Dysplasia and DNA ploidy to prognosticate clinical outcome in oral potentially malignant disorders

DNA ploidy status as a predictor for malignant transformation in oral leukoplakia: a systematic review and meta-analysis

OBJECTIVE

To synthesize literature regarding determination of ploidy status in cases of oral leukoplakia (OL) with the research question: Can DNA ploidy assess malignant transformation (MT) in OL cases?

STUDY DESIGN

This systematic review was registered in PROSPERO (CRD42022340184). The PECO (Population, Exposure, Comparator, and Outcome) was patients with OL, aneuploidy, diploidy, and MT in OL. Literature search databases included Scopus, PubMed, and Google Scholar. Risk of bias was assessed using modified REMARK tool. Forest plot for meta-analysis and funnel plot for publication bias were plotted (95% confidence interval).

RESULT

Forest plots revealed that OL with aneuploidy (75.20%) and diploid lesion (8%) had greater risk of MT. The hazard ratio of aneuploid OL had 14.10 times increased risk of MT compared with diploid OL.

CONCLUSION

We could gather evidence that detection of DNA aneuploidy status can help in predicting the MT of OL cases. We would also like to propose grading system of OL as low-risk transformation = diploid + mild or moderate dysplasia, and high-risk transformation = diploid + severe dysplasia / any aneuploid lesion.

Is Aneuploidy a Consistent Marker for Malignant Transformation Risk in Oral Lichen Planus?

BACKGROUND

Numeric chromosomal imbalance, known as aneuploidy, is linked to both malignant and potentially malignant epithelial lesions. Aneuploidy has also been investigated in oral potentially malignant disorders (OPMDs) due to its high incidence in head and neck cancers, particularly in oral squamous cell carcinoma (OSCC). The study aimed to evaluate the potential of aneuploidy, a marker of chromosomal imbalance, as a prognostic tool for assessing malignant transformation risk in oral lichen planus (OLP) patients.

METHODS

Fluorescent in situ hybridization (FISH) analysis targeting centromeric probes for chromosomes 2 and 8 was conducted on samples from 245 patients, with follow-up in 135 cases.

RESULTS

Aneuploid cells (ACs) were detected in 73 patients (29.8%); 24 (32.9%) exhibited non-diploid cells in a normal looking mucosa. Only 2 (0.8%) patients developed OSCC during the follow-up. Among the 135 followed, 11 (8.1%) were positive for Acs in both samples, 15 (11.1%) were were negative initially but positive later. In contrast, 3 patients (2.2%) were initially positive but later negative.

CONCLUSION

These results indicate a low malignant transformation rate (< 1%), despite a high rate of aneuploidy. These also demonstrate variability in aneuploidy results over time. The dynamic nature of aneuploidy observed suggests that it may not be a reliable predictive tool for malignant transformation in OLP.

A head-to-head comparison of four grading systems for oral epithelial dysplasia

AIMS

Oral epithelial dysplasia (OED) carries a risk of malignant transformation to oral squamous cell carcinoma. Clinical risk stratification for these patients is challenging, and reliant upon histological grading. The World Health Organisation (WHO) grading system is the current gold standard, although the binary system, two- and six-point prognostic models have also been proposed. This study assesses the interobserver agreement and malignant transformation outcomes for these four grading systems.

METHODS AND RESULTS

Up to 5 years of outcome data were collected for this retrospective cohort of 137 patients. Archived slides were reviewed by three pathologists, and grades for the WHO, binary, two- and six-point systems were assigned. Interobserver agreement was assessed with Light's kappa coefficient. Kaplan-Meier and Cox regression survival analyses were used to assess the correlation of each grading system with malignant transformation. The WHO, binary, two- and six-point systems had kappa coefficients of 0.42, 0.31, 0.17 and 0.41, respectively. All grading systems stratified lesions by malignant transformation risk, except the two-point model. Moderate OED (WHO) did not show an increased risk of malignant transformation, while severe OED had a hazard ratio (HR) of 13.7 (P = 0.02). The high-risk category for the binary and six-point systems had HRs of 4.67 (P = 0.03) and 5.28 (P = 0.03), respectively.

CONCLUSIONS

The interobserver agreement of the WHO, binary and six-point systems is comparable. The six-point and binary systems provided the most useful risk stratification. This study highlights the potential value of the six-point prognostic model for OED grading, which has comparable performance with the current gold standard.

