Patterns of recurrence in oral tongue cancer with perineural invasion

Adjuvant Radiotherapy in Moderately Advanced (T3) Oral Cavity Cancers

OBJECTIVE

To investigate the impact of adjuvant radiotherapy in isolated locally advanced oral cavity cancers (pT3N0M0) without adverse features.

METHODS

We selected all patients from the National Cancer Database (2004-2019) who underwent surgical treatment where the final pathology was T3N0M0 with negative margins. Demographics, details of treatment, and outcomes were abstracted. The impact of radiotherapy on survival was assessed with univariable, multivariable, and propensity score-matched analyses.

RESULTS

We identified 571 patients in our survival cohort. Most were male (348, 60.9%), and median age was 65. Less than one-third (176, 30.8%) received adjuvant radiotherapy. The median length of follow-up was 29 months. Overall, adjuvant radiotherapy was associated with improved survival (87.2% vs. 77.7%, at 2 years, p < 0.01). On multivariable analysis controlling for age and comorbidities, this survival difference persisted (HR: 0.62, 95% CI: 0.43-0.90, p = 0.01). In a propensity score-matched population of 278 patients matched on age and comorbidities, adjuvant radiotherapy was still associated with longer survival (87.4% vs. 78.5%, p = 0.014).

CONCLUSION

In our study, adjuvant radiotherapy was associated with improved survival in completely excised locally advanced oral cavity tumors (T3N0M0). However, a significant proportion of patients do not receive adjuvant radiotherapy. These findings highlight the need for continued efforts to promote guideline-recommended care.

LEVEL OF EVIDENCE

3 Laryngoscope, 134:2236-2242, 2024.

Prognostic DNA mutation and mRNA expression analysis of perineural invasion in oral squamous cell carcinoma

This study analyzed oral squamous cell carcinoma (OSCC) genomes and transcriptomes in relation to perineural invasion (PNI) and prognosis using Cancer Genome Atlas data and validated these results with GSE41613 data. Gene set enrichment analysis (GSEA), gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes were conducted. We identified 22 DNA mutations associated with both overall survival (OS) and PNI. Among them, TGFBR1 and RPS6KA4 mRNAs were overexpressed, while TYRO3 and GPR137 mRNAs were underexpressed in PNI patients. Among the 141 mRNA genes associated with both OS and PNI, we found overlap with PNI-related DNA mutations, including ZNF43, TEX10, TPSD1, and PSD3. In GSE41613 data, TGFBR1, RPS6KA4, TYRO3, GPR137, TEX10 and TPSD1 mRNAs were expressed differently according to the prognosis. The 22 DNA-mutated genes clustered into nervous system development, regulation of DNA-templated transcription, and transforming growth factor beta binding. GSEA analysis of mRNAs revealed upregulation of hallmarks epithelial mesenchymal transition (EMT), TNFα signaling via NF-κB, and IL2 STAT5 signaling. EMT upregulation aligned with the TGFBR1 DNA mutation, supporting its significance in PNI. These findings suggest a potential role of PNI genes in the prognosis of OSCC, providing insights for diagnosis and treatment of OSCC.

Metabolic heterogeneity in cancer

Cancer cells rewire their metabolism to survive during cancer progression. In this context, tumour metabolic heterogeneity arises and develops in response to diverse environmental factors. This metabolic heterogeneity contributes to cancer aggressiveness and impacts therapeutic opportunities. In recent years, technical advances allowed direct characterisation of metabolic heterogeneity in tumours. In addition to the metabolic heterogeneity observed in primary tumours, metabolic heterogeneity temporally evolves along with tumour progression. In this Review, we summarize the mechanisms of environment-induced metabolic heterogeneity. In addition, we discuss how cancer metabolism and the key metabolites and enzymes temporally and functionally evolve during the metastatic cascade and treatment.

Pre-operative incisional biopsy of oral squamous cell carcinoma: high podoplanin expression is related to perineural invasion and may be a useful predictor of disease progression

OBJECTIVE

Immunohistochemical analysis of podoplanin expression as a pre-operative molecular marker for perineural invasion (PNI) may represent an attractive strategy for surgical management of oral squamous cell cancer (OSCC). We evaluated the relationship between podoplanin expression and PNI in pre-operative incisional biopsies of OSCC.

STUDY DESIGN

After performing pathological staging and histologic and immunohistochemical evaluation of 83 surgical specimens, we performed multivariable logistic regression analysis to examine the relationship between PNI and independent variables. To evaluate the utility of podoplanin immunopositivity for discrimination of PNI status pre-operatively, we calculated the sensitivity, specificity, positive predictive value, and negative predictive value. We performed receiver operating characteristic curve analysis to evaluate the diagnostic accuracy of podoplanin immunopositivity for predicting PNI alone and in combination with age, T stage, N stage, and index site.

RESULTS

We observed podoplanin expression in 42 (50.6%) of all the 83 pre-operative incisional biopsies and 29 of the pre-operative biopsies of the 31 (93.5%) postoperative specimens with PNI. The rate of podoplanin expression was significantly higher in patients with pT3 to pT4 stage and pN+ stage disease. Podoplanin positivity in the pre-operative biopsy showed high sensitivity in predicting PNI in the surgical specimen.

CONCLUSION

Podoplanin expression appears to be an independent pre-operative variable significantly related to PNI and a possibly valuable prognostic marker for therapeutical planning and surgical treatment of OSCC.

Evaluation of the prognostic and therapeutic potential of inhibin beta B for oral squamous cell carcinoma

Background/purpose

Oral squamous cell carcinoma (OSCC) is a common cancer worldwide, and its metastasis is difficult to predict and prevent. Inhibin beta B (INHBB) protein has been linked to cancer prognosis and epithelial-mesenchymal transition (EMT). However, previous study about INHBB expression focused on patients in a single region while the risk factors vary among regions. This study aimed to provide a broader perspective on INHBB expression in OSCC.

Materials and methods

Tissue micro-arrays comprising 118 specimens were subjected to immunohistochemistry, and all slides were quantified using StrataQuest software.

Results

The ratio of INHBB-positive cells to total cells was significantly higher in OSCC samples than in normal samples, and the intensity of INHBB expression was significantly greater in the late-stage OSCC. After classifying specimens into high and low INHBB expression groups, a significant association with clinical staging was found. Though a previous study suggested that menin regulates INHBB, menin expression was not detected in specimens.

Conclusion

The ratio of INHBB-positive cells in OSCC may be druggable for targeting tumor cells or assisting in diagnosis, and the intensity of INHBB expression may provide prognostic information for predicting potential metastasis. Moreover, the regulatory mechanism of INHBB in OSCC remains unclear and requires further investigation.

Perineural Invasion Is a Significant Prognostic Factor in Oral Squamous Cell Carcinoma: A Systematic Review and Meta-Analysis

(1) Objectives: This systematic review and meta-analysis aimed to summarize current evidence regarding the prognostic role of perineural invasion (PNI) in patients with oral squamous cell carcinoma (OSCC). (2) Methods: We searched Cochrane Central, ProQuest, PubMed, Scopus, Science Direct, and Web of Science, using relevant keywords to identify eligible articles. Two independent reviewers conducted two-stage screening, data extraction, and quality assessment. The risk of bias was assessed using the Newcastle-Ottawa Scale (NOS) criteria. All analyses were performed using comprehensive meta-analysis (CMA; version 3.3.070) software. (3) Results: The study included 101 published articles encompassing 26,062 patients. The pooled analyses showed that PNI was associated with significantly worse overall survival (OS; HR = 1.45, 95% CI: 1.32-1.58; p < 0.001), worse disease-specific survival (DSS; HR = 1.87, 95% CI: 1.65-2.12; p < 0.001), and worse disease-free survival (DFS; HR = 1.87, 95% CI: 1.65-2.12; p < 0.001). Similarly, both local recurrence-free survival (LRFS) and regional recurrence-free survival (RRFS) were worse in patients with PNI (HR = 2.31, 95% CI: 1.72-3.10, p < 0.001; and HR = 2.04, 95% CI: 1.51-2.74, p < 0.001), respectively. The random-effect estimate of three studies demonstrated that the presence of PNI was associated with worse failure-free survival (FFS; HR = 2.59, 95% CI: 1.12-5.98, p < 0.001). (4) Conclusions: The current evidence suggests that PNI can be used as an independent predictor of the prognosis for patients with OSCC. The presence of PNI was associated with worse OS, DFS, DSS, FFS, and with recurrence. Asian patients and patients with extra-tumoral or peripheral PNI invasion were associated with worse prognosis.

