Sentinel lymph node biopsy for management of the N0 neck in oral cavity squamous cell carcinoma

Sentinel lymph node biopsy versus elective neck dissection in management of the clinically negative (cN0) neck in patients with oral squamous cell carcinoma: A systematic review and meta-analysis

Oral squamous cell carcinoma (OSCC) is the most prevalent type of head and neck cancer, and lymph node metastasis is a crucial prognostic factor that has a direct correlation with the survival rate. The standard procedure for managing clinically negative (cN0) neck in OSCC patients is elective neck dissection (END), but it can lead to various complications that affect the patient's quality of life. Therefore, medical professionals are exploring the use of the sentinel lymph node biopsy (SLNB) to manage cN0 neck in OSCC patients. The aim of this systematic review and meta-analysis was to compare the overall survival (OS) and disease-free survival (DFS) of patients undergoing SLNB and END in the surgical management of early cN0 neck in OSCC patients. To conduct this study, the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement was used to report the systematic reviews. The study included all comparative clinical studies, including randomized clinical trials (RCTs), clinical perspective studies, and retrospective studies that compared END to SLNB for early cN0 neck in OSCC patients. The hazard ratio (HR) and risk ratio (RR) with 95% confidence interval (CI) were calculated using comprehensive meta-analysis. The primary outcome variables were OS, DFS, and disease-specific survival (DSS). The secondary outcome variable was the nodal recurrence rate without local or distant metastasis. The GRADE system was used to assess the evidence's certainty. The meta-analysis included 12 clinical studies, comprising three RCTs and seven non-RCTs. The results showed no statistically significant difference between END and SLNB concerning OS (HR = 0.993, CI: 0.814 to 1.211, P = 0.947, low-quality evidence), DFS (HR = 0.705, CI: 0.408 to 1.29, P = 0.21, low-quality evidence), and nodal recurrence (RR = 1.028, CI: 0.969 to 1.090, P = 0.907, low-quality evidence). Additionally, SLNB was non-inferior to END regarding DSS (RR = 1.028, CI: 0.969 to 1.090, P = 0.907, low-quality evidence). In conclusion, this research affirms the safety and precision of SLNB as a means to stage cN0 OSCC patients, with outcomes that are comparable to END in terms of survival and nodal recurrence. Nevertheless, it's crucial to acknowledge that the quality of evidence in this study was relatively low. Therefore, additional RCTs comparing END to SLNB are warranted to validate these results and offer more robust guidance for managing cN0 OSCC patients.

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.

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.

Identification of occult metastatic disease via lymphoscintigraphy-guided neck dissection in N0 oral squamous cell carcinoma

BACKGROUND

The purpose of this study is to assess the efficacy of lymphoscintigraphy-guided neck dissection (LSG-ND) in the treatment of N0 oral squamous cell carcinoma.

METHODS

A retrospective cohort study of patients with N0 oral squamous cell carcinoma (SCC) who had either LSG-ND or neck dissection (ND) at our institution between 2008 and 2020.

RESULTS

Eighty-seven patients met criteria with N0 oral squamous cell carcinoma with no previous treatment or neck surgery (27 LSG-ND, 60 ND). Sentinel lymph nodes were identified on the contralateral side in 14.8% of patients with unilateral tumors in the LSG-ND group, with 22.2% of cases with unexpected lymphatic drainage outside ipsilateral levels I-III. No recurrences to date have occurred in the LSG-ND cohort, while 13.3% of patients with ND had regional recurrence (p = 0.04).

CONCLUSIONS

LSG-ND provides a greater ability to identify occult metastatic disease with a significant reduction in regional recurrence in N0 oral SCC.

Evaluation of a streamlined sentinel lymph-node imaging protocol in early-stage oral cancer

OBJECTIVE

Sentinel lymph-node (SLN) mapping for early-stage oral squamous cell carcinoma (OSCC) is comprehensive and consequently time-consuming and costly. This study evaluated the clinical value of several SLN imaging components and analyzed the accuracy for SLN identification using a streamlined SLN imaging protocol in early-stage OSCC.

MATERIALS AND METHODS

This retrospective within-patient evaluation study compared both number and localization of identified SLNs between the conventional SLN imaging protocol and a streamlined imaging protocol (dynamic lymphoscintigraphy (LSG) for 10 min directly post-injection and SPECT-CT at ~ 2 h post-injection). LSG and SPECT-CT images of 77 early-stage OSCC patients, scheduled for SLN biopsy, were evaluated by three observers. Identified SLNs using either protocol were related to histopathological assessment of harvested SLNs, complementary neck dissection specimens and follow-up status.

RESULTS

A total of 200 SLNs were identified using the streamlined protocol, and 12 additional SLNs (n = 212) were identified with the conventional protocol in 10 patients. Of those, 9/12 were identified on early static LSG and 3/12 on late static LSG. None of the additionally identified SLNs contained metastases; none of those in whom additional SLNs were identified developed regional recurrence during follow-up. Only inferior alveolar process carcinoma showed a higher rate of additionally identified SLNs with the conventional protocol (p = 0.006).

CONCLUSION

Early dynamic LSG can be reduced to 10 min. Late static LSG may be omitted, except in those with a history of oncological neck treatment or with OSCC featuring slow lymphatic drainage. Early static LSG appeared to be contributory in most OSCC subsites.

