Photodynamic therapy in the treatment of oral leukoplakia: A systematic review

Effect of 5-Aminolevulinic Acid (5-ALA) in "ALADENT" Gel Formulation and Photodynamic Therapy (PDT) against Human Oral and Pancreatic Cancers

Oral squamous-cell and pancreatic carcinomas are aggressive cancers with a poor outcome. Photodynamic therapy (PDT) consists of the use of photosensitizer-induced cell and tissue damage that is activated by exposure to visible light. PDT selectively acts on cancer cells, which have an accumulation of photosensitizer superior to that of the normal surrounding tissues. 5-aminolevulinic acid (5-ALA) induces the production of protoporphyrin IX (PpIX), an endogenous photosensitizer activated in PDT. This study aimed to test the effect of a new gel containing 5% v/v 5-ALA (ALAD-PDT) on human oral CAL-27 and pancreatic CAPAN-2 cancer cell lines. The cell lines were incubated in low concentrations of ALAD-PDT (0.05%, 0.10%, 0.20%, 0.40%, 0.75%, 1.0%) for 4 h or 8 h, and then irradiated for 7 min with 630 nm RED light. The cytotoxic effects of ALAD-PDT were measured using the MTS assay. Apoptosis, cell cycle, and ROS assays were performed using flow cytometry. PpIX accumulation was measured using a spectrofluorometer after 10 min and 24 and 48 h of treatment. The viability was extremely reduced at all concentrations, at 4 h for CAPAN-2 and at 8 h for CAL-27. ALAD-PDT induced marked apoptosis rates in both oral and pancreatic cancer cells. Elevated ROS production and appreciable levels of PpIX were detected in both cell lines. The use of ALA-PDT as a topical or intralesional therapy would permit the use of very low doses to achieve effective results and minimize side effects. ALAD-PDT has the potential to play a significant role in complex oral and pancreatic anticancer therapies.

Prediction of the short-term efficacy and recurrence of photodynamic therapy in the treatment of oral leukoplakia based on deep learning

BACKGROUND

The treatment of oral leukoplakia (OLK) with aminolaevulinic acid photodynamic therapy (ALA-PDT) is widespread. Nonetheless, there is variation in efficacy. Therefore, this study constructed a model for predicting the short-term efficacy and recurrence of OLK after ALA-PDT.

METHODS

The short-term efficacy and recurrence of ALA-PDT were calculated by statistical analysis, and the relevant influencing factors were analyzed by Logistic regression and COX regression model. Finally, prediction models for total response (TR) rate, complete response (CR) rate and recurrence in OLK patients after ALA-PDT treatment were established. Features from pathology sections were extracted using deep learning autoencoder and combined with clinical variables to improve prediction performance of the model.

RESULTS

The logistic regression analysis showed that the non-homogeneous (OR: 4.911, P: 0.023) OLK and lesions with moderate to severe epithelial dysplasia (OR: 4.288, P: 0.042) had better short-term efficacy. The area under receiver operating characteristic curve (AUC) of CR, TR and recurrence predict models after the ALA-PDT treatment of OLK patients is 0.872, 0.718, and 0.564, respectively. Feature extraction revealed an association between inflammatory cell infiltration in the lamina propria and recurrence after PDT. Combining clinical variables and deep learning improved the performance of recurrence model by more than 30 %.

CONCLUSIONS

ALA-PDT has excellent short-term efficacy in the management of OLK but the recurrence rate was high. Prediction model based on clinicopathological characteristics has excellent predictive effect for short-term efficacy but limited effect for recurrence. The use of deep learning and pathology images greatly improves predictive value of the models.

Clinical efficacy of photodynamic therapy of oral potentially malignant disorder

OBJECTIVE

To investigate the clinical efficacy of aminovalerate hydrochloride photodynamic therapy (PDT) for oral potentially malignant disorder (OPMD),oral leukoplakia (OLK), along with identifying the influencing factors.Additionally, the study aims to detect the rates of recurrence and malignancy after PDT.

METHOD

60 patients with OPMD who received PDT at our hospital from 2006 to 2021 were included in this study. Relevant patient medical data were collected and analyzed using SAS 9.4 software.The Mann-Whitney U test was used to retrospectively analyze the factors influencing clinical efficacy, as well as recurrence rate and malignant transformation rate (MTR) after treatment.