The impact of multifocal perineural invasion in predicting survival in patients with oral squamous cell carcinoma: A multicenter investigation

BACKGROUND

Perineural invasion (PNI) in oral squamous cell carcinoma (OSCC) does not contribute to the current American Joint Committee on Cancer 8th edition (AJCC8) staging manual. This study seeks to validate the effect of multifocal PNI in a large cohort of patients.

METHODS

Patients undergoing primary surgical treatment of OSCC with curative intent between 1995 and 2022 was retrieved from two Australian head and neck databases. PNI was categorized as a single focus or multiple foci. Study end points included disease-specific survival (DSS) and overall survival (OS).

RESULTS

Complete data for survival analysis was available in 993 patients. Multifocal PNI was associated with a 61% increased risk of death due to OSCC (HR 1.61, 95% CI 1.11-2.33, p = 0.014) and a 32% increased risk of death from any cause (HR 1.32, 95% CI 1.01-1.73, p = 0.045).

CONCLUSIONS

Multifocal PNI is a significant predictor of survival in OSCC.

Integrin β1 regulates the perineural invasion and radioresistance of oral squamous carcinoma cells by modulating cancer cell stemness

Perineural invasion and radioresistance are the main determinants of treatment outcomes in oral squamous cell carcinoma (OSCC), but the exact mechanism is still unknown. We conducted an in vitro experiment to evaluate the role of integrin β1 (ITGB1) in the perineural invasion, radioresistance, and tumor aggressiveness of OSCC. Two OSCC cell lines (SCC25, SCC15) and radiation-induced radioresistant OSCC cell lines were used in this study. The expression of ITGB1 was compared between control radiosensitive and radioresistant OSCC cell lines. ITGB1 was inhibited by small hairpin RNA, and then the adhesion to neuronal cells, responsiveness to radiation, and aggressiveness of both OSCC cell lines were evaluated. Expression of ITGB1 and adhesion to neuronal cells were increased in radioresistant OSCC compared with control radiosensitive OSCC, and increased ITGB1 expression was more prominent in cancer stem cell-like cells. When the expression of ITGB1 was inhibited, the adhesion to neuronal cells, resistance to radiation, and invasion and migration of radioresistant OSCC were significantly reduced. Moreover, the expression of cancer stem cell markers and size of spheroid formations were also significantly attenuated by inhibiting ITGB1. These findings suggest that ITGB1 may be a significant contributor to perineural invasion and the maintenance of radioresistance in OSCC cells, and is associated with cancer stem cell-like cells. Furthermore, our results suggest a possible relationship between perineural invasion and radioresistance of OSCC. More detailed research is warranted to evaluate the role of ITGB1 as a novel emerging therapeutic target for radioresistant OSCC.

Perineural Invasion (PNI) Definition, Histopathological Parameters of PNI in Oral Squamous Cell Carcinoma With Molecular Insight and Prognostic Significance

Oral squamous cell carcinoma is associated with severe morbidity, recurrence of tumor, and reduced survival rate despite advances in treatment. Perineural invasion (PNI) is associated with neurotropic malignancy. PNI is due to the tropism of cancer cells toward nerve bundles in tissue. The aim of this literature review is to study the definition, patterns of PNI, Prognostic and therapeutic significance, and mechanism of PNI along with a molecular insight into oral cavity squamous cell carcinoma. Liebig type A pattern defines PNI as the presence of tumor cells within the peripheral nerve sheath & infiltration into the epineurium, perineurium, or endoneurium. Liebig type B pattern defines PNI as a tumor encircling at least 33% of a nerve. Few studies demonstrated an association between PNI and cervical metastasis which indicate poor prognosis. A higher level of expression of nerve growth factor and tyrosine kinase is associated with PNI in OSCC which can be considered as a biomarker of PNI. PNI needs to be studied in detail as it is associated with the aggressiveness of the tumor and decreased survival.

Establishment of a Machine Learning Model for the Risk Assessment of Perineural Invasion in Head and Neck Squamous Cell Carcinoma

Perineural invasion is a prevalent pathological finding in head and neck squamous cell carcinoma and a risk factor for unfavorable survival. An adequate diagnosis of perineural invasion by pathologic examination is limited due to the availability of tumor samples from surgical resection, which can arise in cases of definitive nonsurgical treatment. To address this medical need, we established a random forest prediction model for the risk assessment of perineural invasion, including occult perineural invasion, and characterized distinct cellular and molecular features based on our new and extended classification. RNA sequencing data of head and neck squamous cell carcinoma from The Cancer Genome Atlas were used as a training cohort to identify differentially expressed genes that are associated with perineural invasion. A random forest classification model was established based on these differentially expressed genes and was validated by inspection of H&E-stained whole image slides. Differences in epigenetic regulation and the mutational landscape were detected by an integrative analysis of multiomics data and single-cell RNA-sequencing data were analyzed. We identified a 44-gene expression signature related to perineural invasion and enriched for genes mainly expressed in cancer cells according to single-cell RNA-sequencing data. A machine learning model was trained based on the expression pattern of the 44-gene set with the unique feature to predict occult perineural invasion. This extended classification model enabled a more accurate analysis of alterations in the mutational landscape and epigenetic regulation by DNA methylation as well as quantitative and qualitative differences in the cellular composition in the tumor microenvironment between head and neck squamous cell carcinoma with or without perineural invasion. In conclusion, the newly established model could not only complement histopathologic examination as an additional diagnostic tool but also guide the identification of new drug targets for therapeutic intervention in future clinical trials with head and neck squamous cell carcinoma patients at a higher risk for treatment failure due to perineural invasion.

Oncologic safety of the pedicled submental island flap for reconstruction in oral tongue squamous cell carcinoma: An analysis of 101 cases

OBJECTIVE

To evaluate whether the pedicle submental island flap (SIF) can be safely used in the oral tongue squamous cell carcinoma (OTSCC) patients with pathologically node-positive (pN+) neck, especially pN+ at level I.

METHODS

Retrospectively, 101 OTSCC patients with SIF reconstruction were enrolled. Oncological outcomes included the total locoregional recurrence, the SIF related locoregional recurrence (SRLR) which referred to the local recurrence at flap and ipsilateral neck recurrence at level I, recurrence free survival (RFS), overall survival (OS), and disease specific survival (DSS).

RESULTS

Sixty-one patients were pathologically node-negative (pN0) and 40 were pN+. Thirteen patients experienced locoregional recurrence, of which 5 had a SRLR. The pN+ group had a significantly higher locoregional recurrence rate, lower 5-year RFS, OS and DSS than pN0 group (P < 0.05). Patients with pN0 had a significantly higher neck RFS when compared to those with pN+ either at level I (P = 0.005) or at other levels (P < 0.001). However, the neck RFS was similar between the two subgroups of pN+ (P = 0.550). Especially, patients with pN+ at level I had a significantly higher SRLR rate (P = 0.006) compared to those with pN0 at level I. Multivariate analysis showed that pN+ was an unfavorable factor for tumor recurrence and OS.

CONCLUSION

Our data did not support the use of SIF in OTSCC patients with pN+ neck at level I due to an significantly increased SRLR rate compared to those with pN0 neck at level I.

Pattern and localization of perineural invasion predict poor survival in oral tongue carcinoma

BACKGROUND

Survival rate for oral tongue squamous cell carcinoma (OTSCC) is still poor and, despite Tumor-Node-Metastasis staging system has been recently updated, patients included under the same stage still show difference in prognosis. Perineural invasion (PNI) emerged to be an indicator of tumor aggressive behavior and unfortunate events. In this study, we investigate the clinic and prognostic value of PNI in a cohort of OTSCC patients.

METHODS

About 200 patients with OTSCC were retrospectively evaluated the presence of PNI. PNI was furtherly descripted as uni-/multifocal and as intra-/peritumoral. Disease-Specific and Relapse-Free Survival (DSS; RFS) were estimated; moreover, we included PNI in the current AJCC 8th Staging System, improving the prognostication model.

RESULTS

Perineural invasion was found in 40.5% of patients. Intratumoral PNI predicted patients at high risk of being diagnosed with lymph-node metastasis. Tumors with positive PNI reported a worse DSS (Hazard Ratio=1.878, p-value = 0.008). Moreover, patients exhibiting both multifocal intra- and peritumoral PNI reported poorest DSS (Hazard Ratio = 2.409, p-value = 0.010). Patients were reclassified in a new staging system in case of multifocal PNI, providing better stratification capacity.

