Malignant development in patients with oral potentially malignant disorders detected through nationwide screening: Outcomes of 5-year follow-up at a single hospital

The evil companion of OSCC: Candida albicans

OBJECTIVE

Microbial dysbiosis and microbiome-induced inflammation may play a role in the etiopathogenesis of oral squamous cell carcinoma (OSCC). Candida albicans (C. albicans) is the most prevalent opportunistic pathogenic fungus in the oral cavity, and Candida infection is considered as one of its high-risk factors. Although oral microbiota-host interactions are closely associated with the development of OSCC, the interrelationship between fungi and OSCC is poorly understood compared to that between bacteria and viruses.

RESULTS

We accumulated knowledge of the evidence, pathogenic factors, and possible multiple mechanisms by which C. albicans promotes malignant transformation of OSCC, focusing on the induction of epithelial damage, production of carcinogens, and regulation of the tumor microenvironment. In addition, we highlight the latest treatment strategies for Candida infection.

CONCLUSION

This review provides a new perspective on the interrelationship between C. albicans and OSCC and contributes to the establishment of a systematic and reliable clinical treatment system for OSCC patients with C. albicans infection.

Leveraging artificial intelligence for perioperative cancer risk assessment of oral potentially malignant disorders

Oral potentially malignant disorders (OPMDs) are mucosal conditions with an inherent disposition to develop oral squamous cell carcinoma. Surgical management is the most preferred strategy to prevent malignant transformation in OPMDs, and surgical approaches to treatment include conventional scalpel excision, laser surgery, cryotherapy, and photodynamic therapy. However, in reality, since all patients with OPMDs will not develop oral squamous cell carcinoma in their lifetime, there is a need to stratify patients according to their risk of malignant transformation to streamline surgical intervention for patients with the highest risks. Artificial intelligence (AI) has the potential to integrate disparate factors influencing malignant transformation for robust, precise, and personalized cancer risk stratification of OPMD patients than current methods to determine the need for surgical resection, excision, or re-excision. Therefore, this article overviews existing AI models and tools, presents a clinical implementation pathway, and discusses necessary refinements to aid the clinical application of AI-based platforms for cancer risk stratification of OPMDs in surgical practice.

Progression to malignancy in oral potentially malignant disorders: a retrospective study of 5,036 patients in Ontario, Canada

OBJECTIVES

Determine the rate of malignant transformation (MT) of oral potentially malignant disorders (OPMDs) and risk factors for transformation.

STUDY DESIGN

The OPMD database (2001-2015) from 2 biopsy services in Ontario, Canada, was linked to the Ontario Cancer Registry to determine the rate of progression to oral squamous cell carcinoma (OSCC). Clinical and histologic features of progressed and non-progressed cases were compared to determine risk factors for progression.

RESULTS

The MT rate was 6.4% (322/5,036 cases). The mean time for cancer development was 51.2 months. 33.6% of cases (107/322) progressed after over 60 months. The risk of cancer increased with age and was higher in non-smokers. The MT rate was highest in the tongue (11.4%), followed by the floor of mouth (7.1%) and gingiva (6.5%). Histologic grade was associated with progression to cancer (P < .0001). Atypical verrucous-papillary lesions with no or mild dysplasia predominantly affected older patients' gingiva, and the progression rate was significantly higher than conventional mild dysplasia (9.2% vs 3.2%, P = .0002).

CONCLUSIONS

Our population-based retrospective study showed that <10% of OPMDs progressed to cancer, which could take many years. Atypical papillary-verrucous proliferation without high-grade dysplasia is a subtype of OPMD requiring further study.

Evaluating surgical excision to prevent progression of oral precancerous lesions: Highlighting randomized controlled trials and cohort studies

Currently, surgical excision remains a common intervention for oral precancerous lesions (OPL). However, the studies focusing on conventional surgery by scalpel for OPL are not analyzed collectively in detail. Therefore, the objective of this short communication is to summarize and evaluate the evidence on scalpel surgery in preventing the progression of OPL patients. There are 16 eligible studies on surgery management of the recurrence (13 studies) or malignant transformation (13 studies) of OPL. The pooled recurrence rate (95% confidence interval) of OPL patients received scalpel surgery and laser therapy is 29.5% (26.3-33.0%) and 32.2% (26.1-38.9%), respectively. The pooled rate of malignant transformation of OPL patients received scalpel surgery, laser therapy, and clinical observation is 8.9% (7.3-10.9%), 6.0% (3.5-10.1%), and 10.2% (8.6-12.1%), respectively. The important limitation of current evidence available for prognosis of dysplastic OPL is based on retrospective observational studies. It highlights that surgical management of OPL needs more randomized controlled trials and cohort studies to explore more reliable methods for routine clinical use to facilitate high- or low-risk stratification and further select more appropriate treatment option.

