Differences in the response of normal oral mucosa, oral leukoplakia, oral squamous cell carcinoma-derived mesenchymal stem cells, and epithelial cells to photodynamic therapy.

OBJECTIVE: The objective of this study is to investigate the variances in transcriptome gene expression of normal oral mucosa-derived mesenchymal stem cell (OM-MSC), oral leukoplakia-derived MSC (OLK-MSC) and oral squamous cell carcinoma-derived MSC(OSCC-MSC). as Additionally, the study aims to compare the in vitro proliferation, migration, invasion ability, and response to photodynamic therapy (PDT) of these three MSC, HOK, DOK, leuk1, and Cal27 cell lines. METHODS: HOK, DOK, leuk1, Cal27 cells were cultured in vitro. 3 MSC cells were obtained from OM, OLK, OSCC tissue (n = 3) and identified through flow cytometry. They were also cultured in vitro for osteogenic and lipogenic-induced differentiation. Based on the Illumina HiSeq high-throughput sequencing platform, OM-MSC, OLK-MSC, OSCC-MSC (n = 3) were subjected to transcriptome sequencing, functional annotation, and enrichment analysis of differentially expressed genes and related genes. CCK8 assay, wound healing assay, and transwell assay were performed to compare the proliferation, migration, and invasion of the seven types of cells. The 7 cells were incubated with 0, 0.125 mM, 0.25 mM, 0.5 mM, 1 mM, and 2 mM of the photosensitizer (5-aminolevulinic acid, 5-ALA) in vitro. Subsequently, they were irradiated with a 150 mM, 635 nm laser for 1 min, and the cell activity was detected using the CCK8 assay after 24 h. The mitochondrial changes in the 7 cells before and after the treatment of PDT were detected using the JC-10 probe, and the changes in ATP content were measured before and after the PDT treatment. RESULTS: OM-MSC, OLK-MSC, and OSCC-MSC expressed positive MSC surface markers. After osteogenic and lipogenic-induced differentiation culture, stained calcium nodules and lipid droplets were visible, meeting the identification criteria of MSC. Pathway enrichment analysis revealed that the differentially expressed genes (DEGs) of OSCC-MSC compared to OLK-MSC were primarily associated with the PI3K-Akt signaling pathway and tumor-related pathways. OSCC-MSC exhibited stronger migratory and invasive abilities compared to Cal27. The IC50 values required for OM, OLK, and OSCC-derived MSC were lower than those required for epithelial cells treated with PDT, which were 1.396 mM, 0.9063 mM, and 2.924 mM, respectively. Cell membrane and mitochondrial disruption were observed in seven types of cells after 24 h of PDT treatment. However, HOK, DOK, leuk1, and Cal27 cells had an ATP content increased. CONCLUSIONS: OLK, OSCC epithelial cells require higher concentrations of 5-ALA for PDT treatment than MSC of the same tissue origin. The concentration of 5-ALA required increases with increasing cell malignancy. Differences in the response of epithelial cells and MSC to PDT treatment may have varying impacts on OLK recurrence and malignancy.

Proliferative verrucous leukoplakia: a general dental practitioner-focused clinical review.

Proliferative verrucous leukoplakia (PVL) is a distinct type of oral leukoplakia which has the potential to enlarge or develop into new areas of leukoplakia coupled with areas of a warty surface texture. PVL is usually diagnosed from the fifth decade onwards and is more common in female patients. The most frequent sites involved tend to be gingivae, followed by buccal mucosa and lateral border of tongue. It is one of the oral potentially malignant conditions with a high risk of malignant transformation. It is important for general dental practitioners (GDPs) to identify such lesions to facilitate referral for further investigation and diagnosis. Management is challenging with long-term monitoring and surgical excision when appropriate; however, PVL tends to recur following surgical excision. This article provides an up-to-date review tailored for GDPs on the present knowledge of PVL and illustrates the management challenges with clinical cases.

