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

Histopathological predictors of lymph node metastasis in oral cavity squamous cell carcinoma: a systematic review and meta-analysis

Objectives

Lymph node metastasis (LNM) is the most significant parameter affecting overall survival in patients with oral cavity squamous cell carcinomas (OCSCC). Elective neck dissection (END) is the standard of care in the early management of OCSCC with a depth of invasion (DOI) greater than 2-4 mm. However, most patients show no LNM in the final pathologic report, indicating overtreatment. Thus, more detailed indicators are needed to predict LNM in patients with OCSCC. In this study, we critically evaluate the existing literature about the risk of different histological parameters in estimating LNM.

Methods

A systematic review was conducted using PRISMA guidelines. PubMed, Web of Science, Cochrane, and Scopus were searched from inception to December 2023 to collect all relevant studies. Eligibility screening of records was performed, and data extraction from the selected studies was carried out independently. Inclusion in our systematic review necessitated the following prerequisites: Involvement of patients diagnosed with OCSCC, and examination of histological parameters related to lymph node metastasis in these studies. Exclusion criteria included animal studies, non-English articles, non-availability of full text, and unpublished data.

Results

We included 217 studies in our systematic review, of which 142 were eligible for the meta-analysis. DOI exceeding 4 mm exhibited higher risk for LNM [Risk ratio (RR) 2.18 (1.91-2.48), p<0.00001], as did perineural invasion (PNI) [RR 2.04 (1.77-2.34), p<0.00001], poorly differentiated tumors [RR 1.97 (1.61-2.42), p<0.00001], lymphovascular invasion (LVI) [RR 2.43 (2.12-2.78), p<0.00001], groups and single pattern of invasion [RR 2.47 (2.11-2.89), p<0.00001], high tumor budding [RR 2.65 (1.99-3.52), p<0.00001], tumor size over 4 cm [RR 1.76 (1.43-2.18), p<0.00001], tumor thickness beyond 4 mm [RR 2.72 (1.91-3.87), p<0.00001], involved or close margin [RR 1.73 (1.29-2.33), p = 0.0003], and T3 and T4 disease [RR 1.98 (1.62-2.41), p <0.00001].

Conclusion

Our results confirm the potential usefulness of many histopathological features in predicting LNM and highlight the promising results of others. Many of these parameters are not routinely incorporated into pathologic reports. Future studies must focus on applying these parameters to examine their validity in predicting the need for elective neck treatment.

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.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Imaging of Neck Nodes in Head and Neck Cancers - a Comprehensive Update

Cervical lymph node metastases from head and neck squamous cell cancers significantly reduce disease-free survival and worsen overall prognosis and, hence, deserve more aggressive management and follow-up. As per the eighth edition of the American Joint Committee on Cancer staging manual, extranodal extension, especially in human papillomavirus-negative cancers, has been incorporated in staging as it is important in deciding management and significantly impacts the outcome of head and neck squamous cell cancer. Lymph node imaging with various radiological modalities, including ultrasound, computed tomography and magnetic resonance imaging, has been widely used, not only to demonstrate nodal involvement but also for guided histopathological evaluation and therapeutic intervention. Computed tomography and magnetic resonance imaging, together with positron emission tomography, are used widely for the follow-up of treated patients. Finally, there is an emerging role for artificial intelligence in neck node imaging that has shown promising results, increasing the accuracy of detection of nodal involvement, especially normal-appearing nodes. The aim of this review is to provide a comprehensive overview of the diagnosis and management of involved neck nodes with a focus on sentinel node anatomy, pathogenesis, imaging correlates (including radiogenomics and artificial intelligence) and the role of image-guided interventions.

Sentinel node-assisted neck dissection in advanced oral squamous cell carcinoma-A new protocol for staging and treatment

BACKGROUND

Sentinel lymph node biopsy (SLNB) is used to improve the staging of and guide treatment in patients with early-stage T1-T2 N0 oral squamous cell carcinoma (OSCC). The role of sentinel nodes (SNs) and the use of SN-technique in advanced OSCC (T3-T4 and/or N+) remain to be evaluated. This study investigates the nodal drainage and the rate of positive SNs (SNs+) in all stages of OSCC.

