Elective Neck Dissection in T1N0M0 Oral Squamous Cell Carcinoma: When Is It Necessary?

Intraoral ultrasonography: an adjunct in oral onco-surgery

OBJECTIVE

To determine the precision and accuracy of intraoral sonography in assessing the depth of invasion in oral cancer.

MATERIAL AND METHODS

A prospective study was conducted in 30 cases of oral cancer. Subjects were subjected to computerised tomography and intraoral sonography before surgery. The depth of invasion assessed through clinical palpation and radiological tools was compared with surgical histopathology.

RESULTS

The depth of invasion assessed on clinical palpation and computerized tomography had statistically significant difference with histopathology whereas intraoral sonography didn't show any difference. The intraoral sonography and computerised tomography had comparable precision and accuracy, with a slight dominance of the computerised tomography in assessing the tumor's depth of invasion greater than 4 mm. However, intraoral sonography was more precise and accurate than computerised tomography in assessing the depth of invasion beyond 10 mm.

CONCLUSION

Intraoral sonography was found to be a reliable tool in the assessment of the depth of invasion in oral cancer. It can prove beneficial during surgery in achieving tumour-free surgical margins.

Foregoing elective neck dissection for elderly patients with oral cavity squamous cell carcinoma

OBJECTIVE

Elective neck dissection (END) improves outcomes among clinically node-negative patients with oral cavity squamous cell carcinoma (OCSCC). However, END is of questionable value, considering the potentially higher comorbidities and operative risks in elderly patients.

METHODS

A retrospective review of all patients older than 65 years of age who were treated for OCSCC at a tertiary care centre between 2005 and 2020 was conducted.

RESULTS

Fifty-three patients underwent primary tumour resection alone, and 71 had simultaneous END. Most primary tumours were located on the mobile tongue. The patients who did not undergo END had a higher mean age (81.2 vs. 75.1 years, P < 0.00001), significantly shorter surgeries, and shorter hospitalizations. Occult cervical metastases were found in 24% of the patients who underwent END. The two groups showed no significant differences in overall survival or recurrence rates. Similar results were shown in a subpopulation analysis of patients older than 75 years.

CONCLUSION

Foregoing END in elderly patients with no clinical evidence of neck metastases did not result in lower survival rates or higher recurrence rates.

Association of Elective Neck Dissection With Survival in cT1N0M0 Floor of Mouth Squamous Cell Carcinoma: A Population-Based Propensity Score Matching Analysis

BACKGROUND

Studies on neck management of early-stage floor of mouth (FOM) squamous cell carcinoma (SCC) are very few and controversial. We aimed to study whether elective neck dissection (END) for patients with clinically stage T1N0M0 (cT1N0M0) FOM SCC is beneficial for survival.

METHODS

Information on patients diagnosed with cT1N0M0 FOM SCC between 2004 and 2015 was collected from the Surveillance, Epidemiology and End Results (SEER) database. Cox proportional risk models and Kaplan-Meier curves were used for survival analysis and log-rank tests were performed to compare whether overall survival (OS) and cancer-specific survival (CSS) differed. Propensity score matching (PSM) was performed to eliminate the effect of confounding variables.

RESULTS

There were 1014 patients with cT1N0M0 FOM SCC. Among them, END group: 455 cases; observation group: 559 cases. COX regression analysis before PSM demonstrated hazard ratio (HR) in the observation group compared to END (OS: 1.108 (.926-1.326), P = .262; CSS: 1.033 (.772-1.382), P = .827). There was no survival difference between END and observation survival before PSM (5-year OS: 71.8% vs. 67.8%, P = .180; 5-year CSS: 84.5% vs. 84.8%, P = .930); the matched results were the same as before PSM.

CONCLUSION

Observation may be a more appropriate option compared with END in cT1N0M0 FOM SCC.

Indications for elective neck dissection in cT1N0M0 oral cavity cancer according to the AJCC eight edition: A nationwide study

OBJECTIVES

According to the NCCN guidelines, there is weak evidence to support the use of elective neck dissection (END) in early-stage oral cavity squamous cell carcinoma (OCSCC). We sought to examine the indications for END in patients with cT1N0M0 OCSCC defined according to the AJCC Staging Manual, Eight Edition.

METHODS

Of the 3886 patients diagnosed with cT1N0M0 included in the study, 2065 underwent END and 1821 neck observation.

