Oral leukoplakia: A clinicopathological study and malignant transformation

Epidemiology, Diagnostics, and Therapy of Oral Cancer-Update Review

Oral cavity and lip cancers are the 16th most common cancer in the world. It is widely known that a lack of public knowledge about precancerous lesions, oral cancer symptoms, and risk factors leads to diagnostic delay and therefore a lower survival rate. Risk factors, which include drinking alcohol, smoking, HPV infection, a pro-inflammatory factor-rich diet, and poor oral hygiene, must be known and avoided by the general population. Regular clinical oral examinations should be enriched in an oral cancer search protocol for the most common symptoms, which are summarized in this review. Moreover, new diagnostic methods, some of which are already available (vital tissue staining, optical imaging, oral cytology, salivary biomarkers, artificial intelligence, colposcopy, and spectroscopy), and newly researched techniques increase the likelihood of stopping the pathological process at a precancerous stage. Well-established oral cancer treatments (surgery, radiotherapy, chemotherapy, and immunotherapy) are continuously being developed using novel technologies, increasing their success rate. Additionally, new techniques are being researched. This review presents a novel glance at oral cancer-its current classification and epidemiology-and will provide new insights into the development of new diagnostic methods and therapies.

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.

Clinical and mycological analysis of colonization by Candida spp. in oral leukoplakia and oral lichen planus

OBJECTIVE

This study aims to analyze the prevalence of Candida spp. colonization in oral leukoplakia and oral lichen planus lesions, verify the influence of systemic and local factors, besides identify and determine the in vitro antifungal susceptibility profile of Candida species.

MATERIALS AND METHODS

Samples were collected by swabbing from oral lesions and healthy mucosa and cultured on Sabouraud Dextrose and CHROMagar® Candida plates. Species identification was confirmed with MALDI-TOF MS analysis.

RESULTS

Candida spp. was found in 36.8% of cases of oral leukoplakia and 18.2% of cases of oral lichen planus. Candida albicans was the only species found in oral lichen planus lesions (n = 2, 100%) and the most prevalent in oral leukoplakia (n = 5, 76.4%). Among the non-albicans Candida species found in oral leukoplakia were C. parapsilosis (n = 2, 25.5%) and C. tropicalis (n = 1, 14.1%). Candida isolates were susceptible to all antifungals tested.

CONCLUSION

C. albicans was the most commonly found species in the studied lesions. No correlation was found between systemic and local factors with positive cases of oral lichen planus. However, smoking and alcohol consumption may be associated with positive cases of oral leukoplakia, especially the non-homogeneous clinical form. In addition, there is a possible predisposition to associated Candida colonization in cases of epithelial dysplasia found in oral leukoplakia. The antifungal medications tested showed excellent efficacy against isolates.

Single-cell transcriptome dissecting the microenvironment remodeled by PD1 blockade combined with photodynamic therapy in a mouse model of oral carcinogenesis

Oral squamous cell carcinoma (OSCC) stands as a predominant and perilous malignant neoplasm globally, with the majority of cases originating from oral potential malignant disorders (OPMDs). Despite this, effective strategies to impede the progression of OPMDs to OSCC remain elusive. In this study, we established mouse models of oral carcinogenesis via 4-nitroquinoline 1-oxide induction, mirroring the sequential transformation from normal oral mucosa to OPMDs, culminating in OSCC development. By intervening during the OPMDs stage, we observed that combining PD1 blockade with photodynamic therapy (PDT) significantly mitigated oral carcinogenesis progression. Single-cell transcriptomic sequencing unveiled microenvironmental dysregulation occurring predominantly from OPMDs to OSCC stages, fostering a tumor-promoting milieu characterized by increased Treg proportion, heightened S100A8 expression, and decreased Fib_Igfbp5 (a specific fibroblast subtype) proportion, among others. Notably, intervening with PD1 blockade and PDT during the OPMDs stage hindered the formation of the tumor-promoting microenvironment, resulting in decreased Treg proportion, reduced S100A8 expression, and increased Fib_Igfbp5 proportion. Moreover, combination therapy elicited a more robust treatment-associated immune response compared with monotherapy. In essence, our findings present a novel strategy for curtailing the progression of oral carcinogenesis.

