A Review of the Dermatologic Clinical Applications of Topical Photodynamic Therapy

Topical photodynamic therapy is a widely approved therapy for actinic keratoses and low-risk nonmelanoma skin cancers with a rapidly growing range of emerging indications for other cutaneous diseases. This review summarizes the best-available evidence to provide a clinical update for dermatologists on the approved and emerging indications of photodynamic therapy. The body of evidence suggests that photodynamic therapy is superior or noninferior to other available treatment modalities for actinic keratoses, low-risk basal cell carcinomas, Bowen's disease, skin field cancerization, chemoprevention of keratinocyte carcinomas in organ transplant recipients, photoaging, acne vulgaris, and cutaneous infections including verrucae, onychomycosis, and cutaneous leishmaniasis. There is emerging evidence that photodynamic therapy plays a role in the management of actinic cheilitis, early-stage mycosis fungoides, extramammary Paget disease, lichen sclerosis, and folliculitis decalvans but there are no comparative studies with other active treatment modalities. Common barriers to topical photodynamic therapy include procedural pain, costs, and the time required for treatment delivery. There is significant heterogeneity in the photodynamic therapy protocols reported in the literature, including different photosensitizers, light sources, number of treatments, time between treatments, and use of procedural analgesia. Topical photodynamic therapy should be considered in the management of a spectrum of inflammatory, neoplastic, and infectious dermatoses. However, more comparative research is required to determine its role in the treatment algorithm for these dermatologic conditions and more methodological research is required to optimize photodynamic therapy protocols to improve the tolerability of the procedure for patients.

Evaluation of HPV infection helps to direct ALA-PDT of condyloma acuminata

BACKGROUND AND OBJECTIVES

Aminolaevulinic acid-mediated photodynamic therapy (ALA-PDT) is increasingly applied for the treatment of condyloma acuminata (CA). However, the determinants for the sessions and end points of ALA-PDT treatment remains unclear. Here, we recorded HPV screening, evaluated the frequency and efficacy of ALA-PDT in different types of CA, in order to individualize ALA-PDT treatment to CA.

METHODS

A total of 227 CA patients with HPV infection and visible warts were recruited. Prior to PDT, visible lesions were removed by radio frequency or microwave. HPV DNA detection were performed before each PDT treatment and at follow-up. Treatment was ended after two consecutive negative HPV DNA detection.

RESULTS

Of the 227 patients, 119 patients received ALA-PDT and 116 patients completed all treatments. We found that CA patients with multiple-site infection, intra-luminal infection or multiple-type of HPV infection required more sessions of ALA-PDT. The recurrence rate was 8.62% (10/116). Viral load was significantly lower after six PDT treatments compared to viral load after three PDT treatments. Gender, HPV subtypes and warts location had no significant effect on the recurrence rate.

CONCLUSION

Comprehensive evaluation of HPV infection state helps to individualize ALA-PDT treatment scheme for CA patients and predict the therapeutic efficacy.

Clinical observation of laser combined with 5-aminolevulinic acid photodynamic therapy for female vulva condyloma acuminatum

BACKGROUND

Condylomata acuminata, or genital warts (GW), are exceedingly prevalent, with human papilloma virus infection accounting for 90% of cases. It can be treated in a variety of methods, but the high recurrence rate and cervical scars make it difficult to choose the best treatment option. Hence, the study aims to find the effect of laser combined with 5-aminolevulinic acid (ALA) photodynamic therapy for condyloma acuminata in the vulva, vagina, and cervix.

METHODS

A total of 106 female patients with GW of the vulva, vagina, and cervical condyloma acuminata were treated in the Dermatology Department of Subei People's Hospital in Yangzhou from May 2020 to July 2021. All these patients were treated with laser combined with 5-ALA photodynamic therapy to observe the therapeutic effect.

RESULTS

About 84.9% of patients responded to the first session of ALA-photodynamic treatment. Five patients relapsed in the 2nd week, two patients relapsed in the 4th week, one relapsed in the 8th week, one relapsed in the 12th week, and the relapsed patients were given 1-3 times of photodynamic therapy again, and no recurrence was seen in the 24th week. After four courses of treatment in 106 patients, the wart clearance rate was 100%.

