The global prevalence of oral leukoplakia: a systematic review and meta-analysis from 1996 to 2022

Knowledge, Attitude, and Practice of Dutch Dentists on Oral Leukoplakia and Their Possible Role in Its Follow-Up

OBJECTIVE

To assess the knowledge, attitude, and practice of Dutch dentists on oral leukoplakia (OL) and to what extent these aspects are related to whether or not dentists regularly monitor patients with OL.

MATERIAL AND METHODS

A self-developed questionnaire was distributed via a web survey among a sample of dentists participating in an intervision program. Of 1626 invited dentists, 437 (26.9%) answered the questionnaire; 52.6% were females and 47.4% males, 36.4% were 44 years or younger, 24.0% were 45 to 54 years old and 39.6% were 55 years or older, 94.1% were general dental practitioners, 60.2% were practice owners, and 49.9% work more than 31 hours per week.

RESULTS

In total, 57.0% performed regular follow-up of patients with OL. Compared to dentists who do not perform regular follow-up of patients with OL, those who do were more confident in performing control, were more likely to be practice owners, checked a greater number of oral subsites during dental check-ups, had encountered more cases of suspected oral cancer among their own patients, and were more likely to implement effective policies when faced with mucosal lesions without a clear diagnosis. The vast majority of all participants indicated that their knowledge about oral mucosal diseases, OL, and oral cancer is limited. Just over half reported receiving insufficient education on these topics during their dental study.

CONCLUSIONS

It seems that interested dentists who have an affinity for oral mucosal diseases can properly fulfil the controlling and detecting role on selected patients with OL. Additional education on various aspects of OL is required.

CLINICAL RELEVANCE

In the Netherlands, interested dentists can responsibly follow up on a large proportion of patients with OL.

Label-based comparative proteomics of oral mucosal tissue to understand progression of precancerous lesions to oral squamous cell carcinoma

Introduction

Oral squamous cell carcinomas typically arise from precancerous lesions such as leukoplakia and erythroplakia. These lesions exhibit a range of histological changes from hyperplasia to dysplasia and carcinoma in situ, during their transformation to malignancy. The molecular mechanisms driving this multistage transition remain incompletely understood. To bridge this knowledge gap, our current study utilizes label based comparative proteomics to compare protein expression profiles across different histopathological grades of leukoplakia, erythroplakia, and oral squamous cell carcinoma samples, aiming to elucidate the molecular changes underlying lesion evolution.

Methodology

An 8-plex iTRAQ proteomics of 4 biological replicates from 8 clinical phenotypes of leukoplakia and erythroplakia, with hyperplasia, mild dysplasia, moderate dysplasia; along with phenotypes of well differentiated squamous cell carcinoma and moderately differentiated squamous cell carcinoma was carried out using the Orbitrap Fusion Lumos mass spectrometer. Raw files were processed with Maxquant, and statistical analysis across groups was conducted using MetaboAnalyst. Statistical tools such as ANOVA, PLS-DA VIP scoring, and correlation analysis were employed to identify differentially expressed proteins that had a linear expression variation across phenotypes of hyperplasia to cancer. Validation was done using Bioinformatic tools such as ClueGO + Cluepedia plugin in Cytoscape to extract functional annotations from gene ontology and pathway databases.

Results and discussion

A total of 2685 protein groups and 12,397 unique peptides were identified, and 61 proteins consistently exhibited valid reporter ion corrected intensities across all samples. Of these, 6 proteins showed linear varying expression across the analysed sample phenotypes. Collagen type VI alpha 2 chain (COL6A2), Fibrinogen β chain (FGB), and Vimentin (VIM) were found to have increased linear expression across pre-cancer phenotypes of leukoplakia to cancer, while Annexin A7 (ANXA7) was seen to be having a linear decreasing expression. Collagen type VI alpha 2 chain (COL6A2) and Annexin A2 (ANXA2) had increased linear expression across precancer phenotypes of erythroplakia to cancer. The mass spectrometry proteomics data have been deposited to the ProteomeXchanger Consortium via the PRIDE partner repository with the data set identifier PXD054190. These differentially expressed proteins mediate cancer progression mainly through extracellular exosome; collagen-containing extracellular matrix, hemostasis, platelet aggregation, and cell adhesion molecule binding.