[Research progress in the diagnosis and management of proliferative verrucous leukoplakia].

Proliferative verrucous leukoplakia (PVL) is one of the oral potentially malignant disorders (OPMD) with the highest malignant potential. PVL tends to be easily misdiagnosed owing to the resemblance in clinical manifestations between PVL and other diseases such as oral leukoplakia or oral lichen planus. PVL is considered as a special type of oral leukoplakia by some scholars, which is characterized by its tendency of recurrence and metastasis, along with its high risk of malignant transformation. So far, the accurate clinic diagnosis and management of PVL are still intractable due to the lack of definite histopathological definition, unified diagnostic criteria and effective treatment modalities. This review aims to provide the clinical practitioners with a series of advices on the clinical diagnosis and management of PVL by systematically reviewing the diagnostic logistics, therapeutic strategies, malignant transformation detection based on tremendous relevant data and evidence-based medicine.

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-1ß 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.

Identification of Proteomic Biomarkers in Proliferative Verrucous Leukoplakia through Liquid Chromatography With Tandem Mass Spectrometry.

Proliferative verrucous leukoplakia (PVL) is an oral potentially malignant disorder associated with high risk of malignant transformation. Currently, there is no treatment available, and restrictive follow-up of patients is crucial for a better prognosis. Oral leukoplakia (OL) shares some clinical and microscopic features with PVL but exhibits different clinical manifestations and a lower rate of malignant transformation. This study aimed to investigate the proteomic profile of PVL in tissue and saliva samples to identify potential diagnostic biomarkers with therapeutic implications. Tissue and saliva samples obtained from patients with PVL were compared with those from patients with oral OL and controls. Label-free liquid chromatography with tandem mass spectrometry was employed, followed by qualitative and quantitative analyses, to identify differentially expressed proteins. Potential biomarkers were identified and further validated using immunohistochemistry. Staining intensity scan analyses were performed on tissue samples from patients with PVL, patients with OL, and controls from Brazil, Spain, and Finland. The study revealed differences in the immune system, cell cycle, DNA regulation, apoptosis pathways, and the whole proteome of PVL samples. In addition, liquid chromatography with tandem mass spectrometry analyses showed that calreticulin (CALR), receptor of activated protein C kinase 1 (RACK1), and 14-3-3 Tau-protein (YWHAQ) were highly expressed in PVL samples. Immunohistochemistry validation confirmed increased CARL expression in PVL compared with OL. Conversely, RACK1 and YWHA were highly expressed in oral potentially malignant disorder compared to the control group. Furthermore, significant differences in CALR and RACK1 expression were observed in the OL group when comparing samples with and without oral epithelial dysplasia, unlike the PVL. This research provides insights into the molecular mechanisms underlying these conditions and highlights potential targets for future diagnostic and therapeutic approaches.

Practice patterns for initial management of oral leukoplakia amongst otolaryngologists and oral and maxillofacial surgeons.

OBJECTIVE: Oral leukoplakia is encountered frequently by otolaryngologists and oral and maxillofacial surgeons (OMFS). There are no consensus practice management guidelines for oral leukoplakia, resulting in heterogeneity in practice patterns. Characterization of practice patterns of providers who treat oral leukoplakia will be valuable to establish standards of care and future practice guidelines. MATERIAL AND METHODS: A survey was designed by the American Head and Neck Society Cancer Prevention Service collecting demographic and practice management data for treating oral leukoplakia. The survey was approved and distributed to members of the American Academy of Otolaryngology-Head and Neck Surgery and American Association of Oral and Maxillofacial Surgeons. Data analysis was performed using chi square and t-test where appropriate. RESULTS: 396 responses were collected: 83 OMFS, 81 head and neck fellowship-trained providers, and 232 otolaryngologists (non-head and neck fellowship-trained). Providers saw a wide volume of oral leukoplakia (23.0% >30 cases/year, 35.1% 11-30 cases/year, 41.2% 10 or less cases/year), with OMFS seeing more cases of oral leukoplakia. Factors most associated with consideration of initial biopsy included physical exam findings (94.4%), erythroplakia (82.3%), and smoking status (81.6%). The majority of respondents saw patients in follow-up within 1 month (24.8%) or within 1-3 months (46.5%). CONCLUSION: This survey identifies a range of practice patterns in initial management of oral leukoplakia, including indications for biopsy, and time for follow-up. This data provide insight into practice patterns amongst different groups of providers and can potentially lead to consensus guidelines for initial management of oral leukoplakia.

