsy as a faster and more convenient technique. The objective of our study was to investigate the feasibility of SLN biopsy using ICG-imaging in early oral squamous cell carcinoma (OSCC).

METHODS

Single-centre pilot study of five patients with early-stage OSCC. For all patients, both techniques (99mTc and ICG) were performed. We injected 99mTc preoperatively in the awake patient, followed by SPECT/CT imaging. Intraoperatively ICG was injected around the primary tumor. Then the neck incision was performed according to the SPECT/CT images and SLN were detected by using a gamma probe and near-infrared fluorescence imaging of the ICG-marked lymph nodes intraoperatively. The excised lymph nodes were sent to histopathological examination according to the SLN dissection protocol.

RESULTS

In all five patients sentinel lymph nodes were identified. A total of 7 SLN were identified after injection of 99mTc, imaging with SPECT/CT and intraoperative use of a gamma probe. All these SLN were fluorescent and visible with the ICG technique. In two patients, we could identify additional lymph nodes using the ICG technique. Pathological analysis demonstrated occult metastasis in two of the cases.

CONCLUSIONS

Our study shows that ICG-guided SLN biopsy is a feasible technique, especially in combination with conventional radioisotope method and may help for intraoperative localization of SLN. Validation studies with bigger patient cohorts are needed to prove our results.

Prognostic significance of RKIP, TGM2, and CMTM4 expression in oral squamous cell carcinoma

BACKGROUND

The expression of RKIP, TGM2, and CMTM4 in oral squamous cell carcinoma (OSCC) and normal oral tissues was detected and their correlations were analyzed. The relationships between RKIP, TGM2, and CMTM4 and the clinicopathological parameters and prognosis of patients were analyzed.

METHODS

Seventy cancerous and adjacent normal tissue samples were selected, recorded in the pathology department, and embedded in paraffin. Protein expression was detected by immunohistochemistry. Statistical software (SPSS 25.0, IBM Corporation) was used for the statistical analysis. The chi-squared (χ2) test was used to analyze the expression of RKIP, TGM2, and CMTM4 proteins and their clinicopathological features. Differences in RKIP, TGM2, and CMTM4 protein levels between OSCC and normal tissues were compared using a χ2 test. Survival analysis was performed using the Kaplan-Meier method, and differences between survival curves were determined using the log-rank test. The effects of RKIP, TGM2, and CMTM4 expression on patient prognosis were analyzed using a multivariate Cox proportional hazards regression model. P < .05 was considered statistically significant.

RESULTS

The expression level of RKIP correlated with age and clinical stage (P < .05). TGM2 was associated with clinical stage and lymph node metastasis (P < .05). The expression of CMTM4 increased with a decrease in cancer differentiation. Kaplan-Meier survival analysis suggested that the positive expression of TGM2 and CMTM4 may predict poor prognosis in patients with OSCC. The multivariate Cox proportional hazards regression model suggested that TGM2 could be an independent prognostic factor for patients with OSCC.

CONCLUSION

Combined expression of TGM2 and CMTM4 can be used as an indicator to evaluate the risk of metastasis and prognosis of OSCC.

Indications for sentinel lymph node biopsy in node-negative oral cancers

BACKGROUND

We aimed to define the indications for sentinel lymph node biopsy (SLNB), the third option for cervical treatment in oral cancer with negative cervical lymph nodes.

METHODS

The greatest depth of invasion (DOI) and long diameter (LD) of the primary site were used as exposures. SLN metastasis was considered the outcome.

RESULTS

In three trials conducted between 2009 and 2016, 158 patients were eligible and reassigned to this study group. The scatterplot based on the respective values of DOI and LD would eventually be divided into three sections. In cases of sections T1, T2, and T3, the proportions of SLN metastasis positivity were 21.3%, 35.3%, and 51.2%, respectively. In certain cases of T1 with 2 mm < DOI ≤ 5 mm and 8 mm < LD ≤ 20 mm, the proportion of SLN metastasis positivity was 40.9%.

CONCLUSIONS

SLNB-navigated or assisted neck dissection can be added as an effective procedure for N0 neck control.

Predictive factors for dissection-free sentinel node micrometastases in early oral squamous cell carcinoma

This sentinel node (SN) biopsy trial aimed to assess its effectiveness in identifying predictive factors of micrometastases and to determine whether elective neck dissection is necessary in oral squamous cell carcinoma. This retrospective study included 55 patients from three previous trials, with positive SNs. The relationship between the sizes of the metastatic focus and metastasis in non-sentinel node (NSN) was investigated. Four of the 55 largest metastatic focus were isolated tumor cells, and the remaining 51 were ranged from 0.2 to 15 mm, with a median of 2.6 mm. The difference of prevalence between 46 negative- and 9 positive-NSN was statistically significant with regard to age, long diameter of primary site and number of cases with regional recurrence. In comparing the size of largest metastatic focus dividing the number of positive SN, with metastaic focus range of < 3.0 mm in one-positive SN group, there were 18 (33%) negative-NSN and no positive-NSN. Regarding prognosis, 3-year overall survival rate of this group (n = 18) and other (n = 37) were 94% and 73% (p = 0.04), and 3-year recurrence free survival rate of this group and other were 94% and 51% (p = 0.03), respectively. Absolutely a further prospective clinical trial would be needed, micrometastases may be defined as solitary SN metastasis with < 3.0 mm of metastatic focus, and approximately 33% of neck dissections could be avoided using these criteria.

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.

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.