CONCLUSIONS

Perineural invasion might serve as an additional prognostic factor in OTSCC, and by integrating PNI in the staging system, further improvements in prognostication might be reached.

Extratumoral invasion: A unique phenomenon of aggressive recurrent oropharyngeal squamous cell carcinoma

BACKGROUND

Oropharyngeal squamous carcinomas cause significant morbidity and mortality. Poor prognosticators include lymphovascular and perineural invasion. Extratumoral phenotypes of these histologic findings confer worse prognoses.

METHODS

We report eight cases of recurrent oropharyngeal cancer with diffuse extratumoral lymphovascular invasion (ELVI) or extratumoral perineural invasion (EPNI) and review the existing literature.

RESULTS

On salvage resection for recurrence following primary radiation or chemoradiation, six patients manifested ELVI and two showed EPNI. These patterns conferred difficulty with complete surgical clearance; final pathologic analysis demonstrated positive margins for all eight patients. The six patients with ELVI were p16+ and the two with EPNI were p16-. Currently, two patients are deceased and six patients are alive at an average follow-up of 17.4 months. Of the six living patients, 2 have a new recurrence and are in hospice while 4 have no evidence of disease.

CONCLUSIONS

ELVI and EPNI have received little consideration in the literature as unique histopathologic features of oropharyngeal squamous carcinoma. We present the first series on these adverse extratumoral features in recurrent disease. We call attention to these unique histologic features in the setting of recurrent oropharyngeal cancer to encourage others to track the results of therapeutic intervention and to identify successful strategies for treatment.

Prognostic significance of the neural invasion in oral squamous cell carcinoma

BACKGROUND

Although nerve involvement can predict recurrence and prognosis in oral squamous cell carcinomas, there still have controversies and limitations regarding the standardization for its detection. In this study, we explore the impact of neural invasion in oral squamous cell carcinomas prognosis, comparing intraneural invasion (tumor cells inside nerve structure) and perineural invasion (cells involving the nerve, but not invading its sheath).

METHODS

Surgical slides stained with hematoxylin and eosin from 235 patients with oral squamous cell carcinomas were carefully verified for the presence of intraneural invasion and perineural invasion. The location in the tumor (intratumoral vs. peritumoral) and number of foci (unifocal or multifocal) were also explored. Survival analyses for cancer-specific survival and disease-free survival were performed with Cox proportional model.

RESULTS

Neural invasion was identified in 74 cases, 64.9% displayed intraneural invasion and 35.1% displayed perineural invasion. Univariate analysis revealed a significantly poorer cancer-specific survival, but not disease-free survival, in patients with intraneural invasion, in contrast to cases with perineural invasion that did not achieve significant association with both cancer-specific survival and disease-free survival. Further analyses revealed that the location in the tumor and number of foci had little impact on discriminatory ability of intraneural invasion. Multivariate analysis confirmed that intraneural invasion is significantly and independently associated with poor cancer-specific survival (hazard ratio: 2.50, 95% CI: 1.31-3.79, p = 0.003).

CONCLUSION

This study provides evidence that intraneural invasion, but not perineural invasion, is a relevant predictor of survival in patients with oral squamous cell carcinomas, suggesting that its association with other clinical and pathological prognostic factors should be consider in determining the optimal treatment protocol and prognosis of these patients.

[Staging cancers of the oral cavity according to the 8th edition of AJCC TNM system: Issues and recommendations]

Stage of cancer at the time of the diagnosis is a key factor for the prognosis and the determination of appropriate treatment. Several cancer staging systems are used worldwide. The most useful staging system is the tumor, node and metastasis (TNM) staging system develop by the American Joint Committee on Cancer (AJCC) in collaboration with the Union for International Cancer Control (UICC) referred to as the AJCC TNM staging system. The AJCC TNM system classifies cancers by the size and extend of the primary tumor (T), involvement of regional lymph nodes (N) and the presence of distant metastases (M). AJCC and UICC periodically modify the AJCC TNM staging system according to newly acquired clinical, pathological and biological data improving understanding of cancer physiopathology. The 8th edition of AJCC TNM system is effective for cancer patients diagnosed on or after January 1, 2018. Here, we report the issues of the staging cancers of the oral cavity according to the 8th edition of AJCC TNM system. We focus on 2 new concepts defined in the 8th edition of AJCC TNM system: depth of invasion (DOI) and extranodal extension (ENE).

Dosimetric Comparison of Intensity-Modulated Radiation Therapy (IMRT) and Intensity-Modulated Proton Therapy (IMPT) for a Novel Oral Tongue Avoidance Concept in Low-Risk Squamous Cell Carcinoma of the Oral Tongue

Purpose

After adequate surgical resection, early-stage oral tongue cancer patients can harbor a low risk of local recurrence but remain at risk of regional recurrence. Oral tongue avoidance during adjuvant radiation therapy is an attractive potential treatment strategy to mitigate treatment toxicity. We sought to quantify the dosimetric advantages of this approach and hypothesized that intensity-modulated proton therapy (IMPT) may further reduce organs at risk doses compared with intensity-modulated radiation therapy (IMRT).

Materials and Methods

Five patients with oral tongue cancer treated with postoperative radiation therapy from August 2020 to September 2021 were retrospectively reviewed. Novel clinical target volume contours, excluding the oral tongue, were generated while maintaining coverage of bilateral at-risk lymph nodes. Comparison IMRT (X) and IMPT (PBT) plans were generated using standard treatment volumes (control) and avoidance volumes (study) (n = 4 plans/patient). Dosimetric variables for organs at risk were compared using the paired t test.

Results

The prescribed dose was 60 Gy in 30 fractions. D95% clinical target volume coverage was similar between X and PBT plans for both control and study clinical target volumes. Comparing control with study plans, both X (58.9 Gy vs 38.3 Gy, P = .007) and PBT (60.2 Gy vs 26.1 Gy, P < .001) decreased the oral cavity dosemean. The pharyngeal constrictor dosemean was also reduced (P < .003). There was no difference between control and study plans for larynx (P = .19), parotid (P = .11), or mandible dose (P = .59). For study plans, PBT significantly reduced oral cavity dosemean (38.3 Gy vs 26.1 Gy, P = .007) and parotid dosemean (23.3 Gy vs 19.3 Gy, P = .03) compared with X. For control plans, there was no difference in oral cavity dosemean using PBT compared with X, but PBT did improve the parotid dosemean (26.6 Gy vs 19.7 Gy, P = .02).

Conclusion

This study quantifies the feasibility and dosimetric advantages of oral tongue avoidance while still treating the at-risk lymph nodes for oral tongue cancer. The dosimetric difference between PBT and X was most prominent with an oral tongue-avoidance strategy.

The 3D's of Neural Phenotypes in Oral Cancer: Distance, Diameter, and Density

Squamous cell carcinoma of the oral cavity (OSCC) is the most common type of head and neck cancer; survival is poor, and response to treatment varies. Metastasis or recurrence in the regional lymph nodes is associated with poor survival. Consequently, overt or occult spread to the lymph nodes is used to identify patients who will receive adjuvant radiation therapy. Perineural invasion and the diameter of nerves exhibiting perineural invasion have also been suggested to be of prognostic significance. The explosion of interest in cancer neuroscience in the last two decades has led to novel biological insights into interactions between nerves and tumor cells. However, the criteria for defining perineural invasion have lagged behind current knowledge. It is important to re-evaluate the concept of perineural invasion and identify other neural phenotypes in OSCC that can impact treatment selection and prognosis. In addition to perineural invasion, neural phenotypes that are of potential relevance to tumor progression include nerve-tumor distance, nerve diameter, and nerve density. This manuscript discusses the translational significance of recent mechanistic studies on the progression of oral cancer.

Subcategorization of Perineural Invasion and Its Impact on Survival in Patients with Oral Squamous Cell Carcinoma

BACKGROUND

Perineural invasion (PNI) is  recognized as a poor prognostic factor in oral squamous cell carcinoma (OSCC). However, the prognostic significance of further histologic  subcategorization of PNI is inconclusive. In this study, we determined the prognostic relevance of histologic subcategories of PNI and their correlation with the presence of other clinical and pathological parameters METHODS: This is a retrospective study of 207 homogeneously treated OSCC patients with histologically documented PNI from a single center. Univariate and multivariate survival outcomes, namely, local recurrence-free survival (LRFS), disease-free survival (DFS), and overall survival (OS) of patients with various subcategories of PNI,namely- number of foci, size of the involved nerve, extratumoral or intratumoral extent, and intraneural or perineural location-were determined.

