Current Challenges in the Staging of Oral Cancer

Portable SERS for salivary-based detection of oral pre-malignant lesions and carcinomas: a step toward clinical implementation

The rising incidence of oral cancer has emerged as a serious menace to our civilization. Modern dietary habits, lack of awareness, and delays in early detection are major contributing factors to the global spread of this issue. This work reports the promising findings for diagnostic accuracy of oral cancer in pre-malignant stages by analyzing surface enhanced Raman spectroscopy (SERS) profiles of different stages of oral cancer combined with multivariate analysis. Using 99 clinical samples from which 39 samples were from malignant stage, 28 from pre-malignant and 32 from healthy controls, SERS analysis was carried out by employing label-free silver nanorods as SERS substrates. The SERS spectra of malignant and pre-malignant samples manifest distinct peaks associated with varying concentrations of inorganic metabolites and proteins. Primarily, the elevated level of thiocyanate dominates the SERS spectra in malignant samples while antioxidants like uric acid, xanthine and hypoxanthine's are the key elements in the pre-malignant samples. A ratio-metric analysis of 2130 and 1435 cm-1 peak revealed that the pre-malignant lesions consistently lie between 2 and 3, whereas malignant samples have ratio greater than 3 due to higher intensity of thiocyanate peak. The multivariate analysis successfully separates between oral cancer positive and negative samples with a sensitivity and specificity of 93.5 and 92.7 % respectively. This study presents promising results for the early detection of oral cancer, which could assist clinicians in saving lives.

Post-operative radiotherapy for oral cavity squamous cell carcinoma: Review of the data guiding the selection and the delineation of post-operative target volumes

BACKGROUND AND PURPOSE

To date, no consensus guidelines have been published that systematically guide delineation of primary and nodal Clinical Target Volumes (CTVs) in patients who require post-operative radiotherapy (PORT) for head and neck squamous cell carcinoma (HNSCC). As a result, significant individual, institutional and national variation exists in the way that CTVs are delineated in the post-operative setting, leading to considerable heterogeneity in radiotherapy treatment.

METHODS

A multi-disciplinary group of experts was convened by the European Society for Radiotherapy and Oncology (ESTRO), including radiation oncologists from Europe, North America and Asia, as well as surgery, radiology and pathology representatives. Oral cavity squamous cell carcinoma (OCSCC), where surgery followed by PORT is the standard of care, was first selected for focus. The indications for PORT, and the influence of tumour subsite and stage on post-operative treatment volumes, were considered with reference to current evidence, and clinical experience within the group.

RESULTS

We present clear recommendations regarding the indications for PORT in OCSCC, and propose a new classification of lateralised and non-lateralised OCSCC, to help guide the delineation of post-operative nodal CTVs.

CONCLUSIONS

The evidence and expert opinion summarised in this manuscript provides the background and context required to underpin new international consensus guidelines for the delineation of primary and nodal CTVs for OCSCC in the post-operative setting.

Deep learning-based hyperspectral technique identifies metastatic lymph nodes in oral squamous cell carcinoma-A pilot study

AIMS

To establish a system based on hyperspectral imaging and deep learning for the detection of cancer cells in metastatic lymph nodes.

MAIN METHODS

The continuous sections of metastatic lymph nodes from 45 oral squamous cell carcinoma (OSCC) patients were collected. An improved ResUNet algorithm was established for deep learning to analyze the spectral curve differences between cancer cells and lymphocytes, and that between tumor tissue and normal tissue.

KEY FINDINGS

It was found that cancer cells, lymphocytes, and erythrocytes in the metastatic lymph nodes could be distinguished basing hyperspectral image, with overall accuracy (OA) as 87.30% and average accuracy (AA) as 85.46%. Cancerous area could be recognized by hyperspectral image and deep learning, and the average intersection over union (IOU) and accuracy were 0.6253 and 0.7692, respectively.

SIGNIFICANCE

This study indicated that deep learning-based hyperspectral techniques can identify tumor tissue in OSCC metastatic lymph nodes, achieving high accuracy of pathological diagnosis, high work efficiency, and reducing work burden. But these are preliminary results limited to a small sample.

Prognosis, Controversies and Assessment of Bone Erosion or Invasion of Oral Squamous Cell Carcinoma

Objectives: To discuss the prognostic outcomes, controversies and assessment of bone erosion or invasion of oral squamous cell carcinoma (OSCC). Methods: A structured literature review was conducted to critically analyse relevant evidence. The Web of Science database was searched using specific keywords aligned with the review question. After identifying initial studies, their references were also reviewed to include any additional relevant publications, ensuring a comprehensive evaluation of the available evidence. Results: The search identified 11 relevant studies, including 5 from the initial search and 6 from reference review. The significance of bone involvement is unclear in OSCC, with varying definitions of cortical bone erosion and medullary bone infiltration contributing to conflicting results regarding the prognostic significance of bone involvement. The majority of evidence stems from retrospective cohort studies without clear study criteria and a lack of power to draw valid conclusions. Conclusions: There are currently a lack of high-quality studies assessing bone invasion in OSCC. While there appears to be some evidence that medullary bone infiltration is prognostic, further well-designed studies are warranted.