RESULT

Among the 60 OPMD patients receiving PDT, complete remission in 13 (21.67 %), partial remission in 39 (65.00 %), and no remission in eight (13.33 %), resulting in an overall effective rate of 86.67 %.Fifteen patients experienced relapse, leading to a recurrence rate of 25.00 %. Among these relapses,11 patients occurred within one year after treatment, corresponding to an 18.33 % recurrence rate during that period. Moreover, nine patients developed malignant transformation (MT), resulting in an MTR of 15.00 %. Out of these patients, six individuals developed MT within one year after treatment, resulting in a one-year MTR of 10.00 %.

CONCLUSION

The study findings indicate that PDT shows promising clinical efficacy in the treatment of OPMD, with relatively limited and tolerable postoperative adverse reactions. However, there remains a certain rate of recurrence and malignancy after treatment. Therefore, close attention should be paid to postoperative monitoring, regular follow-up, and further expansion of the sample size to observe its long-term efficacy.

Clinical evaluation of photodynamic therapy for oral leukoplakia: a retrospective study of 50 patients

BACKGROUND

Topical photodynamic therapy (PDT) has demonstrated encouraging results in the treatment of oral leukoplakia (OLK). However, data on the clinical efficacy of PDT in Chinese patients with OLK are still limited.

METHODS

Fifty patients diagnosed with OLK were enrolled, including patients with various dysplastic tissues. All patients received topical PDT with 5-aminolevulinic acid (5-ALA) as a photosensitizer. Clinical efficacy was evaluated 4 weeks after treatment. Follow-up was performed every 3 months during the first year and every 6 months during the second year.

RESULTS

The overall response rate was 68% (34/50): 12% (n = 6) complete and 56% (n = 28) partial responses. Aneuploidy was reduced in the patients with dysplastic lesions. Oral pain and local ulcers developed in 52% of the patients (n = 26). Patients with a long history of OLK including hyperplasia and dysplastic lesions, as well as those with non-homogenous lesions, were more likely to develop pain and ulcer. During follow-up, the recurrence rate of hyperplasia and dysplastic lesions was 32% (n = 16) and the malignant transformation rate of dysplastic lesions was 4% (n = 2). Lesions on the buccal mucosa were associated with recurrence (P = 0.044; OR: 0.108, 95% CI: 0.013-0.915).

CONCLUSION

Topical 5-ALA-mediated PDT is an effective treatment for OLK, particularly for homogenous leukoplakia, with few side effects. The buccal mucosa may be a protective factor that can reduce recurrence.

The Potential of Nano-Based Photodynamic Treatment as a Therapy against Oral Leukoplakia: A Narrative Review

Oral leukoplakia is a predominantly white lesion of the oral mucosa that cannot be classified as any other definable lesion with the risk of progressing into malignancy. Despite the advancements in conventional therapy, the rates of malignant transformation remain notably high, affecting 4.11% of adults, due to the difficulty of accurate diagnosis and indistinct treatment. Photodynamic therapy (PDT), being a minimally invasive surgical intervention, employs a variety of factors, including light, nano-photosensitizers (PSs) and oxygen in the management of precancerous lesions. PDT faces limitations in administering photosensitizers (PSs) because of their low water solubility. However, these challenges could be effectively resolved through the incorporation of PSs in nanostructured drug delivery systems, such as gold nanoparticles, micelles, liposomes, metal nanoparticles, dendrimers and quantum dots. This review will give an overview of the different innovative PS approaches in the management of premalignant lesions, highlighting the most recent advancements. From a clinical perspective, it is expected that nanotechnology will overcome barriers faced by traditional therapeutics and will address critical gaps in clinical cancer care.

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).