CONCLUSION

Laser combined with 5-ALA photodynamic therapy for female vulva, vagina, and cervix condyloma acuminata has a reliable curative effect, low recurrence rate, few adverse reactions, and less pain. It is worth promoting in female vulva, vagina, and cervical condyloma acuminata.

Peripheral blood CD4+ T cell count predicts recurrence of condyloma acuminatum after photodynamic therapy in HIV-positive patients

BACKGROUND

Few studies have reported postoperative relapse of condyloma acuminatum (CA) after 5-aminolevulinic acid photodynamic therapy (ALA-PDT) in human immunodeficiency virus (HIV) positive patients.

METHODS

The clinical data of HIV-positive CA patients treated with ALA-PDT from October 2018 to December 2019 were analyzed retrospectively. Univariate and multivariate Cox regression was used to analyze the variables related to postoperative recurrence. Pearson correlation test was employed to analyze the correlation between CD4⁺ T cell count and postoperative recurrence rate. Kaplan-Meier method was used to compare the CA recurrence after ALA-PDT in low CD4 group and high CD4 group.

RESULTS

A total of 38 HIV-positive patients with CA were included in the study. Among them, 26 patients experienced CA recurrence within 6 months, and the recurrence rate was 68.4%. CD4⁺ T cell count was 187.0 (79.0-596.0) cells/μl in relapsed patients and 406.0 (89.0-612.0) cells/μl in non-relapsed patients, showing a statistically significant difference (p = .005). Pearson correlation coefficient analysis revealed a negative correlation between CD4⁺ T cell count and postoperative recurrence rate (p = .005, r = -.443). Univariate regression analysis showed that CD4⁺ T cell count was correlated with postoperative recurrence, hazard ratio (HR) was 0.99 [95% Confidence interval (CI) = 0.99-1.0, p = .012]. Multivariate Cox regression analysis showed that with the low CD4⁺ T cell count as the reference, the high CD4⁺ T cell count was negatively correlated with postoperative recurrence (HR = 0.09, 95% CI 0.01-0.87, p = .038).

CONCLUSIONS

Peripheral blood CD4⁺ T cell count can predict the CA recurrence rate after ALA-PDT in HIV-positive patients.

Evidence-Based Clinical Practice Guidelines for Laser-Assisted Drug Delivery

Importance

Laser-assisted drug delivery (LADD) is used for various medical and cosmetic applications. However, there is insufficient evidence-based guidance to assist clinicians performing LADD.

Objective

To develop recommendations for the safe and effective use of LADD.

Evidence Review

A systematic literature review of Cochrane Central Register of Controlled Trials, Embase, and MEDLINE was conducted in December 2019 to identify publications reporting research on LADD. A multidisciplinary panel was convened to draft recommendations informed by the systematic review; they were refined through 2 rounds of Delphi survey, 2 consensus meetings, and iterative review by all panelists until unanimous consensus was achieved.

Findings

Of the 48 published studies of ablative fractional LADD that met inclusion criteria, 4 were cosmetic studies; 21, oncologic; and 23, medical (not cosmetic/oncologic), and 6 publications of nonablative fractional LADD were included at the request of the expert panel, producing a total of 54 studies. Thirty-four studies (63.0%) were deemed to have low risk of bias, 17 studies (31.5%) had moderate risk, and 3 (5.5%) had serious risk. The key findings that informed the guidelines developed by the expert panel were as follows: LADD is safe in adults and adolescents (≥12 years) with all Fitzpatrick skin types and in patients with immunosuppression; it is an effective treatment for actinic keratosis, cutaneous squamous cell carcinoma in situ, actinic cheilitis, hypertrophic scars, and keloids; it is useful for epidermal and dermal analgesia; drug delivery may be increased through the application of heat, pressure, or occlusion, or by using an aqueous drug solution; laser settings should be selected to ensure that channel diameter is greater than the delivered molecule; antibiotic prophylaxis is not recommended, except with impaired wound healing; antiviral prophylaxis is recommended when treating the face and genitalia; and antifungal prophylaxis is not recommended. The guideline's 15 recommendations address 5 areas of LADD use: (I) indications and contraindications; (II) parameters to report; (III) optimization of drug delivery; (IV) safety considerations; and (V) prophylaxis for bacterial, viral, and fungal infections.

Conclusions and Relevance

This systematic review and Delphi consensus approach culminated in an evidence-based clinical practice guideline for safe and effective use of LADD in a variety of applications. Future research will further improve our understanding of this novel treatment technique.