Conclusion

Label-based proteomics is an ideal platform to study oral cancer progression. The differentially expressed proteins provide insights into the molecular mechanisms underlying the progression of oral premalignant lesions to malignant phenotypes. The study has translational value for early detection, risk stratification, and potential therapeutic targeting of oral premalignant lesions and in its prevention to malignant forms.

Clinical Management Update of Oral Leukoplakia: A Review From the American Head and Neck Society Cancer Prevention Service

BACKGROUND

Oral potentially malignant disorders (OPMDs) occur in up to 4%-5% of the population, of which oral leukoplakia (OL) is the most common subtype. Predicting high-risk OL remains a challenge. Early diagnosis and effective treatment are thought to be of paramount importance to improve outcomes.

METHODS

We searched PubMed and Clinicaltrials.gov data for updates in the clinical management of OL from 2015 to current.

RESULTS

Recent publication of large cohorts of patients with OL aids in counseling patients regarding risk of malignant transformation. Management for OL includes surveillance, excision, and laser surgery, as well as local and systemic approaches to chemoprevention. Several new entities show promise regarding candidate biomarkers, chemoprevention agents, and diagnostic adjuncts, though all require further validation.

CONCLUSION

This update serves to further inform clinical management of OL and provide impetus for future investigations.

TRIAL REGISTRATION

NCT00099021, NCT00951379, NCT05727761, NCT05727761.

Oncological Outcomes of Patients With Oral Potentially Malignant Disorders

Importance

Understanding the clinical course and malignant transformation rate of oral potentially malignant disorders (OPMDs)-including oral leukoplakia, oral erythroplakia, oral submucous fibrosis, and oral lichen planus-is crucial for early detection and improved survival rates in patients with oral cancer.

Objective

To evaluate the progression of oral cancer from OPMDs using a large US electronic medical database.

Design, Setting, and Participants

This retrospective cohort study used data from the University of California, San Francisco's PatientExploreR database between January 1973 and March 2024. Patients with oral leukoplakia, oral erythroplakia, oral submucous fibrosis, and oral lichen planus were identified using International Statistical Classification of Diseases and Related Health Problems, Tenth Revision, codes and keywords. Demographics, tobacco and alcohol use, HIV status, and other known risk factors for oral cancer were recorded to identify factors associated with malignant transformation. Logistic regression and descriptive analyses were used.

Exposure

Diagnosis of oral leukoplakia, oral erythroplakia, oral submucous fibrosis, or oral lichen planus.

Main Outcomes and Measures

Incidence of oral cancer, malignant transformation rate, median time to progression, and associations between demographics and risk factors and the development of oral cancer.

Results

Among 4 225 251 individuals in the database, 4371 were diagnosed with oral cancer (median [IQR] age, 63 [53-71] years; 2610 [59.9%] male; 0.1% of the cohort), and 110 (2.5%) had a preceding OPMD. Oral leukoplakia was found in 1124 patients, with 94 (8.4%) undergoing malignant transformation (median [IQR] time to progression, 25 [7-129] months). HIV-positive patients with oral leukoplakia were more likely to develop oral cancer (odds ratio, 3.80; 95% CI, 1.35-10.70). Of 22 patients with oral erythroplakia, 11 (50.0%) developed oral cancer (median [IQR] time to progression, 3.7 [0.2-334] months). Those who smoked tobacco with oral erythroplakia showed a higher malignant transformation rate (odds ratio, 3.75; 95% CI, 0.54-26.05). Of the 78 patients with oral submucous fibrosis, 4 (5.1%) underwent malignant transformation (median [IQR] time to progression, 36 [36-48] months). Only 1 patient with oral lichen planus developed oral cancer after 5 years.