Continuous artificial intelligence-assisted DNA aneuploidy cytology for surveilling dysplastic oral leukoplakia treated by photodynamic therapy

Oral leukoplakia (OLK) is one of the most common potentially malignant disorders. High-risk lesions require early intervention before developing into oral cancer. Photodynamic therapy (PDT) is a noninvasive technique for premalignant lesions. Scalpel biopsy remains a reliable method for monitoring the prognosis of OLK, but it is an invasive procedure with poor reproducibility to suspicious lesions. DNA aneuploidy cytology by oral cytobrush has been proposed as a promising objective and noninvasive tool in screening and diagnosing premalignant and malignant lesions. Here, we discussed the significance of artificial intelligence (AI)-assisted DNA aneuploidy cytology by image cytometry (DNA-ICM) for surveilling non-homogeneous OLK with moderate-to-severe dysplasia that was treated by 5-aminolevulinic acid-mediated PDT (ALA-PDT). The present study provides a scheme of the sequential management and surveillance strategy for OLK.

Developmental synergism in the management of oral potentially malignant disorders

Oral potentially malignant disorders (OPMDs) are associated with an increased risk of occurrence of cancers of the oral cavity or lips. The unifying theme of OPMDs is their potential risk for cancer development. Therefore, the primary objective of the management should be to prevent carcinogenesis. Beyond diagnosis, current strategies for the management of OPMDs predominantly include non-surgical and surgical interventions and a "watch-and-see" approach, such as disease monitoring or surveillance, and preventive strategies. Though no optimal clinical treatment has gained universal approval for reducing or preventing malignant development of OPMDs. Therefore, an urgent need exits for improved treatment properties and effective predictive markers for OPMDs treatment. This review aims to outline recent synergism regarding to the management of OPMDs. Developing new technologies and improved application parameters to promote the treatment efficacy and a novel management prescription approach to OPMDs are proposed.

Revisiting the evidence of photodynamic therapy for oral potentially malignant disorders and oral squamous cell carcinoma: an overview of systematic reviews

BACKGROUND

This study summarized the available evidence about the use of photodynamic therapy (PDT) for the management of oral potentially malignant disorders (OPMD) and oral squamous cell carcinoma (OSCC).

METHODS

An overview of systematic reviews was undertaken based on the 2020 PRISMA statement. Electronic searches were performed in five databases. Studies published up to November 2022 were included. Risk of bias was assessed with the AMSTAR 2 tool.

RESULTS

A total of 30 studies enrolling 9,245 individuals with OPMD (n=7,487) or OSCC (n=1,758) met the selection criteria. All studies examined the efficacy and/or safety of PDT. OPMD were investigated individually in 82.8% of the studies, the most common being oral lichen planus and actinic cheilitis. OSCC was addressed separately in 10.3% of the studies, while only 6.9% evaluated both OPMD and OSCC. Fourteen different types of photosensitizers were described. PDT was used according to the following setting parameters: 417-670 nm, 10-500 mW/cm², 1.5-200 J/cm², and 0.5-143 minutes. Regarding OPMD, leukoerythroplakia showed the best response rates, while oral lichen planus presented a partial or no response in nearly 75% of documented cases. A complete response was observed in 85.9% of OSCC cases, while 14.1% had no resolution.

CONCLUSION

Overall, the response to PDT depended on the type of OPMD/OSCC and the parameters used. Although PDT is an emerging candidate for the treatment of OPMD and OSCC, there is heterogeneity of the methodologies used and the clinical data obtained, particularly regarding the follow-up period.

Reaching new lights: a review on photo-controlled nanomedicines and their in vivo evaluation

The selective and efficient delivery of bioactive molecules to sites of interest remains a formidable challenge in medicine. In recent years, it has been shown that stimuli-responsive drug delivery systems display several advantages over traditional drug administration such as an improved pharmacokinetic profile and the desirable ability to gain control over release. Light emerged as one of the most powerful stimuli due to its high biocompatibility, spatio-temporal control, and non-invasiveness. On the road to clinical translation, various chemical systems of high complexity have been reported with the aim to improve efficacy, safety, and versatility of drug delivery under complex biological conditions. For future research on the chemical design of such photo-controlled nanomedicines, it is essential to gain an understanding of their in vivo translation and efficiency. Here, we discuss photo-controlled nanomedicines that have been evaluated in vivo and provide an overview of the state-of-the-art that should guide future research design.