RESULTS

Within the histologic subcategories of PNI, tongue primary and presence of lymph node metastasis correlated significantly with the number of nerves involved with PNI. Larger size of involved nerve correlated with advanced tumor stage. Number of foci, extent, and location of PNI were not prognostically significant except size of the involved nerve which showed an inverse correlation with disease outcome as involvement of larger nerves displayed better outcomes in terms of DFS and LRFS but not of OS on multivariate analysis. Addition of adjuvant chemotherapy to radiotherapy emerged as a significant predictor of improved LRFS, DFS, and OS.

CONCLUSIONS

Histologic subcategorization of PNI did not have prognostic relevance in our study. Involvement of even small nerves was associated with poor prognosis. Addition of chemoradiation was seen to improve prognosis.

Histopathological prognosticators and their clinicopathological correlation in oral squamous cell carcinomas of the tongue

Background

Tongue carcinomas account for 25%-40% of intraoral squamous cell carcinomas (OSCCs). Although TNM staging systems is an international standard for cancer reporting, prognosis evaluation, and treatment planning, multiple histopathological risk assessment predictors such as tumor thickness (TT), tumor shape, tumor growth pattern, and invasive malignancy grading scoring systems have been studied and should form a basis for prediction and prognostication of such aggressive carcinomas.

Aim

To evaluate and characterize the histomorphological prognostic indicators in OSCCs of tongue and compare it with OSCCs of other anatomic sites within the oral cavity. Furthermore, to elucidate the significance of histopathological indicators in predicting prognosis of tongue squamous cell carcinomas (SCCs).

Materials and Methods

Forty SCC cases with 20 each of tongue and 20 from other intraoral sites were retrieved from department archives. Clinical data and staging were obtained for each case. Histomorphological parameters including pattern of invasion (POI), tumor budding (TB), depth of invasion (DOI), TT, lymphocytic host response, tumor-associated tissue eosinophilia (TATE), vascular invasion, perineural invasion (PNI), and muscular invasion were assessed. The results were statistically evaluated.

Results

TB, DOI, and sarcolemmal spread were significant histologic predictors in tongue SCC. Upon correlation of histomorphological parameters with clinical staging, TT, POI, and TATE were observed to be significantly correlated (P ≤ 0.05).

Conclusion

The histomorphological risk assessment model may serve as important addition to the existing prognosticators and may be used as a prognostic index to help plan and individualize treatment protocol in cases with aggressive high-risk disease for whom the use of multimodality treatment seems beneficial.

Midline involvement and perineural invasion predict contralateral neck metastasis that affects overall and disease-free survival in locally advanced oral tongue squamous cell carcinoma

Introduction

Although patients with oral squamous cell carcinoma who develop contralateral neck metastasis (CLNM) have worse survival outcomes than those without CLNM, accurate prediction of occult CLNM in clinically negative contralateral neck (contralateral cN0) remains difficult. This study aimed to identify clinicopathological factors that could reliably predict CLNM in patients with locally advanced (clinical T3 and T4a) tongue squamous cell carcinoma (TSCC).

Patients and methods

The medical data of 32 patients with cT3–4a TSCC who underwent curative surgery between 2010 and 2017 were retrospectively analyzed. The correlation of clinicopathological variables with CLNM was examined using logistic regression analysis. The diagnostic performance of significant variables was evaluated using the area under the receiver operating characteristic curves (AUC). Overall survival (OS) and disease-free survival (DFS) were assessed using a Cox proportional hazards model.

Results

CLNM was eventually confirmed in 11 patients (34.4%). Multivariate logistic regression showed that midline involvement [odds ratio (OR) = 23.10, P = 0.017] and perineural invasion (PNI, OR = 14.96, P = 0.014) were independent predictors of CLNM. Notably, the prediction model comprising a combination of midline involvement and PNI exhibited superior diagnostic performance with an even higher OR of 80.00 (P &lt; 0.001), accuracy of 90.3%, and AUC of 0.876. The multivariate Cox hazards model revealed independent significance of CLNM as an unfavorable prognostic factor for both OS [hazard ratio (HR) = 5.154, P = 0.031] and DFS (HR = 3.359, P = 0.038), as well as that of PNI for OS (HR = 5.623, P = 0.033).

Conclusion

Our findings suggest that coexisting midline involvement and PNI of the primary tumor is highly predictive of CLNM development, which independently affects both OS and DFS in patients with locally advanced TSCC. Such reliable prediction enables efficient control of CLNM by optimizing management of the contralateral cN0 neck, which will likely contribute to improved prognosis of those patients without unnecessarily compromising their quality of life.

A domain knowledge enhanced yield based deep learning classifier identifies perineural invasion in oral cavity squamous cell carcinoma

BACKGROUND

Perineural invasion (PNI), a form of local invasion defined as the ability of cancer cells to invade in, around, and through nerves, has a negative prognostic impact in oral cavity squamous cell carcinoma (OCSCC). Unfortunately, the diagnosis of PNI suffers from a significant degree of intra- and interobserver variability. The aim of this pilot study was to develop a deep learning-based human-enhanced tool, termed domain knowledge enhanced yield (Domain-KEY) algorithm, for identifying PNI in digital slides.

METHODS

Hematoxylin and eosin (H&E)-stained whole-slide images (WSIs, n = 85) were obtained from 80 patients with OCSCC. The model structure consisted of two parts to simulate human decision-making skills in diagnostic pathology. To this aim, two semantic segmentation models were constructed (i.e., identification of nerve fibers followed by the diagnosis of PNI). The inferred results were subsequently subjected to post-processing of generated decision rules for diagnostic labeling. Ten H&E-stained WSIs not previously used in the study were read and labeled by the Domain-KEY algorithm. Thereafter, labeling correctness was visually inspected by two independent pathologists.

RESULTS

The Domain-KEY algorithm was found to outperform the ResnetV2_50 classifier for the detection of PNI (diagnostic accuracy: 89.01% and 61.94%, respectively). On analyzing WSIs, the algorithm achieved a mean diagnostic accuracy as high as 97.50% versus traditional pathology. The observed accuracy in a validation dataset of 25 WSIs obtained from seven patients with oropharyngeal (cancer of the tongue base, n = 1; tonsil cancer, n = 1; soft palate cancer, n = 1) and hypopharyngeal (cancer of posterior wall, n = 2; pyriform sinus cancer, n = 2) malignancies was 96%. Notably, the algorithm was successfully applied in the analysis of WSIs to shorten the time required to reach a diagnosis. The addition of the hybrid intelligence model decreased the mean time required to reach a diagnosis by 15.0% and 23.7% for the first and second pathologists, respectively. On analyzing digital slides, the tool was effective in supporting human diagnostic thinking.

CONCLUSIONS

The Domain-KEY algorithm successfully mimicked human decision-making skills and supported expert pathologists in the routine diagnosis of PNI.

Spatial and Transcriptomic Analysis of Perineural Invasion in Oral Cancer

PURPOSE

Perineural invasion (PNI), a common occurrence in oral squamous cell carcinomas, is associated with poor survival. Consequently, these tumors are treated aggressively. However, diagnostic criteria of PNI vary and its role as an independent predictor of prognosis has not been established. To address these knowledge gaps, we investigated spatial and transcriptomic profiles of PNI-positive and PNI-negative nerves.

EXPERIMENTAL DESIGN

Tissue sections from 142 patients were stained with S100 and cytokeratin antibodies. Nerves were identified in two distinct areas: tumor bulk and margin. Nerve diameter and nerve-to-tumor distance were assessed; survival analyses were performed. Spatial transcriptomic analysis of nerves at varying distances from tumor was performed with NanoString GeoMx Digital Spatial Profiler Transcriptomic Atlas.

RESULTS

PNI is an independent predictor of poor prognosis among patients with metastasis-free lymph nodes. Patients with close nerve-tumor distance have poor outcomes even if diagnosed as PNI negative using current criteria. Patients with large nerve(s) in the tumor bulk survive poorly, suggesting that even PNI-negative nerves facilitate tumor progression. Diagnostic criteria were supported by spatial transcriptomic analyses of >18,000 genes; nerves in proximity to cancer exhibit stress and growth response changes that diminish with increasing nerve-tumor distance. These findings were validated in vitro and in human tissue.

CONCLUSIONS

This is the first study in human cancer with high-throughput gene expression analysis in nerves with striking correlations between transcriptomic profile and clinical outcomes. Our work illuminates nerve-cancer interactions suggesting that cancer-induced injury modulates neuritogenesis, and supports reclassification of PNI based on nerve-tumor distance rather than current subjective criteria.