Traversing the Terrain: Potential Pitfalls within the AJCC 8th Edition Staging System for Lip and Oral Cavity Cancers

In 1977, the American Joint Committee on Cancer (AJCC) introduced the inaugural Cancer Staging Manual, which implemented the T (tumor extent), N (regional lymph node status), and M (presence or absence of distant metastasis) staging system. This systematic approach aimed to convey the extent of disease across various cancer types, providing clinicians with a practical framework to plan treatment strategies, predict prognosis, and assess outcomes. The AJCC 8th edition, effective from January 1, 2018, continues this tradition. However, certain shortcomings persist in the AJCC 8th edition, as identified through clinical experience. Specifically, challenges arise in accurately assessing depth of invasion in unique histological variants of oral squamous cell carcinoma (e.g., Oral verrucous carcinoma, Carcinoma cuniculatum, and Papillary squamous cell carcinoma) and minor salivary gland tumors. Additionally, discrepancies exist in the perception of bone invasion patterns and in reporting practices. There is also a need for staging guidelines for malignant odontogenic tumors and multifocal tumors of the oral cavity, supplemented by diagrammatic representations. Lastly, there is a call for comprehensive staging criteria for carcinomas of the ear, external auditory canal, and temporal bone. We advocate for the inclusion of these considerations in future editions of the AJCC Cancer Staging Manual.

Computed tomography/magnetic resonance imaging for mandibular boundary invasion of oral squamous cell carcinoma assessment

BACKGROUND

The range of mandibular invasion by a tumour needs to be determined accurately to minimize unnecessary damage to the mandible. This study aimed to compare tumour boundary lines on computed tomography/magnetic resonance (CT/MR) images with those from pathological findings during the preoperative assessment of mandibular invasion by oral squamous cell carcinoma (OSCC). By comparing the methods, the potential of CT/MR for this application could be further elucidated.

METHODS

Eight patients with OSCC were imaged with CT/MR, mandibular specimens were collected, and the material site was measured. Haematoxylin-eosin staining was used for histopathological assessment. The presence and boundaries of bone invasion were evaluated. The CT/MR and histopathological boundaries of bone invasion were delineated and merged to compare and calculate the deviation of CT/MR and histopathological boundaries using the Fréchet distance.

RESULTS

The mean Fréchet distance between the CT and pathological tumour boundaries was 2.69 mm (standard error 0.46 mm), with a minimum of 1.18 mm, maximum of 3.64 mm, median of 3.10 mm, and 95% confidence interval of 1.40-3.97 mm. The mean Fréchet distance between the tumour boundaries on the MR and pathological images was 3.07 mm (standard error 0.56 mm), with a minimum of 1.53 mm, maximum of 4.74 mm, median of 2.90 mm, and 95% confidence interval of 1.53-4.61 mm.

CONCLUSIONS

CT/MR imaging can provide an effective preoperative assessment of mandibular invasion of OSCC. Pathology images can be positioned on CT/MR scans with the help of computer software to improve the accuracy of the findings. The introduction of the Fréchet distance to compare tumour boundary lines is conducive to computer image diagnosis of tumour invasion of jaw boundaries.

[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).

Salivary-Based Cell-Free Mitochondrial DNA Level Is an Independent Prognostic Biomarker for Patients with Head and Neck Squamous Cell Carcinoma

Changes in the copy numbers of cell-free nuclear DNA (cf-nDNA) and cell-free mitochondrial DNA (cf-mtDNA) have shown promising diagnostic utilities among patients with head and neck squamous cell carcinoma (HNSCC). Considering the absence of objective prognostic tools for HNSCC surveillance, this study aimed to assess the utility of saliva-based cf-nDNA and cf-mtDNA in predicting the overall survival of patients with HNSCC. The study included ninety-four patients with a confirmed HNSCC diagnosis with a mean follow-up time of 32.04 months (±19.1). A saliva-based liquid biopsy was collected from each patient. A multiplex quantitative PCR was used to determine the absolute number of cf-nDNA and cf-mtDNA. The Kaplan-Meier estimator and Cox proportional hazards regression models were used to assess overall survival. The absolute copy numbers of cf-nDNA and cf-mtDNA were statistically significantly higher among the deceased patients than among the censored ones (p < 0.05). Individuals with elevated levels of cf-nDNA or cf-mtDNA were associated with a significantly poorer overall survival (p ≤ 0.05). A univariate analysis showed that only the absolute copy number of cf-mtDNA was the sole predictor of overall survival. However, the multivariate analysis showed that all the absolute copy numbers of cf-nDNA, the absolute copy numbers of cf-mtDNA, and the stage of HNSCC were predictors of overall survival. Our study confirms that saliva is a reliable and non-invasive source of data that can be used to predict the overall survival of patients with HNSCC, where cf-mtDNA levels act as the sole predictor.