Conclusions and Relevance

This cohort study showed that OPMDs have notable but varying propensities to progress to oral cancer. Early detection and monitoring of OPMDs are crucial for improving patient outcomes. However, the risk, etiopathogenesis, and clinical presentation vary for each OPMD and should, therefore, be considered distinct diseases.

Is autoimmunity associated with the development of premalignant oral conditions and the progression to oral squamous cell carcinoma?: A literature review

OBJECTIVE

Oral potentially malignant disorders (OPMDs) are oral mucosal conditions that may progress to oral squamous cell carcinoma (OSCC). Although autoimmunity has linked to the malignant transformation potential of various precancerous conditions, its role in OPMD remains unclear. This review aimed to identify the role of systemic autoimmunity on OPMD development and their progression to OSCC.

METHODS

A comprehensive literature search was conducted using PubMed, Cochrane CENTRAL, and SCOPUS database for articles published up to January 2024. The key questions addressed by this review were "Is autoimmunity associated with the development of OPMD" and "How does systemic autoimmunity influence the potential for malignant transformation of OPMD?". This review followed the PRISMA guidelines for scoping reviews (PRISMA-ScR).

RESULTS

Of the 1265 articles initially identified, 21 fulfilled the search criteria. Three themes were emerged; 1) the prevalence and prognosis of oral cancers in patients with systemic autoimmune diseases, 2) circulating autoantibodies in OPMD patients, and 3) autoimmune-related markers linked to malignant transformation in OPMD patients. This review indicated that systemic autoimmunity may contribute to chronic inflammatory conditions, disruption of oral mucosal integrity, and interference with the DNA damage repair process, thus influencing malignant transformation in the oral epithelium of patients with OPMD.

CONCLUSION

The co-occurrence of OPMD with circulating autoantibodies or systemic autoimmune diseases underscores the importance of understanding these interactions for improved management of OPMD and early detection of OSCC.

Evaluation of Clinical Outcomes and Recurrence After Surgical Excision of Oral Leukoplakia: A Prospective Cohort Study

OBJECTIVE

This study aimed to evaluate the clinical outcomes and recurrence patterns in cases of surgical excision of oral leukoplakia and identify key factors associated with disease recurrence and malignant transformation.

MATERIALS AND METHODS

Thirty patients aged 18-70 years who were diagnosed with oral leukoplakia through clinical and histopathological evaluation, with lesions larger than 1 cm2 requiring surgical excision, and who had ceased tobacco use or irritant habits for at least two months before surgery were considered. All the patients were monitored for 18 months postoperatively. Recurrence was defined as the reappearance of leukoplakia at or near the surgical site. Postoperative complications, including infection, scarring, and functional impairments affecting speech or mastication, were comprehensively documented at each follow-up: one week, one month, three months, six months, 12 months, and 18 months after surgery. The data were subjected to statistical analysis.

RESULTS

Overall, 27% of patients experienced recurrence, with higher recurrence rates in nonhomogenous lesions (40%), tobacco users (35%), and dysplastic lesions (100%). Factors such as a history of tobacco use and histopathological dysplasia were strongly associated with an increased risk of recurrence.

CONCLUSION

This study highlighted the significance of lesion type, dysplasia, and patient risk factors such as tobacco use in predicting postsurgical recurrence. Close follow-up and risk factor modification are recommended to optimize patient outcomes.

The Diagnostic Potential of Non-Invasive Tools for Oral Cancer and Precancer: A Systematic Review

OBJECTIVES

This systematic review aimed to analyse the published evidence for the use of non-invasive methods for the early detection of oral squamous cell carcinoma (OSCC) and oral potentially malignant disorders (OPMDs).

METHODS

The literature was systematically searched through several databases: PubMed, Cochrane Library, and Web of Science. Additional exploration was performed through cross-checks on the bibliographies of selected reviews. The inclusion criteria involved studies assessing the application of non-invasive tests on humans in the screening, diagnosis, or surveillance of OSCC or OPMDs and reporting sensitivity (SE) and specificity (SP). The Newcastle-Ottawa scale (NOS) was applied to assess the quality of the studies included.

