Sentinel node biopsy using indocyanine green in oral/oropharyngeal 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.

Determining Accurate Dye Combinations for Sentinel Lymph Node Detection: A Systematic Review

Background

Lymphatic dyes are commonly used to map the drainage path from tumor to lymphatics, which are biopsied to determine if spread has occurred. A blue dye in combination with technetium-99 is considered the gold standard for mapping, although many other dyes and dye combinations are used. Not all of these substances have the same detection efficacy.

Methods

A systematic review of PubMed, SCOPUS, Web of Science, and Medline was performed. The predefined search terms were (indocyanine green OR isosulfan blue OR lymphazurin OR patent blue OR methylene blue OR fluorescein OR technetium-99) AND combination AND dye AND (sentinel lymph node biopsy OR lymphedema OR lymphatics OR lymph OR microsurgery OR cancer OR tumor OR melanoma OR carcinoma OR sarcoma).

Results

The initial search returned 4267 articles. From these studies, 37 were selected as candidates that met inclusion criteria. After a full-text review, 34 studies were selected for inclusion. Eighty-nine methods of sentinel lymph node (SLN) detection were trialed using 22 unique dyes, dye combinations, or other tracers. In total, 12,157 SLNs of 12,801 SLNs were identified. Dye accuracy ranged from 100% to 69.8% detection. Five dye combinations had 100% accuracy. Dye combinations were more accurate than single dyes.

Conclusions

Combining lymphatic dyes improves SLN detection results. Replacing technetium-99 with ICG may allow for increased access to SLN procedures with comparable results. The ideal SLN tracer is a low-cost molecule with a high affinity for lymphatic vessels due to size and chemical composition, visualization without specialized equipment, and no adverse effects.

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.

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSION

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

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

PURPOSE

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

METHODS

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

RESULTS

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

CONCLUSION

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

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

AIM

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

METHODS

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

RESULTS

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

CONCLUSION

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

Diagnostic test accuracy of sentinel lymph node biopsy in squamous cell carcinoma of the oropharynx, larynx, and hypopharynx: A systematic review and meta-analysis

The aim of this meta-analysis was to determine the diagnostic test accuracy of sentinel lymph node biopsy (SLNB) in patients with oropharyngeal, laryngeal, and hypopharyngeal squamous cell carcinoma (SCC). For this purpose, MEDLINE, EMBASE, and Web of Science were searched from inception to March 8, 2022. Included were studies evaluating diagnostic test accuracy of SLNB to identify cervical lymph node metastases with elective neck dissection or follow-up as reference. A bivariate generalized linear mixed model approach was used for the meta-analysis. Nineteen studies were eligible, evaluating 377 cases in total. The pooled estimates of sensitivity and negative predictive value were 0.93 (95% CI: 0.86-0.96) and 0.97 (95% CI: 0.94-0.98), respectively. The excellent accuracy of SLNB justifies a place in the diagnostic workup of patients with larynx and pharynx SCC. Randomized trials are required to demonstrate oncologic safety and benefits on treatment related morbidity and quality of life when omitting elective neck treatment based on SLNB.

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

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

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.

A retrospective analysis of 5-year post surgery recurrence of N0 neck and the role of methylene blue in sentinel lymph node biopsy

The aim of this study is to perform a retrospective analysis of the feasibility of the clinical application of SLNB using methylene blue dye (MBD) for the identification of SLN followed by frozen section biopsy to detect occult metastasis in clinically N0 necks. Hence, to know the reliability of MBD in reducing the need for extensive surgery.

Methods

We retrospectively analyzed the clinic pathological data of 48 patients with early oral cancer.The SLN identification rate (IR) was calculated in SLNB with MBD and the false-negative rate (FNR). Intra operative frozen section biopsy was done for all patients was compared with post-operative paraffin histopathology report and the prognosis of patients was analyzed.

Results

Analysis of the 48 SLNB cases showed that there were significant differences in SLN successful detection rate among patients with different site (p = 0.043) and clinical presentation (p = 0.007). Similar significant results (p < 0.05) were observed with intra-operative frozen and post-operative paraffin histopathology sections. SLNs were successfully detected in 37(77.1%) patients out of 48. The intra operative frozen histopathology completely matched with the post-operative paraffin histopathology showing 39 (81.2%) negative and 09 (18.8%) positive cases. A prognostic analysis of SLN detection based on 48 patients showed that the 5-year survival rate was 100%.

Conclusion

MBD has acceptable SLN identification rate and a low FNR(false negative report) in frozen sections. Stained SLNs with no SLN metastasis are associated with disease-free survival (DFS). Hence, MBD-SLN biopsy has significantly reduced the need for extensive neck dissection in N0 neck with less morbidity.

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

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

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

BACKGROUND

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

MATERIAL AND METHODS

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

RESULTS

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

CONCLUSIONS

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

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

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

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.

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.