Current and future direction in treatment of HPV-related cervical disease

Human papillomavirus (HPV) is the most common sexually transmitted virus in the world. About 70% of cervical cancers are caused by the most oncogenic HPV genotypes of 16 and 18. Since available prophylactic vaccines do not induce immunity in those with established HPV infections, the development of therapeutic HPV vaccines using E6 and E7 oncogenes, or both as the target antigens remains essential. Also, knocking out the E6 and E7 oncogenes in host genome by genome-editing CRISPR/Cas system can result in tumor growth suppression. These methods have shown promising results in both preclinical and clinical trials and can be used for controlling the progression of HPV-related cervical diseases. This comprehensive review will detail the current treatment of HPV-related cervical precancerous and cancerous diseases. We also reviewed the future direction of treatment including different kinds of therapeutic methods and vaccines, genome-editing CRISPR/Cas system being studied in clinical trials. Although the progress in the development of therapeutic HPV vaccine has been slow, encouraging results from recent trials showed vaccine-induced regression in high-grade CIN lesions. CRISPR/Cas genome-editing system is also a promising strategy for HPV cancer therapy. However, its safety and specificity need to be optimized before it is used in clinical setting.

Phototherapy and optical waveguides for the treatment of infection

With rapid emergence of multi-drug resistant microbes, it is imperative to seek alternative means for infection control. Optical waveguides are an auspicious delivery method for precise administration of phototherapy. Studies have shown that phototherapy is promising in fighting against a myriad of infectious pathogens (i.e. viruses, bacteria, fungi, and protozoa) including biofilm-forming species and drug-resistant strains while evading treatment resistance. When administered via optical waveguides, phototherapy can treat both superficial and deep-tissue infections while minimizing off-site effects that afflict conventional phototherapy and pharmacotherapy. Despite great therapeutic potential, exact mechanisms, materials, and fabrication designs to optimize this promising treatment option are underexplored. This review outlines principles and applications of phototherapy and optical waveguides for infection control. Research advances, challenges, and outlook regarding this delivery system are rigorously discussed in a hope to inspire future developments of optical waveguide-mediated phototherapy for the management of infection and beyond.

Multiple-type HPV infection predicting condyloma acuminatum recurrence after aminolevulinic acid photodynamic therapy

BACKGROUND

Aminolevulinic acid photodynamic therapy (ALA-PDT) has been widely used in the treatment of condyloma acuminatum (CA), but there is a lack of reports on clinical factors related to CA relapse after photodynamic therapy.

METHODS

The clinical data of patients with CA treated with ALA-PDT from April 2018 to December 2019 were retrospectively analyzed, including HPV type, follow-up time and recurrence within 6 months after treatment. The patients were classified into single-type HPV infection and multiple-type HPV infection groups. Besides, the patients were also classified into high-risk HPV infection, low-risk HPV infection, and low + high-risk HPV infection groups. Univariate and multivariate COX regression was performed to analyze whether HPV type was related with CA relapse after photodynamic therapy.

RESULTS

A total of 161 CA patients who underwent ALA-PDT were analyzed in this study. CA recurred in 20 patients within 6 months after treatment, with a recurrence rate of 12.4%. Of them, the patients with multiple-type HPV infection made up 85%. Multivariate COX regression analysis revealed that multiple-type HPV infection was associated with CA recurrence (HR:5.0; 95% CI: 1.1-21.4; P = 0.032). Of the patients with CA recurrence, 70% developed low + high-risk infections, a proportion significantly higher than that in patients without CA relapse (16.3%, P < 0.001). Using low-risk infection as a reference, low + high-risk infection was positively correlated with postoperative recurrence (HR: 6.7; 95% CI: 1.6-26.2; P = 0.006).

CONCLUSION

Multiple-type HPV infection were closely associated with CA recurrence after photodynamic therapy.