Photodynamic therapy for the successful management of cyclosporine-related gum hypertrophy: A novel therapeutic option

Background

Drug-induced gingival overgrowth is associated with the intake of three classes of drugs: anticonvulsants, immunosuppressants, and calcium channel blockers. It is clinically characterized by hyperplasia of the gingival connective tissue which appears edematous, bloody, and purplish-red in color. In more severe cases, drug-induced gingival hyperplasia negatively affects the patient's quality of life, making it difficult to eat and practice good oral hygiene. Drug-induced gingival overgrowth therapy is controversial and, in fact, no studies in the literature highlight a well-defined therapeutic protocol. The therapies that are described provide primarily for non-surgical periodontal treatment and second-line surgical treatment. The aim of this work is to highlight a case of drug-induced gingival hyperplasia which was completely resolved thanks to photodynamic therapy which is completely free from side effects.

Design and Methods

Photodynamic therapy was performed on an 18 year-old female patient with LEDs at a power of 450-470 nm and 5500 mW/cm² + 7500 mW/cm², combined with a Curcuma longa-based photosensitizer. A single session was performed, with applications of approximately 30 s for each interdental papilla.

Results

The patient improved markedly after only one cycle of PDT. There was an absence of clinically detectable inflammation, edema, and rubor of the involved dental papillae. At the 4, 6, and 12 week follow-ups there were no recurrences.

Conclusions

This case report highlights the first case of drug-induced gingival hypertrophy entirely treated with photodynamic therapy to be described in the literature. Therefore, although it is only a case report, this therapy which is free from side effects should be investigated as an alternative to current therapies.

The Oral Microbiota: Community Composition, Influencing Factors, Pathogenesis, and Interventions

The human oral cavity provides a habitat for oral microbial communities. The complexity of its anatomical structure, its connectivity to the outside, and its moist environment contribute to the complexity and ecological site specificity of the microbiome colonized therein. Complex endogenous and exogenous factors affect the occurrence and development of the oral microbiota, and maintain it in a dynamic balance. The dysbiotic state, in which the microbial composition is altered and the microecological balance between host and microorganisms is disturbed, can lead to oral and even systemic diseases. In this review, we discuss the current research on the composition of the oral microbiota, the factors influencing it, and its relationships with common oral diseases. We focus on the specificity of the microbiota at different niches in the oral cavity, the communities of the oral microbiome, the mycobiome, and the virome within oral biofilms, and interventions targeting oral pathogens associated with disease. With these data, we aim to extend our understanding of oral microorganisms and provide new ideas for the clinical management of infectious oral diseases.

Management of oral leukoplakia by ablative fractional laser‐assisted photodynamic therapy: A 3‐year retrospective study of 48 patients

Objectives

This study aimed to review the results of oral leucoplakia (OL) using ablative fractional laser‐assisted photodynamic therapy (AFL‐PDT) and to further evaluate the risk factors for recurrence and malignant transformation.

Materials and Methods

Forty‐eight patients diagnosed with OL using histopathology were enrolled in this study. All patients received one session of AFL‐PDT. Therapeutic efficacy was evaluated 1 month posttreatment. Follow‐up was scheduled every 3 months in the first year and every 6 months thereafter.

Results

An overall positive response rate of 87.5% (42/48) was achieved, including 62.5% (30/48) complete responses and 25.0% (12/48) partial responses. During the 3‐year follow‐up period, the recurrence and malignant transformation rates were 37.5% (18/48) and 8.3% (4/48), respectively. Lesions on gingiva/palate seemed to be associated with recurrence (p < 0.001; odds ratio [OR]: 1.64, 95% confidence interval [CI]: 1.13–2.37). The severity of epithelial dysplasia (p = 0.02; OR: 2.93, 95% CI: 1.96–4.42) and recurrence (p = 0.016; OR: 3.14, 95% CI: 2.04–4.84) were associated with a predisposition to malignant transformation.

Conclusions

AFL‐PDT is an effective management of OL, but requires close follow‐up. OL lesions on the gingiva/palate are predisposed to recurrence. OLs that recur with moderate/severe epithelial dysplasia have a higher risk of transforming into oral squamous cell carcinoma.