RESULTS

The search strategy resulted in 8012 preliminary records. After a duplicate check, 116 titles remained. After abstract analysis, 70 papers remained. After full text analysis, only 54 of the 70 papers fit the inclusion criteria (28 were original articles and 26 were reviews). Those 26 reviews were used to manually search for further original articles. From this last search, 33 original articles were found. Thus, a total of 61 original studies were included and investigated. Findings from this systematic review indicate useful information, such as a description of the mechanisms, ease of use, limitations, and SE and SP values, to drive the choice of the optimal minimally invasive method to be utilized as an adjunctive tool to examine the suspicious lesions.

CONCLUSIONS

Each of the analysed tools can be improved or implemented, considering their high SE and low SP. Despite advancements, incisional biopsy continues to be the gold standard for the definitive diagnosis of oral cancer and precancerous lesions. Further research and development are essential to improving the sensitivity, specificity, and reliability of non-invasive tools for widespread clinical application.

Enhanced mucoadhesive properties of ionically cross-linked thiolated gellan gum films

Localized oral drug delivery offers several advantages for treating various disease conditions. However, drug retention at the disease site within the oral cavity is indeed a significant challenge due to the dynamic oral environment. The present study aimed to develop a mucoadhesive inner layer for a three-layer mucoadhesive bandage suitable for localized oral drug delivery. using gellan gum (GG) biopolymer. Gellan gum (GG) was modified using L-cysteine moieties via carbodiimide chemistry. Subsequently, gellan gum solution at different extents of thiolation was ionically cross-linked using aluminum ammonium sulfate. Thiolated gellan gum films of uniform thickness were prepared using a solvent casting method. The thickness of bare gellan gum film was 0.035 ± 0.0043 mm, whereas the thiolated gellan gum films, GG 1S and GG 2S showed a thickness of 0.0191 ± 0.0011 mm and 0.0188 ± 0.0004 mm respectively. A high work of adhesion was noted for thiolated gellan gum (GG 2S) with a value of 10 N.mm while using porcine buccal mucosa. An average tensile strength of 48.2 ± 2.46 MPa was measured for thiolated gellan gum films irrespective of the extent of thiolation. The high work of adhesion, favorable cytocompatibility, desirable mechanical properties, and free swell capacity in saline confirmed the suitability of ionically cross-linked thiolated gellan gum films as an inner mucoadhesive layer for the mucoadhesive bandage.

Epidemiological Trends and Clinicopathological Characteristics of Oral Leukoplakia: A Retrospective Analysis From a Single Institution in Chennai, Tamil Nadu, India

Background India has a high prevalence of oral potentially malignant disorders and malignant transformation. Cases of oral leukoplakia are not commonly encountered, and only a small cohort of patients undergo biopsies for the same. This study aims to assess the various etiological factors causing leukoplakia, the clinical features, histopathological findings, and treatment received by the patients who were histopathologically diagnosed with oral leukoplakia. Methodology Oral leukoplakia cases were included in this study from total biopsy samples received in the oral pathology department. Details were collected from the Dental Information Archival Software of our institution. The period analyzed was from January 1, 2021, to December 31, 2023. Relevant clinical and histopathological details were retrieved and tabulated. Statistical analysis (chi-square test) was used to assess the association between the clinicopathological parameters using SPSS software version 21.0 (IBM Corp., Armonk, NY, USA) with a significance level set at a p-value <0.05. Results A total of 76 oral leukoplakia cases were retrieved from 2,600 biopsy samples. The prevalence of oral leukoplakia was 3.1% to 3.4% for the three years. Leukoplakia was commonly observed in those aged 51 to 60 years (33%). Overall, 21% of the patients with leukoplakia showed severe epithelial dysplasia, 22% showed mild epithelial dysplasia, and 39% showed moderate epithelial dysplasia. Moreover, 30% of the patients presented with leukoplakia and oral submucous fibrosis and showed varying degrees of epithelial dysplasia. Finally, 45% of the patients were managed conservatively using pharmacotherapy. Conclusions Severe epithelial dysplasia was commonly associated with oral leukoplakia. Oral submucous fibrosis was also found to be associated with leukoplakia and showed epithelial dysplasia. None of our proliferative verrucous leukoplakia cases showed any association with oral submucous fibrosis. Surgical management was the preferred treatment.