2019 IUSTI-Europe guideline for the management of anogenital warts

This guideline is an update of the 2011 European Guideline for the Management of Anogenital Warts. It is intended to support best practice in the care of patients with anogenital warts by including evidence-based recommendations on diagnosis, treatment, follow-up and advice to patients. It is intended for use by healthcare professionals in sexual healthcare or dermato-venereology clinics in Europe but may be adapted for use in other settings where the management of anogenital warts is undertaken. As a European guideline, recommendations should be adapted according to national circumstances and healthcare systems. Despite the availability of vaccine to prevent HPV types 6 and 11, the cause of >95% anogenital warts, they remain an important and frequent health problem. The previous systematic review of randomized controlled trials for anogenital warts was updated. The changes in the present guideline include the following: Updated background information on the prevalence, natural history and transmission of human papillomavirus (HPV) infection and anogenital warts. Key recommendations for diagnosis and treatment have been graded according to the strength of the recommendation and the quality of supporting evidence. 5-fluorouracil, local interferon and photodynamic therapy have been evaluated and included as potential second-line treatment options. Evidence of the impact of HPV vaccination on the incidence of anogenital warts has been updated.

A Critical Reappraisal of Off-Label Use of Photodynamic Therapy for the Treatment of Non-Neoplastic Skin Conditions

BACKGROUND

In the past 30 years, topical photodynamic therapy (PDT) has been investigated for the treatment of a broad spectrum of cosmetic, inflammatory, and infectious skin conditions with variable, and often contrasting, results. However, the non-expert clinician may be in difficulty evaluating these results because different sensitizers, concentrations, formulations, light sources, and irradiation protocols have been used. In addition, many of these studies have poor quality design being case reports and uncontrolled studies of few cases.

SUMMARY

With the aim to clarify the potential usefulness of PDT for the treatment of infectious and inflammatory skin diseases as well as selected cosmetic indications, we searched for randomized controlled clinical trials, non-randomized comparative studies, retrospective studies, and case series studies with a number of at least 10 patients, published since 1990. Later, we reappraised the results in order to give a simple critical overview. Key Messages: Evidence from the literature seems to strongly support the use of ALA- and MAL-PDT for the treatment of common skin diseases such as acne, warts, condylomata, and Leishmania skin infection and for photorejuvenation, i.e., the correction of selected cosmetic changes of aging and photoaging. For other disorders, the level of evidence and strength of recommendation are lower, and controlled randomized studies with prolonged follow-ups are necessary in order to assess the clinical usefulness and other potential advantages over current treatment options.

Contrasting the efficacy of pulsed dye laser and photodynamic methylene blue nanoemulgel therapy in treating acne vulgaris

The treatment of acne remains a challenge for dermatologists. A variety of conventional therapies are available for acne treatment such as topical and systemic medications. Although many of these traditional acne treatments are effective, the wide-spread nature of the disease and its sometimes resistant nature delineate the need for alternative therapies. Therefore, over the past decade, phototherapy has been introduced for the treatment of acne, such as pulsed dye lasers (PDLs) and photodynamic therapy (PDT). The aim of this study was to compare the safety and efficacy of PDL and methylene blue-mediated photodynamic therapy (MB-PDT) in the treatment of mild to moderate acne. Split-face clinical trial including fifteen patients presenting with mild to moderate acne were treated with 585 nm PDL on the right side of the face and MB-PDT with 665-nm diode laser on the left side. The photosensitizer MB was prepared in nanoemulgel formulation, and the treatment was carried out for three sessions maximum at 2-weeks intervals. Results revealed that both PDL and MB-PDT were effective therapies in the treatment of acne, as manifested by the reduction of inflammatory and non-inflammatory lesions throughout the treatment period. However, the latter therapy was proven more potent in the reduction of acne severity, and in terms of patients' tolerance. Therefore, it can be concluded that MB in the nanoemulgel form is a promising treatment approach for acne, and can be further experimented in the treatment of other dermatological diseases.

Local Management of Anogenital Warts in Non-Immunocompromised Adults: A Network Meta-Analysis of Randomized Controlled Trials

INTRODUCTION

No hierarchy of first-line treatments for anogenital warts (AGWs) is provided in international guidelines. This study aimed to determine the efficacy of topical treatments and ablative procedures for the management of AGWs.

METHODS

Twelve electronic databases were systematically searched from inception to August 2018. All randomized controlled trials (RCTs) comparing immunocompetent adults with AGWs who received at least 1 provider-administered or patient-administered treatment in at least 1 parallel group were included. Risk of bias assessment followed the Cochrane Handbook. The study endpoint was complete lesion response after clearance and recurrence assessment. A network meta-analysis was performed.

