Double sentinel lymph node mapping with indocyanine green and 99m-technetium–tin colloid in oral squamous cell carcinoma

Application value of a hybrid tracer during sentinel lymph node biopsy for head and neck malignancies: A systematic review and meta-analysis

To address the limitations of conventional sentinel lymph node biopsy (SLNB), a novel hybrid tracer (indocyanine green [ICG]-99mTc-nanocolloid) has been developed. This meta-analysis aimed to compare the differences between the novel hybrid tracer and conventional methods using ICG or radioisotope (RI) for SLNB in head and neck malignancies. This study was registered in the International Prospective Register of Systematic Reviews (CRD42023409127). PubMed, Embase, Web of Science, and the Cochrane Library were systematically searched. This study included raw data on the number of sentinel lymph nodes (SLNs) identified using different modalities during surgery for head and neck malignancies. The identification rate of SLNs was the main outcome of interest. Prognostic data and complication rate cannot be deduced from this article. The heterogeneity test (I2) determined the use of a fixed- or random-effects model for the pooled risk ratio (RR). Overall, 1275 studies were screened, of which 11 met the inclusion criteria for the meta-analysis. In SLN identification of head and neck malignancies, ICG-99mTc-nanocolloid was superior to ICG or RI. In the subgroup analyses, the detection rates of ICG and RI tracers in SLNB were comparable, regardless of the device, tumor type, or tumor stage. In conclusion, in SLN identification of head and neck malignancies, the use of ICG-99mTc-nanocolloid is superior to the single technique of ICG or RI. This study suggests that Hospitals using ICG or RI may find it beneficial to change their practice to ICG-99mTc-nanocolloid, especially in the head and neck area, owing to its superior effectiveness.

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

PURPOSE

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

METHODS

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

RESULTS

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

CONCLUSION

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

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.

Role of sentinel lymph node biopsy for oral squamous cell carcinoma: Current evidence and future challenges

Sentinel lymph node biopsy (SLNB) has been used across oncological specialties for prognostication, staging, and identification of occult nodal metastasis. Recent studies demonstrated the potential clinical utility of SLNB in oral cavity squamous cell carcinoma (OCSCC). Elective neck dissection is the current standard of care in early management of OCSCC with depth of invasion greater than 2-4 mm; however, majority of patients ultimately do not have nodal disease on final pathology. SLNB is an alternative procedure widely adopted in early cancer management in many oncological subspecialities. Several considerations such as depth of invasion, nodal mapping, histopathology methods, operator variability, postoperative complications, and advancement in preoperative and intraoperative imaging technology can guide the appropriate application to SLNB in OCSCC. The aim of this review is to discuss the current evidence for SLNB in the treatment of early stage OCSCC, imaging technologies that support SLNB procedures, and studies that are currently underway.

Efficacy of different sentinel lymph node biopsy protocols in oral squamous cell carcinoma: Systematic review and meta-analysis

The sentinel node biopsy (SNB) is highly protocolized in other cancers, however, this is not the case for oral squamous cell carcinoma patients, hence our objective was to evaluate the different protocols published. A specific study protocol was designed and subsequently registered on PROSPERO (Ref. CRD42021279217). Twenty‐three articles were included in the meta‐analysis. The grouped sensitivity of the SNB was 82% (95% CI: 0.74–0.88), and the grouped specificity was 100% (95% CI: 0.99–1.00). The use of other radiotracers other than pre‐operative lopamidol showed higher values of sensitivity of 82.80% (95% CI: 76.90%–87.50%; p < 0.001). The use of the blue dye stain showed higher sensitivity values of 85.60% (95% CI: 71.90%–93.20%), compared to sensitivity values of 77.50% when it was not used (95% CI: 69.10%–84.20%) (p < 0.001). Diagnostic rates are variable and they were significantly better when 99mTc was used in all its variations and accompanied by the blue dye staining.

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.