Clinicopathological evaluation of oral leukoplakia: a single-center study of 676 cases in Japan

OBJECTIVES

To analyze the clinical and histopathological characteristics of oral leukoplakia (OL) in the Japanese population and investigate the prevalence and risk factors for epithelial dysplasia (ED) and carcinoma within lesions.

STUDY DESIGN

Data, including age, sex, lesion site, and histopathological features, of 676 cases diagnosed with OL over the previous 10 years were analyzed. Dysplasia and carcinoma prevalence were determined.

RESULTS

In male patients, the most affected site was the gingiva (42.7%), whereas in females, it was the tongue (47.6%). Moreover, ED was more prevalent in males (41.9%), whereas epithelial hyperplasia was more common in females (44.7%). A significant difference was observed between affected sites with regard to the presence of dysplasia. The ED rates by site were 64.6% and 33.7% for the tongue and gingiva, respectively (P < 0.05). The squamous cell carcinoma rates by site were 23.4%, 5.4%, and 3.4% for the tongue, buccal mucosa, and gingiva, respectively (P < 0.05). Logistic regression analysis revealed a higher prevalence of dysplasia in males than it did in females and that the risk for both dysplasia and carcinoma was highest in the tongue.

CONCLUSIONS

Dysplasia is common in OL cases, often showing carcinoma. Early biopsy and interventions are key in OL management.

Precursor Lesions, Overdiagnosis, and Oral Cancer: A Critical Review

Despite the profession placing great emphasis on oral potentially malignant disorders (OPMDs) as a gateway for early recognition and consequently better outcomes for oral cancer, the death rates for lip and oral cavity cancer have remained stagnant for three decades. Evidence shows that only a small fraction of oral cancers are in fact preceded by OPMDs, and that most OPMDs have an annual transformation rate of less than 1%. As OPMDs encompass a very heterogeneous group of oral conditions, it could be argued that only patients with oral mucosal diseases bearing a substantial risk of malignant transformation warrant close surveillance and treatment, these include proliferative leukoplakia, erythroplakia, non-homogeneous leukoplakia, as well as diseases presenting with severe dysplasia at biopsy. In this narrative review, I discuss the intricate epidemiology of the malignancies that we colloquially refer to as oral cancer, explore the limitations of focusing on OPMDs to reduce the incidence and mortality of oral cavity cancer, and argue that a may-be cancer label represents overdiagnosis for most OPMDs.

Laser therapy decreases oral leukoplakia recurrence and boosts patient comfort: a network meta-analysis and systematic review

BACKGROUND

Oral leukoplakia (OLK) is a prevalent precancerous lesion with limited non-pharmacological treatment options. Surgery and various lasers are the mainstay of treatment; however, their relative efficacy and optimal choice remain unclear. This first network meta-analysis compared the effects of different lasers and surgical excision on post-treatment recurrence and comfort in OLK patients.

METHODS

We searched four databases for relevant randomized controlled trials (RCTs) up to April 2023. The primary outcome was post-treatment recurrence, and secondary outcomes included intraoperative hemorrhage and postoperative pain scores. The Cochrane Risk of Bias tool was used to assess the study quality. Meta-analysis and network meta-analysis were employed to determine efficacy and identify the optimal intervention.