Lymph Node Ratio as a Prognostic Factor in Neck Dissection in Oral Cancer Patients: A Systematic Review and Meta-Analysis

Simple Summary

Lymph node ratio (LNR) is a well-studied prognostic factor in colorectal and breast cancer, and it has been recently evaluated as a clinically relevant biomarker in oral squamous cell carcinoma. LNR represents the ratio of positive lymph nodes extracted in a neck dissection to the total number of nodes harvested (lymph node yield, LNY). Many single-center cohort studies and a few multicenter have assessed the significance of LNR as a prognostic factor in oral cancer. In this systematic review and meta-analysis of 32 studies and 20,994 oral cancer patients, we demonstrate that LNR is an independent prognostic indicator in patients with oral squamous cell carcinoma.

Abstract

Many studies have evaluated the clinical implications of lymph node ratio (LNR) as a prognostic factor in patients with oral squamous cell carcinoma (OSCC). The main purpose of this systematic review and meta-analysis was to address LNR as a prognosticator in patients with OSCC. A systematic search was conducted in the following databases: PubMed, EMBASE, Google Scholar, OpenGrey, Cochrane library, and ClinicalTrials.gov, and studies between 2009 and 2020 were sought. The pooled relative risk was calculated along with 95% confidence intervals for the following endpoints: overall survival (OS), disease-free survival (DFS), disease-specific survival (DSS), distant metastasis-free survival (DMFS), locoregional disease-free survival (LRDFS), local recurrence-free survival (LRFS), and recurrence-free survival (RFS) according to the random-effects model (Der Simonian–Laird approach). Subgroup and meta-regression analyses were performed as well. Finally, 32 cohort studies were eligible, which included 20,994 patients with OSCC. Patients were subdivided into two categories, group YES (studies that included in their analysis only patients with positive lymph nodes) and group NO (studies that did not exclude LNR = 0 patients). In the group YES, patients with high LNR had shorter OS (RR = 1.68, 95% CI: 1.47–1.91), DFS (RR = 1.68, 95% CI: 1.42–1.99), DSS (RR = 1.94, 95% CI: 1.56–2.42), DMFS (RR = 1.83, 95% CI: 1.13–2.96), LRDFS (RR = 1.55, 95% CI: 1.10–2.20), and LRFS (RR = 1.73, 95% CI: 1.41–2.13) compared to patients with low LNR. In the group NO, patients with high LNR in comparison had shorter OS (RR = 2.38, 95% CI: 1.99–2.85), DFS (RR = 2.04, 95% CI: 1.48–2.81), and DSS (RR = 2.90, 95% CI: 2.35–3.57) compared to patients with low LNR. Based on those findings, LNR might be an independent prognostic factor for OS in patients with OSCC and could be incorporated into future classification systems for better risk stratification.

New Scenarios in Pharmacological Treatments of Head and Neck Squamous Cell Carcinomas

Head and neck squamous cell carcinoma (HNSCC) is one of the most frequent types of cancer with a lethal outcome in half of the diagnosed cases. Mostly, HNSCC develops in the oral cavity, and its development is associated with tobacco and areca nut/betel quid usage, alcohol consumption, and HPV infection. Oral squamous cell carcinoma, as other head and neck cancers, presents a high degree of intratumor heterogeneity, which makes their treatment difficult, and directly correlates with drug resistance. Since the classical treatments for HNSCC oftentimes do not resolve the clinical picture, there is great need for novel therapeutic approaches, models for drug testing, and new drug delivery systems.

Diagnostic accuracy of imaging modalities in detection of histopathological extranodal extension: A systematic review and meta-analysis

OBJECTIVE

To present an up to date systematic review and meta-analysis evaluating the diagnostic accuracy of the most used imaging modalities in detection of histopathological extra nodal extension (ENE) in head and neck squamous cell carcinoma.

MATERIALS AND METHODS

Medline, Embase, and Cochrane databases were systematically searched on March 27th 2020. Screening, inclusion, quality assessment, and data extraction were done by two reviewers. Meta-analysis was conducted using the bivariate model approach after pooling the studies according to imaging modality. Heterogeneity was explored by meta-regression. Comparison was done by meta-regression and sub-group analyses.