Sentinel lymph node biopsy in oral cavity cancer using indocyanine green: A systematic review and meta-analysis

This meta-analysis was conducted to evaluate the value of indocyanine green (ICG) in guiding sentinel lymph node biopsy (SLNB) for patients with oral cavity cancer. An electronic database search (PubMed, MEDLINE, Cochrane Library, Embase, and Web of Science) was performed from their inception to June 2020 to retrieve clinical studies of ICG applied to SLNB for oral cavity cancer. Data were extracted from 14 relevant articles (226 patients), and 9 studies (134 patients) were finally included in the meta-analysis according to the inclusion and exclusion criteria. The pooled sentinel lymph node (SLN) sensitivity, specificity, positive likelihood ratio, negative likelihood ratio, and diagnostic odds ratio were 88.0% (95% confidence interval [CI], 74.0-96.0), 64.0% (95% CI, 61.0-66.0), 2.45 (95% CI, 1.31-4.60), 0.40 (95% CI, 0.17-0.90), and 7.30 (95% CI, 1.74-30.68), respectively. The area under the summary receiver operating characteristic curve was 0.8805. In conclusion, ICG applied to SLNB can effectively predict the status of regional lymph nodes in oral cavity cancer.

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

In the current study, the utility of sentinel node (SN) identification using indocyanine green (ICG) was investigated for oral cancers in the clinical N0 stage. The current study was a prospective, multicentre, phase II clinical trial that was conducted in Japan. A total of 18 patients were included. Before surgery, the patients underwent lymphoscintigraphy to map the SNs. During surgery, radioactive isotope (RI) mapping was used to detect the SNs, and ICG was subsequently injected. ICG mapping of the SNs was then performed through the skin. The primary tumour was resected, and a neck flap was elevated for neck dissection, followed by SN biopsy (SNB) using RI or ICG mapping. With the RI method, a total of 63 SNs were detected. Among these SNs, 8 (12.7%) were positive for metastasis, including those with isolated tumour cells (ITCs). The median number of SNs per patient identified by SNB was 4. With the ICG method, a total of 67 SNs were detected. Among these SNs, 7 (10.4%) were positive for metastasis, including those with ITCs. The median number of SNs per patient identified by SNB was 4 (range, 1-6). The 5-year overall survival (OS) of all patients was 83.3%, and the 5-year disease-free survival (DFS) of all patients was 76.7%. The neck compression technique is a simple method that can be used to facilitate surgical procedures of ICG fluorescence navigated SNB for head and neck cancer.

Usefulness of Sentinel Lymph Node Biopsy for Oral Cancer: A Systematic Review and Meta-Analysis

OBJECTIVE

We assessed the diagnostic accuracy of sentinel lymph node biopsy (SLNB) for detecting neck nodal metastasis in early oral squamous cell carcinoma (OSCC) as an alternative to elective neck dissection.

STUDY DESIGN

A systematic search for relevant literature was conducted in the PubMed, SCOPUS, Embase, Web of Science, and Cochrane databases.

METHODS

Two reviewers individually searched the five databases up to November 2019. For studies that met inclusion criteria, data on patient diagnoses were pooled, including true positives, true negatives, false positives, and false negatives. Methodological quality was checked with the Quality Assessment of Diagnostic Accuracy Studies (version 2) tool.

RESULTS

In total, 98 observational or retrospective studies were included. The diagnostic odds ratio of SLNB was 326.165 (95% confidence interval [CI]: 231.477-459.587; I²  = 0%). The area under the summary receiver operating characteristic curve was 0.982. Sensitivity was 0.827 (95% CI: 0.804-0.848), and specificity was 0.981 (95% CI: 0.975-0.986). The correlation between sensitivity and the false positive rate was -0.076, which indicates that heterogeneity did not exist. Subgroup analyses were performed with the subgroups reference test type, publication year, and study type. No significant difference was found within the reference test type subgroup. However, differences within the publication year and study type subgroups were significant, where the retrospective study subgroup was significantly more sensitive and specific than the prospective study subgroup.

