A prospective study on sentinel lymph node biopsy in early oral cancers using methylene blue dye alone

Effectiveness of sentinel lymph node biopsy and bilateral pelvic nodal dissection using methylene blue dye in early-stage operable cervical cancer-A prospective study

OBJECTIVE

To evaluate the effectiveness of methylene blue dye in detecting sentinel lymph nodes (SLNs) in women with early-stage operable (defined as FIGO I-IIA) cervical cancer. It also aims to evaluate procedural challenges and accuracy.

METHOD

This prospective study, which focused on 20 women with early-stage cervical cancer, was carried out between June 2016 and December 2017. These patients had SLN mapping with methylene blue dye injections and thorough examinations, including imaging. All patients underwent radical hysterectomy and complete bilateral pelvic lymphadenectomy. No additional investigation was done on the lymph node in cases where a metastasis was found in the first H&E-stained segment of the sentinel node.

RESULT

20 patients were included in the analysis. The median age of the subjects was 53, and 95 % of them had squamous cell carcinoma. 90 % of the time, the identification of SLNs was effective, and 55 SLNs were found, of which 52.7 % were on the right side of the pelvis and 47.3 % on the left. The obturator group had the most nodes, followed by the external and internal iliac groups in descending order of occurrence. Metastasis was detected in 3 patients, resulting in a sensitivity of 100 % and a specificity of 93.75 % for SLN biopsy. Notably, no false-negative SLNs were found. Complications related to methylene blue usage included urine discoloration in 30 % of patients.

CONCLUSION

This trial highlights the promising efficacy and safety of methylene blue dye alone for SLN identification in early-stage operable cervical cancer, with a notably higher success rate. Despite limitations like a small sample size, healthcare professionals and researchers can build upon the insights from this study to enhance cervical cancer management.

[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.

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.

Methods for sentinel lymph node mapping in oral cancer: a literature review

Oral cancers, excluding non-melanoma skin cancer, are the most common cancers of the head and neck. Of these, 90% are squamous cell carcinomas (SCC). Surgery, which consists of dissection of the primary tumor and lymphadenectomy, is considered a radical method of treatment. There are several ranges of cervical lymphadenectomy: selective neck dissection (SND), modified radical neck dissection (MRND), and radical neck dissection (RND). The extension of surgery depends on the stage of clinical advancement, which can be determined by TNM classification, among other methods. The greatest controversy is related to SND in patients with cN0 (no evidence of regional lymph node metastasis), which is currently standard procedure. This approach is dictated by the possibility of hidden or subclinical metastases. The use of the sentinel lymph node (SLN) concept in patients with early stage of oral cancer and appropriate methods of its mapping may lead to a reduction in the extent of the lymphadenectomy procedure, thus reducing postoperative mortality and maintaining the patient’s function and quality of life, with correct oncological results. So far, available methods for SLN mapping are based on use of markers: methylene blue dye (MBD), metastable radioactive isotope Technetium (99mTc), or the fluorescent substance indocyanine green (ICG).

Quantitative and Semi-quantitative Methods for Assessing the Degree of Methylene Blue Staining in Sentinel Lymph Nodes in Dogs

Background: To develop a digital algorithm for quantitative assessment of surface methylene blue staining in whole lymph nodes and validate a semi-quantitative visual scoring method for patient-side use.

Methods: Lymph nodes from canine patients with spontaneous tumors undergoing sentinel lymph node mapping were prospectively assessed ex vivo and photographed. Using an open-source computer-based imaging software, an algorithm was developed for quantification of staining based on a signal-to-background ratio. Next, two blinded observers evaluated images and assigned a semi-quantitative visual score based on surface staining (0—no blue stain, 1−1–50% stained, and 2−51–100% stained) and those results were compared to the established quantitative standard.