Histopathological risk assessment in multisite epithelial dysplasia: A meta-analysis

OBJECTIVE

Histopathological grading of oral epithelial dysplasia (OED) is the current standard for stratifying cancer progression risk but is associated with subjectivity and variability. This problem is not commonly seen regarding the grading of epithelial dysplasia in other sites. This systematic review aims to compare grading systems for oral, anal, penile, and cervical epithelial dysplasia to determine their predictive accuracy for recurrence and malignant transformation (MT) outcomes.

METHODS

The review protocol was registered in PROSPERO (CRD42023403035) and was reported according to the PRISMA checklist. A comprehensive search was performed in the main databases and gray literature. The risk of bias in individual studies was analyzed using the Joanna Briggs Institute checklist for each study design.

RESULTS

Forty-six studies were deemed eligible and included in this systematic review, of which 45 were included in the quantitative analysis. Meta-analysis revealed that the binary system demonstrated a higher predictive ability for MT/recurrence of OED compared to multilevel systems. Higher predictive accuracy of MT was also observed for binary grading systems in anal intraepithelial neoplasia.

CONCLUSIONS

No significant difference was found between the current grading systems of epithelial dysplasia in different body parts. However, binary grading systems have shown better clinical outcomes.

Clinical, histopathological characteristics and malignant transformation of proliferative verrucous leukoplakia with 36 patients: a retrospective longitudinal study

BACKGROUND

Proliferative verrucous leukoplakia (PVL), distinguished by its malignant transformation rate of 43.87% to 65.8%, stands as the oral potentially malignant disorder with the highest propensity for malignancy. PVL is marked by distinctive heterogeneity regarding the clinical or histopathological characteristics as well as prognostic factors pertinent to this condition. The purpose of this study is to compile and assess the clinicopathological features, malignant transformation, and associated risk factors in patients diagnosed with PVL.

METHODS

This study is a hospital-based retrospective longitudinal study of 36 patients diagnosed with PVL from 2013 to 2023. We conducted complete clinical and histopathological evaluations of the patients.

RESULTS

The cohort comprised 16 males and 20 females, yielding a male-to-female ratio of 1:1.25. The follow-up period ranged from 8 to 125 months, with an average of 47.50 months. The most common clinical type of lesion was the verrucous form (58.33%), and the gingiva was the most common site (44.44%). Each patient had between 2 to 7 lesions, averaging 3.36 per patient. During the follow-up period, twelve patients (33.3%) developed oral cancer, with an average time to malignant transformation of 35.75 months. Kaplan-Meier survival analysis indicated that patients with complaints of pain, roughness, or a rough sensation, with diabetes, and the presence of cytologic atypia histologically showed a higher risk of malignant transformation (p < 0.05). In this study, the rate of malignant transformation in the treatment group (5/23) was lower than that in the untreated group (7/13), however, no statistically significant difference (p = 0.05).

CONCLUSION

The main complaints of pain, roughness, or foreign body sensation, coupled with cytologic atypia histologically are indicative of an increased risk of malignant transformation in PVL. Further research is needed to elucidate the influence of these clinicopathological parameters on the malignant progression of PVL.

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.

Decreased inflammatory profile in oral leukoplakia tissue exposed to cold physical plasma ex vivo

BACKGROUND

Oral leukoplakia (OL) is an unfavorable oral disease often resistant to therapy. To this end, cold physical plasma technology was explored as a novel therapeutic agent in an experimental setup.