Wolf in sheep's clothing - Oral proliferative verrucous leukoplakia: Progression with longitudinal molecular insights.

BACKGROUND: Oral proliferative verrucous leukoplakia (OPVL) is a chronic form of oral leukoplakia that progresses to a multifocal disease with confluent, exophytic and proliferative features. The clinical differential diagnosis for OPVL includes frictional keratosis, leukoplakia, chronic hyperplastic candidiasis, squamous papilloma, verrucous hyperplasia, verrucous carcinoma and squamous cell carcinoma. In this study, we aimed to delineate the dynamic changes in molecular signature during OPVL progression. We compare to a cohort of oral cavity keratinizing squamous cell carcinoma (OSCC) patients covering the spectrum of verrucous carcinoma to invasive squamous cell carcinoma including cytologically bland cuniculatum variant. METHODS: Samples from a large OPVL lesion that exhibited a histopathologic continuum of OPVL progression. RESULTS: Canonical hotspot TERT promoter mutations were identified in all patients. TERT C228T was dominant and mutually exclusive with TERT C250T. In patients with TERT C250T, there was concurrent PI3 point mutation. TP53 mutations were also consistently found (8/10). At the protein level, p53 was abnormal, with loss of function and gain of function. CONCLUSIONS: OPVL is a pathology that shows proximity to the gene expression profile of OSCC, highlighting signatures in common that can be important targets for drug treatment, as well as in the development of diagnostic and prognostic strategies for this disease.

Oral leukoplakia diagnosis and treatment in Europe and Australia: Oral Medicine Practitioners' attitudes and practice.

The management of oral potentially malignant disorders (OPMD) including oral leukoplakia (OL) is not currently structured according to agreed guidelines. The current report presents survey data gathered from Oral Medicine Practitioners (OMPs) in Europe and Australia and is aimed to investigate attitudes and practice in the diagnosis, risk stratification and treatment of OL. In the presence of a clinical provisional diagnosis of OL, respondents reported always undertaking biopsy in 83% of cases, with most OMPs also relying on diagnostic adjuncts. The potential for malignant transformation is almost invariably assessed through epithelial dysplasia status, with other biomarkers described in the literature used less often. Active treatment of OL was considered mandatory by 20% of OMPs, while others reserve treatment for selected cases only. OMPs are mostly driven to active treatment by lesion-related features which are frequently jointly considered including lesion site, clinical appearance and dysplasia status. Inconsistent assessment was observed regarding mild dysplasia, lesion size, presence of unavoidable trauma, exposure to tobacco and patient age. Frequently observed geographical variations were seldom statistically significant. In agreement with previous surveys, a lack of consensus around the management of OL was observed, supporting claims from learned academies and societies for treatment guidelines aiming to reduce inter-practitioner variability.

Segmentation of Oral Leukoplakia (OL) and Proliferative Verrucous Leukoplakia (PVL) Using Artificial Intelligence Techniques.