MATERIALS AND METHODS

In total, 85 patients with T1-T4 OSCC diagnosed 2019-2021 were included. We used a prolonged interval between peritumoral injection of radionuclide and SPECT-CT to include all SNs.

RESULTS

Patients with advanced OSCC presented a higher proportion of contralateral lymphatic drainage and a higher rate of SN+ compared to patients with early-stage disease. T3-T4 and N+ tumors presented a tendency for a higher rate of contralateral lymphatic drainage compared to T1-T2 and N0 tumors (p = 0.1). The prevalence of positive nodes (SNs+) was higher among patients with advanced disease, T3-T4 versus T1-T2 (p = 0.0398).

CONCLUSION

SN-assisted ND enables identification and removal of all SNs + and has the potential for more accurate staging and could possibly give prognostic advantages regarding regional recurrence for all OSCC patients, especially among those with advanced disease. The precise localization of the SNs + also suggests that a more individualized ND approach might be possible in the future even for patients with advanced OSCC.

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.

CT Lymphography Using Lipiodol® for Sentinel Lymph Node Biopsy in Early-Stage Oral Cancer

This study evaluated sentinel lymph node (SLN) identification with CT lymphography (CTL) following peritumoral administration of Lipiodol^® relative to conventional ^99mTc-nanocolloid lymphoscintigraphy (including SPECT/CT) in 10 early-stage oral cancer patients undergoing SLN biopsy. Patients first underwent early dynamic and static scintigraphy after peritumoral administration of ^99mTc-nanocolloid. Subsequently, Lipiodol^® was administered at the same injection sites, followed by fluoroscopy and CT acquisition. Finally, late scintigraphy and SPECT/CT were conducted, enabling the fusion of late CTL and SPECT imaging. The next day, designated SLNs were harvested, radiographically examined for Lipiodol^® uptake and histopathologically assessed. Corresponding images of CT, ^99mTc-nanocolloid lymphoscintigraphy and SPECT/late CTL fusion were evaluated. ^99mTc-nanocolloid lymphoscintigraphy identified 21 SLNs, of which 7 were identified with CTL (33%). CTL identified no additional SLNs and failed to identify any SLNs in four patients (40%). Out of six histopathologically positive SLNs, two were identified by CTL (33%). Radiographic examination confirmed Lipiodol^® uptake in seven harvested SLNs (24%), of which five were depicted by CTL. CTL using Lipiodol^® reached a sensitivity of 50% and a negative predictive value (NPV) of 75% (median follow-up: 12.3 months). These results suggest that CTL using Lipiodol^® is not a reliable technique for SLN mapping in early-stage oral cancer.

Patients of stage I oral cancer with pathologically low‐risk feature managed by primary tumor resection alone: Impact of depth of invasion and a nomogram analysis

Objectives

To evaluate the importance of depth of invasion (DOI) in patients with pathologically low‐risk feature stage I oral squamous cell carcinoma (OSCC) managed by primary tumor resection alone.

Methods

Patients with stage I OSCC, at pathologically low risk, underwent primary tumor resection without neck dissection were enrolled retrospectively between 2007 and 2015. Low risk was defined as the absence of positive or close margins, lymphovascular invasion, perineural invasion, worst pattern of invasion‐5, and poor differentiation in histologic grade. The primary endpoints included overall survival (OS), cancer specific survival (CSS), local recurrence free survival (LRFS), and regional recurrence free survival (RRFS). A nomogram based on the DOI was established for predicting RRFS.

Results

A total of 198 patients were enrolled in this study. DOI was the only prognosticator to achieve statistical significance in all primary endpoints according to univariate analysis. Patients with DOI <3 mm tumor showed better five‐year OS, CSS, LRFS, and RRFS than those with DOI ≥3 mm tumor. The concordance index of the nomogram model without DOI was 0.684, which could increase to 0.733 when DOI was included in the calculation.