METHODS

Biopsies with a diameter of 3 mm were obtained from non-diseased and OL tissues. Subsequently, cold atmospheric pressure plasma (CAP) exposure was performed ex vivo in the laboratory. After 20 h of incubation, biopsies were cryo-conserved, and tissue sections were quantified for lymphocyte infiltrates, discriminating between naïve and memory cytotoxic and T-helper cells. In addition, the secretion pattern related to inflammation was investigated in the tissue culture supernatants by quantifying 10 chemokines and cytokines.

RESULTS

In CAP-treated OL tissue, significantly decreased overall lymphocyte numbers were observed. In addition, reduced levels were observed when discriminating for the T-cell subpopulations but did not reach statistical significance. Moreover, CAP treatment significantly reduced levels of C-X-C motif chemokine 10 (CXCL10) and granulocyte-macrophage colony-stimulating factor in the OL biopsies' supernatants. In idiopathically inflamed tissues, ex vivo CAP exposure reduced T-cells and CXCL10 as well but also led to markedly increased interleukin-1β secretion.

CONCLUSION

Our findings suggest CAP to have immuno-modulatory properties, which could be of therapeutic significance in the therapy of OL. Future studies should investigate the efficacy of CAP therapy in vivo in a larger cohort.

The Magic Triangle in Oral Potentially Malignant Disorders: Vitamin D, Vitamin D Receptor, and Malignancy

OPMDs (oral potentially malignant disorders) are a group of disorders affecting the oral mucosa that are characterized by aberrant cell proliferation and a higher risk of malignant transformation. Vitamin D (VitD) and its receptor (VDR) have been extensively studied for their potential contributions to the prevention and therapeutic management of various diseases and neoplastic conditions, including oral cancer. Observational studies suggest correlations between VitD deficiency and higher cancer risk, worse prognosis, and increased mortality rates. Interestingly, emerging data also suggest a link between VitD insufficiency and the onset or progression of OPMDs. Understanding the role of the VitD-VDR axis not only in established oral tumors but also in OPMDs might thus enable early detection and prevention of malignant transformation. With this article, we want to provide an overview of current knowledge about OPMDs and VitD and investigate their potential association and ramifications for clinical management of OPMDs.

Malignant transformation rate of oral leukoplakia in the past 20 years: A systematic review and meta-analysis

BACKGROUND

This meta-analysis aimed to assess the rate of malignant transformation (MT) of oral leukoplakia (OL) and to study potential risk factors for the MT of OL into oral squamous cell carcinoma (OSCC).

METHOD

We performed a bibliographic search on nine electronic databases, including PubMed, MEDLINE, and Wanfang Data, for data on the MT rate of OL. Possible risk factors were calculated using Comprehensive Meta-Analysis and Open Meta [Analyst] software.

RESULTS

The pooled proportion of OL MT for the total population described in the 26 selected studies was 7.20% (95% confidence interval: 5.40-9.10%). Nonhomogeneous type lesions, higher grades of dysplasia, the location of the lesion (tongue and multifocal), and female sex had significant effects on the MT of OL.

CONCLUSION

OL tended to develop into OSCC (7.2%), and those with significant MT risk factors should be subjected to regular follow-up and observation. However, we require large-scale prospective studies to validate these results, together with unified clinicopathological diagnostic criteria, standardized risk factor recording/assessment methods, and long-term follow-up guidelines.

Photodynamic therapy (PDT) for oral leukoplakia: a systematic review and meta-analysis of single-arm studies examining efficacy and subgroup analyses

OBJECTIVE

This study aims to evaluate the efficacy of photodynamic therapy (PDT) in the treatment of oral leukoplakia and explore the subgroup factors that may influence its effectiveness.

METHODS

A systematic search was conducted in PubMed, Embase, the Cochrane Library, and Web of Science databases to identify relevant studies. Meta-analysis was performed using Stata15.0 software. Cochran's Q test and I2 statistics were used to evaluate heterogeneity, egger's test was used to evaluate publication bias.