RESULTS

The 5-year outcomes for patients who received END versus neck observation before and after propensity score matching (n = 1406 each) were as follows: neck control, 96 %/90 % (before matching), p < 0.0001; 96 %/90 % (after matching), p < 0.0001; disease-specific survival (DSS), 93 %/92 % (before matching), p = 0.0227; 93 %/92 % (after matching), p = 0.1436. Multivariable analyses revealed that neck observation, depth of invasion (DOI) > 2.5 mm, and poor differentiation were independent risk factors for 5-year outcomes. Upon the application of a scoring system ranging from 0 (no risk factor) to 3 (presence of the three risk factors), the following 5-year rates were observed: neck control, 98 %/95 %/84 %/85 %; DSS, 96 %/93 %/88 %/85 %; and overall survival, 90 %/86 %/79 %/59 %, respectively (all p < 0.0001). The survival outcomes of patients with scores of 0 and 1 were similar. The occult metastasis rates in the entire study cohort, DOI > 2.5 mm, and poor differentiation were 6.8 %/9.2 %/17.1 %, respectively.

CONCLUSION

Because all patients who received neck observation had a score of 1 or higher, END should be performed when a DOI > 2.5 mm or poorly differentiated tumors are present. Under these circumstances, 48.6 % (1888/3886) of cT1N0M0 patients may avoid END without compromising oncological outcomes.

Small tongue squamous cell carcinoma with neck metastasis at diagnosis: operative insights and surgical technique

BACKGROUND

The treatment of tongue tumors includes different surgical procedures ranging from a simple mucosal resection to complex combined resection depending on the tumor stage and size. In 2019 we reported an international glossectomy classification with the purpose of standardizing all the different types of surgical procedures adopted for tongue cancer.

METHODS

The present communication aims at providing further insight into the glossectomy classification. More specifically, it is intended to better specify the indications to glossectomy type IIIA and B in selected tongue cancers, with positive cervical lymph nodes at the diagnosis.

RESULTS AND CONCLUSIONS

Type IIIA glossectomy permits a high function sparing surgery in selected cases, with better postoperative functional outcomes. From an oncological perspective, it permits a radical surgery, avoiding postoperative radiation in the absence of extracapsular spread, multiple nodal metastases or T-N tract involvement.

Development and validation of a nomogram for the prediction of lymph node metastasis within 2-year postoperatively in cT1-T2N0 oral squamous cell carcinoma

BACKGROUND

The current neck management for early oral squamous cell carcinoma (OSCC) has always been a controversial issue. A comprehensive model is necessary for predicting an individual's metastasis risk and appropriate patient counseling.

METHODS

A nomogram for predicting 2-year LNM in patients with cT1-2N0 OSCC was developed and validated using clinicopathological data from 642 patients from 2000 to 2018 in four hospitals, China.

RESULTS

Three variables (pathology grade, depth of invasion, tumor-infiltrating lymphocytes) were included in nomogram. C-indices were 0.826 (95% CI: 0.786-0.866) and 0.726 (95% CI: 0.653-0.780) in the internal and external validation. Kaplan-Meier method found the 2-year LNM rate of high-risk group (35.8%) was much higher than that of the low-risk group (14.5%). The nomogram model has an advantage over the 8th AJCC TNM stage in predicting the individual 2-year LNM probability for early OSCC.

CONCLUSION

Patients with low-risk nomogram score may receive neck observation; those with high-risk score should receive END.

High-Frequency Intraoral Ultrasound for Preoperative Assessment of Depth of Invasion for Early Tongue Squamous Cell Carcinoma: Radiological-Pathological Correlations