PVL (proliferative verrucous leukoplakia) has distinct clinical characteristics. They have a proclivity for multifocality, a high recurrence rate after treatment, and malignant transformation, and they can progress to verrucous or squamous cell carcinoma. AI can aid in the diagnosis and prognosis of cancers and other diseases. Computational algorithms can spot tissue changes that a pathologist might overlook. This method is only used in a few studies to diagnose LB and PVL. To see if their cellular nuclei differed and if this cellular compartment could classify them, researchers used a computational system and a polynomial classifier to compare OLs and PVLs. 161 OL and 3 PVL specimens in the lab were grown, photographed, and used for training and computation. Exam orders revealed patients' sociodemographics and clinical pathologies. The nucleus was segmented using Mask R-CNN, and LB and PVL were classified using a polynomial classifier based on nucleus area, perimeter, eccentricity, orientation, solidity, entropies, and Moran Index (a measure of disorderliness). The majority of OL patients were male smokers; most PVL patients were female, with a third having malignant transformation. The neural network correctly identified cell nuclei 92.95% of the time. Except for solidity, 11 of the 13 nuclear characteristics compared between the PVL and the LB showed significant differences. The 97.6% under the curve of the polynomial classifier was used to classify the two lesions. These results demonstrate that computational methods can aid in diagnosing these two lesions.

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.

Recombinant Human Adenovirus-p53 Therapy for the Treatment of Oral Leukoplakia and Oral Squamous Cell Carcinoma: A Systematic Review.

Background and Objectives: Oral cancer is the 6th most common cancer in the world and oral leukoplakia is an oral potentially malignant disorder that could develop into oral cancer. This systematic review focusses on randomized clinical trials for recombinant adenovirus p-53 (rAD-p53) therapy for the treatment of oral leukoplakia and cancer. Materials and Methods: We searched for research articles on various databases such as Pubmed/Medline, Embase, CNKI (China National Knowledge Infra-structure), Springerlink, cochrane and Web of sciences from 2003 to 2020. MeSH (Medical Subject Headings) terms were used for the search. Inclusion criteria included original research, randomized clinical trials and articles only in English language. Exclusion criteria were any articles that were not research articles, not randomized trials, non-human studies, etc. The articles were further graded on the Jadad scale. Results: 578 articles were assessed from various databases; only 3 articles were found to be appropriate for this review. Thus, meta-analysis was not performed because of heterogeneity and lack of data. In the three studies, whether rAD-p53 was used as a standalone therapy or with other therapies, there was a beneficial effect of the therapy. Furthermore, there were no serious adverse events and the only adverse events reported were fever, pain at the local injection site, flu-like symptoms and lowered WBC count. Conclusions: Thus, we can conclude that this therapy has a potential for beneficial therapeutic effects and further clinical trials with more patients need to be performed to get better understanding of the effect of rAD-p53 therapy, which probably will pave the way to its approval in other parts of the world.

Management of oral leukoplakia: a position paper of the Society of Oral Medicine, Chinese Stomatological Association.

OBJECTIVE: The objective of this study was to develop the first edition of a Chinese evidence-based position paper on the management of oral leukoplakia (OLK). STUDY DESIGN: The consultant group for drafting the position paper consisted of 31 oral medicine specialists and 2 evidence-based medicine specialists. English studies (searched in PubMed, EMBASE, and the Cochrane Library) and Chinese studies (searched in China National Knowledge Infrastructure and WanFang) published before January 2018 were used. The quality of the study was assessed using the Grading of Recommendations Assessment, Development, and Evaluation grid, and the strength of the recommendations was determined based on the results of 3 rounds of voting among the consultant group members using the Delphi method. RESULTS: Twenty-two evidence-based guidelines for clinical management and monitoring of OLK were established in this position paper. A clinical path diagram for oral health practitioners was constructed based on the recommendations. CONCLUSION: Current evidence suggests that management and monitoring of patients with OLK should be performed by experienced clinicians to control the lesion and for early detection of malignant transformation. However, all recommendations are based on evidence of low or extremely low quality and may require further modification as new evidence is produced.

Recurrences following treatment of proliferative verrucous leukoplakia: A systematic review and meta-analysis.