Targeting tumor innervation: premises, promises, and challenges

A high intratumoral nerve density is correlated with poor survival, high metastasis, and high recurrence across multiple solid tumor types. Recent research has revealed that cancer cells release diverse neurotrophic factors and exosomes to promote tumor innervation, in addition, infiltrating nerves can also mediate multiple tumor biological processes via exosomes and neurotransmitters. In this review, through seminal studies establishing tumor innervation, we discuss the communication between peripheral nerves and tumor cells in the tumor microenvironment (TME), and revealed the nerve-tumor regulation mechanisms on oncogenic process, angiogenesis, lymphangiogenesis, and immunity. Finally, we discussed the promising directions of ‘old drugs newly used’ to target TME communication and clarified a new line to prevent tumor malignant capacity.

Prognostic impact of perineural invasion in oral cancer: a systematic review

Introduction

Numerous studies have evaluated the prognostic significance of perineural invasion (PNI) in oral cancer; however, the results are inconclusive.

Purpose

To identify the prognostic value of PNI in oral cancer through a metanalysis.

Methods

A literature review was carried out, searching the MedLine databases via Pubmed, Scielo, Lilacs, Cochrane and Websco.

Results

A total of 56 studies were included. The results indicate that PNI in oral cancer has an incidence of 28% (95% confidence interval (CI) 24-31%); 5-year survival with relative risk (RR) 0.67 (0.59-0.75); 5-year disease-free survival RR 0.71 (0.68-0.75); locoregional recurrence with RR 2.09 (1.86-2.35).

Conclusions

PNI is a negative prognostic factor in oral cancer.

Phytochemically Derived Zingerone Nanoparticles Inhibit Cell Proliferation, Invasion and Metastasis in Human Oral Squamous Cell Carcinoma

Due to its aggressiveness and high mortality rate, oral cancer still represents a tough challenge for current cancer therapeutics. Similar to other carcinomas, cancerous invasion and metastasis are the most important prognostic factors and the main obstacles to therapy for human oral squamous cell carcinoma (OSCC). Fortunately, with the rise of the nanotechnical era and innovative nanomaterial fabrication, nanomaterials are widely used in biomedicine, cancer therapeutics, and chemoprevention. Recently, phytochemical substances have attracted increasing interest as adjuvants to conventional cancer therapy. The ginger phenolic compound zingerone, a multitarget pharmacological and bioactive phytochemical, possesses potent anti-inflammatory, antioxidant, and anticancer activities. In our previous study, we generated phytochemically derived zingerone nanoparticles (NPs), and documented their superior antitumorigenic effect on human hepatoma cells. In the present study, we further investigated the effects of zingerone NPs on inhibiting the invasiveness and metastasis of human OSCC cell lines. Zingerone NPs elicited significant cytotoxicity in three OSCC cell lines compared to zingerone. Moreover, the lower dose of zingerone NPs (25 µM) markedly inhibited colony formation and colony survival by at least five-fold compared to zingerone treatment. Additionally, zingerone NPs significantly attenuated cell motility and invasiveness. In terms of the signaling mechanism, we determined that the zingerone NP-mediated downregulation of Akt signaling played an important role in the inhibition of cell viability and cell motility. Zingerone NPs inhibited matrix metalloproteinase (MMP) activity, which was highly correlated with the attenuation of cell migration and cell invasion. By further detecting the roles of zingerone NPs in epithelial–mesenchymal transition (EMT), we observed that zingerone NPs substantially altered the levels of EMT-related markers by decreasing the levels of the mesenchymal markers, N-cadherin and vimentin, rather than the epithelial proteins, ZO-1 and E-cadherin, compared with zingerone. In conclusion, as novel and efficient phytochemically derived nanoparticles, zingerone NPs may serve as a potent adjuvant to protect against cell invasion and metastasis, which will provide a beneficial strategy for future applications in chemoprevention and conventional therapeutics in OSCC treatment.

Distant metastasis in oral squamous cell carcinoma: Does the neutrophil-to-lymphocyte ratio act as a surrogate of the host immune status?

OBJECTIVES

Distant metastasis (DM) is an important prognostic factor for oral squamous cell carcinoma (OSCC). The aim of this study is to evaluate the influence of host and tumor factors in development of DM.

MATERIALS AND METHODS

After IRB approval, 1369 patients with OSCC undergoing primary surgery were eligible for the study. The primary endpoint was the development of distant metastasis (DM). Patients were pathologically staged according to the American Joint Committee on Cancer, 8th Edition. Pre-operative peripheral blood counts were used to calculate neutrophil-to-lymphocyte ratio (NLR).

RESULTS

Median follow-up was 39 months (range 1-221). DM were identified in 126 patients during follow-up. When analyzed as a time-dependent covariate, neck recurrence (NR) was a significant predictor of DM (HR 16.35, 95% CI: 11.39-23.47, p < 0.001). NLR, margin status, vascular invasion, perineural invasion (PNI), grade, pT, number of metastatic lymph nodes, level IV involvement, and extra nodal-extension (ENE) were also significant. In multivariable analysis, NLR, margins, PNI, number of metastatic lymph nodes, and ENE maintained independent predictive capacity. Patients with NLR ≥ 5.7 were 3 times more likely to develop DM compared to NLR ≤ 2.9 (95% CI: 1.74-5.59, p < 0.001), patients with ≥ 5 metastatic lymph nodes were 2 times more likely to develop DM (95% CI: 1.18-3.60, p = 0.011), and those with ENE were 4 times more likely (95% CI: 2.67-8.20, p < 0.001) when compared to pNx/pN0 patients.

CONCLUSIONS

NLR, number of metastatic lymph nodes, and ENE were the strongest independent predictors of DM in OSCC treated with primary surgery and appropriate adjuvant therapy.

Indication to postoperative radiotherapy for oral cavity squamous cell carcinoma: what’s new in the Depth of Infiltration (DOI) era?

Objectives:

The last edition of the American Joint Committee on Cancer (AJCC eighth) has introduced the depth of infiltration (DOI) as a new prognostic parameter in oral cavity squamous cell carcinomas (OCSCCs). Aim of this study is to analyze the impact of stage migration on the indication to postoperative radiotherapy (PORT).

Methods:

OCSCCs treated at two Institutions between 2014 and 2019 were retrieved. Per the AJCC eighth, only pT3 primarily OCSCCs were considered; availability of the pathologic specimen was a further inclusion criterion. Risk factors considered for PORT were: pT3-pT4, nodal involvement, positive/close surgical margins, perineural and lymph vascular invasion.

Results:

One-hundred forty-nine patients staged as pT3 AJCC eighth were included. A four-fold increase in the number of patients staged as pT3 from the seventh to the eighth AJCC was found. Stage migration to pT3 was equally due to the downstaging from former pT4 (38%) and upstaging of former pT1-pT2 (35%). Considering the former pT1-pT2 53 patients, 13 (25%) had no risk factors for PORT other than DOI. Among 25 cases with former pT1-pT2 and negative lymph nodes no additional risk factors were found in 11 (44%).

Conclusion:

Ninety percent of patients had at least one risk factor besides DOI and would have received PORT also according to the AJCC seventh; notably, of former pT1-pT2N0, half of them have been upstaged to pT3 in the current TNM classification. The role of PORT in this cohort of patients has not been clarified yet.

Advances in knowledge:

Other-than-DOI risk factors leading to PORT indication are highly prevalent in OCSSC patients classified as pT3 per the latest AJCC TNM staging system and should therefore be considered for a comprehensive oncological assessment.

The Impact of Histopathological Features on the Prognosis of Oral Squamous Cell Carcinoma: A Comprehensive Review and Meta-Analysis

OBJECTIVE

Over many decades, studies on histopathological features have not only presented high-level evidence of contribution for treatment directions and prognosis of oral squamous cell carcinoma (OSCC) but also provided inconsistencies, making clinical application difficult. The 8th TNM staging system of OSCC has acknowledged the importance of some histopathological features, by incorporating depth of invasion (DOI) to T category and extranodal extension (ENE) to N category. The aim of this systematic review with meta-analysis is to determine the most clinically relevant histopathological features for risk assessment and treatment planning of OSCC and to elucidate gaps in the literature.

METHODS

A systematic review was conducted using PRISMA guidelines, and the eligibility criteria were based on population, exposure, comparison, outcome, and study type (PECOS). PubMed, Cochrane, Scopus, and Web of Science were searched for articles exploring the impact of histopathological features on OSCC outcomes with Cox multivariate analysis. Pooled data were subjected to an inverse variance method with random effects or fixed effect model, and the risk of bias was evaluated using quality in prognosis studies (QUIPS). Quality of evidence was assessed with the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) criteria.