Multifunctional photodynamic/photothermal nano-agents for the treatment of oral leukoplakia

Oral leukoplakia (OLK) has gained extensive attention because of the potential risk for malignant transformation. Photosensitizers (PSs) played an indispensable role in the photodynamic therapy (PDT) of OLK, but the poor light sensitivity greatly hampered its clinical application. Herein, a novel organic photosensitive ITIC-Th nanoparticles (ITIC-Th NPs) were developed for OLK photodynamic/photothermal therapy (PTT). ITIC-Th NPs present both high photothermal conversion efficiency (~ 38%) and suitable reactive oxygen species (ROS) generation ability under 660 nm laser irradiation, making them possess excellent PDT and PTT capability. In 4-nitroquinoline 1-oxide (4NQO)-induced oral precancerous animal models, ITIC-Th NPs effectively suppress the OLK's cancerization without apparent topical or systemic toxicity in vivo. This study offers a promising therapeutic strategy for PDT and PTT in OLK treatment, and this study is the first interdisciplinary research in the field of multimodal therapy for OLK.

Photodynamic therapy for oral potentially malignant disorders: A Systematic Review and Meta-analysis

OBJECTIVES

To evaluate the effectiveness of Photodynamic Therapy (PDT) in the treatment of Oral Potentially Malignant Disorders (OPMDs) patients.

METHODOLOGY

An electronic search was conducted to retrieve articles published until September 2021. Meta-analyses were conducted for the outcomes of complete response (CR) and any response (AR) after treatment with PDT using data from single-arm studies, case series and non-randomised controlled trials (NRCTs).

RESULTS

In total, 49 articles were included. RCTs revealed insignificant mean difference (MD) in efficacy index between PDT and comparison groups (MD: 1.32; 95% CI:-28.10-30.72, p=0.930). The likelihood of CR (OR:0.84; 95% CI: 0.42-1.71, p=0.637) or AR (OR:2.10; 95% CI: 0.31-14.25, p=0.448) was not different in PDT group when compared with any comparison treatments in NRCTs. CR/AR among single arm studies was 60.6% (95% CI: 50.5-70.7, P<0.001) and 93.7% (95% CI:91.5-95.8, P<0.001) respectively. Higher prevalence of CR and AR was observed for dysplasia or carcinoma insitu (CIS) (CR: 81%, 95% CI: 70.8-91.3, P<0.001; AR: 94.3%; 95% CI: 89-99.6, P<0.001) and actinic cheilitis (AC) (CR: 73.9%, 95% CI: 65.9-81.9, P<0.001; AR:97%; 95% CI:94.9-99, P<0.001).

CONCLUSIONS

More than half of the patients receiving PDT showed CR, with more than 90% responding to the treatment. PDT was most effective on oral dysplasias, followed by AC.

An active surveillance program in oral preneoplasia and translational oncology benefit

OBJECTIVE

We desired to establish an active surveillance clinic for head and neck cancer. In this review we examined.

METHODS

We examined the natural history of human oral carcinogenesis, the types of preneoplastic lesions, and efforts at oral chemoprevention over the past decades for presentation here.

RESULTS

We established a clinic and program for patients with oral premalignant lesions approximately over 15 years ago based on an unmetneed for this service. We have completed over 4000 outpatient visits for this cohort and have a place for referrals of difficult oral lesions. We have leveraged this population for multiple federally funded trials on oral cancer prevention as well as specimen banking.

CONCLUSION

There is need for routine active surveillance for oral preneoplastic conditions in patients at high risk for conversion to cancer. There are no effective durable treatment or preventions for these individuals and we have attempted to fill this unmet need with our program.

Overview of Oral Potentially Malignant Disorders: From Risk Factors to Specific Therapies

Oral squamous cell carcinoma (OSCC) is a very aggressive cancer, representing one of the most common malignancies worldwide. Oral potentially malignant disorders (OPMDs) regroup a variegate set of different histological lesions, characterized by the potential capacity to transform in OSCC. Most of the risk factors associated with OSCC are present also in OPMDs' development; however, the molecular mechanisms and steps of malignant transformation are still unknown. Treatment of OSCC, including surgery, systemic therapy and radiotherapy (alone or in combination), has suffered a dramatic change in last years, especially with the introduction of immunotherapy. However, most cases are diagnosed during the advanced stage of the disease, decreasing drastically the survival rate of the patients. Hence, early diagnosis of premalignant conditions (OPMDs) is a priority in oral cancer, as well as a massive education about risk factors, the understanding of mechanisms involved in malignant progression and the development of specific and more efficient therapies. The aim of this article is to review epidemiological, clinical, morphological and molecular features of OPMDs, with the purpose to lay the foundation for an exhaustive comprehension of these lesions and their ability of malignant transformation and for the development of more effective and personalized treatments.