Determining agreement between preoperative computed tomography lymphography and indocyanine green near infrared fluorescence intraoperative imaging for sentinel lymph node mapping in dogs with oral tumours

Lymphatic drainage from the head and neck is variable with significant crossover, therefore sentinel lymph node (SLN) mapping can help ensure the appropriate lymph node(s) are sampled. To improve sensitivity, SLN mapping utilizing multiple modalities and a combination of preoperative computed tomography lymphography (CTL) and intraoperative near infrared fluorescence imaging (NIRF) with indocyanine green (ICG) +/- methylene blue (MB) dye has been suggested. The aim of this study was to describe a method for intraoperative ICG lymphography and determine agreement for SLN detection using preoperative CTL and intraoperative ICG NIRF + MB lymphography (IOL) in dogs with oral tumours. Fourteen client-owned dogs were included. All dogs had preoperative CTL with iodinated contrast and intraoperative IOL with an exoscope. Lymph nodes with CTL contrast-enhancement, blue staining or fluorescence were considered sentinel. The overall SLN identification rate was 100% when CTL and IOL were combined. A total of 57 SLNs were identified. Indocyanine green NIRF identified a greater proportion of SLNs (91%; 52/57) compared with MB (50.8%; 29/57) and CTL (42.1%; 24/57). Eighteen SLNs were identified by all three modalities with a fair level of agreement using Fleiss kappa. These findings suggest a combination of preoperative CTL with intraoperative SLN mapping techniques may greatly improve the ability to accurately detect the SLN in dogs with oral tumours.

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.

New Developments in Imaging for Sentinel Lymph Node Biopsy in Early-Stage Oral Cavity Squamous Cell Carcinoma

Sentinel lymph node biopsy (SLNB) is a diagnostic staging procedure that aims to identify the first draining lymph node(s) from the primary tumor, the sentinel lymph nodes (SLN), as their histopathological status reflects the histopathological status of the rest of the nodal basin. The routine SLNB procedure consists of peritumoral injections with a technetium-99m [^99mTc]-labelled radiotracer followed by lymphoscintigraphy and SPECT-CT imaging. Based on these imaging results, the identified SLNs are marked for surgical extirpation and are subjected to histopathological assessment. The routine SLNB procedure has proven to reliably stage the clinically negative neck in early-stage oral squamous cell carcinoma (OSCC). However, an infamous limitation arises in situations where SLNs are located in close vicinity of the tracer injection site. In these cases, the hotspot of the injection site can hide adjacent SLNs and hamper the discrimination between tracer injection site and SLNs (shine-through phenomenon). Therefore, technical developments are needed to bring the diagnostic accuracy of SLNB for early-stage OSCC to a higher level. This review evaluates novel SLNB imaging techniques for early-stage OSCC: MR lymphography, CT lymphography, PET lymphoscintigraphy and contrast-enhanced lymphosonography. Furthermore, their reported diagnostic accuracy is described and their relative merits, disadvantages and potential applications are outlined.

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.

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

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.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

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.

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

PURPOSE

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

PATIENTS AND METHODS

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

RESULTS

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

CONCLUSION

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

Diagnostic value of sentinel lymph node biopsy for cT1/T2N0 tongue squamous cell carcinoma: a meta-analysis

The aim of this study was to systematically evaluate the diagnostic value of the sentinel lymph node biopsy (SLNB) for cT1/T2N0 tongue squamous cell carcinoma (TSCC) patients. A comprehensive and systematic literature review was performed by searching the Embase and PubMed databases for English language articles published up to December 2016. The pooled overall sentinel lymph node (SLN) detection rate, sensitivity and negative predictive value (NPV) were used to evaluate the diagnostic value of SLNB which used neck dissection or follow-up as a reference test. The Q test and I ² statistic were used to assess the heterogeneity across the studies. Subgroup analyses were performed in consideration of higher contribution of different clinical characteristics on the SLNB diagnostic value. Begg's linear regression and Egger's regression tests were conducted to evaluate the publication bias. Thirty-five studies (with 1084 patients) were included. The pooled SLN detection rate was 98% (95% CI 97-100%). The pooled overall sensitivity and NPV of SLNB were 0.92 (95% CI 0.88-0.95) and 0.96 (95% CI 0.94-0.97), respectively. The subgroup analyses demonstrated that higher extracted number of patients (n ≥ 30) from the included studies achieved a more stable NPV than lower number of patients. SLNB can effectively predict the status of regional lymph nodes in cT1/T2N0 TSCC patients. With high sensitivity and NPV, SLNB can guide the treatment of SLNB-positive patients with neck dissections and those with negative SLNBs with follow-ups in order to avoid unnecessary surgical morbidity.

Contrast-enhanced ultrasound mapping of sentinel lymph nodes in oral tongue cancer-a pilot study

OBJECTIVES

To assess the usefulness of contrast-enhanced ultrasound (CEUS) with peritumoral injection of microbubble contrast agent for detecting the sentinel lymph nodes for oral tongue carcinoma.