Clinico-pathological characterisation of human papillomavirus-associated oral epithelial dysplasia

BACKGROUND

Human papillomavirus-associated oral epithelial dysplasia (HPV-OED) has been recently recognised by the World Health Organisation (WHO) as a distinct type of oral epithelial dysplasia. The rarity of HPV-OED, together with gaps in the current understanding of risk factors and clinical behaviour raise the risk of under-recognition and misdiagnosis. To address this, we describe the clinico-pathological features of a consecutive series of HPV-OED from a single institution to provide additional insight into the presentation and behaviour of this disease.

METHODS

Consecutive cases of HPV-OED were identified over a 20-year period from the pathology routine diagnostic archives of a single centre. Cases with features of viral cytopathic changes in a background of OED underwent HPV-specific testing in addition to p16 immunohistochemistry to confirm HPV positivity.

RESULTS

Fifty-three consecutive patients with HPV-OED were identified. The mean age at diagnosis was 55 years-old and there was a strong male predilection (83 %). Most patients were smokers or former smokers, and almost a fifth of individuals were Human Immunodeficiency Virus (HIV)-positive. The latero-ventral tongue was the most common index site. Twenty-eight percent of cases were associated with invasive oral squamous cell carcinoma. There was a statistically significant association between with patient's HIV status and malignant transformation (p = 0.022).

CONCLUSIONS

Findings from our cohort of HPV-OED patients suggests that malignant transformation is relatively frequent and associated with the HIV status of patients.

Recommendations for Research to Develop a Patient-Centered Clinical Follow-Up Protocol for Oral Epithelial Dysplasia

Oral epithelial dysplasia (OED) is the primary histological marker for assessing the progression of oral potentially malignant disorders (OPMDs) to cancer. Despite challenges in grading and low inter-pathologist reproducibility, OED severity remains the key predictor of malignant transformation. However, globally accepted guidelines for OED monitoring are lacking, despite calls for individualized management based on host and lesion characteristics. The proposed research protocol involves acquiring high-quality intraoral images, assessing oral hygiene and periodontal status, eliminating chronic mechanical irritation and Candida infections, and applying adjunctive diagnostic methods like toluidine blue staining, optical evaluation, and brush cytology. Tailored follow-up regimens based on individual risk assessments are emphasized, with frequent monitoring for high-grade dysplasia or patients at higher risk of progression. Therefore, effective OED management should consider the patient's immune status, dietary habits, and oral microbiota, aiming to develop personalized treatment strategies that optimize patient-centered care.

Treatment outcomes of oral leukoplakia on the irradiated or nonirradiated mucosa among survivors of head and neck cancer in the papulation where practice of betel nut chewing and cigarette smoking are widespread

BACKGROUND

Radiotherapy (RT) has numerous effects on the oral mucosa, primarily genetic alterations and changes in the microenvironment. The characteristics of oral leukoplakia (OL) may differ between patients who have received previous head and neck cancer (HNC) treatment with radiation therapy and those who have not. Due to a lack of data on this scenario, we aimed to investigate the surgical outcomes of OL by comparing these two patient groups.

METHODS

This retrospective cohort study enrolled a total of 224 OL lesions in 124 patients who underwent carbon dioxide laser (CO2 laser) surgery from July 2002 to Aug 2021. All patients had received previous treatments for HNC, with 59 patients undergoing only surgical approach, 65 patients undergoing RT, and 46 patients undergoing concurrent chemotherapy during RT. The analysis was performed on a per-lesion basis, not a per-capita basis. We investigated the associations of clinicopathological characteristics and treatment outcomes of OL lesions that developed from irradiated or nonirradiated oral mucosa.

RESULTS

The median follow-up time was 5.87 years. Postoperative recurrence of OL occurred in 30 patients. Malignant transformation occurred in 17 patients with the incidence rate 4.19% annually and 13.7% cumulatively. The average time for OL transforming into squamous cell carcinoma was 3.27 ± 3.26 years (median 1.82, range 0.11 - 11.90). In univariate analysis, non-homogeneous morphology (P = 0.042), moderate to high-grade dysplasia (P = 0.041), and nonirradiated oral mucosa (P = 0.0047) were predictors for malignant transformation. However, in the Cox proportional hazard model, only nonirradiated oral mucosa remained an independent prognostic factor related to postoperative malignant transformation of OL (P = 0.031, HR 5.08, CI95 1.16 - 22.25).

CONCLUSION

In the population whose OL is strongly aetiologically linked to environmental carcinogens such as betel nut and tobacco, OL lesions that develop on previously irradiated oral mucosa have a lower risk for postoperative malignant transformation compared to those that develop on nonirradiated mucosa. This finding highlights the potential impacts of radiation on OL. Further research is needed to confirm this observation and elucidate the underlying mechanism.