RESULTS

The analysis of 17 studies included in this study suggests that PDT may be effective in achieving complete response (CR) [ES = 0.50, 95%CI: (0.33,0.66)], partial response (PR) [ES = 0.42, 95%CI: (0.27,0.56)], no response (NR) [ES = 0.19, 95%CI: (0.11,0.27)]in patients with oral leukoplakia. The recurrence rate was also evaluated [ES = 0.13, 95%CI: (0.08,0.18)]. Subgroup analysis showed that various factors such as light source, wavelength, medium, duration of application, clinical and pathological diagnosis classification influenced efficacy of PDT. The lesion areas of the leukoplakia after treatment were reduced by 1.97cm2 compared with those before treatment.

CONCLUSION

Our findings show that PDT is a viable treatment for oral leukoplakia. However, the effectiveness of the therapy may depend on several factors, as suggested by our subgroup analyses. (Registration no. CRD42023399848 in Prospero, 26/02/2023).

Effect of clinical and histologic features on time to malignancy in 224 cases of oral leukoplakia treated by surgery

Objectives

Our main purpose and research question were to analyze and quantify whether there were significant differences in the time to develop cancer among patients with oral leukoplakia (OL), comparing the more susceptible cases to those with the least susceptibility to malignancy.

Materials and methods

We followed 224 cases of OL after surgical or CO₂ laser treatment for a mean time of 6.4 years. A Bayesian mixture cure model based on the Weibull distribution was used to model the relationship between our variables and cancer risk. In this model type, the population is considered a mixture of individuals who are susceptible or non-susceptible to developing cancer. The statistical model estimates the probability of cure (incidence model) and then infers the time to malignancy. The model was adjusted using the R-package INLA using default priors.

Results

Histology type (moderate or severe dysplasia) and tongue location showed hazard ratios (HR) of 3.19 (95% CI [1.05–8.59]) and 4.78 (95% CI [1.6–16.61]), respectively. Both variables increased the risk of malignant transformation, thus identifying a susceptible subpopulation with reduced time required to develop cancer, as with non-homogeneous leukoplakias. The median time for cancer development was 4 years and 5 months, with a minimum of 9 months after the diagnosis of OL and a maximum of 15 years and 2 months.

Conclusions

Susceptible patients with non-homogeneous leukoplakia, dysplasia, or leukoplakia in the tongue develop cancer earlier than those with homogeneous OL and those without dysplasia.

Clinical relevance

The novel contribution of this research is that, until now, the time it took for oral leukoplakias to develop cancer based on whether they were homogeneous or non-homogeneous, and if they have or not epithelial dysplasia, had not been comparatively described and quantified. As a final result, the time to malignant transformation in non-homogeneous and dysplastic leukoplakias is significantly shorter.

Development and Validation of a Non-Invasive, Chairside Oral Cavity Cancer Risk Assessment Prototype Using Machine Learning Approach

Oral cavity cancer (OCC) is associated with high morbidity and mortality rates when diagnosed at late stages. Early detection of increased risk provides an opportunity for implementing prevention strategies surrounding modifiable risk factors and screening to promote early detection and intervention. Historical evidence identified a gap in the training of primary care providers (PCPs) surrounding the examination of the oral cavity. The absence of clinically applicable analytical tools to identify patients with high-risk OCC phenotypes at point-of-care (POC) causes missed opportunities for implementing patient-specific interventional strategies. This study developed an OCC risk assessment tool prototype by applying machine learning (ML) approaches to a rich retrospectively collected data set abstracted from a clinical enterprise data warehouse. We compared the performance of six ML classifiers by applying the 10-fold cross-validation approach. Accuracy, recall, precision, specificity, area under the receiver operating characteristic curve, and recall–precision curves for the derived voting algorithm were: 78%, 64%, 88%, 92%, 0.83, and 0.81, respectively. The performance of two classifiers, multilayer perceptron and AdaBoost, closely mirrored the voting algorithm. Integration of the OCC risk assessment tool developed by clinical informatics application into an electronic health record as a clinical decision support tool can assist PCPs in targeting at-risk patients for personalized interventional care.