The eighth edition of the TNM classification officially introduced "depth of invasion" (DOI) as a criterion for determining the T stage in tongue squamous cell carcinoma. The DOI is a well-known independent risk factor for nodal metastases. In fact, several experts strongly suggest elective neck dissection for tongue cancer with a DOI > 4 mm due to the high risk of early and occult nodal metastases. Imaging plays a pivotal role in preoperative assessments of the DOI and, hence, in planning the surgical approach. Intraoral ultrasound (IOUS) has been proposed for early-stage SCC of the oral tongue as an alternative to magnetic resonance imaging (MRI) for local staging. The aim of this work is to investigate the accuracy of IOUS in the assessment of the DOI in early oral SCC (CIS, pT1, and pT2). A total of 41 patients with tongue SCCs (CIS-T2) underwent a preoperative high-frequency IOUS. An IOUS was performed using a small-size, high-frequency hockey-stick linear probe. The ultrasonographic DOI (usDOI) was retrospectively compared to the pathological DOI (pDOI) as the standard reference. In patients who underwent a preoperative MRI, their usDOI, magnetic resonance DOI (mriDOI), and pDOI were compared. Specificity and sensitivity for the IOUS to predict a pDOI > 4 mm and to differentiate invasive and noninvasive tumors were also evaluated. A high correlation was found between the pDOI and usDOI, pDOI and mriDOI, and usDOI and mriDOI (Spearman's ρ = 0.84, p < 0.0001, Spearman's ρ = 0.79, p < 0.0001, and Spearman's ρ = 0.91, p < 0.0001, respectively). A Bland-Altman plot showed a high agreement between the usDOI and pDOI, even though a mean systematic error was found between the usDOI and pDOI (0.7 mm), mriDOI and pDOI (1.6 mm), and usDOI and mriDOI (-0.7 mm). The IOUS was accurate at determining the T stage (p < 0.0001). The sensitivity and specificity for the IOUS to predict a pDOI ≥4 mm were 92.31% and 82.14%, respectively, with an AUC of 0.87 (p < 0.0001). The specificity, sensitivity, negative predictive value (NPV), and positive predictive value (PPV) for the IOUS to predict an invasive cancer were 100%, 94.7%, 60%, and 100%, respectively. The AUC was 0.8 (95% CI 0.646-0.908, p < 0.0001). The IOUS was accurate in a preoperative assessment of a pDOI and T stage, and can be proposed as an alternative to MRI in the preoperative staging of tongue SCC.

Comparative study on Classifications of AJCC 8th and 7th in the patients with tongue squamous cell carcinoma

OBJECTIVES

Depth of invasion (DOI) is the most important predictor for lymph node metastasis in early-stage oral cancer. This study aims to investigate the effects of the different classifications of AJCC 7th and 8th on predicting lymph node metastasis and the optimal cutoff point for DOI predicting the lymph node metastasis in patients with tongue squamous cell carcinoma (TSCC).

MATERIALS AND METHODS

We performed a retrospective study in 208 TSCC patients in early T-stage without clinical or radiological signs of lymph node metastasis. Those patients were treated with elective neck dissection (END) between April 2019 and December 2020. And the relation between DOI and lymph node metastasis was analyzed.

RESULTS

Metastases were found in 58 of 208 patients (27.88%). Of those 58 patients, the mean DOI was 8.311 mm compared to 5.425 mm in patients without metastases (P < 0.0001). The receiver operating characteristic curve (ROC-curve) showed an area under the curve of 0.7066 with the most optimal cutoff point on a DOI of 4.050 mm (sensitivity 86.21%, specificity 52%). Linear regression analysis (1 mm≤DOI≤6 mm) revealed that a DOI ≥ 3.211 mm predicated an incidence of occult lymph node metastasis greater than 20%. Regional metastases were found in 12.82% of patients with DOI ≤ 4.0 mm. Within the entire cohort, 60 cases (28.85%) got upgraded with respect to T-stage. No tumor underwent downstaging.

CONCLUSION

The 8th edition provides better lymph node metastasis prediction for TSCC than the 7th. And DOI is a poor predictor for regional metastasis in patients with early T-stage clinically node-negative TSCC. END in patients with early-stage TSCC should be performed in patients with DOI ≥ 3.211 mm.

Elective neck dissection improves the survival of patients with T2N0M0 oral squamous cell carcinoma: a study of the SEER database

Background

Treatment of clinical N0 neck tumours is controversial in early-stage oral squamous cell carcinoma (OSCC), possibly because T1N0M0 and T2N0M0 merge together at early stages. The purposes of this study were to compare survival outcomes only for T2N0M0 cases based upon treatment elective neck dissection versus neck observation.

Methods

T2N0M0 OSCC cases were identified in the Surveillance, Epidemiology, and End Results database of the United States National Cancer Institute between 2004 and 2015. Survival curves for different variable values were generated using Kaplan-Meier estimates and compared using the log-rank test. Variables that achieved significance at P < 0.05 were entered into multivariable analyses via the Cox proportional hazards multivariate regression.

Results

A total of 2857 patients were selected, and 2313 cases were available for disease specific survival (DSS). The 5-year and 10-year overall survival (OS) were 66.7 and 46% for patients receiving elective neck dissection (END), respectively, and 56.4 and 37.2% for patients with neck observation (P < 0.0001). The 5-year and 10-year DSS were 73.6 and 64% for the END group, respectively, versus 64.5 and 54.5% for the neck observation group (P < 0.0001). More importantly, performing END was independently associated with favourable DSS and OS for patients with T2N0M0 OSCC [hazard ratio (HR) = 0.769, P = 0.0069 for DSS; HR = 0.829, P = 0.0031 for OS, neck observation group as reference] according to multivariate survival analysis.