Copy Number Alterations Predict Development of OSCC from Oral Leukoplakia

Oral leukoplakia (OLK) is a common type of potentially malignant disorder. Early identification of the malignancy potential leads to a better management of OLK and prediction of development of oral squamous cell carcinoma (OSCC). However, there has been no effective biomarker to assess the risk of malignancy in OLK. Genomic copy number alteration (CNA) is a complex chromosomal structural variation in the genome and has been identified as a potential biomarker in multiple cancers. This study aimed to develop a predictive model for the malignant transformation risk of OLK by copy number analysis. A total of 431 OLK samples with long-term follow-up (median follow-up of 67 mo) from multiple academic centers were analyzed for CNAs. CNA events increased with the severity of hyperplasia, mild dysplasia, moderate dysplasia, and severe dysplasia. More CNA events were present in patients with OLK who later developed OSCC than in those with OLK who did not. By multivariate Cox regression analysis, the OLK of the CNA scorehigh group showed an increased risk of malignant transformation than the CNA scorelow group (P < 0.001). A CNA score model was developed to accurately predict the prognosis (area under the receiver operating characteristic curve [AUC] = 0.879; 95% confidence interval [CI], 0.799-0.959) and was validated using data from 2 external centers (AUC = 0.836, 95% CI, 0.683-0.989; AUC = 0.876, 95% CI, 0.682-1.000), and all of them showed better prediction performances than histopathological grade in assessing the transformation risk of OLK. Furthermore, we performed CNA models among 4 subgroups of OLK with hyperplasia, mild dysplasia, moderate dysplasia, and severe dysplasia and found that CNA score can accurately predict malignant transformation of different subgroups. CNA score may be a useful biomarker to predict malignant transformation of OLK. Subtyping of OLK by the CNA score could contribute to better management of OLK and predicting development of OSCC.

Predictors of malignant transformation in oral leukoplakia and proliferative verrucous leukoplakia: An observational prospective study including the DNA ploidy status

BACKGROUND

This prospective observational study investigated the determinants of malignant transformation (MT) in localized oral leukoplakia (OL) and proliferative verrucous leukoplakia (PVL).

METHODS

Demographic, clinical, histological, and DNA ploidy status data were collected at enrolment. Survival analysis was performed (MT being the event of interest).

RESULTS

One-hundred and thirty-three patients with OL and 20 patients with PVL entered the study over 6 years (mean follow-up 7.8 years). The presence of OED, DNA ploidy, clinical presentation, and lesion site were associated with MT in patients with OL in a univariate analysis. In a multivariate model, OED was the strongest predictor of MT in patients with OL. Adding DNA ploidy increased the model's predictive power. None of the assessed predictors was associated with MT in patients with PVL.

CONCLUSIONS

DNA ploidy might identify a subset OL with low risk or minimal risk of MT, but it does not seem to be a reliable predictor in patients with PVL.

Biomarkers of malignant transformation in oral leukoplakia: from bench to bedside

Oral leukoplakia is a common precursor lesion of oral squamous cell carcinoma, which indicates a high potential of malignancy. The malignant transformation of oral leukoplakia seriously affects patient survival and quality of life; however, it is difficult to identify oral leukoplakia patients who will develop carcinoma because no biomarker exists to predict malignant transformation for effective clinical management. As a major problem in the field of head and neck pathologies, it is imperative to identify biomarkers of malignant transformation in oral leukoplakia. In this review, we discuss the potential biomarkers of malignant transformation reported in the literature and explore the translational probabilities from bench to bedside. Although no single biomarker has yet been applied in the clinical setting, profiling for genomic instability might be a promising adjunct.

The clinical utility of contemporary oral epithelial dysplasia grading systems

INTRODUCTION

Clinical management of oral potentially malignant disorders relies on accurate histopathological assessment of the presence and grade of oral epithelial dysplasia. Whilst adjunctive laboratory tests have provided useful prognostic information, none are in widespread clinical use. This study was performed to assess the clinical utility of two contemporary oral epithelial dysplasia grading systems.

METHODS

Patients were identified from a clinical database. Oral epithelial dysplasia grading was performed by three oral and maxillofacial pathologists blinded to clinical outcome using the WHO 2017 system and a binary classification. The primary outcome measure was the development of oral squamous cell carcinoma, termed 'malignant transformation'.