RESULTS

The study included 172 articles published from 1999 to 2021. Meta-analyses confirmed the prognostic potential of DOI, ENE, perineural invasion, lymphovascular invasion, and involvement of the surgical margins and brought promising results for the association of bone invasion, tumor thickness, and pattern of invasion with increased risk for poor survival. Although with a small number of studies, the results also revealed a clinical significance of tumor budding and tumor-stroma ratio on predicted survival of patients with OSCC. Most of the studies were considered with low or moderate risk of bias, and the certainty in evidence varied from very low to high.

CONCLUSION

Our results confirm the potential prognostic usefulness of many histopathological features and highlight the promising results of others; however, further studies are advised to apply consistent designs, filling in the literature gaps to the pertinence of histopathological markers for OSCC prognosis.

SYSTEMATIC REVIEW REGISTRATION

International Prospective Register of Systematic Reviews (PROSPERO), identifier CRD42020219630.

Perineural invasion/lymphovascular invasion double positive predicts distant metastasis and poor survival in T3-4 oral squamous cell carcinoma

Postoperative adjuvant therapy has been indicated by advanced T classification for T3–4 oral squamous cell carcinoma (OSCC) and the significance of perineural invasion (PNI) and lymphovascular invasion (LVI) in treatment for T3–4 OSCC remains unclear. Ninety-eight cumulative patients with T3–4 OSCC who underwent curative surgery between Jan 2002 and Dec 2010 were recruited and analyzed. Twenty-seven (27.6%) patients were PNI/LVI double positive. PNI/LVI double positive demonstrated independent predictive values for higher neck metastasis (LN+), higher distant metastasis (DM) and low 5-year disease-specific survival (DSS) rates (p < 0.001, p = 0.017, and p < 0.001, respectively) after controlling for other pathologic features of the primary tumors. A high DM rate of 33.3% was noted in PNI/LVI double-positive patients. Among the PNI/LVI double negative, single positive to double positive subgroups, increasing LN+, DM rates and decreasing DSS rate were observed. Among the 44 LN+ patients, PNI/LVI double positive remained associated with a markedly high DM rate of 42.9% and a poor 5-year DSS of 27.7%. PNI/LVI double positive plays important roles in prognostication and potential clinical application for T3–4 OSCC by independently predicting LN+, DM, and poor DSS, and can be used as a good marker to select DM high-risk patients for novel adjuvant therapy trials.

Nerve density in cancer: Less is better

The density of nerves in cancer is emerging as a relevant clinical parameter for patient survival. Nerves in the tumor microenvironment have been associated with poor survival and recurrence, particularly if involved in perineural invasion. However, usually only a few nerves inside a tumor are affected by perineural invasion, while most nerves are not. Mechanistic studies have shown nerve-secreted factors promote tumor growth and invasion thereby making tumors more aggressive. Therefore, the overall number of nerves in the tumor microenvironment should be more representative of the nerve-tumor biological interaction than perineural invasion. This review summarizes the available clinical information about nerve density as a measure of clinical outcome in cancer and explores the mechanisms underlying nerve density in cancer, specifically, neurogenesis, axonogenesis, and neurotropism.

The Impact of Post-Operative Radiotherapy in Early Stage (pT1-pT2N0M0) Oral Tongue Squamous Cell Carcinoma in Era of DOI

Simple Summary

The aim of the present study was to clarify the role of depth of infiltration (DOI) as an independent prognosticator in early stage (T1-T2N0M0) oral cavity tumors. Moreover, whether patients upstaged to pT3 for DOI > 10 mm need postoperative radiotherapy (PORT) in the absence of other risk factors has not been established yet. The DOI alone was not sufficient to impact the prognosis and therefore other risk factors should be considered to indicate PORT indications in upstaged patients due to DOI > 10 mm.

Abstract

Background: This study investigated the role of depth of infiltration (DOI) as an independent prognosticator in early stage (T1-T2N0M0) oral cavity tumors and to evaluate the need of postoperative radiotherapy in the case of patients upstaged to pT3 for DOI > 10 mm in the absence of other risk factors. Methods: We performed a retrospective analysis on patients treated with surgery and re-staged according to the 8th edition of malignant tumors classification (TNM). The role of DOI as well as other clinical/pathological features was investigated at both univariable and multivariable analyses on overall survival (OS), disease free survival (DFS), relapse free survival (RFS), and local RFS. Results: Among the 94 included patients, 23 would have been upstaged to pT3 based on DOI. Multivariable analysis showed that DOI was not an independent prognostic factor for any of the considered outcomes. The presence of perineural invasion was associated with a significant worse RFS (p = 0.02) and LRFS (p = 0.04). PORT was found to be significantly associated with DFS (p = 0.04) and RFS (p = 0.06). Conclusions: The increasing DOI alone was not sufficient to impact the prognosis, and therefore, should not be sufficient to dictate PORT indications in early-stage patients upstaged on the sole basis of DOI.

Adrenergic Blockade by Nebivolol to Suppress Oral Squamous Cell Carcinoma Growth via Endoplasmic Reticulum Stress and Mitochondria Dysfunction

Adrenergic nerve fibers in the tumor microenvironment promote tumor growth and represent a potential target for cancer therapy. However, the effectiveness of targeting adrenergic nerve fibers for oral squamous cell carcinoma (OSCC) therapy needs to be evaluated by preclinical data. Herein, the 4NQO-induced and orthotopic xenograft OSCC mice models were established. We demonstrated that using 6OHDA chemical denervation as well as using nebivolol adrenergic blockade could halt the oral mucosa carcinogenesis. Our preclinical studies suggested that nebivolol, which is widely used to treat cardiovascular diseases, can be repositioned as a potential candidate to treat OSCC. Remarkably, we revealed the precise effect and mechanism of nebivolol on OSCC cells proliferation, cell cycle, and cell death. Administration of nebivolol could activate the endoplasmic reticulum (ER) stress signaling pathway through increasing the expression of inducible nitric oxide synthase, which subsequently triggers the integrated stress response and cell growth arrest. Simultaneously, ER stress also induced mitochondrial dysfunction in OSCC cells. We found that the accumulation of dysfunctional mitochondria with the impaired electron transport chain caused increasing reactive oxygen species production, which ultimately resulted in OSCC cell death. Altogether, our finding suggested a novel therapeutic opportunity for OSCC by targeting adrenergic nerve fibers, and repurposing nebivolol to treat OSCC can be represented as an effective strategy.

Prognostic Value of Perineural Invasion in Oral Tongue Squamous Cell Carcinoma: A Systematic Review and Meta-Analysis

OBJECTIVES

A significant number of recently published research has outlined the contribution of perineural invasion (PNI) to clinical outcomes in oral tongue squamous cell carcinoma (OTSCC), but some results remain conflicting. This study aimed to determine whether patients with OTSCC with PNI have a worse prognosis than those without PNI.

MATERIALS AND METHODS

PubMed, Embase, and the Cochrane Library were queried for potentially eligible articles published up to December 2020. The primary outcomes were the hazard ratio (HR) for locoregional recurrence, overall survival (OS), disease-free survival (DFS), and cancer-specific survival (CSS). The random-effect model was used in all analyses.

RESULTS

Seventeen studies (4445 patients) were included. Using adjusted HRs, the presence of PNI was associated with a higher risk of locoregional recurrence (HR=1.73, 95%CI: 1.07-2.79, P=0.025, I2 = 33.1%, Pheterogeneity=0.224), worse OS (HR=1.94, 95%CI: 1.39-2.72, P<0.001, I2 = 0.0%, Pheterogeneity=0.838), worse DFS (HR=2.13, 95%CI: 1.53-2.96, P<0.001, I2 = 48.4%, Pheterogeneity=0.071), and worse CSS (HR=1.93, 95%CI: 1.40-2.65, P<0.001, I2 = 25.5%, Pheterogeneity=0.251). PNI had an impact on locoregional recurrence in early-stage OTSCC but not in all stages, and on OS, DFS, and CSS in all-stage and early-stage OTSCC. The sensitivity analyses showed that the results were robust.

CONCLUSION

The presence of PNI significantly affects the locoregional recurrence and survival outcomes among patients with OTSCC.