Conclusion

Patients with pathologically low‐risk stage I OSCC correlate with a higher chance in occult neck metastasis if increasing DOI (≥3 mm) is noticed. Indeed, the chance of occult neck metastasis is significantly higher in this group (14% vs. 2%) than in those with DOI <3 mm. Elective neck dissection is advised if DOI is ≥3 mm to achieve better clinical outcomes.

Level of Evidence

4.

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

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

Centralised pathology service for sentinel node biopsy in oral cavity cancer: The Southeast England Consortium experience

BACKGROUND

Sentinel lymph node biopsy is an increasingly recognised option for accurate staging and subsequent management of the clinically negative neck in early stage oral cavity squamous cell carcinoma. However, the technique is currently underused due to several logistic constraints including increased burden on pathology services. Here, we describe the feasibility of an outsourced centralised pathology processing and reporting service for sentinel lymph node biopsies in oral cavity squamous cell carcinoma.

PATIENTS AND METHODS

The Southeast England Consortium comprises four surgical centres utilising a central pathology service. Consecutive cases between January 2016 and February 2020 were retrospectively evaluated for survival outcomes and laboratory turnaround times.

RESULTS

Twenty-eight per cent from a cohort of 139 patients had positive sentinel nodes. There was a trend towards greater overall, disease-free and disease-specific survival (OS, DFS and DSS, respectively) in sentinel node negative compared to sentinel node positive patients, but these differences were not statistically significant. The sensitivity, negative predictive value and false negative rate were 92.8%, 97.0% and 6.8%, respectively. The mean and mode laboratory TAT were 5 and 4 working days, respectively.

CONCLUSION

An outsourced centralised pathology service is a feasible option to widen the availability of sentinel node biopsy in oral cavity squamous cell carcinoma.

Oral squamous cell carcinoma – clinical characteristics, treatment, and outcomes in a single institution retrospective cohort study

<b>Introduction:</b> Squamous cell carcinoma (SCC) is a common malignancy with high morbidity and mortality. </br></br> <b>Aim:</b> The aim of this study was to analyze the data of patients treated for malignant tumours of the oral cavity at the Department of Otolaryngology, Head and Neck Surgery, and Laryngological Oncology Ludwik Rydygier Collegium Medicum in Bydgoszcz between 2003–2011 to asses the influence of risk factors on survival in patients with squamous cell carcinoma of the oral cavity. </br></br> <b> Material and methods:</b> Material was collected from 62 patients treated for oral SCC between 2003–2011. Forty-three were men (69.35%) with a mean age of 56.33 years. The medical records were analysed, especially history, operative reports, histopathology reports, survival, adjuvant treatment and recurrence. </br></br> <b>Results:</b> All patients underwent surgical treatment (33.87% also had partial removal of the lower jaw, 67.74% adjuvant radio-therapy, 11.29% radiochemotherapy). More than half reported to the doctor within 6 to 15 weeks from the onset of symptoms. The majority smoked and drank alcohol (96.32%). Five-year disease specific survival (DSS) was 68.69%. </br></br> <b>Conclusions:</b> The age over 65 did not significantly influence DSS. The location on the anterior two thirds of the tongue gave the best outcome, while the worst outcome was observed in the retromandibular triangle area which was statistically almost significant (p = 0.06843). In the case of higher degrees of local and regional advancement and a higher stadium, a worse out-come was recorded. Positive surgical margins were identified in 11.29% of the cases, but they had no impact on the results of treatment. No worsening of the outcome was proven for the patients who reported to the doctor later than 15 weeks following the occurrence of symptoms.

Application of the laboratory risk indicator for necrotizing fasciitis score to the head and neck: a systematic review and meta-analysis

BACKGROUND

Recent studies have attempted to verify the predictive capability of the Laboratory Risk Indicator for Necrotizing Fasciitis (LRINEC) for cervical necrotizing fasciitis (CNF).