BACKGROUND: A systematic review and meta-analysis were made of the incidence of recurrences in patients with proliferative verrucous leukoplakia (PVL) subjected to different types of treatment. METHODS: The study was carried out following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement guidelines. A literature search was made in the Medline (PubMed), EMBASE, and Web of Science databases, together with a manual search, covering the period from 1985 to January 2020, with no language restrictions. Studies were included if they described treatments applied to at least 10 patients with the corresponding outcomes. Methodological quality was evaluated using Jadad scale and Newcastle-Ottawa tool. Global incidence was calculated by random effects meta-analysis using the Comprehensive Meta-analysis version 3.0 software. Publication bias was assessed using funnel plots and the Duval and Tweedie trim and fill method. RESULTS: Of the 922 identified articles, 12 were found to meet the inclusion criteria. Most of them presented moderate or low risk of bias. A total of 397 patients were analyzed. The mean age was 62.34 years and 248 were women (62.5%). The mean follow-up was 79.3 months. The most frequent treatment was surgical removal with a cold scalpel or laser (339 patients). A total of 232 subjects presented lesion recurrence. The combination of proportions global effect meta-analysis yielded a recurrence rate of 67.2% (95% CI: 48.3-81.8), with the absence of publication bias. CONCLUSIONS: There is not enough scientific evidence to conclude that any treatment strategy is able to reduce the recurrence in PVL.

Annual malignant transformation rate of oral leukoplakia remains consistent: A long-term follow-up study.

OBJECTIVES: Numerous clinical and histopathological characteristics have been associated with malignant transformation (MT) of oral leukoplakia (OL), including classic and differentiated epithelial dysplasia, but MT predictions remain suboptimal. The objective of this study was to determine the annual MT rate of OL and to identify clinicopathological risk factors associated with MT. PATIENTS AND METHODS: 170 patients with OL were included in this retrospective cohort study, 117 females and 53 males. Follow-up ranged from 12 to 219 months (median 54). The analyzed variables included age, gender, smoking habits, clinical presentation, subsite, size and treatment. In a subgroup of 140 patients, histopathological diagnoses were reviewed with regard to the presence of dysplasia, discerning both classic dysplasia and differentiated dysplasia. RESULTS: MT occurred in 23% of the patients, resulting in an annual MT rate of 4.9% (95% CI: 3.5 - 6.6) which remained consistent. High-risk subsite (tongue and floor of mouth) was the only clinical predictor for MT (Hazard Ratio = 2.7, 95% CI: 1.3 - 5.5, p = 0.007). In 140 patients, classic dysplasia (Hazard Ratio = 7.2, 95% CI: 1.6 - 33.1, p = 0.012) and differentiated dysplasia (Hazard Ratio = 6.6, 95% CI: 1.2 - 25.4, p = 0.026) were predictors for MT. Binary grading between dysplasia and no dysplasia was significant for predicting MT (Hazard Ratio = 6.4, 95% CI: 1.5 - 27.5, p = 0.013). CONCLUSION: Since annual MT rate of OL remains stable during follow-up, regular long-term or even life-long follow-up is advocated. Specific oral subsites and epithelial dysplasia are predictors for MT of OL.

Clinical comparison between Er: YAG and CO2 laser in treatment of oral tumorous lesions: A meta-analysis.

BACKGROUND: To compare clinical effect between Er: YAG and CO2 laser in treatment of oral tumorous lesions. METHODS: A comprehensive search was conducted from 2000 to 2019. The quality assessment was performed by the QUADAS-2 tool (The Cochrane Collaboration, 2011). The clinical value of comparison between Er: YAG and CO2 laser was evaluated by using the pooled estimate of sensitivity and specificity. In addition, sensitivity analysis and bias analysis were applied to ensure the accuracy of the results. RESULTS: Finally, 268 patients were enrolled in 6 studies and ultimately met the eligibility criteria. The Er: YAG and CO2 groups were 141 and 127, respectively. The meta-analysis showed significant difference in success (risk ratio  = 21.29, 95% confidence interval [1.09, 1.52], P = .002; P for Heterogeneity = .99, I = 0%) and time of surgery ((P of heterogeneity = .29, I = 20%, Z = 25.69, P of over effect < .00001). The recurrence and complications of CO2and Er: YAG groups had no difference. CONCLUSION: Er: YAG laser had better effects than CO2 laser in eliminating oral tumorous lesions while it needed longer operation time than CO2 laser.