Description of clinicopathological characteristics of oral potentially malignant disorders with special focus on two histopathologic grading systems and subepithelial inflammatory infiltrate

OBJECTIVE

This study was conducted to evaluate the clinicopathological features of oral potentially malignant disorders (OPMDs) with a focus on two histologic grading systems and subepithelial inflammatory infiltrates.

MATERIALS AND METHODS

This cross-sectional and multicenter study was conducted from April 2016 to September 2021 and comprised patients diagnosed with OPMDs. Hematoxylin and eosin-stained slides of 127 cases were assessed based on the World Health Organization (WHO) 2005 classification system, namely, epithelial precursor lesions and binary system of oral epithelial dysplasia (OED). Chi-square test and Fisher's exact test were used to compare different categorical variables related to OPMDs.

RESULTS

The mean age of OPMD cases at presentation was 54.72 13.30 (P < 0.01) with a male to female ratio of 1.6:1. Oral leukoplakia (52.8%) was the most commonly diagnosed form of OPMD. Most OPMDs were classified as oral epithelial hyperplasia (59.1%) and the remaining (40.9%) as OED (P < 0.01). Of the 52 OPMDs with OED, all cases of mild dysplasia (36.5%) and carcinoma in situ (9.6%) were categorized as low-risk and high-risk lesions, respectively. Chronic inflammatory infiltrate (79.5%) was the most common subepithelial inflammatory alteration observed among OPMDs.

CONCLUSIONS

Early detection of OPMDs is vital due to increased risk of developing into oral cancer. Timely clinicopathological risk assessment of OPMD is desirable for improving the prognosis and preventing the malignant transformation in oral premalignancy. Besides the epithelial precursor lesions' classification by the WHO, binary system of grading OED use can be encouraged. Also, subepithelial inflammatory infiltrate can be of importance in future research regarding OPMDs.

Oral Chronic Hyperplastic Candidiasis and Its Potential Risk of Malignant Transformation: A Systematic Review and Prevalence Meta-Analysis

Chronic hyperplastic candidiasis (CHC) is a prototypical oral lesion caused by chronic Candida infection. A major controversy surrounding CHC is whether this oral lesion owns malignant transformation (MT) potential. The aim of the present study was to evaluate current evidence on the MT of CHC and to determine the variables which have the greatest influence on cancer development. Bibliographical searches included PubMed, Embase, Web of Science, Scopus and LILACS. The cohort studies and case series used to investigate the MT of CHC were deemed suitable for inclusion. The quality of the enrolled studies was measured by the Joanna Briggs Institute scale. Moreover, we undertook subgroup analyses, assessed small study effects, and conducted sensitivity analyses. From 338 studies, nine were finally included for qualitative/quantitative analysis. The overall MT rate for CHC across all studies was 12.1% (95% confidential interval, 4.1–19.8%). Subgroup analysis showed that the MT rate increased when pooled analysis was restricted to poor quality studies. It remains complex to affirm whether CHC is an individual and oral, potentially malignant disorder according to the retrieved evidence. Prospective cohort studies to define the natural history of CHC and a consensus statement to clarify a proper set of diagnostic criteria are strongly needed. PROSPERO ID: CRD42022319572.

Oral potentially malignant disorder research in Taiwan and mainland China: A scientometric analysis

Scientometric analysis of a disease is often conducted to recognize research trends and study hotspots. In this report, we analyze the scientometric characteristics of oral potentially malignant disorder (OPMD) research in Taiwan and mainland China. There are 324 and 718 articles on OPMD research originating from Taiwan and Mainland between 2006 and 2021, respectively. The most common subtype of OPMD research in Taiwan and Mainland is oral submucous fibrosis and lichen planus, respectively. Based on the list of main keywords extracted from the included articles, areca/betel quid chewing and alcohol use are the distinctive risk factors in Taiwan. Research on cancer screening, fibroblast/myofibroblast, and smooth muscle actin α are distinctive keywords in Taiwan; whereas the research on apoptosis, cytokine, and inflammation are distinctive keywords in Mainland. The distinctive characteristics of OPMD research are analyzed between Taiwan and mainland China, which may reflect the importance and concerned topics of research.