Conclusion

END is recommended for T2N0M0 OSCC cases and it is associated with improved DSS and OS.

Molecular and Cellular Mechanisms of Perineural Invasion in Oral Squamous Cell Carcinoma: Potential Targets for Therapeutic Intervention

Simple Summary

Squamous cell carcinoma is the most common type of oral cavity cancer. It can spread along and invade nerves in a process called perineural invasion. Perineural invasion can increase the chances of tumor recurrence and reduce survival in patients with oral cancer. Understanding how oral cancer interacts with nerves to facilitate perineural invasion is an important area of research. Targeting key events that contribute to perineural invasion in oral cavity cancer may reduce tumor recurrence and improve survival. In this review, we describe the impact of perineural invasion in oral cancer and the mechanisms that contribute to perineural invasion. Highlighting the key events of perineural invasion is important for the identification and testing of novel therapies for oral cancer with perineural invasion.

Abstract

The most common oral cavity cancer is squamous cell carcinoma (SCC), of which perineural invasion (PNI) is a significant prognostic factor associated with decreased survival and an increased rate of locoregional recurrence. In the classical theory of PNI, cancer was believed to invade nerves directly through the path of least resistance in the perineural space; however, more recent evidence suggests that PNI requires reciprocal signaling interactions between tumor cells and nerve components, particularly Schwann cells. Specifically, head and neck SCC can express neurotrophins and neurotrophin receptors that may contribute to cancer migration towards nerves, PNI, and neuritogenesis towards cancer. Through reciprocal signaling, recent studies also suggest that Schwann cells may play an important role in promoting PNI by migrating toward cancer cells, intercalating, and dispersing cancer, and facilitating cancer migration toward nerves. The interactions of neurotrophins with their high affinity receptors is a new area of interest in the development of pharmaceutical therapies for many types of cancer. In this comprehensive review, we discuss diagnosis and treatment of oral cavity SCC, how PNI affects locoregional recurrence and survival, and the impact of adjuvant therapies on tumors with PNI. We also describe the molecular and cellular mechanisms associated with PNI, including the expression of neurotrophins and their receptors, and highlight potential targets for therapeutic intervention for PNI in oral SCC.

A Combined Prediction Model for Lymph Node Metastasis Based on a Molecular Panel and Clinicopathological Factors in Oral Squamous Cell Carcinoma

Objective

Lymph node metastasis is the most important factor influencing the prognosis of oral squamous cell carcinoma (OSCC) patients. However, there is no proper method for predicting lymph node metastasis. This study aimed to construct and validate a preoperative prediction model for lymph node metastasis and guide personalized neck management based on the gene expression profile and clinicopathological parameters of OSCC.

Methods

Based on a previous study of related genes in OSCC, the mRNA expression of candidate genes was evaluated by real-time PCR in OSCC specimens. In this retrospective study, the gene expression profile and clinicopathological parameters of 112 OSCC patients were combined to construct the best prediction model for lymph node metastasis of OSCC. The model was validated with 95 OSCC samples in this study. Logistic regression analysis was used. The area under the curve (AUC) ultimately determined the diagnostic value of the prediction model.

Results

The two genes CDKN2A + PLAU were closely related to lymph node metastasis of oral squamous cell carcinoma. The model with the combination of CDKN2A, PLAU, T stage and pathological grade was the best in predicting lymph node metastasis (AUC = 0.807, 95% CI: 0.713-0.881, P=0.0001). The prediction model had a specificity of 96% and sensitivity of 72.73% for stage T1 and T2 OSCC (AUC = 0.855, 95% CI: 0.697-0.949, P=0.0001).

Conclusions

High expression of CDKN2A and PLAU was associated with lymph node metastasis in OSCC. The prediction model including CDKN2A, PLAU, T stage and pathological grade can be used as the best diagnostic model for lymph node metastasis in OSCC.

Contribution of Genomics to the Surgical Management and Study of Oral Cancer

Background

Oral squamous cell carcinoma (OSCC) is the most frequent type of tumor arising from the oral cavity. Surgery is the cornerstone of the treatment of these cancers. Tumor biology has long been overlooked as an important contributor to the outcome of surgical procedures, but recent studies are challenging this concept. Molecular analyses of tumor DNA or RNA provide a rich source of information about the biology of OSCC.

Methods

We searched for relevant articles using PubMed. We examined in particular the prospect of applying molecular methods for minimally invasive exploration of OSCC biology.