RESULTS

A total of 11 RCTs including 917 patients and 1138 lesions were included. Er,Cr:YSGG laser treatment showed significantly lower recurrence rates compared to CO2 laser (OR: 0.04; 95% CI: 0.01-0.18), CO2 laser with margin extension (OR: 0.06; 95% CI: 0.01-0.60), Er:YAG laser (OR: 0.10; 95% CI: 0.03-0.37), electrocautery (OR: 0.03; 95% CI: 0.00-0.18), and standard care (OR: 0.08; 95% CI: 0.02-0.33). Er,Cr:YSGG laser also ranked the best for reducing recurrence, followed by standard care and CO2 laser combined with photodynamic therapy (PDT). Er:YAG and Er:Cr:YSGG lasers minimized bleeding and pain, respectively. None of the interventions caused severe adverse effects.

CONCLUSION

For non-homogeneous OLK, Er:YAG, Er:Cr:YSGG, and CO2 laser combined with PDT offer promising alternatives to surgical excision, potentially reducing recurrence and improving patient comfort. Further high-quality RCTs are necessary to confirm these findings and determine the optimal laser-PDT combination for OLK treatment.

Oral Potentially Malignant Disorders and Oral Cancer in Saudi Arabia: An Epidemiological Review of the Literature

Background: Oral potentially malignant disorders (OPMDs) are a group of chronic oral mucosal diseases associated with an increased risk of malignant transformation. Multiple studies have investigated the prevalence of these conditions in multiple regions; however, there are limited data about the prevalence of OPMDs in the Kingdom of Saudi Arabia (KSA). This paper aims to review the prevalence of OPMDs in the KSA, to ensure better understanding of the population risk and propose a more standardised approach to the diagnosis and management of this group across the KSA. In addition, this review will discuss the prevalence of oral cancer in the KSA, considering independent risk factors for oral cancer development. Methods: Electronic databases including PubMed, Medline, Medscape, ScienceDirect, StatPearls, BMC Oral Health and the Cochrane Library were searched with the keywords "Oral Potentially Malignant Disorders"; "Saudi Arabia"; and "Oral Cancer". Identified articles were reviewed independently by 2 reviewers against defined inclusion and exclusion criteria. Results: 16 studies were included in this review. The prevalence of OPMDs in KSA varies significantly depending on age, gender, social habits, background disease and dental status. Conclusions: This review highlights the need for up-to-date data on the prevalence, distribution, and characteristics of OPMDs in KSA. The diverse prevalence rates and distinct characteristics of various OPMDs emphasise the necessity for targeted preventive measures. As the data on OPMDs in KSA remains limited, future research efforts should prioritise the establishment of comprehensive epidemiological studies to inform effective public health interventions in this region.

Oral Leukoplakia. A Five-Year Follow-Up Study

Background: Oral leukoplakia (OLK) is the most studied oral potentially malignant disorders in the scientific literature. Its malignant transformation (MT) rate varies between 1.1% and 40.8%, depending on the type of study and population group studied. There is no universal agreement to treat or manage these lesions, so it is up to each clinician's experience and expertise in how he/she manages these patients. Objective:The aim of this retrospective study was to assess the clinical aspects and pattern of evolution of OLK in 30 patients five years or more after the initial diagnosis. Material and methods:We selected 30 OLK patients from our database. Demographic, clinical and evolutive data was retrieved from the medical files. The following variables were analysed: age and sex, smoking habits, clinical features (form, dimension, site of the lesion), result of mycological examination, treatment and outcomes of the lesions over a follow-up of more than five years. Results:For a follow-up of 119.63 months, we detected a value of 0.2% MT rate per year. Outcomes varied from the complete disappearance of the lesion to recurrence and malignant transformation with a variety of treatment methods applied. Conclusion:Despite the low MT rate for a long follow-up, it is hard to say which treatment method is the best, due to the heterogeneity of the clinical aspects of the lesions and because there is no standardised test method, either genetic testing or immunohistochemical testing. We recommend a varied approach, suitable for each patient's needs and medical context, always when possible histopathological confirmation for grading epithelial dysplasia, which remains the most reliable method of checking the process of malignant transformation.