CONCLUSION

Results of this meta-analysis imply that the high specificity of SLNB supports its role as a diagnostic tool for patients with clinical tumor stage (CT)1-2 clinically negative (N0) OSCC. More studies should be done to further verify the results of this study.

LEVEL OF EVIDENCE

2a Laryngoscope, 131:E459-E465, 2021.

Sentinel Lymph Node Biopsy Using Preoperative Computed Tomographic Lymphography and Intraoperative Indocyanine Green Fluorescence Imaging in Patients With Localized Tongue Cancer

Importance

The indocyanine green method alone is unsuitable for sentinel lymph node biopsy in patients with oral cancer because of poor transcutaneous identification of the fluorescent signal through the platysma and sternocleidomastoid muscles.

Objective

To assess the utility of a novel sentinel lymph node biopsy technique using preoperative computed tomographic (CT) lymphography followed by the intraoperative indocyanine green fluorescence method.

Design, Setting, and Participants

In this prospective study performed at Akita University Hospital, Akita, Japan, participants comprised 18 patients with previously untreated cN0 tongue cancer (squamous cell carcinoma) were enrolled from November 2012 to November 2016. Median observer period was 38 (range, 14-62) months. Analysis was completed between January 10 and March 10, 2018.

Interventions

For preoperative sentinel lymph node mapping, CT lymphography was performed the day before sentinel lymph node biopsy. For sentinel lymph node biopsy, a minimum skin incision was made according to the predetermined location of sentinel lymph nodes. Sentinel lymph nodes were excised under indocyanine green fluorescence guidance.

Main Outcomes and Measures

Identification rate of preoperative sentinel lymph node mapping by CT lymphography and the number of sentinel lymph node successfully identified by the intraoperative indocyanine green fluorescence method.

Results

Among 18 patients (8 men, 10 women; median age, 65.5 [range, 40-83] years), sentinel lymph nodes could be mapped by preoperative CT lymphography in 16 patients (89%). At least 1 sentinel lymph node was successfully identified and excised in each of these 16 patients using intraoperative indocyanine green fluorescence. Among the 16 patients in whom sentinel lymph nodes were excised, metastases to sentinel lymph nodes were found in 5 patients (31%).

Conclusions and Relevance

The novel sentinel lymph node biopsy technique of preoperative CT lymphography mapping with intraoperative indocyanine green fluorescence has a high potential for identifying sentinel lymph nodes in patients with cN0 tongue cancer. Because the intraoperative indocyanine green method alone cannot identify sentinel lymph nodes in the neck region, this combined method has clinical potential as a sentinel lymph node biopsy technique that does not require radioisotopes.

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

INTRODUCTION

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Surgical margins in oral cavity squamous cell carcinoma: Current practices and future directions

OBJECTIVE

To discuss the current available techniques for intraoperative margin assessment in the surgical treatment of oral squamous cell carcinoma (OSCC) through a review of the available literature.

METHODS

A systematic review was undertaken of the available English literature between 2008 through 2018 regarding surgical margins in OCSS. A total of 893 relevant articles were returned; 144 met criteria for review; and 64 articles were included.

RESULTS

In this review, we discuss the data surrounding the use of frozen section in OCSS. Additionally, alternative techniques for margin assessment are discussed, including Mohs, molecular analysis, nonfluorescent dyes, fluorescent dyes, autofluorescent imaging, narrow-band imaging, optical coherence tomography, confocal microscopy, high-resolution microendoscopy, and spectroscopy. For each technique, particular emphasis is placed on the local recurrence, disease-free survival, and overall survival rates when available.

CONCLUSION

This review provides support for the practice of specimen-driven margin assessment when using frozen section analysis to improve the utility of the results. Finally, several alternatives for intraoperative margin assessment currently under investigation, including pathologic, wide-field imaging and narrow-field imaging techniques, are presented. We aim to fuel further investigation into methods for margin assessment that will improve survival for patients with OSCC through a critical analysis of the available techniques.