Results

We examined five potential applications of genomics to the surgical management and study of OSCC: i) assessing oral potentially malignant lesions; ii) tumor staging prior to surgery; iii) predicting postoperative risk in locally advanced tumors; iv) measuring minimal residual disease and optimizing the longitudinal monitoring of OSCC; and v) predicting the efficacy of medical treatment.

Conclusions

Genomic information can be harnessed in order to identify new biomarkers that could improve the staging, choice of therapy and management of OSCC. The identification of new biomarkers is awaited for better personalization of the surgical treatment of OSCC.

The Indications for Elective Neck Dissection in T1N0M0 Oral Cavity Squamous Cell Carcinoma

PURPOSE

The management of the clinically node-negative neck in T1 oral cavity squamous cell carcinoma (SCC) is controversial. The purpose of this study was to investigate tumor characteristics of surgically managed patients with T1N0 oral cavity SCC and determine the possible benefits of elective neck dissection (END).

MATERIALS AND METHODS

A retrospective cohort study was conducted assessing outcomes for patients with stage I oral SCC at Waikato Hospital, New Zealand, between 2008 and 2018. Clinical staging was based on the American Joint Committee on Cancer Cancer Staging Manual, 8^th Edition. Patients with T1N0 SCC either had an END or had the neck observed. These data were used to determine the rate of occult nodal disease, recurrence rate, and survival. Data collected included patient demographics, location, tumor characteristics including differentiation, depth of invasion (DOI), perineural invasion (PNI), lymphovascular invasion, closest histologic margin, management of the neck, the number of pathologic lymph nodes, adjuvant treatment, recurrence, and survival.

RESULTS

A total of 70 patients were included in the study (40 male, 30 female; age range 30 to 91; mean age 65 years). Twenty-seven (38.6%) patients underwent END, whereas 43 patients (61.4%) were observed. Occult nodal metastases were diagnosed in 6 of 27 (22.2%) patients who underwent END. Regional relapse occurred in 7 of 43 (16.3%) patients who were observed. Risk factors for nodal disease included increasing DOI ≥ 3 mm (P = .049), poor tumor differentiation (P = .003), and presence of PNI (P = .002). Negative prognostic factors for overall survival included male gender (P = .02, hr = 3.55, CI for HR (1.18, 10.65)), presence of PNI (P = .001, hr = 4.52, CI for HR (1.77, 11.57)), and locoregional recurrence (P < .005, hr = 6.55, CI for HR (2.69, 15.98)). Six of the 7 tumors that relapsed in the neck after observation had a primary tumor DOI < 3 mm.

CONCLUSIONS

There is little data published for management outcomes of the node-negative neck in stage I oral squamous cell carcinoma. Given salvage neck dissection carries a poorer prognosis, END should be recommended for all T1N0 oral SCC with DOI ≥ 3 mm. In cases of DOI < 3 mm undergoing primary ablation only, a staging neck dissection as a second procedure should be considered in the presence of poor tumor differentiation or PNI on final histology.

Intraoral ultrasonography in the assessment of DOI in oral cavity squamous cell carcinoma: a comparison with magnetic resonance and histopathology

Objective

The first-line therapeutic approach for oral cavity squamous cell carcinoma (OCSCC) is complete surgical resection. Preoperative assessment of depth of invasion (cDOI) is crucial to plan the surgery. Magnetic resonance (MR) and intraoral ultrasonography (IOUS) have been shown to be useful tools for assessment of DOI. The present analysis investigates the accuracy of MR and IOUS in evaluating DOI in OCSCC compared to histological evaluation (pDOI).

Materials and methods

Forty-nine previously untreated patients with cT1-T3 OCSCC were reviewed. Nine patients were staged with MR alone, 10 with IOUS alone, and 30 with both MR and IOUS.

Results

Mean difference between cDOI_MR and pDOI values of 0.2 mm (95% CI − 1.0–1.3 mm) and between cDOI_IOUS and pDOI of 0.3 mm (95% CI − 1.0–1.6 mm). Spearman R between cDOI_MR and pDOI was R = 0.83 and between cDOI_IOUS and pDOI was R = 0.76. Both radiological techniques showed high performance for the correct identification, with the optimum cut-off of 5 mm, of patients with a pDOI ≥ 4 mm and amenable to a neck dissection, with an AUC of 0.92 and 0.82 for MR and IOUS, respectively.

Conclusion

Both examinations were valid approaches for preoperative determination of DOI in OCSCC, although with different cost-effectiveness profiles and indications.

Electronic supplementary material

The online version of this article (10.1007/s00405-020-06421-w) contains supplementary material, which is available to authorized users.