Photodynamic therapy of oral lichen planus

Oral lichen planus (OLP) is a chronic inflammatory and immune-mediated disease affecting the oral mucosa. OLP presents with asymptomatic, lacelike white stripes and/or symptomatic red, ulcerated mucous membranes. Eating, drinking and oral hygiene procedures may be painful resulting in reduced quality of life (QOL). The histopathological picture is a zone of cellular infiltrate, mainly CD8+ cells, in the superficial layer of the connective tissue and signs of liquefaction degeneration of the basal membrane. Conventional treatment is corticosteroids. Local and systemic side effects are common, and patients may develop drug resistance. The intention with this article is to demonstrate the heterogeneity in photodynamic therapy (PDT) of OLP. A search in PubMed, Embase (Ovid) and Medline (Ovid) identified seventeen clinical studies investigating PDT of OLP. Only five were randomised controlled studies and the study groups varied from 5 to 50 patients. Five different photosensitisers or precursors were tested. Both broadband spectrum lamps, lasers and light-emitting-diodes (LEDs), with wavelengths from 420 nm to 682 nm, were used. The number of treatment sessions varied from one to ten. The patients were followed up for 0 to 48 months, but in thirteen studies the post treatment observation time was ≤6 months. Single arm studies demonstrated improvement of OLP except in one study. In all controlled studies except for one, PDT was superior or equal to conventional treatment. The majority of patients experienced a slight burning sensation during light activation, but no serious adverse events were reported. Only few studies examined the effect of PDT on a cellular level.

Sublingual administration of 5-aminolevulinic acid for laser-induced photodiagnostics and photodynamic therapy of oral cavity and larynx cancers

BACKGROUND

The study aimed to develop a method for sublingual administration of 5-aminolevulinic acid to patients and evaluate its effectiveness in fluorescence diagnostics and photodynamic therapy of neoplasms of the oral cavity and larynx.

METHODS

The boundaries of the neoplasms were established by the video-fluorescence diagnostics and clarified using spectral-fluorescent diagnosis before and after photodynamic therapy.

RESULTS

The fluorescence diagnostics demonstrated a high accumulation of protoporphyrin IX, induced by sublingual administration of 5-aminolevulinic acid to patients before the photodynamic therapy and photobleaching of protoporphyrin IX in pathologically altered tissues after the photodynamic therapy. Glucose contained in the sublingual dose supports active transport of 5-ALA into the cells. It increases the PpIX accumulation in the cells, therefore improving the PD and PDT efficacy.

CONCLUSION

The study and the initially obtained results demonstrated the possibility and effectiveness of laser-induced photodiagnostics and photodynamic therapy with sublingual administration of 5-ALA to patients with premalignant lesions of the oral cavity and larynx. It can eliminate the threat of the transformation of these diseases into malignant tumors and prevent the need for surgical treatment.

Photodynamic therapy using topical toluidine blue for the treatment of oral leukoplakia: A prospective case series

BACKGROUND

Photodynamic therapy (PDT) is a minimally invasive method for the treatment of oral leukoplakia (OL) through the activation of a photosensitizer, after exposure to a specific wavelength light source.

METHODS

To investigate the effectiveness of toluidine blue as topical photosensitizer. Eleven patients participated in this study; fifteen oral leukoplakia lesions were treated, in several sessions, with 2.5 % toluidine blue and an LED source of 630 nm wavelength. Patients were evaluated at baseline (t0), at the end of treatment cycles (t1) and one year from the end of treatment (t2). All the treated sites were photographed at each visit. Images were processed with ImageJ 1.52 software in order to obtain the areas (mm2) of the treated lesions. Comparison between data at different follow-up was performed using a paired T-test.

RESULTS

At t1, complete response was obtained in six lesions, partial response in seven lesions while only two lesions showed no response. At t2, a further improvement was observed in two patients. The analysis of the areas showed significant reduction of the lesion size from t0 to t1 (p = 0.003), and from t1 to t2 (p = 0.01).