Results: Forty-three lymph nodes were included. Image analysis successfully quantified blue staining and differentiated from normal lymph node tissue in all cases. Agreement between observers using the Kappa coefficient demonstrated strong agreement (k = 0.8581, p < 0.0001) between semi-quantitative visual scoring and image analysis. There was substantial interobserver and intraobserver agreement for the scoring system (k = 0.7340, p < 0.0001 and k = 0.8983, p < 0.0001, respectively).

Conclusion: A digital algorithm using an open-source software was simple and straightforward to use for quantification of blue staining. The use of a semi-quantitative visual scoring system shows promise for a simple, objective, repeatable assessment of methylene blue staining at the time of surgery. This study demonstrates reliable and repeatable methods for blue staining quantification thereby providing a novel and objective reporting mechanism in scientific research involving sentinel lymph node mapping.

Diagnostic yield of sentinel lymph node biopsy in oral squamous cell carcinoma T1/T2-N0: systematic review and meta-analysis

The objective of this study was to conduct a systematic review and meta-analysis on the efficacy of sentinel lymph node biopsy (SLNB) in T1/T2-N0 oral squamous cell carcinoma (OSCC). A systematic review of the literature on SLNB until March 2019 was conducted. The review was organized according to the PRISMA protocol, considering the following PICO (population, intervention, comparison, outcome) question: What is the sensitivity of sentinel lymph node biopsy in OSCC? 'P' was patients with head and neck squamous cell carcinoma T1/2-N0; 'I' was SLNB; 'C' was neck treated with elective neck dissection and haematoxylin-eosin histopathology; 'O' was sensitivity and specificity. A meta-analysis and meta-regression were performed on the selected studies. The sensitivity of SLNB was up to 88% (95% confidence interval (CI) 72-96%) and specificity was up to 99% (95% CI 96-100%). The area under the summary receiver operating characteristic curve was 0.99 (95% CI 0.98-1.00). In the four studies where immunohistochemistry was performed, both the sensitivity and specificity were higher than in the studies without immunohistochemistry: 93% (95% CI 88-97%) and 98% (95% CI 96-100%), respectively. In conclusion, SLNB is an effective technique for treating patients with some types of stage T1/2-N0 OSCC. Some parameters such as immunohistochemistry could determine the level of diagnostic accuracy.

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.

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.

Nanotechnology in Oral Cavity Carcinoma: Recent Trends and Treatment Opportunities

Oral cavity carcinoma (OCC) remains an ongoing public health problem. Emerging nanotechnology provides alternative treatment approaches. This review covers the up-to-date literature in the human OCC treatment field. We explored the growing body of evidence to reveal novel and highly promising diagnostic and therapeutic applications of nanotechnology in this field. Various types of nanoparticles have been tested for applications in OCC. Imaging modalities in addition to nanocarriers are discussed. The encouraging contribution of lymphotropic nanoparticles contrast in the diagnosis of metastatic cervical lymph nodes needs to be confirmed. The development of the sentinel lymph node procedure and photodynamic therapy may lead to breakthrough therapies in order improve clinical outcomes and quality of life. In this perspective, cancer nanotechnology has the potential to revolutionize the treatment of OCC patients.

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.

Sentinel Lymph Node Biopsy: A new approach in the management of head and neck cancers

Cervical lymph node metastasis affects the prognosis and overall survival rate of and therapeutic planning for patients with head and neck squamous cell carcinomas (HNSCCs). However, advanced diagnostic modalities still lack accuracy in detecting occult neck metastasis. A sentinel lymph node biopsy is a minimally invasive auxiliary method for assessing the presence of occult metastatic disease in a patient with a clinically negative neck. This technique increases the specificity of neck dissection and thus reduces morbidity among oral cancer patients. The removal of sentinel nodes and dissection of the levels between the primary tumour and the sentinel node or the irradiation of target nodal basins is favoured as a selective treatment approach; this technique has the potential to become the new standard of care for patients with HNSCCs. This article presents an update on clinical applications and novel developments in this field.

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.