Malignant Transformation Rate of Oral Submucous Fibrosis: A Systematic Review and Meta-Analysis

Oral submucous fibrosis (OSF) is a chronic progressive condition affecting the oral cavity, oropharynx and upper third of the oesophagus. It is a potentially malignant disorder. The authors collated and analysed the existing literature to establish the overall malignant transformation rate (MTR). A retrospective analysis of medical and dental scientific literature using online indexed databases was conducted for the period 1956 to 2021. The quality of the enrolled studies was assessed by the Newcastle-Ottawa Scale (NOS). A meta-analysis using a random effects model of a single proportion was performed along with statistical tests for heterogeneity. The overall proportion of malignancy across all studies was 0.06 (95% CI, 0.02–0.10), indicating an overall 6% risk of malignant transformation across all studies and cohorts. Sub-group analyses revealed strong differences in proportion of malignancy according to ethnicity/cohort; Chinese = 0.02 (95% CI 0.01–0.02), Taiwanese = 0.06 (95% CI, 0.03–0.10), Indian = 0.08 (95% CI, 0.03–0.14) and Pakistani = 0.27 (95% CI 0.25–0.29). Overall, the MTR was 6%; however, wide heterogeneity of the included studies was noted. Geographic variations in MTR were noted but were not statistically significant. Further studies are required to analyse the difference between cohort groups.

Taxonomic and Functional Dysregulation in Salivary Microbiomes During Oral Carcinogenesis

Exploring microbial community compositions in humans with healthy versus diseased states is crucial to understand the microbe-host interplay associated with the disease progression. Although the relationship between oral cancer and microbiome was previously established, it remained controversial, and yet the ecological characteristics and their responses to oral carcinogenesis have not been well studied. Here, using the bacterial 16S rRNA gene amplicon sequencing along with the in silico function analysis by PICRUSt2 (Phylogenetic Investigation of Communities by Reconstruction of Unobserved States 2), we systematically characterized the compositions and the ecological drivers of saliva microbiome in the cohorts of orally healthy, non-recurrent oral verrucous hyperplasia (a pre-cancer lesion), and oral verrucous hyperplasia–associated oral cancer at taxonomic and function levels, and compared them with the re-analysis of publicly available datasets. Diversity analyses showed that microbiome dysbiosis in saliva was significantly linked to oral health status. As oral health deteriorated, the number of core species declined, and metabolic pathways predicted by PICRUSt2 were dysregulated. Partitioned beta-diversity revealed an extremely high species turnover but low function turnover. Functional beta-diversity in saliva microbiome shifted from turnover to nestedness during oral carcinogenesis, which was not observed at taxonomic levels. Correspondingly, the quantitative analysis of stochasticity ratios showed that drivers of microbial composition and functional gene content of saliva microbiomes were primarily governed by the stochastic processes, yet the driver of functional gene content shifted toward deterministic processes as oral cancer developed. Re-analysis of publicly accessible datasets supported not only the distinctive family taxa of Veillonellaceae and Actinomycetaceae present in normal cohorts but also that Flavobacteriaceae and Peptostreptococcaceae as well as the dysregulated metabolic pathways of nucleotides, amino acids, fatty acids, and cell structure were related to oral cancer. Using predicted functional profiles to elucidate the correlations to the oral health status shows superior performance than using taxonomic data among different studies. These findings advance our understanding of the oral ecosystem in relation to oral carcinogenesis and provide a new direction to the development of microbiome-based tools to study the interplay of the oral microbiome, metabolites, and host health.