RESULTS

131 cases satisfied the inclusion criteria, of which 23 underwent malignant transformation. There was substantial inter-rater agreement between the study pathologists for both grading systems, measured using kappa statistics (κ = 0.753-0.784). However, there was only moderate agreement between the consensus WHO 2017 dysplasia grade for the study against the original grade assigned by a pool of six pathologists in the context of the clinical service (κ = 0.491). Higher grade categories correlated with an increased risk of developing cancer using both grading systems.

CONCLUSION

This study demonstrates that the WHO 2017 and binary grading systems are reproducible between calibrated pathologists and that consensus reporting is likely to improve the consistency of grading. The WHO and binary systems were prognostically comparable. We recommend that institutions implement consensus oral epithelial dysplasia grading and prospectively audit the effectiveness of risk stratifying their patients with oral potentially malignant disorders. (249 words).

Oral epithelial dysplasia: Recognition, grading and clinical significance

Histopathological grading of epithelial dysplasia remains the principal laboratory method for assessing the risk of malignant transformation in oral potentially malignant disorders (OPMDs). Current views on the molecular pathogenesis and histological interpretation of the features of epithelial dysplasia are described, and the use of grading systems for epithelial dysplasia is discussed. Changes to the current 2017 WHO criteria for diagnosis are proposed with emphasis on the architectural features of epithelial dysplasia. The predictive values of three-grade and binary systems are summarised, and categories of epithelial dysplasia are reviewed, including lichenoid and verrucous lesions, keratosis of unknown significance, HPV-associated dysplasia, differentiated and basaloid epithelial dysplasia. The implications of finding epithelial dysplasia in an oral biopsy for clinical management are discussed from the pathologists' viewpoint.

Predicting progression of low-grade oral dysplasia using brushing based DNA ploidy and Chromatin Organization analysis

Most oral cancers arise from oral potentially malignant lesions, which show varying grades of dysplasia. Risk of progression increases with increasing grade of dysplasia, however risk prediction among oral low-grade dysplasia (LGDs) i.e., mild and moderate dysplasia can be challenging as only 5-15% transform. Moreover, grading of dysplasia is subjective and varies with the area of the lesion being biopsied. To date, no biomarkers or tools are used clinically to triage oral LGDs. This study utilizes a combination of DNA ploidy and chromatin organization (CO) scores from cells obtained from lesion brushings to identify oral LGDs at high-risk of progression. A total of 130 lesion brushings from patients with oral LGDs were selected of which 16 (12.3%) lesions progressed to severe dysplasia or cancer. DNA ploidy and CO scores were analyzed from nuclear features measured by our in-house DNA image cytometry (DNA-ICM) system and used to classify brushings into low risk and high risk. A total of 57 samples were classified as high-risk of which 13 were progressors. High-risk DNA brushing was significant for progression (P = 0.001) and grade of dysplasia (P = 0.004). Multivariate analysis showed high-risk DNA brushing showed 5.1 to 8-fold increased risk of progression, a stronger predictor than dysplasia grading and lesion clinical features. DNA-ICM can serve as a non-invasive, high throughput tool to identify high-risk lesions several years prior to transformation. This will help clinicians focus on such lesions while low-risk lesions may be spared from unnecessary biopsies.

Early-Phase Interventional Trials in Oral Cancer Prevention

Simple Summary

Oral cancer is a devastating disease with increasing incidence worldwide. Oral epithelial dysplasia (OED) is a potentially malignant disorder and patients with OED are at increased risk of developing oral cancer. Current strategies for management of OED include surgery or close observation and both fail to address the underlying pathogenesis of the disease. There is an urgent need for evidence-based medical treatments for OED to prevent oral cancer development in this cohort. Chemoprevention trials to date have not delivered therapeutic agents for routine clinical practice. Historically, there has been significant heterogeneity in the design of oral cancer chemoprevention trials, with most failing to selectively recruit patients with biopsy-proven OED, which limits the usefulness of the findings in the OED population. The present paper aims to review the current evidence and the methodology of early-phase trials in oral cancer chemoprevention. Novel strategies in oral cancer chemoprevention will also be discussed.