Clinicopathologic analysis of verrucous hyperplasia, verrucous carcinoma and squamous cell carcinoma as part of the clinicopathologic spectrum of oral proliferative verrucous leukoplakia: A literature review and analysis.

OBJECTIVE: Proliferative verrucous leukoplakia is classified as a potentially malignant disorder because of its high rate of malignant transformation. PVL progresses in a series of clinical stages where the early stage represents multiple, multifocal leukoplakias with a high recurrence rate. The intermediate and late stages are clinically exophytic lesion, diagnosed microscopically as verrucous hyperplasia that often progresses into verrucous carcinoma and/or squamous cell carcinoma. There is no single histologic definition and the diagnosis is retrospective following observed progression of the disorder. The goal of the current study was to conduct a literature review and analysis of PVL in the later stages to gain further knowledge on their clinicopathologic features. DATA SOURCES: Medline's PubMed and Google Scholar were searched for adequately documented cases from 1985 to 2018. References of published articles were searched for additional cases. REVIEW METHODS: Overall, 57 manuscripts were analyzed. 35/57 manuscripts provided adequate data on the clinicopathologic features in the premalignant and malignant stages. RESULTS: Malignant transformation rate was 50% (average of 57 months). Gingiva, palate and buccal mucosa were the most common locations. Clinicopathologic features included; well differentiated carcinoma (78%), perineural invasion (3%), lymph node metastasis (4%); distant metastasis (0%), average duration of illness (65 months), DOD-dead of disease (44%). Moderate dysplasia, severe dysplasia and carcinoma in situ were exceptionally uncommon in the premalignant stages (0.8%). CONCLUSION: Prognostic factors such as perineural invasion, lymph node metastasis and distant metastasis were uncommon occurrences which may have practical implications on treatment. Further studies are needed to substantiate our findings.

Oral human papilloma virus infection: an overview of clinical-laboratory diagnosis and treatment.

OBJECTIVE: The aim of this review is to describe the "hot points" of current clinical governance for oral HPV comprising the use of new diagnostic molecular procedures, namely, Pyrosequencing and Next Generation Sequencing. MATERIALS AND METHODS: The data on oral HPV was collected through two levels of research. First for all, we used the canonical medical search engines, PubMed, and Medline, followed by the study of current commercial tools for HPV diagnosis, particularly within commercial companies involved in the molecular procedures for HPV detecting and genotyping. RESULTS: Different medical procedures are now described and used throughout the world in HPV diagnosis and treatment. However, the laboratory methods are often validated and used for genital infections, and, in these cases, data are missing in the literature as regards the clinical approach for oral lesions. CONCLUSIONS: Dental care units are often the front line for a clinical evaluation of a possible HPV lesion in the oral cavity, which means that correct clinical governance could avoid a viral neoplastic progression of this disease with great advantages for the patient. In this case, the problem is due to the difficulty in lesion recognition but also and more especially the absence of correct laboratory diagnosis and subsequent treatment in the clinical course.

Photodynamic therapy guidelines for the management of oral leucoplakia.

With recent developments in photosensitizers and light delivery systems, topical 5-aminolevulinic acid-mediated photodynamic therapy (ALA-PDT) has become the fourth alternative therapeutic approach in the management of oral leucoplakia (OLK) due to its minimally invasive nature, efficacy, and low risk of systemic side effects and disfigurement. This report presents step-by-step guidelines for applying topical ALA-PDT in the management of OLK based on both the clinical experience of the authors and a systematic review of the current literature. Studies using protocols with standardized parameters and randomized clinical trials at multiple centres with adequate sample sizes and both interim and long-term follow-ups are needed before universally applicable guidelines can be produced in this field.