Management of Oral Potentially Malignant Disorders

Patients with oral potentially malignant disorders (OPMDs), including oral leukoplakia and erythroplakia, proliferative verrucous leukoplakia, oral submucous fibrosis, and oral lichen planus/lichenoid lesions can be challenging to manage. A small proportion will undergo cancer development and determining a patient's cancer risk is key to making management decisions. Yet, our understanding of the natural history of OPMDs has not been fully elucidated, and a precision approach based on the integration of numerous predictive markers has not been validated by prospective studies. Evidence-based health promotion by clinicians and healthcare systems is not embraced universally. Medical and surgical interventions evaluated by rigorous research measuring important endpoints, such as cancer development, mortality, or survival are difficult and expensive to run. Most of these studies employ non-ideal surrogate endpoints and have deep methodologic flaws. Diagnostic criteria for enrolling research subjects are not uniform, and patients with the highest risk for cancer development comprise small proportions of those enrolled. Few studies explore quality of life and patient preferences. It is time to rethink how we approach the management of these patients, across each OPMD, and considering the healthcare infrastructure and cost effectiveness. Global networks with well-characterized patient populations with OPMDs and well-designed interventional trials using validated outcome measures are needed.

LINC00084/miR-204/ZEB1 Axis Mediates Myofibroblastic Differentiation Activity in Fibrotic Buccal Mucosa Fibroblasts: Therapeutic Target for Oral Submucous Fibrosis

Oral submucosal fibrosis (OSF) is a precancerous condition in the oral cavity and areca nut consumption has been regarded as one of the etiologic factors implicated in the development of OSF via persistent activation of buccal mucosal fibroblasts (BMFs). It has been previously reported that an epithelial to mesenchymal transition (EMT) factor, ZEB1, mediated the areca nut-associated myofibroblast transdifferentiation. In the current study, we aimed to elucidate how areca nut affected non-coding RNAs and the subsequent myofibroblast activation via ZEB1. We found that long non-coding RNA LINC00084 was elicited in the BMFs treated with arecoline, a major alkaloid of areca nut, and silencing LINC00084 prevented the arecoline-induced activities (such as collagen gel contraction, migration, and wound healing capacities). The upregulation of LINC00084 was also observed in the OSF tissues and fibrotic BMFs (fBMFs), and positively correlated with several fibrosis factors. Moreover, we showed knockdown of LINC00084 markedly suppressed the myofibroblast features in fBMFs, including myofibroblast phenotypes and marker expression. The results from the luciferase reporter assay confirmed that LINC00084 acted as a sponge of miR-204 and miR-204 inhibited ZEB1 by directly interacting with it. Altogether, these findings suggested that the constant irritation of arecoline may result in upregulation of LINC00084 in BMFs, which increased the ZEB1 expression by sequestering miR-204 to induce myofibroblast transdifferentiation.

Oral tongue leukoplakia: analysis of clinicopathological characteristics, treatment outcomes, and factors related to recurrence and malignant transformation

OBJECTIVES

The tongue is identified as a high-risk site for oral leukoplakia and malignant transformation. The purpose of this study is to investigate the clinicopathological characteristics and treatment outcomes of tongue leukoplakia and assess the factors related to recurrence and malignant transformation.

MATERIALS AND METHODS

One hundred and forty-four patients who received carbon dioxide laser surgery for tongue leukoplakia from 2002 to 2019 were analyzed statistically.

RESULTS

The follow-up period was 54.90 ± 54.41 months. Thirty patients showed postoperative recurrence (20.83%), and 12 patients developed malignant transformation (8.33%). The annual transformation rate was 2.28%. Univariate analysis showed that a history of head and neck cancer, size of lesion area, clinical appearance, and pathology were significant factors for both recurrence and malignant transformation. In the multivariate logistic regression, a history of head and neck cancer and size of lesion area were independent prognostic factors for recurrence, and a history of head and neck cancer was the only independent factor for postoperative malignant change.

CONCLUSIONS

Clinicians should adopt more aggressive strategies for tongue leukoplakia patients with a history of head and neck cancer.

CLINICAL RELEVANCE

These results may help clinicians gain a better understanding of oral tongue leukoplakia.