LEVEL OF EVIDENCE

NA Laryngoscope, 130:128-138, 2020.

Hybrid intraoperative imaging techniques in radioguided surgery: present clinical applications and future outlook

PURPOSE

This review aims to summarise the hybrid modality radioguidance techniques currently in clinical use and development, and to discuss possible future avenues of research. Due to the novelty of these approaches, evidence of their clinical relevance does not yet exist. The purpose of this review is to inform nuclear medicine practitioners of current cutting edge research in radioguided surgery which may enter standard clinical practice within the next 5-10 years. Hybrid imaging is of growing importance to nuclear medicine diagnostics, but it is only with recent advances in technology that hybrid modalities are being investigated for use during radioguided surgery. These modalities aim to overcome some of the difficulties of surgical imaging while maintaining many benefits, or providing entirely new information unavailable to surgeons with traditional radioguidance.

METHODS

A literature review was carried out using online reference databases (Scopus, PubMed). Review articles obtained using this technique were citation mined to obtain further references.

RESULTS

In total, 2367 papers were returned, with 425 suitable for further assessment. 60 papers directly related to hybrid intraoperative imaging in radioguided surgery are reported on. Of these papers, 25 described the clinical use of hybrid imaging, 22 described the development of new hybrid probes and tracers, and 13 described the development of hybrid technologies for future clinical use. Hybrid gamma-NIR fluorescence was found to be the most common clinical technique, with 35 papers associated with these modalities. Other hybrid combinations include gamma-bright field imaging, gamma-ultrasound imaging, gamma-β imaging and β-OCT imaging. The combination of preoperative and intraoperative images is also discussed.

CONCLUSION

Hybrid imaging offers new possibilities for assisting clinicians and surgeons in localising the site of uptake in procedures such as in sentinel node detection.

Clinically Approved Nanoparticle Imaging Agents

Nanoparticles are a new class of imaging agent used for both anatomic and molecular imaging. Nanoparticle-based imaging exploits the signal intensity, stability, and biodistribution behavior of submicron-diameter molecular imaging agents. This review focuses on nanoparticles used in human medical imaging, with an emphasis on radionuclide imaging and MRI. Newer nanoparticle platforms are also discussed in relation to theranostic and multimodal uses.

Short-Term Dynamic Observation of the Color Change and Enhancement Effect of Polyethylenimine-Entrapped Gold Nanoparticles Used for Indirect Lymphography

AIMS

To dynamically observe the color change and enhancement effect of gadolinium-loaded polyethylenimine-entrapped gold nanoparticles (Gd-Au PENPs) as a dual-mode CT/MRI contrast agent for sentinel lymph node (SLN) identification.

METHODS

In 6 rabbits, Gd-Au PENPs were injected into the right side tongue submucosa, after which the color change of cervical draining lymph nodes was observed. Then the draining lymph nodes were examined by CT/MRI scan. Another 6 rabbits were randomly divided into a CT lymphography (CT-LG) and a MRI lymphography (MRI-LG) group and examined by CT/MRI scan 1 and 30 min after injection. Then SLNs were identified under the guidance of CT/MRI-LG.

RESULTS

The ipsilateral afferent lymphatic vessels, cervical draining lymph nodes and efferent lymphatic vessels were stained black orderly and constantly after Gd-Au PENPs injection. Thirty minutes after injection, all cervical lymph nodes were excised to be examined by CT/MRI scan, and only the black-stained draining lymph nodes were enhanced. The 6 rabbits with CT/MRI-LG showed clear enhancement of SLNs. With indirect lymphography, the black-stained SLNs were easily visualized at autopsy. In all rabbits, the identification rate of lingual SLNs was 100%.

CONCLUSIONS

Rabbit lingual SLNs could be identified with indirect lymphography using Gd-Au PENPs as a dual-mode contrast agent.