Abstract

The increasing breadth of molecular targets, promise of immune-targeted therapies and repurposed agents have heightened interest in cancer prevention. While, to date, testing of oral cancer chemoprevention strategies has failed to deliver therapeutic agents for routine clinical practice, there remains an urgent need for further clinical research to overcome this hurdle. Patients at the greatest risk of disease stand to benefit the most from inclusion in clinical trials; therefore, there is a need to carefully define this population using validated clinical and molecular markers. Safety, tolerability and the efficacy of interventions is assessed through carefully selected endpoints. These endpoints may include pharmacodynamic, clinical, histological and on-target molecular modifications as an individual or as a composite endpoint. Early-phase trials provide an area of opportunity to explore novel and repurposed agents in the setting of oral cancer chemoprevention, eventually leading to phase III trials with clinical endpoints such as transformation and clinical outcome; these studies are large, lengthy and expensive and should be reserved for the most promising of agents. This paper will explore current evidence in oral cancer chemoprevention, drug repurposing, selection of appropriate endpoints for early-phase trials and novel therapeutic angles in oral cancer chemoprevention.

Insight into metastatic oral cancer tissue from novel analyses using FTIR spectroscopy and aperture IR-SNOM

A novel machine learning algorithm is shown to accurately discriminate between oral squamous cell carcinoma (OSCC) nodal metastases and surrounding lymphoid tissue on the basis of a single metric, the ratio of Fourier transform infrared (FTIR) absorption intensities at 1252 cm-1 and 1285 cm-1. The metric yields discriminating sensitivities, specificities and precision of 98.8 ± 0.1%, 99.89 ± 0.01% and 99.78 ± 0.02% respectively, and an area under receiver operator characteristic (AUC) of 0.9935 ± 0.0006. The delineation of the OSCC and lymphoid tissue revealed by the image formed from the metric is in better agreement with an immunohistochemistry (IHC) stained image than are either of the FTIR images obtained at the individual wavenumbers. Scanning near-field optical microscopy (SNOM) images of the tissue obtained at a number of key wavenumbers, with high spatial resolution, show variations in the chemical structure of the tissue with a feature size down to ∼4 μm. The image formed from the ratio of the SNOM images obtained at 1252 cm-1 and 1285 cm-1 shows more contrast than the SNOM images obtained at these or a number of other individual wavenumbers. The discrimination between the two tissue types is dominated by the contribution from the 1252 cm-1 signal, which is representative of nucleic acids, and this shows the OSCC tissue to be accompanied by two wide arcs of tissue which are particularly low in nucleic acids. Haematoxylin and eosin (H&E) staining shows the tumour core in this specimen to be ∼40 μm wide and the SNOM topography shows that the core centre is raised by ∼1 μm compared to the surrounding tissue. Line profiles of the SNOM signal intensity taken through the highly keratinised core show that the increase in height correlates with an increase in the protein signal. SNOM line profiles show that the nucleic acids signal decreases at the centre of the tumour core between two peaks of higher intensity. All these nucleic acid features are ∼25 μm wide, roughly the width of two cancer cells.

Oral Squamous Cell Carcinoma Associated with Precursor Lesions

Oral squamous cell carcinoma (OSCC) may be associated with precursor lesions known as oral potentially malignant disorders (OPMD). Few studies have reported on how OPMD diagnosis affects early detection and outcome of OSCC. We reviewed a large series of OSCC to determine the proportion that was associated with preceding OPMD and to compare the outcome of OSCC with or without precursor. Cases of oral-oropharyngeal carcinoma diagnosed between 2005 and 2015 were retrieved from the Ontario Cancer Registry (OCR) and matched to records of OPMD between 2001 and 2015 in two large oral pathology diagnostic services and the pathology databases of two hospitals with oral pathology services, to identify cases with precursor. Of 10,987 cancer cases, 378 (3.44%) had a preceding OPMD. Patients living in Central Ontario were more likely to have OPMD diagnosed before carcinoma than those in North Ontario (4.73% vs. 1.63%, P = 0.05). 329 of 5,257 cases of oral cancer were linked to a precursor, compared with 24 of 4,174 cases of oropharyngeal cancer (6.26% vs. 0.57%, P < 0.0001). Oral cancers with precursor were predominantly diagnosed at stage I (49.30%), compared with those without precursor, where stage IV disease predominated (41.28%). Sixty-nine of 309 (22.33%) patients with precursor-associated oral cancer have died of disease, compared with 1,551 of 4,656 (33.31%) patients without a precursor (P = 0.02). We conclude that patients with OSCC associated with a precursor had significantly lower odds of dying from disease. The beneficial effect of precursor lesion diagnosis on outcome is related to a higher proportion of stage I disease. PREVENTION RELEVANCE: OSCC causes significant morbidity and mortality, especially if diagnosed at late stages. Precursor lesions to OSCC can be recognized by clinical examination. Our study shows that early diagnosis of OSCC at the precursor stage can improve the outcome of oral cancer.