RESULTS

Out of 476 initial hits, 25 studies were included for analysis. Of these, 14 dealt with CT, nine with PET/CT, four with MRI, two with ultrasound, and none with PET/MRI. Meta-analysis based on a total sample size of 3391 showed that CT had a sensitivity of 76% [67-82%] and specificity of 77% [69-83%], MRI a sensitivity of 72% [64-79%] and specificity of 78% [57-90%], and PET/CT a sensitivity of 80% [76-84%] and specificity of 83% [74-90%] in the ability to predict ENE. No meta-analysis could be done on ultrasound. There were no significant differences between modalities in overall accuracy; however, PET/CT had significantly higher sensitivity than CT and MRI.

CONCLUSION

There was no significant difference in the ability of CT, MRI, and PET/CT to diagnose histopathological ENE, except that PET/CT had a significantly higher sensitivity than CT and MRI.

Feasibility of Use of the 8th Edition of the American Joint Committee on Cancer Staging for Head and Neck Cancers in Indian Scenario: An Evaluative Study

INTRODUCTION

Inclusion of depth of invasion (DOI) and a separate classification for human papillomavirus (HPV)-associated Oropharyngeal Cancers (OPCs) are two of the many major changes in the 8th edition of the American Joint Committee on Cancer staging system. After more than 2 years of implementation, the authors found the need to evaluate if the Indian clinicians found it feasible to apply the system in their practice and if the same has influenced their decision-making.

METHODS

The survey was done in the form of a questionnaire which was distributed personally and via the internet to 100 clinicians. Seventy-two clinicians responded to the questionnaire. The results were analyzed and frequency distribution was computed.

RESULTS

Eighty-three percent of the clinicians experienced that palpation of the tumour was not a reliable method to determine the DOI. The common issues stated by the clinicians were difficulty in assessing DOI in certain subsites of the oral cavity (most commonly retromolar trigone-83%), inability to determine DOI in patients with trismus, and inability to correlate pathological and clinical DOI. Thirteen percent of the clinicians did not rely on radiological tools for measuring the DOI. Seventy percent of the clinicians did not perform a P16 assay for patients with oropharyngeal cancers. Fifty percent of the clinicians preferred chemoradiotherapy for early HPV positive oropharyngeal cancers.

DISCUSSION

Based on the results of the survey, the authors recommend a need for more interpretative guidelines and methods for determining the DOI. The authors also emphasize the need for determining HPV status for all oropharyngeal carcinomas.

Lymph node characteristics and their prognostic significance in oral squamous cell carcinoma

BACKGROUND

The prognostic significance of various histopathologic lymph node-based biomarkers in oral squamous cell carcinoma (OSCC) needs further evaluation.

METHODS

Retrospective analysis of 212 OSCC patients with regional metastasis to determine the association of extranodal extension (ENE), extent of ENE, size of metastatic deposit, lymph node yield (LNY), lymph node ratio (LNR), and topography of involvement with survival outcomes.

RESULTS

The presence of ENE, larger nodal deposit, higher pN stage, lymph nodes in the lower levels, and patients who did not receive adjuvant treatment had poor disease-free survival (DFS). In addition, more positive nodes and high LNR showed worse overall survival (OS). ENE beyond 5 mm resulted in poorer outcomes. Larger sizes of metastatic deposit predisposed to ENE. Multivariate analyses showed only lower level of neck involvement to affect both DFS and OS.

CONCLUSIONS

Lymph node metastasis to lower levels and other lymph node characteristics affect prognosis and must be considered in the evolution of staging systems for OSCC.

Histopathological Definitions of Extranodal Extension: A Systematic Review

Extranodal extension (ENE) is a very strong prognostic factor in head and neck squamous cell carcinoma. However, significant variance in reported incidence of ENE suggests discordance in perception of ENE among pathologists. This study aims to map the different definitions of histopathological ENE used in the literature. A systematic review was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses Statement. Guided by the research question: "How is histopathological ENE defined?" the databases Medline, Embase, and Cochrane were systematically searched. All retrieved studies were reviewed and qualitatively analyzed. Three categories of existing definitions were formed. The systematic literature search yielded 1786 studies after removal of duplicates. Nine hundred and thirty-four full text articles were assessed for inclusion and 44 unique ENE definitions were identified and categorized 1-3; (1) simple definitions only describing a breach in the capsule (48%), (2) definitions also including a description of the perinodal tissue (43%), and (3) definitions adding a description of a specific reaction in the perinodal structure (9%). No consensus definition of ENE exists, but based on the level of details in the identified definitions, three overall categories of ENE definitions were established.

New AJCC: How does it impact oral cancers?

PURPOSE OF REVIEW

The objective of this article is to critically review the rationale for the changes in the staging of the oral cavity cancers.

RECENT FINDINGS

After reviewing many recent studies about oral cancer and analyzing multi-institutional data for outcomes, the staging system was updated to include new knowledge of the disease and its biological behavior.

SUMMARY

This article reviews the changes in the staging of oral cavity cancers published in the 8th edition of the AJCC/UICC TNM cancer staging manual and discusses future directions.

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.