RESULTS

A network geometry was constructed based on 49 of the 70 RCTs included in our systematic review. All but 4 RCTs had a high risk of bias. The most efficacious treatments compared to placebo were surgery (RR 10.54; CI 95% 4.53-24.52), ablative therapy + imiquimod (RR 7.52; CI 95% 4.53-24.52), and electrosurgery (RR 7.10; CI 95% 3.47-14.53). SUCRA values confirmed the superiority of surgery (90.9%), ablative therapy + imiquimod (79.8%), and electrosurgery (77.1%). The most efficacious patient-administered treatments were podophyllotoxin 0.5% solution (63.5%) and podophyllotoxin 0.5% cream (62.2%).

CONCLUSIONS

With low-level evidence of most included RCTs, surgery and electrosurgery were superior to other treatments after clearance and recurrence assessment. Podophyllotoxin 0.5% was the most efficacious patient-administered treatment. Combined therapies should be evaluated in future RCTs in view of their identified effectiveness. The results of future RCTs should systematically include clinical type, number and location of AGWs, and sex of the patient, to refine therapeutic indications.

PROTOCOL REGISTRATION

PROSPERO-CRD42015025827.

European Dermatology Forum guidelines on topical photodynamic therapy 2019 Part 2: emerging indications - field cancerization, photorejuvenation and inflammatory/infective dermatoses

In addition to approved indications in non-melanoma skin cancer in immunocompetent patients, topical photodynamic therapy (PDT) has also been studied for its place in the treatment of, as well as its potential to prevent, superficial skin cancers in immune-suppressed patients, although sustained clearance rates are lower than for immune-competent individuals. PDT using a nanoemulsion of ALA in a daylight or conventional PDT protocol has been approved for use in field cancerization, although evidence of the potential of the treatment to prevent new SCC remained limited. High-quality evidence supports a strong recommendation for the use of topical PDT in photorejuvenation as well as for acne, refractory warts, cutaneous leishmaniasis and in onychomycosis, although these indications currently lack approvals for use and protocols remain to be optimized, with more comparative evidence with established therapies required to establish its place in practice. Adverse events across all indications for PDT can be minimized through the use of modified and low-irradiance regimens, with a low risk of contact allergy to photosensitizer prodrugs, and no other significant documented longer-term risks with no current evidence of cumulative toxicity or photocarcinogenic risk. The literature on the pharmacoeconomics for using PDT is also reviewed, although accurate comparisons are difficult to establish in different healthcare settings, comparing hospital/office-based therapies of PDT and surgery with topical ointments, requiring inclusion of number of visits, real-world efficacy as well as considering the value to be placed on cosmetic outcome and patient preference. This guideline, published over two parts, considers all current approved and emerging indications for the use of topical photodynamic therapy in Dermatology prepared by the PDT subgroup of the European Dermatology Forum guidelines committee. It presents consensual expert recommendations reflecting current published evidence.

Local Management of Anogenital Warts in Non-immunocompromised Adults: A Systematic Review and Meta-analyses of Randomized Controlled Trials

INTRODUCTION

Several therapeutic options are available to manage anogenital warts (AGWs). However, no hierarchy of treatments is provided in the latest European and American recommendations. This study aimed to determine the efficacy and safety of local treatments for the management of AGWs.

METHODS

A search was conducted through 12 databases from inception to August 2018. All randomized controlled trials (RCTs) in which at least one parallel treatment group composed of immunocompetent adults with AGWs received at least one provider-administered or patient-administered treatment were included. Risk of bias assessment and meta-analyses of aggregated study data were performed on the basis of the Cochrane Handbook, and quality of evidence evaluation followed the Grading of Recommendation Assessment, Development and Evaluation (GRADE) approach. Primary endpoints were complete clearance and recurrence at 3 months.

RESULTS

Seventy RCTs (9931 patients) were included. All but four RCTs had a high risk of bias. CO2 laser was slightly more efficacious than cryotherapy [risk ratio (RR) 2.05; 95% confidence interval (CI) 1.61-2.62], with fewer recurrences at 3 months (RR 0.28; 95% CI 0.09-0.89). Electrosurgery was slightly more efficacious than cryotherapy. No differences in efficacy or side effects were found between cryotherapy and imiquimod or trichloroacetic acid. Podophyllotoxin gel was slightly more efficacious than podophyllotoxin cream. 5-Fluorouracil (5-FU) was slightly more efficacious and caused less erosion than CO2 laser (RR 1.37; 95% CI 1.11-1.70).