Predictive factors for false negatives following sentinel lymph node biopsy in early oral cavity cancer

Prophylactic elective neck dissection (ND) with navigation surgery using radioisotope-based sentinel lymph node biopsy (SLNB) is non-inferior to elective ND in terms of survival but has an advantage in postoperative functional disability. We conducted a subgroup analysis to identify predictive factors for false-negative (FN)-SLNB in patients with early oral cavity cancer. This study is a supplementary analysis using the dataset of a previously reported randomized clinical trial on SLN navigation surgery for oral cancers. This study investigated the association of clinical and SLN-related factors with false-negative cases in the SLNB group. From 2011 to 2016, 275 patients were enrolled and randomly assigned to the ND and SLNB study groups, with 134 patients assigned to the SLNB group. In the SLNB group, seven cases with negative SLNs and neck recurrences were judged as FN-SLNBs according to the general definition. The number of detected SLNs with and without adjusting for the propensity score was significantly associated with FNs in the logistic analysis. FN-SLNB was associated with the number of identified SLNs, suggesting the need for careful postoperative monitoring for neck recurrence in patients with one or two identified SLNs after acquiring sufficient experience in the identification technique.

A Systematic Review of Oral Biopsies, Sample Types, and Detection Techniques Applied in Relation to Oral Cancer Detection

Background: Early identification of the stage of oral cancer development can lead to better treatment outcomes and avoid malignant transformation. Therefore, this review aims to provide a comprehensive overview that describes the development of standardized procedures for oral sample collection, characterization, and molecular risk assessment. This can help investigators to choose the appropriate sampling method and downstream analyses for different purposes. Methods: This systematic review was conducted according to the PRISMA guidelines. Using both PubMed and Web of Science databases, four independent authors conducted a literature search between 15 and 21 June 2021. We used key search terms to broaden the search for studies. Non-conforming articles were removed using an EndNote-based and manual approach. Reviewers used a designed form to extract data. Results: This review included a total of 3574 records, after eliminating duplicate articles and excluding papers that did not meet the inclusion criteria. Finally, 202 articles were included in this review. We summarized the sampling methods, biopsy samples, and downstream analysis. The biopsy techniques were classified into tissue and liquid biopsy. The common sequential analysis of tissue biopsy includes histopathological examination such as H&E or IHC to identify various pathogenic features. Meanwhile, liquid samples such as saliva, blood, and urine are analyzed for the purpose of screening to detect mutations in cancer. Commonly used technologies are PCR, RT-PCR, high-throughput sequencing, and metabolomic analysis. Conclusions: Currently, tissue biopsies provide increased diagnostic value compared to liquid biopsy. However, the minimal invasiveness and convenience of liquid biopsy make it a suitable method for mass screening and eventual clinical adoption. The analysis of samples includes histological and molecular analysis. Metabolite analysis is rising but remains scarce.

Novel double injection technique for sentinel lymph node biopsy in oral cancer

The development of new lymphatic tracers and the advancement of hybrid tracers, such as indocyanine green (ICG)-Nanocoll (GE Healthcare), represent an exciting step in the future of sentinel lymph node biopsy (SLNB). These tracers aim to improve our ability to detect sentinel lymph nodes by enhancing their localisation. The aim of this study was to assess the performance of a novel dual tracer, double injection technique of ICG-'cold'-Nanocoll and radiolabelled Nanocoll, in SLNB for early-stage oral cancer. A double injection technique was performed first using ^99mTc-Nancoll prior to sentinel node imaging followed by ICG-'cold'-Nanocoll injection in theatre. Analysis involved examination of the number, labelling, and location of the nodes harvested, sentinel node status, survival analysis, false negative rate, and complications associated with use of the technique. ICG 'cold' Nanocoll results showed concordance of fluorescence and radioactivity detection in 74 nodes in 24 patients. Most importantly, all nodes found positive for metastasis (6 nodes) were discovered to be both 'hot' and fluorescent; 74 nodes removed were both 'hot' and fluorescent, eight fluorescent only and six 'hot' only. Our results indicate that two sets of tracer injections given at two different time points will flow to the same sentinel nodes. This double labelling increased our confidence that the retrieved node was a sentinel node.

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.

Imaging-based navigation technologies in head and neck surgery

PURPOSE OF REVIEW

Image guided navigation has had significant impact in head and neck surgery, and has been most prolific in endonasal surgeries. Although conventional image guidance involves static computed tomography (CT) images attained in the preoperative setting, the continual evolution of surgical navigation technologies is fast expanding to incorporate both real-time data and bioinformation that allows for improved precision in surgical guidance. With the rapid advances in technologies, this article allows for a timely review of the current and developing techniques in surgical navigation for head and neck surgery.

RECENT FINDINGS

Current advances for cross-sectional-based image-guided surgery include fusion of CT with other imaging modalities (e.g., magnetic resonance imaging and positron emission tomography) as well as the uptake in intraoperative real-time 'on the table' imaging (e.g., cone-beam CT). These advances, together with the integration of virtual/augmented reality, enable potential enhancements in surgical navigation. In addition to the advances in radiological imaging, the development of optical modalities such as fluorescence and spectroscopy techniques further allows the assimilation of biological data to improve navigation particularly for head and neck surgery.

SUMMARY

The steady development of radiological and optical imaging techniques shows great promise in changing the paradigm of head and neck surgery.

Progress in application of near-infrared fluorescence imaging in the diagnosis and treatment of oral cancer

The preliminary screening of oral cancer mostly depends on the experience of clinicians, The surgical margin of tumor is mostly based on physical examination and preoperative imaging examination. It lacks real-time and objective intraoperative evaluation methods. Indocyanine green (ICG), as a safe and pollution-free organic fluorescent pigments, combined with near-infrared fluorescence imaging can be applied in the screening of early oral cancer, the determination of tumor resection margins, sentinel lymph node biopsy, cervical lymph node dissection, targeted chemotherapy, and other aspects. Near-infrared fluorescence imaging may become a key link in the early diagnosis and accurate treatment for oral cancer in the future.