CONCLUSION

Toluidine blue appears to be a promising photosensitizer in the photodynamic therapy of oral leukoplakia.

Anti-inflammatory effect of photodynamic therapy using guaiazulene and red lasers on peripheral blood mononuclear cells

INTRODUCTION

Photodynamic therapy improves oral mucositis treatment. The reactive oxygen species (ROS) generated from this reaction could contribute to an anti-inflammatory effect by suppressing inflammatory cells.

OBJECTIVE

To evaluate the anti-inflammatory effect of photodynamic therapy using guaiazulene and a red laser in peripheral blood mononuclear cells (PBMCs).

METHODS

Guaiazulene solutions (1, 2, 5, 25, 35, and 100 μM in 99.8 % methanol) were irradiated with red laser light (625 nm, 146.2 mW/cm²) in continuous mode at 0, 4, and 8 J/cm² in black 96-well plates. ROS were measured using spin trapping technique with electron spin resonance (ESR) spectroscopy and fluorescence. The two highest concentrations were tested using cell viability (PrestoBlue®) and anti-inflammation (RANTES and PGE₂ ELISA) assay kits. Kruskal-Wallis and Dunn Bonferroni tests were used for statistical analyses with significant differences at p-value < 0.05.

RESULTS

Guaiazulene solutions between 2 and 5 μM exposed to red laser light at 4-8 J/cm² generated significantly more singlet oxygen compared to the no guaiazulene group (p < 0.01) and reduced RANTES and PGE₂ levels in TNF-α-inflamed peripheral blood mononuclear cells without affecting cell viability.

CONCLUSION

Photodynamic activation of guaiazulene generated singlet oxygen and suppressed inflammatory markers in PBMCs.

Light Sources and Dosimetry Techniques for Photodynamic Therapy

Effective treatment delivery in photodynamic therapy (PDT) requires coordination of the light source, the photosensitizer, and the delivery device appropriate to the target tissue. Lasers, light-emitting diodes (LEDs), and lamps are the main types of light sources utilized for PDT applications. The choice of light source depends on the target location, photosensitizer used, and light dose to be delivered. Geometry of minimally accessible areas also plays a role in deciding light applicator type. Typically, optical fiber-based devices are used to deliver the treatment light close to the target. The optical properties of tissue also affect the distribution of the treatment light. Treatment light undergoes scattering and absorption in tissue. Most tissue will scatter light, but highly pigmented areas will absorb light, especially at short wavelengths. This review will summarize the basic physics of light sources, and describe methods for determining the dose delivered to the patient.

The Combination of Antimicrobial Photodynamic Therapy and Photobiomodulation Therapy for the Treatment of Palatal Ulcers: A Case Report

Introduction: One of the unexpected side effects of the Haas type palatal expander is ulcers progressing to necrotic lesions in the palatal area due to poor hygiene. The use of antibiotic therapy is mandatory. However, long periods of healing/pain and the need for a systemic host response with the aid of metabolization, especially in children, are issues that should be taken into account in the management of this type of injury. Since phototherapy modalities (antimicrobial photodynamic therapy [aPDT] and photobiomodulation therapy [PBMT]) are able to enhance and accelerate the healing process and reduce the bacterial load, this case report aimed to describe the use of the above-mentioned therapies to treat palatal ulcers occurring during orthodontic expansion. Case Report: The patient, a 10-year-old boy, with a chief complaint of bleeding and continuous pain in the region of his expander was verified on a follow-up visit. After a dental examination, the expander was removed and two necrotic lesions which were in contact with the acrylic part of the tooth-tissue expander were found in the palatal region. The proposal was to use one aPDT session with methylene blue followed by 4 sessions of PBMT with a red laser diode. On the 5th day, reorganized tissue was verified, with the absence of bleeding, swelling, and pain. On the 20th day of follow-up, the area showed no signs of inflammation, healthy tissue without any pathological clinical symptoms, and complete wound healing. Conclusion: The concomitant use of PBMT and aPDT therapies may be considered feasible as an adjunct treatment to manage palatal ulcers resulting from the incorrect use of tooth-tissue types of expanders.