CONCLUSION

The vast majority of included RCTs had a low level of evidence, thereby preventing the establishment of a hierarchy of treatments. Nevertheless, our results provide an overview of the main AGW treatments available for general practitioners and specialists. While provider-administered treatments are superior, patient-administered treatments (e.g., imiquimod, podophyllotoxin) are useful solutions for compliant patients.

PROTOCOL REGISTRATION

PROSPERO-CRD42015025827.

Trends and targets in antiviral phototherapy

Photodynamic therapy (PDT) is a well-established treatment option in the treatment of certain cancerous and pre-cancerous lesions. Though best-known for its application in tumor therapy, historically the photodynamic effect was first demonstrated against bacteria at the beginning of the 20^th century. Today, in light of spreading antibiotic resistance and the rise of new infections, this photodynamic inactivation (PDI) of microbes, such as bacteria, fungi, and viruses, is gaining considerable attention. This review focuses on the PDI of viruses as an alternative treatment in antiviral therapy, but also as a means of viral decontamination, covering mainly the literature of the last decade. The PDI of viruses shares the general action mechanism of photodynamic applications: the irradiation of a dye with light and the subsequent generation of reactive oxygen species (ROS) which are the effective phototoxic agents damaging virus targets by reacting with viral nucleic acids, lipids and proteins. Interestingly, a light-independent antiviral activity has also been found for some of these dyes. This review covers the compound classes employed in the PDI of viruses and their various areas of use. In the medical area, currently two fields stand out in which the PDI of viruses has found broader application: the purification of blood products and the treatment of human papilloma virus manifestations. However, the PDI of viruses has also found interest in such diverse areas as water and surface decontamination, and biosafety.

Treatment of condyloma acuminatum using the combination of laser ablation and ALA-PDT

BACKGROUND

Human papilloma virus (HPV) infection and condyloma acuminatum (CA) in the genital area often exist in extensive and multi-point fashion. Laser ablation combined with topical photodynamic therapy (PDT) is a feasible approach for genital CA but its effectiveness and limitations need to be evaluated.

METHODS

This single-arm prospective study consisted of 100 newly diagnosed CA cases of both sexes. All patients underwent laser ablation and then three times aminolaevulinic acid-based photodynamic therapy (ALA-PDT). The outcomes were evaluated and analyzed 3 months after the treatment.

RESULTS

A total of 98 patients completed the study. Except for 6 patients (4 males and 2 females) showed some residual lesions other 92 patients (93.8%) showed complete cure. However, there were 18 patients (10 males and 8 females) showed new lesions near the treated areas. Although the HPV types of 18 patients before and after treatment were not completely consistent, 94.4% percent of patients (17/18) had the same HPV type as the primary lesion, which suggested that these late-onset CA might have latent infection or subclinical infection in the early stage of the disease but the length of the incubation period was longer.

CONCLUSION

Combination approach is effective in treating genital CA and preventing CA recurrence. But its limitations need to be recognized as the late-onset CA might occur near the treated area. The treatment plan needs to be optimized for multiple genital CA lesions.

Topical PDT in the Treatment of Benign Skin Diseases: Principles and New Applications

Photodynamic therapy (PDT) uses a photosensitizer, light energy, and molecular oxygen to cause cell damage. Cells exposed to the photosensitizer are susceptible to destruction upon light absorption because excitation of the photosensitizing agents leads to the production of reactive oxygen species and, subsequently, direct cytotoxicity. Using the intrinsic cellular heme biosynthetic pathway, topical PDT selectively targets abnormal cells, while preserving normal surrounding tissues. This selective cytotoxic effect is the basis for the use of PDT in antitumor treatment. Clinically, PDT is a widely used therapeutic regimen for oncologic skin conditions such as actinic keratosis, squamous cell carcinoma in situ, and basal cell carcinoma. PDT has been shown, under certain circumstances, to stimulate the immune system and produce antibacterial, and/or regenerative effects while protecting cell viability. Thus, it may be useful for treating benign skin conditions. An increasing number of studies support the idea that PDT may be effective for treating acne vulgaris and several other inflammatory/infective skin diseases, including psoriasis, rosacea, viral warts, and aging-related changes. This review provides an overview of the clinical investigations of PDT and discusses each of the essential aspects of the sequence: its mechanism of action, common photosensitizers, light sources, and clinical applications in dermatology. Of the numerous clinical trials of PDT in dermatology, this review focuses on those studies that have reported remarkable therapeutic benefits following topical PDT for benign skin conditions such as acne vulgaris, viral warts, and photorejuvenation without causing severe side effects.