METHODS

The study was carried out on 12 patients with T1-2cN0 oral tongue cancer. A radical resection of the primary disease was planned; a modified radical supraomohyoid neck dissection was reserved for patients with larger lesions (T2, n = 8). The treatment plan and execution were not influenced by sentinel node mapping outcome. The Sonovue^™ contrast agent (Bracco Imaging, Milan, Italy) was utilized. After detection, the position and radiologic features of the sentinel nodes were recorded.

RESULTS

The identification rate of the sentinel nodes was 91.7%; one patient failed to demonstrate any enhanced areas. A total of 15 sentinel nodes were found in the rest of the 11 cases, with a mean of 1.4 nodes for each patient. The sentinel nodes were localized in: Level IA-1 (6.7%) node; Level IB-11 (73.3%) nodes; Level IIA-3 (20.0%) nodes. No contrast-related adverse effects were observed.

CONCLUSIONS

For oral tongue tumours, CEUS is a feasible and potentially widely available approach of sentinel node mapping. Further clinical research is required to establish the position of CEUS detection of the sentinel nodes in oral cavity cancers.

Diagnostic Efficacy of Sentinel Lymph Node Biopsy in Early Oral Squamous Cell Carcinoma: A Meta-Analysis of 66 Studies

OBJECTIVES

The diagnostic efficacy of sentinel lymph node biopsy(SLNB) in early oral squamous cell carcinoma(OSCC) still remains controversial. This meta-analysis was conducted to assess the diagnostic value of SLNB in clinically neck-negative T1-2 OSCC.

METHODS

A systematic literature search for relevant literature published up to September 11, 2016 was conducted in PubMed, Embase, Web of Science, Cochrane Library and ClinicalTrials, and the reference lists of eligible studies were examined. Data from different studies were pooled to estimate the summary sentinel lymph node(SLN) identification rate, sensitivity, negative predictive value. Summary receiver operator characteristic curve(SROC) was plotted and area under the SROC curve (AUC) was calculated to evaluate the overall diagnostic efficacy. Threshold effect was assessed with use of the spearman correlation coefficient. Between-study heterogeneity was tested using the Q tests and the I2 statistics. Subgroup analyses were conducted in view of the greater effect of different study characteristics on diagnostic efficacy of SLN. Deeks' funnel plot asymmetry test was performed to evaluate publication bias. Sensitivity analysis was evaluated through omitting studies one by one and comparing the pooled results of random-effects model and fixed-effects model. All analyses were performed using Review Manager (version 5.3.5), Meta-DiSc (version 1.4), Comprehensive Meta Analysis (version 2.0) and STATA (version 12).

RESULTS

66 studies comprising 3566 patients with cT1-2N0 OSCC were included in this meta-analysis. The pooled SLN identification rate was 96.3%(95% CI: 95.3%-97.0%). The pooled sensitivity was 0.87 (95% CI: 0.85-0.89), pooled negative predictive value was 0.94 (95% CI: 0.93-0.95), and AUC was 0.98 (95% CI: 0.97-0.99). Subgroup analyses indicated that SLN assessment with immunohistochemistry(IHC) achieved a significantly higher sensitivity than without IHC.

CONCLUSIONS

This meta-analysis suggests that SLNB has a high diagnostic accuracy in cT1-2N0 oral squamous cell carcinoma, and is an ideal alternative to elective neck dissection. Furthermore, the use of IHC can significantly improve SLNB diagnostic sensitivity for early OSCC.

Infracentimetric cervical lymph node metastasis in head and neck squamous cell carcinoma: Incidence and prognostic value

OBJECTIVES

Supracentimetric cervical lymph node metastasis is classically a poor prognostic factor for locoregional recurrence and survival in head and neck cancer. Causality, however, is more controversial for infracentimetric cervical lymph node metastases. The objective of this study was to evaluate the incidence and prognostic value of infracentimetric lymph node metastasis.

MATERIALS AND METHODS

Two hundred and forty-three neck dissections from 150 head and neck cancer patients were analyzed. A single pathologist exhaustively inventoried the number and size of all adenopathies in the surgical specimen.

RESULTS

Cervical lymph node metastases were infracentimetric in 38% of cases, with 72% extracapsular spread (versus 91% for supracentimetric adenopathies; P<0.01). Infracentimetric metastases were more often associated with other cervical lymph node metastases (mean 5.3 versus 3.9; P=0.14). Fifty three percent of specimens showed only supracentimetric metastases (versus 13% infracentimetric metastases; P<0.01). Disease-specific and failure-free survival were lower in case of infracentimetric metastasis, associated with supracentimetric metastasis or not, than in case of macrometastasis only.

CONCLUSION

Infracentimetric cervical lymph node metastasis is a factor of poor prognosis, and may represent a different, more aggressive lymphatic process. We suggest complete neck dissection by the surgeon and meticulous analysis by the pathologist, the results of which guide complementary therapy. Close surveillance of recurrence is also recommended.