3D Bioprinting for In Vitro Models of Oral Cancer: Toward Development and Validation

The tumor microenvironment (TME) of oral carcinomas has highly complex contents and a dynamic nature which is difficult to study using oversimplified two-dimensional (2D) cell culture systems. By contrast, three dimensional (3D) in vitro models such as spheroids, organoids, and scaffold-based constructs have been able to replicate tumors three-dimensionality and have allowed a better understanding of the role of various microenvironmental cues in the initiation and progression of cancer. However, the heterogeneity of TME cannot be fully reproduced by these traditional tissue engineering strategies since they are unable to control the organization of multiple cell types in a complex architecture. 3D bioprinting is an emerging field that can be leveraged to produce biomimetic and complex tissue structures. Bioprinting allows for controllable and precise placement of multicomponent bioinks composed of multiple biomaterials, different types of cells, and soluble factors according to the natural compartments of the target tissue, aiming to reproduce the equivalent of the complex tissue. As such, 3D bioprinting provides a unique opportunity to fabricate in vitro tumor models with a complexity similar to that of the in vivo oral carcinoma. This will facilitate a thorough investigation of cellular physiology, cancer progression, and anti-cancer drug screening with unprecedented control and reproducibility. In this review, we discuss the role of 3D bioprinting in reconstituting oral cancer, the prospects of application to fill the literature gap, and the challenges that need to be addressed in order to exploit this emerging technology for future work in oral cancer research.

A New Nomogram for Predicting Overall Survival and Assisting Postoperative Adjuvant Treatment Decision-Making in Stage II Oral Tongue Squamous Cell Carcinoma: A Surveillance, Epidemiology and End Results (SEER) Database Analysis

PURPOSE

The survival benefit of postoperative adjuvant treatment (POAT) for stage II oral tongue squamous cell carcinoma (OTSCC) remains controversial. This large SEER-based study aims to establish a prognostic nomogram to visualize the overall survival of these patients and to aid in POAT decision making.

PATIENTS AND METHODS

The cut-off points of age at diagnosis and examined lymph node number (ELN) were determined using the population-based data from the SEER database. Univariate and multivariate Cox hazards regression models were utilized to identify prognostic factors that were integrated into the establishment of the prognostic nomogram. Patients with stage II OTSCC were then stratified into 3 cohorts based on this nomogram. The survival benefit of POAT was evaluated in these cohorts.

RESULTS

Age at diagnosis (with cutoff points of 50 and 75 years) and ELN (with cutoff points of 0 and 22) was significantly associated with the survival outcomes in patients with stage II OTSCC. After the multivariate analysis, 4 factors, including age at diagnosis, sex, ELN, and differentiation grade, were identified as independent prognostic factors. Additionally, a prognostic nomogram with these factors was constructed to predict overall survival and to stratify these patients. Only patients in the high-risk cohort could significantly benefit from postoperative adjuvant treatment.

CONCLUSIONS

This prognostic nomogram could accurately predict the overall survival of stage II OTSCC patients after curative surgery. Notably, this model could also assist the decision-making of postoperative adjuvant treatment for patients with stage II OTSCC.

Cancer-Associated Neurogenesis and Nerve-Cancer Cross-talk

In this review, we highlight recent discoveries regarding mechanisms contributing to nerve-cancer cross-talk and the effects of nerve-cancer cross-talk on tumor progression and dissemination. High intratumoral nerve density correlates with poor prognosis and high recurrence across multiple solid tumor types. Recent research has shown that cancer cells express neurotrophic markers such as nerve growth factor, brain-derived neurotrophic factor, and glial cell-derived neurotrophic factor and release axon-guidance molecules such as ephrin B1 to promote axonogenesis. Tumor cells recruit new neural progenitors to the tumor milieu and facilitate their maturation into adrenergic infiltrating nerves. Tumors also rewire established nerves to adrenergic phenotypes via exosome-induced neural reprogramming by p53-deficient tumors. In turn, infiltrating sympathetic nerves facilitate cancer progression. Intratumoral adrenergic nerves release noradrenaline to stimulate angiogenesis via VEGF signaling and enhance the rate of tumor growth. Intratumoral parasympathetic nerves may have a dichotomous role in cancer progression and may induce Wnt-β-catenin signals that expand cancer stem cells. Importantly, infiltrating nerves not only influence the tumor cells themselves but also impact other cells of the tumor stroma. This leads to enhanced sympathetic signaling and glucocorticoid production, which influences neutrophil and macrophage differentiation, lymphocyte phenotype, and potentially lymphocyte function. Although much remains unexplored within this field, fundamental discoveries underscore the importance of nerve-cancer cross-talk to tumor progression and may provide the foundation for developing effective targets for the inhibition of tumor-induced neurogenesis and tumor progression.

Prognostic outcomes of treatment naïve oral tongue squamous cell carcinoma (OTSCC): a comprehensive analysis of 14 years

OBJECTIVES

To analyze the factors predicting survival outcomes in treatment naïve oral tongue squamous cell carcinoma (OTSCC).

MATERIALS AND METHODS

A comprehensive review of 531 oral tongue carcinoma patients treated with upfront surgery followed by adjuvant radiotherapy or chemoradiotherapy was conducted from 2004-2018.

RESULTS

The mean age of presentation was 53 years (11-86) with a male to female ratio of 1.3:1. The associated risk factors were smoking (21%), betel nut (16%), naswar (9%) and alcohol (1%). Most of the cases were either well (45.1%) or moderately (46.2%) differentiated. Surgery was performed in 164 patients alone while 368 were treated with surgery in combination with adjuvant modalities. Overall (OS) and disease free survival (DFS) were 66 and 71%, respectively, with a median follow up of 2.5 years. Cox regression analysis showed nodal positivity, increased depth of invasion (DOI) and higher lymph node ratio (LNR) as significant prognosticators impacting OS and DSS.

CONCLUSION

Nodal volume, DOI and LNR are the most consistent predictors of poor outcome in OTSCC. Nodal positivity, depth of invasion > 5 mm and lymph node ratio > 0.04 adversely affect OS and DSS.

A retrospective investigation of minor risk factors as prognostic predictors and treatment indications in oral squamous cell carcinoma

Abstract

Background/purpose

The clinical significance of minor risk factors remins uncertain in oral squamous cell carcinoma (OSCC) patients. The purpose of this study was to investigate the clinical impact of minor risk factors in OSCC patients.

Materials and methods

The cases of OSCC patients that underwent surgery were retrospectively analyzed. Patients with major risk factors for recurrence, such as positive surgical margins or extracapsular spread, were excluded. The impact of possible minor risk factors on treatment outcomes was analyzed. One hundred and seventy-five patients with primary OSCC that underwent surgery were included in this study.

Results

The 5-year overall survival (OS), cancer-specific survival (CSS), and relapse-free survival (RFS) rates were 81.2%, 91.0%, and 72.4%, respectively. In multivariate analyses, RFS exhibited a significant association with the pattern of invasion (grade 4 vs. grades 1–3: hazard ratio: 3.096, 95% confidence interval: 1.367–6.884, p < 0.01), OS exhibited a tendency towards associations with the pattern of invasion and perineural invasion, and CSS displayed a tendency towards an association with perineural invasion. The prognosis of the patients with ≥2 minor risk factors was significantly worse than that of the patients with 0 or 1 minor risk factor(s) (OS: 91.6% vs. 64.5%, respectively, p < 0.01; CSS: 98.9% vs. 78.9%, respectively, p < 0.001; and RFS: 81.2% vs. 58.5%, respectively p < 0.05).

Conclusion

Grade 4 invasion and perineural invasion might be significant minor risk factors in OSCC patients. The presence of ≥2 minor risk factors might be a predictor of a poor prognosis in OSCC patients.

Is Perineural Invasion a Reasonable Indicator for Neck Dissection in cT1N0M0 Squamous Cell Carcinoma of the Oral Cavity?

PURPOSE

Perineural invasion (PNI) is considered an adverse histological feature in oral squamous cell carcinoma (OSCC). Controversy exists regarding elective neck dissection (END) in cT1N0M0 OSCC with PNI as the only risk factor. The purpose of this study was to evaluate PNI as an indicator for END, as well as its utility when combined with the depth of invasion (DOI) as a second indicator.

PATIENTS AND METHODS

cT1N0M0 (AJCC8) OSCC patients treated from August 1998 to July 2017 in the Department of Oral and Maxillofacial Surgery, University of Michigan (MI), and Beijing Stomatological Hospital, Capital Medical University (BSH) were reviewed. Data from these sites included both prospectively captured data housed in a database and retrospective data.