Comparison of the accuracy of diagnoses of oral potentially malignant disorders with dysplasia by a general dental clinician and a specialist using the Taiwanese Nationwide Oral Mucosal Screening Program

Screening for oral potentially malignant disorders (OPMDs) with dysplasia in high-risk groups is suggested in countries with a high prevalence of the disorders. This study aimed to compare the accuracy of diagnoses of OPMDs with dysplasia made by a primary examiner (general dental clinician) and a specialist (oral and maxillofacial surgeon) using the current Taiwanese Nationwide Oral Mucosal Screening Program (TNOMSP). A total of 134 high-risk participants were enrolled for oral mucosal screening via the TNOMSP. A primary examiner and a specialist examined each participant. Mucosal biopsies were obtained and subjected to histopathological analysis. The OPMD most frequently diagnosed by the primary examiner was thin homogeneous leukoplakia (48/134; 35.8%), and in 39/134 participants (29.1%) the diagnosis was uncertain, but abnormalities were suggested. The OPMDs most frequently diagnosed by the specialist were erythroleukoplakia (23/134; 17.2%) and thin homogeneous leukoplakia (21/134; 15.7%), and 51/134 participants (38.1%) were diagnosed with other diseases. Via histopathology, 70/134 participants (52.3%) were diagnosed with dysplasia, and 58/134 (43.3%) were diagnosed with benign conditions. The specialist's diagnoses exhibited a higher specificity, positive predictive value, and accuracy than the primary examiners. A specialist using the current TNOMSP for high-risk participants diagnosed OPMDs with dysplasia more accurately than a primary examiner. Early diagnosis of high-risk OPMDs is crucial in countries with a high prevalence of the disorders. Proficient examination via the current TNOMSP by trained clinician is effective for the management of OPMDs with dysplasia.

Genetic Susceptibility and Protein Expression of Extracellular Matrix Turnover-Related Genes in Oral Submucous Fibrosis

Betel quid (BQ) chewing increased the risk of oral cancer and oral submucous fibrosis (OSMF), an oral premalignant disorder (OPMD) with malignant transformation potential. BQ components such as areca nut (AN), trauma by coarse AN fiber, catechin, copper, alkaloids, stimulated reactive oxygen species (ROS), inflammation and cytotoxicity are suggested to be the contributing factors. They may induce tissue inflammation, proliferation of fibroblasts and collagen deposition, myofibroblast differentiation and contraction, collagen cross-links and inhibit collagen phagocytosis, finally leading to the development of OSMF and oral cancer. These events are mediated by BQ components-induced changes of extracellular matrix (ECM) turnover via regulation of TGF-β1, plasminogen activator inhibitor-1 (PAI-1), cystatin, lysyl oxidase (LOX) and tissue inhibitors of metalloproteinases (TIMPs) and metalloproteinases (MMPs). Genetic susceptibility is also involved in these disease processes. Further understanding the molecular mechanisms of BQ-induced OSMF and oral cancer can be helpful for future disease prevention and treatment.

Profiling risk factors of micro-invasive carcinoma within oral potentially malignant disorders: a cross-sectional study

OBJECTIVES

To investigate the clinicopathological profile and risk factors of micro-invasive carcinoma within oral potentially malignant disorders (OPMD).

METHODS

Micro-invasive carcinomas were identified in a large prospective series of OPMD patients (n = 810) from eastern China. Logistic regression was applied to evaluate odds ratios (OR) with 95% confidence interval (CI) for indicative of malignant risk in general OPMD.

RESULTS

Leukoplakia (41.4%), lichen planus (28.0%), and lichenoid lesion (23.7%) were the most 3 clinical subtypes of OPMD. A total of 62 (7.7%) micro-invasive carcinomas within OPMD were identified, and 96.8% of micro-invasive carcinoma was found within leukoplakia and erythroplakia. Multivariate regression analysis revealed that the risk of malignant change within OPMD located on lateral/ventral tongue (OR, 15.1; 95% CI, 1.85-122.8; P = 0.011) was higher than other sites. The risk of malignant change within non-homogenous type (OR, 103.3; 95% CI, 13.39-796.7; P < 0.001) was strikingly higher than other subtypes of OPMD, respectively. Intriguingly, the risk of micro-invasive carcinoma diagnosed in current smoker (OR, 3.96; 95% CI, 1.31-12.02; P = 0.015) was higher than non-smoker.

CONCLUSION

This large-scale cross-sectional study elucidated the clinical factors and risk assessment of micro-invasive carcinoma within OPMD.

CLINICAL RELEVANCE

Non-homogenous lesions located on lateral/ventral tongue might be monitored at closer intervals, and the need for rigorous management to detect malignant changes.