Current evidence and applications of photodynamic therapy in dermatology

In photodynamic therapy (PDT) a photosensitizer – a molecule that is activated by light – is administered and exposed to a light source. This leads both to destruction of cells targeted by the particular type of photosensitizer, and immunomodulation. Given the ease with which photosensitizers and light can be delivered to the skin, it should come as no surprise that PDT is an increasingly utilized therapeutic in dermatology. PDT is used commonly to treat precancerous cells, sun-damaged skin, and acne. It has reportedly also been used to treat other conditions including inflammatory disorders and cutaneous infections. This review discusses the principles behind how PDT is used in dermatology, as well as evidence for current applications of PDT.

The combination treatment using CO₂ laser and photodynamic therapy for HIV seropositive men with intraanal warts

BACKGROUND

We evaluate the effectiveness of combination treatment using photodynamic therapy after carbon dioxide laser in preventing the recurrence of condylomata acuminata for intraanal warts in HIV positive homosexual men. A retrospective survey of 41 patients referred to the STD clinic of the Fourth People's Hospital of Shenzhen for the treatment of intraanal warts among HIV positive homosexual men between Janurary 2009 and September 2011.

METHODS

The patients who accepted CO₂ laser monotherapy for the same diagnosis were used as the comparison group. After the confirmation of the diagnosis of HIV infection and intraanal warts, the patients were treated with the combination treatment using PDT with 5-ALA thermal gel immediately after CO₂ laser ablation of the warts. PDT was performed with irradiation of 100 J/cm² at an irradiance of 100-150 mW/cm² with a semiconductor laser, wavelength 635 nm. PDT therapy was repeated twice with 2 weekly intervals. Follow up examinations including an anoscopy every 4 weeks after the latest PDT.

RESULTS

After 3 cycles of PDT treatments, 39 cases of anoscopy examination showed no new or recurrent lesions. At the end of the sixth months, recurrence occurred in 12(29%) cases. HPV 11 was present in 6 (50%) of these recurrences. HPV 6/11 or 16/18 remains positive in 19 cases (46.3%) and HPV negative in 22 cases.

CONCLUSIONS

The combination treatment with CO₂ laser and PDT is much more effective in reducing the treatment cycles and the time intervals of the whole treatment for intraanal warts in HIV infected people.

Photodynamic therapy for infections: clinical applications

BACKGROUND AND OBJECTIVE

Photodynamic therapy (PDT) was discovered over 100 years ago by its ability to kill various microorganisms when the appropriate dye and light were combined in the presence of oxygen. However it is only in relatively recent times that PDT has been studied as a treatment for various types of localized infections. This resurgence of interest has been partly motivated by the alarming increase in drug resistance amongst bacteria and other pathogens. This review will focus on the clinical applications of antimicrobial PDT.

STUDY DESIGN/MATERIALS AND METHODS

The published peer-reviewed literature was reviewed between 1960 and 2011.

RESULTS

The basics of antimicrobial PDT are discussed. Clinical applications of antimicrobial PDT to localized viral infections caused by herpes and papilloma viruses, and nonviral dermatological infections such as acne and other yeast, fungal and bacterial skin infections are covered. PDT has been used to treat bacterial infections in brain abscesses and non-healing ulcers. PDT for dental infections including periodontitis and endodontics has been well studied. PDT has also been used for cutaneous Leishmaniasis. Clinical trials of PDT and blue light alone therapy for gastric Helicobacter pylori infection are also covered.

CONCLUSION

As yet clinical PDT for infections has been mainly in the field of dermatology using 5-aminolevulanic acid and in dentistry using phenothiazinium dyes. We expect more to see applications of PDT to more challenging infections using advanced antimicrobial photosensitizers targeted to microbial cells in the years to come.