RESULTS

283 cT1N0M0 OSCC patients were analyzed. The tongue was the most common subsite (56.2%). Ninety-nine (99) patients received END and 184 neck observation. PNI was found in only 8 patients (2.83%) all in the tongue or inferior gingiva. END was performed in 7 of the PNI patients. The mean depth of invasion for tumors with PNI was 3.97 mm, compared to 2.54 mm in tumors without PNI. PNI was statistically correlated with nodal disease (pN+) and extranodal extension (ENE+). After using DOI as a primary indicator for END, no additional PNI patients benefited from END. In addition, only 2 patients had PNI identified preoperatively both with 5 mm DOI, and therefore, already indicated for END on the basis of DOI status.

CONCLUSIONS

PNI status is statistically correlated with pN+ and ENE + pathology in cT1N0M0 OSCC. After using DOI as a primary indicator for END, PNI status had no added value in decision making. Even surgeons who do not use DOI will find very limited value in PNI status with less than 1% preoperative prevalence (0.71%) in this patient population.

Oral Potentially Malignant Disorders and Oral Cavity Cancer

The Surveillance, Epidemiology, and End Results program from the National Cancer Institute reports that the aggregate number of oral cavity and pharyngeal cancer cases has been increasing over the past decade and, despite an overall decline in oral cavity cancers, this increase is largely related to a dramatic increase in cancers involving oropharyngeal subsites. Early detection of oral cavity cancers is commensurate with improved survival, and opportunistic screening by trained clinicians to detect oral cavity cancer and oral potentially malignant disorders is recommended by the American Dental Association and the American Academy of Oral Medicine.

The contralateral based submental island flap for reconstruction of tongue and floor of mouth defects: Reliability and oncological outcome

BACKGROUND

Submental artery island flap (SIF) is a viable alternative to free flaps for selected oral-cavity defects, however, concerns about its oncologic safety still exists. A novel harvesting technique and its outcome is described in here.

METHODS

This is a prospective study for patients with lateralized oral tongue and/or floor of mouth (FOM) cancers who undergone reconstruction using pedicled SIF based on contralateral submental vessels (CSIF) following resection.

RESULTS

Forty-one patients were included. Twenty-four patients had T2, 13 had T3, and 4 had T1 tumors. The largest flap skin paddle was 15 × 9 cm. One patient sustained complete and five sustained partial flap loss. Three patients developed tongue tethering. Median follow-up was 13.6 months. Locoregional recurrence occurred in 11 patients (26.8%); 6 oral-cavity recurrences (14.6%), 6 ipsilateral, and 1 contralateral neck recurrences (2.4%).

CONCLUSION

CSIF is a reliable flap that addresses the oncologic controversy and overcomes the disadvantages of ipsilateral flap.

Neural invasion: a scenic trail for the nervous tumor and hidden therapeutic opportunity

Neural invasion (NI) is the invasion of cancer cells into nerves, influencing the pathological characteristics of malignant tumors. NI promotes metastasis and is associated with reduced survival of affected patients. Although known for decades, its prognostic and therapeutic implications have not been not much appreciated due to the scattered information available on its clinical complications. The use of multiple nomenclatures to describe NI also generated confusions among researchers to understand this pathological process. Here, we discuss the multiple classifications of NI and review its clinical complications. Recent findings of the regulatory roles of nerves on tumor growth have fuelled research in this field, and there has been several attempts to molecularly define the NI interface and the cancer cells involved. Therefore, in this review, we discuss the large datasets available to characterize the cancer cells in NI and also discuss the roles of Schwann cells and macrophages participating in NI.

Perineural invasion in oral squamous cell carcinoma: Incidence, prognostic impact and molecular insight

BACKGROUND

The objective of this study was to characterise the incidence and prognostic correlation of perineural invasion (PNI) in oral squamous cell carcinoma and determine whether nerve growth factor and its receptor tyrosine Kinase A expression could be used as biological markers for PNI.

METHODS

A retrospective review of pathology reports of 430 patients with oral squamous cell carcinoma who were treated from 1992 to 2014 in Tayside, Scotland, was carried out. The expression of nerve growth factor and tyrosine kinase A was assessed with immunohistochemistry in 132 tissue sections of oral squamous cell carcinoma.

RESULTS

Perineural invasion was identified in 17.4% of oral squamous cell carcinomas. High expression of nerve growth factor and tyrosine kinase A was seen in 84% and 92% of oral squamous cell carcinoma, respectively. Tumours with PNI expressed nerve growth factor and tyrosine kinase A with a greater frequency than tumours without PNI. PNI and high expression of nerve growth factor were significantly associated with pain. PNI was significantly associated with stage IV tumours and poor disease-specific survival.

CONCLUSIONS

A higher level of expression of nerve growth factor and tyrosine kinase A may predict PNI and therefore may be considered as biological markers for PNI in oral squamous cell carcinoma. PNI and nerve growth factor overexpression may contribute to the pain generation in oral cancer patients. PNI and nerve growth factor expression can predict the aggressiveness and prognosis of oral squamous cell carcinoma patients.

Management of early oral cavity squamous cancers

Early oral cavity cancers comprise a favorable entity, amenable to clinical staging and single modality treatment. Surgery typically forms the mainstay of treatment and should ideally address both the primary and the neck in all cases. Careful attention must be paid to reconstruction and rehabilitation of such patients. Radical radiotherapy mainly in the form of brachytherapy can achieve excellent disease related and functional outcomes in a carefully chosen subset of patients. Increasingly, a subset of patients is being recognized, who harbor single or multiple adverse features on histopathology and may therefore benefit from escalation of adjuvant therapy. This review discusses the management of early oral cavity squamous carcinomas (Early OSCCs) in detail and highlights the dilemmas and controversies faced in the management of the same.

Nerves in cancer

The contribution of nerves to the pathogenesis of malignancies has emerged as an important component of the tumour microenvironment. Recent studies have shown that peripheral nerves (sympathetic, parasympathetic and sensory) interact with tumour and stromal cells to promote the initiation and progression of a variety of solid and haematological malignancies. Furthermore, new evidence suggests that cancers may reactivate nerve-dependent developmental and regenerative processes to promote their growth and survival. Here we review emerging concepts and discuss the therapeutic implications of manipulating nerves and neural signalling for the prevention and treatment of cancer.

The role of adjuvant (chemo-)radiotherapy in oral cancers in the contemporary era

Squamous cell carcinoma of oral cavity (OSCC) is predominantly managed with surgery. Post-operative radiotherapy (PORT) and chemoradiotherapy (POCRT) enhance disease control in OSCC patients with adverse anatomic and pathologic primary and nodal features. Knowledge about disease behavior, surgery and radiotherapy advances, and the emergence of new systemic agents prompt refinement of PORT volumes and POCRT regimens. Traditional and emerging prognostic models that include adverse histopathological features underpin such approaches. This review summarizes research over recent decades with emphasis on the 2015 to Feb 2019 period describing: (1) Indications for PORT and/or POCRT, addressing surgical "margin status" including the definition of a "clear" margin to permit withholding PORT/POCRT; these concepts include characterizing the specimen yielding these measurements, the optimal time point to assess these findings, and the putative value of a "revised margin" performed during the same operative procedure, (2) Emerging prognostic factors including nodal burden (total number of involved lymph nodes) and perineural invasion, (3) PORT volume design, dose/fractionation and optimal surgery-to-PORT interval, (4) Chemotherapy dose, schedule, and agents, and (5) On-going clinical trials involving systemic agents and combinations of chemotherapy with immunotherapy.

Prognosis of oral squamous cell carcinoma with perineural invasion: A comparative study of classification types

OBJECTIVE

To investigate the histological location and extent of perineural invasion (PNI) as prognostic factors.

DESIGN

Retrospective review of medical records and histological analysis of 116 patients with oral squamous cell carcinoma (OSCC).

SETTING

Two major public tertiary hospitals treating head and neck cancer, Royal Adelaide Hospital and Flinders Medical Centre, in South Australia.

PARTICIPANTS

Patients diagnosed with OSCC who underwent primary surgical treatment with curative intent at these two centres from January 1, 2005 through December 31, 2015.

MAIN OUTCOME MEASURES

The primary end points were disease-free survival (DFS) and disease-specific survival (DSS).

RESULTS

The presence of PNI as a binary factor alone did not significantly influence the clinical outcomes. Extratumoural (ET) PNI as measured from the tumour edge was associated with worse DFS on multivariate analyses. Multifocal PNI was associated with worse DFS and DSS. DFS in multifocal PNI was worse irrespective of whether adjuvant therapy was administered.

CONCLUSIONS

The presence of multifocal and ET PNI in OSCC is associated with poor clinical outcomes. Patients with multifocal PNI were associated with worse DFS even with adjuvant therapy.