Analysis of the Efficiency and Prognostic Value of the Sentinel Node Technique in Oral Squamous Cell Carcinoma after Seven Years

Background and objectives: The purpose of this study was to analyse the diagnostic and prognostic efficiency of the sentinel lymph node biopsy technique (SLNB). Materials and Methods: This is a prospective observational study performed by the Hospital Complex in Santiago de Compostela (CHUS) in Spain, between February 2013 and June 2020. The study included 60 patients, who had been diagnosed with OSCC in stage T1/T2N0M0. Results: 10 patients (16.7%) presented with SN+ (sentinel node positive). The majority (80%) only presented subcapsular affection, however one case also presented with extracapsular affection. Using the Kaplan–Meier curves, we determined that the average survival estimation for SN− patients was 74.0 months (CI95% 67.6–80.5) and it was 45.4 months (CI95% 10.9–24.0) for SN+ patients (p = 0.002). SN+ patients presented an OR = 11.000 (CI95% 2.393–50.589, p = 0.002) for cancer-related mortality. In terms of the diagnostic performance of the SN (sentinel node) test, a 55% sensitivity, a 100% specificity, 100% PPV and a 84% NPV were obtained. The analysis using ROC (receiver operating characteristic) curves revealed an AUC = 0.671 (CI95% 0.492–0.850, p = 0.046). Conclusions: SLNB seems to be an adequate technique for the detection of hidden metastases.

Sentinel Lymph Node Biopsy in Early Stages of Oral Squamous Cell Carcinoma Using the Receptor-Targeted Radiotracer 99mTc-Tilmanocept

Neck management in patients with early-stage, clinically node-negative oral squamous cell carcinoma (OSCC) remains a matter of discussion. Sentinel lymph node biopsy (SLNB) represents a treatment alternative to avoid elective neck dissection (END) in this cohort and different protocols and tracers exist. Here we present the clinical outcome of SLNB using ^99mTc-tilmanocept in a two-day protocol in patients suffering from early-stage OSCC. A total of 13 patients (males: 6; females: 7; mean age: 65.7 years, ranging from 47 to 89 years) were included in this study. Most of the patients suffered from an OSCC of the floor of mouth (n = 6), followed by tongue (n = 5) and upper alveolar crest/hard palate (n = 2). Sentinel lymph nodes (SLNs) were successfully identified in all cases (range: 1–7). The average length of hospital stay was 4.7 days (range: 3–8 days) and mean duration of surgical intervention was 121 min (range: 74–233 min). One patient who suffered from an OSCC of the tongue was sentinel lymph node positive (SLN+). The mean follow-up for all sentinel lymph node negative (SLN-) patients (n = 12) was 20.3 months (range: 10–28 months). No local or nodal recurrences were observed within the observation period. In our patient cohort, SLNB using ^99mTc-tilmanocept in a two-day protocol proved to be a reliable and safe staging method for patients suffering from early-stage, clinically node-negative OSCC. These results and their possible superiority to colloid tracers have to be confirmed in a prospective randomized controlled study.

Serial step sections at narrow intervals with immunohistochemistry are required for accurate histological assessment of sentinel lymph node biopsy in oral squamous cell carcinoma

BACKGROUND

Sentinel lymph node (SLN) biopsy is an accurate staging modality in early oral squamous cell carcinoma (OSCC), but its accuracy relies on labor-intensive histopathology protocols. We sought to determine whether serial step sections with immunohistochemistry (SSSIHC) at narrow intervals of the entire SLN are required to accurately exclude metastasis.

METHODS

Consecutive SLN biopsies over a 13-year period were retrospectively evaluated. If the index section was negative for carcinoma, the entire SLN was subjected to SSSIHC at 150 μm intervals. The first section level and total number of section levels to contain carcinoma were recorded.

RESULTS

One hundred and eighteen SLN+ from 90 patients were included. SSSIHC upstaged the nodal status in 19.5% of patients. Metastasis was identified in 16.7% and 10.2% beyond section levels 4 and 6, respectively. Among SLNs requiring SSSIHC, 47.5% contained carcinoma in a single section level.

CONCLUSION

SSSIHC of the entire SLN at 150 μm intervals are required to identify occult metastasis in OSCC.

Indications and outcomes of superselective neck dissection: A review and analysis of the literature

Superselective neck dissection, defined as dissection of two or less contiguous neck levels, has recently been introduced to reduce surgical morbidity of neck dissection while maintaining favorable oncologic outcomes. The purpose of this review is to report the results of superselective neck dissection when applied to specific settings: the management of regional disease after chemoradiation, head and neck squamous cell carcinoma with clinical N0 necks, and high risk papillary thyroid carcinoma.

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.

Magnetic detection of sentinel nodes in oral squamous cell carcinoma by means of superparamagnetic iron oxide contrast

The aim was to evaluate sentinel node detection capacity by means of a magnetic probe in 11 patients with oral squamous cell carcinoma at stages T1-T2 received submucosal injections of a superparamagnetic iron oxide contrast agent (SPIO). A magnetic probe was used for sentinel node biopsy. The use of SPIO and magnetic probes in the early stages of oral cancer may offer an alternative to conventional radioisotope techniques and/or elective neck dissection.