Treatment of HPV infection-associated cervical condylomata acuminata with 5-aminolevulinic acid-mediated photodynamic therapy

The aim of this study was to investigate the efficacy of 5-aminolaevulinic acid (ALA)-mediated photodynamic therapy (PDT) in treatment of human papillomavirus (HPV)-associated cervical condylomata. A total of 56 patients with cervical and external condylomata lesions were recruited for this open-label study. HPV genotyping of exfoliated cells collected from the cervix and external lesions was performed. Cervical lesions were treated with PDT by applying ALA gel (10%) to the surface of the cervix for 4 h followed by irradiating with a 635 nm laser at 100 J cm(-2). PDT was repeated at 2-week intervals if lesion and HPV infection remained. Patients were followed up for 6-24 months. Genotyping analysis revealed four HPV subtypes (HPV6, 11, 16 and 18). The overall complete remission rate of 1-4 sessions of treatments was 98.2% and the corresponding HPV clearance rate was 83.9%. Ten cases showed complete removal of cervical lesions and HPV infection after a single treatment. Recurrence rate was 3.6%. Adverse effects were minimal and no structural complications were reported. In conclusion, topical ALA PDT is safe and effective for eradicating cervical HPV infection and eliminating condylomata lesion. Its definitive role in treating cervical condylomata deserves further investigation.

[New surgical approaches for the treatment of anogenital HPV infections]

HPV infections in the anogenital region may have very heterogeneous clinical features. Most often typical papillomatous condylomata acuminata are observed that usually present no differential diagnostic difficulty. In contrast, the clinical findings of higher grade intraepithelial dysplasias with flat papules and erythematous/ eczematous lesions are often quite inconspicuous and hardly characteristic. The goal of therapy is to prevent further progression to carcinoma, removal of bothersome tumors and avoidance of complications. Surgical methods are preferentially employed for extensive lesions, unfavorable locations and higher grade dysplasia. Options include removal with scissors or scalpel, laser therapy and electrocautery. For purely intraepithelial alterations, superficial ablative techniques are usually preferable over excision. Further developments such as argon plasma coagulation reduce the risk of unwanted deep thermal destruction with the accompanying complications. The risks for the surgeon and the surgical team during treatment should also not be neglected. With consideration of all relevant aspects, the combination of different methods may reduce the risk of complications and frequency of recurrences. Due to the high recurrence rate independent of the selected therapy, consistent follow-up after primary therapy is crucial for the long-term success.

Photodynamic therapy for localized infections--state of the art

Photodynamic therapy (PDT) was discovered over 100 years ago by observing the killing of microorganisms when harmless dyes and visible light were combined in vitro. Since then it has primarily been developed as a treatment for cancer, ophthalmologic disorders and in dermatology. However, in recent years interest in the antimicrobial effects of PDT has revived and it has been proposed as a therapy for a large variety of localized infections. This revival of interest has largely been driven by the inexorable increase in drug resistance among many classes of pathogen. Advantages of PDT include equal killing effectiveness regardless of antibiotic resistance, and a lack of induction of PDT resistance. Disadvantages include the cessation of the antimicrobial effect when the light is turned off, and less than perfect selectivity for microbial cells over host tissue. This review will cover the use of PDT to kill or inactivate pathogens in ex vivo tissues and in biological materials such as blood. PDT has been successfully used to kill pathogens and even to save life in several animal models of localized infections such as surface wounds, burns, oral sites, abscesses and the middle ear. A large number of clinical studies of PDT for viral papillomatosis lesions and for acne refer to its antimicrobial effect, but it is unclear how important this microbial killing is to the overall therapeutic outcome. PDT for periodontitis is a rapidly growing clinical application and other dental applications are under investigation. PDT is being clinically studied for other dermatological infections such as leishmaniasis and mycobacteria. Antimicrobial PDT will become more important in the future as antibiotic resistance is only expected to continue to increase.

Photodynamic therapy in dermatology

Photodynamic therapy (PDT) is a modern therapy modality, based upon the application of a photosensitizing agent like aminolevulinic acid, a physiological precursor of porphyrins, onto the tissue followed by illumination with light of the visible wavelength spectrum. During this oxygen-dependent reaction, reactive oxygen species (ROS) are generated that have immunomodulatory or cytotoxic effects. PDT shows excellent cosmetic results especially for its key indication in dermatology - the treatment of non-melanoma skin cancer. The associated pain and the low tissue penetration are the most frequent limiting factors of PDT. We review basic principles and recent developments in photosensitizers and light sources. Key oncological and non-oncological indications are presented as well.