METHODS

The two authors independently reviewed six databases (PubMed, Cochrane, Embase, Web of Science, SCOPUS and Google Scholar databases were searched). Seven cohort studies were included in the analysis. Sensitivity and specificity were determined by extracting items from binary classification from each paper. The diagnostic accuracy of the included studies was evaluated using QUADAS ver. 2.

RESULTS

The diagnostic odds ratio (OR) of LRINEC for CNF with the cutoff value of 6 was 13.9952 (95% CI, 3.8537; 50.8255, I²  = 76.7%). The area under the SROC curve was 0.842, suggesting acceptable diagnostic accuracy. The correlation between sensitivity and false positive rate was 0.055, indicating that it was not heterogeneous. The sensitivity, specificity, and negative predictive values were 0.7503 ([0.4637; 0.9126], I²  = 79.1%), 0.8455 ([0.7084; 0.9250], I²  = 96.0%) and 0.9829 ([0.9089; 0.9970], I²  = 93.7%), respectively. In the comparison of subgroups according to a LRINEC score (6-8, and), the cutoff value of 6 showed moderate sensitivity (75%) and high specificity (85%) and greater diagnostic power than other cutoff values.

CONCLUSIONS

LRINEC is a useful adjunctive tool for predicting CNF in patients with a soft tissue infection. In addition, a more accurate diagnosis is possible by using the LRINEC score with a cutoff value of 6.

Elective node dissection versus observation for management of patients with early-stage cT1/T2N0 tongue carcinoma: A systematic review and meta-analysis of prospective studies

OBJECTIVE

To carry out a meta-analysis of prospective literature comparing the clinical efficacy of elective neck dissection (END) vs observation (OBS) in patients with early-stage cT1/T2N0 tongue carcinoma.

DESIGN/SETTING/PARTICIPANTS/OUTCOME MEASURES

We systematically reviewed four databases from inception to 30-October-2020. We considered all studies meeting the following PICOS conditions: (a) Patients: early-stage cT1/T2N0 tongue carcinoma, (b) Intervention: END, (c) Comparator: OBS, (d) Outcomes: local tongue recurrence, cervical nodal recurrence, disease-specific survival (DSS) rate, and disease-free survival (DFS) rate and (e) Study design: prospective reports. We pooled dichotomous data as relative risks (RRs) with 95% confidence intervals (CIs).

RESULTS

Four studies (one case-control study and three randomised controlled trials) met our inclusion criteria. There were 448 eligible patients (225 and 223 patients were treated with END and OBS, respectively). END significantly correlated with improved DSS rate (RR = 1.15, 95% CI: 1.04-1.27, P = .007). Nonetheless, there were no significant differences between END and OBS groups regarding the rates of local tongue recurrence (RR = 1.23, 95% CI: 0.50-3.03, P = .65), cervical nodal recurrence (RR = 0.45, 95% CI: 0.16-1.27, P = .13) and DFS rate (RR = 1.08, 95% CI: 0.91-1.27, P = .38). Pooled analysis for cervical nodal recurrence was heterogeneous, and sensitivity analysis revealed a significantly lower cervical nodal recurrence rate in favour of END group (RR = 0.30, 95% CI: 0.13-0.67, P = .004).

CONCLUSION

END correlated with a significant decrease in cervical nodal recurrence and improved DSS rate. END might be superior to OBS in patients with early-stage cT1/T2N0 tongue cancer.

Distribution and determinants of submandibular gland involvement in oral cavity squamous cell carcinoma

INTRODUCTION

Though the submandibular gland (SMG) is routinely sacrificed for several reasons during neck dissection in patients undergoing curative surgery for oral cavity cancers, it might be an innocent bystander and should be considered for preservation. This study aimed to identify the incidence, different patterns of invasion, and risk factors of SMG involvement in oral cavity squamous cell carcinoma (SCC).

METHODS

This was a retrospective study of the patients who underwent upfront curative surgery for a biopsy-proven oral cavity SCC. A consistent protocol-based treatment strategy was followed during the study period. Data about clinical profile including demographics, clinical and histology details, and treatment profile were extracted and analysed.

RESULTS

A total of 303 patients underwent unilateral and bilateral neck dissections contributing 79.2% (n = 240) and 20.8% (n = 63) of patients respectively. The common primary sites were buccal mucosa (n = 129, 42.5%), tongue (n = 100, 33.0%) and alveolar gingiva (n = 52, 17.2%). A total of four SMGs showed tumor involvement resulting in a prevalence of 1.09% per neck dissection (n = 366) and 1.32% per patient (n = 303). Of these four cases of SMG involvement, one patient with alveolar cancer had direct tumor invasion while the other three (alveolar cancer - two, tongue cancer - one) patients had neck node metastasis.

CONCLUSION

The present study confirms a very low incidence of SMG involvement in patients with oral cavity cancer who undergo neck dissection. It is often observed in patients with high neck node burden (≥N2 disease and the presence of extracapsular spread) or direct invasion by the primary tumor.

Evaluation of Histopathological Risk Model in a Cohort of Oral Squamous Cell Carcinoma Patients Treated with Accompanying Neck Dissection

To investigate the applicability of the validated histological risk model in a cohort of oral cavity squamous cell carcinoma patients treated concurrently with neck dissections. Primary tumours from 85 patients with primary excision of T1 and T2 Oral Squamous Cell Carcinomas (TNM 7th edition) including neck dissection were scored by three pathologists in consensus according to the validated risk model. The risk score data, along with traditional dataset values, were analysed to determine possible association with nodal metastasis and extracapsular spread. Seventy-two patients (54%) were classified with low or intermediate risk and 62 (46%) patients were 'high risk'. A chi squared test showed that cases with nodal metastasis were highly statistically significant with the overall risk model score (X² = 22.62 p = 0.0001). None of the neck dissections from tumours with low risk score showed evidence of metastasis (NPV = 100%) suggesting the risk score may also be a useful tool for predicting an absence of metastasis. Risk assessment of low-stage oral squamous cell carcinoma primary tumours may be predictive of the presence or absence of metastasis at presentation. Knowledge of the risk score and its constituent parts may inform treatment decisions at multidisciplinary meetings. Low risk squamous cell carcinoma may be a rare variant with low metastatic potential and excellent long-term survival.

Perineural invasion, lactate dehydrogenase, globulin, and serum sodium predicting occult metastasis in oral cancer

OBJECTIVE

This study aimed to develop a nomogram to predict the neck occult metastasis in early (T1-T2 cN0) oral squamous cell carcinoma (OSCC).

MATERIALS AND METHODS

The nomogram was developed in a training cohort of 336 early OSCC patients and was validated in a validation cohort including 88 patients. Independent predictors were calculated by univariate and multivariate logistic regression analyses.

RESULTS

In univariate logistical regression analysis, gender, perineural invasion (PNI), blood vessel invasion, mean corpuscular hemoglobin, aspartate aminotransferase, prealbumin, globulin (GLO), lactate dehydrogenase (LDH), serum sodium (NA), and serum chloride were significant associated with neck occult metastasis. Multivariate logistical regression analysis identified PNI (p < .001), LDH (p = .003), GLO (p = .019), and NA (p = .020) as independent predictors of neck occult metastasis. Cut-off values for LDH, GLO, and NA obtained from AUC were 142.5, 26.35, and 139.5, respectively. The nomogram based on PNI and categorical GLO, LDH, and NA exhibited a strong discrimination, with a C-indexes of 0.748 (95%CI = 0.688 to 0.810) in the training cohort and 0.751 (95%CI = 0.639 to 0.863) in the validation cohort.

CONCLUSIONS

A nomogram based on PNI, LDH, GLO, and NA for predicting the risk of neck lymph nodes occult metastasis in OSCC could help surgeons with therapy decision-making.