Daylight photodynamic therapy with MAL cream for large-scale photodamaged skin based on the concept of ‘actinic field damage’: recommendations of an international expert group

Application of microneedling in photodynamic therapy: A systematic review

BACKGROUND

The application of photodynamic therapy (PDT) is pivotal in the management of diverse dermatologic conditions. Microneedling (MN) is a minimally invasive tool that is capable of inducing transient pores on the skin to facilitate transdermal drug delivery. Several studies have reported augmentation of PDT combined with MN. This systematic review analyzes the current studies on the efficacy and safety of MN-assisted PDT for skin diseases.

METHODS

The literature search using the PRISMA standard was completed through PubMed, Embase, Web of Science and CENTRAL from the establishment of the databases to November 2023. Two independent researchers finished the procedure.

RESULTS

A total of 12 articles and 413 subjects met our study criteria. This systematic review suggests that MN-assisted PDT can decrease the incubation time required for the photosensitizer and reduce skin lesions of actinic keratosis (AK) . The common side effect is pain and no serious adverse events were reported.

CONCLUSIONS

MN is an effective method to increase the transdermal delivery rate of photosensitizers. For different photosensitizers and disease, MN may show different clinical effects.

Full-face ALA-PDT for facial actinic keratosis: Two case reports

We reported two cases of full-face 5-aminolevulinic acid-photodynamic therapy (ALA-PDT) for facial multiple actinic keratosis (AK). After the full-face ALA-PDT, we observed that the AK lesions on the faces of the patients were completely cleared and facial rejuvenation was achieved. In our follow-up, one patient was free of recurrence for over 13 months and the other one for over 28 months. The experience of these two cases may indicate that full-face ALA-PDT has an excellent therapeutic effect while potentially preventing the recurrence of AK.

Research Progress of Photodynamic Therapy in Wound Healing: A Literature Review

Light is an efficient technique that has a significant influence on contemporary medicine. Photodynamic therapy (PDT), which involves the combined action of photosensitizers (PSs), oxygen, and light, has emerged as a therapeutically promising method for treating a broad variety of solid tumors and infectious diseases. Photodynamic therapy is minimally invasive, has few side effects, lightens scars, and reduces tissue loss while preserving organ structure and function. In particular, PDT has a high healing potential for wounds (PDT stimulates wound healing by enhancing re-epithelialization, promoting angiogenesis as well as modulating skin homeostasis). Wound healing involves interactions between many different processes, including coagulation, inflammation, angiogenesis, cellular migration, and proliferation. Poor wound healing with diabetes or extensive burns remains a difficult challenge. This review emphasizes PDT as a potential research field and summarizes PDT's role in wound healing, including normal wounds, chronic wounds, and aging wounds.

Comparison of clinical and histologic findings in daylight photodynamic therapy for skin field cancerization: A randomized controlled four-arm study on physical methods-assisted delivery of methyl aminolevulinate

BACKGROUND

Daylight photodynamic therapy (DL-PDT) has similar efficacy to conventional photodynamic therapy in treating actinic keratosis (AKs). Good clinical outcomes have been reported when associated with physical methods such as microneedles, but a comparison of different methods and histologic studies is lacking.

OBJECTIVES

To evaluate clinical and histologic modifications induced by standard DL-PDT and compare with DL-PDT associated with physical methods in treating skin field cancerization of the face.

METHODS

Forty patients with photodamaged skin and at least one AK lesion on the face were randomly distributed into four groups, ten patients in each (I: Standard DL-PDT; II: DL-PDT + microneedles; III: DL-PDT + CO2 laser; IV: DL-PDT + microdermabrasion) and underwent two DL-PDT sessions with methyl aminolevulinate cream and 2-hour daylight exposure. Skin biopsies were performed on all patients before and 3 months after. All fragments were stained using the hematoxylin-eosin, orcein, and picrosirius.

RESULTS

All 40 patients completed the study. Group III had a higher AK-clearance after 1 (p = 0,002) and 3 (p = 0,034) months, but it was similar in every group at 6 months (p = 0,441). Group III and IV had better clinical global improvement on texture, pigmentation and fine lines. In the groups associated with physical methods, the improvement of the keratinocytes' atypia and solar elastosis were remarkable. Only group III showed a significant reduction in solar elastosis (p = 0.034) and increased collagen type I (p = 0.028) after treatment.

CONCLUSION

DL-PDT-associated with physical methods had better clinical and histologic results. AK-clearance were significantly higher after 1 and 3 months with pretreatment-CO2 laser. Photorejuvenation were more evident with pretreatment-CO2 laser and microdermabrasion. Pretreatment-CO2 laser showed a significant reduction in solar elastosis and increase of collagen type 1. These results pointed to the pretreatment with laser as a potentially better option for skin field cancerization of the face.

[Photodynamic therapy-trends and new developments]

Photodynamic therapy (PDT) is a licensed and established procedure for the treatment of actinic keratosis, basal cell carcinoma, and Bowen's disease, but there are several new and clinically relevant developments and trends. These concern on the one hand the main components of PDT, which are the photosensitizer and the light source. Furthermore, modifications and therapy combinations have been developed that lead to an improved therapeutic efficacy. An important aspect of field-directed PDT is also skin cancer prevention. Finally, PDT has been used successfully for nonlicensed indications including inflammatory diseases and skin rejuvenation. This article focuses on these new developments and on recent guideline recommendations.

Daylight Photodynamic Therapy: An Update

Daylight photodynamic therapy (dPDT) uses sunlight as a light source to treat superficial skin cancer. Using sunlight as a therapeutic device has been present for centuries, forming the basis of photodynamic therapy in the 20th century. Compared to conventional PDT, dPDT can be a less painful, more convenient and an effective alternative. The first clinical uses of dPDT on skin cancers began in Copenhagen in 2008. Currently, aminolevulinic acid-mediated dPDT has been approved to treat actinic keratosis patients in Europe. In this review article, we introduce the history and mechanism of dPDT and focus on the pros and cons of dPDT in treating superficial skin cancers. The future applications of dPDT on other skin diseases are expected to expand as conventional PDT evolves.

SmartPDT®: Smartphone enabled real-time dosimetry via satellite observation for daylight photodynamic therapy

BACKGROUND

Actinic keratosis (AK) affects one quarter of over 60  year olds in Europe with the risk of transforming into invasive squamous cell carcinoma. Daylight photodynamic therapy (dPDT) is an effective and patient preferred treatment that uses sunlight to clear AK. Currently, there is no standardised method for measuring the light received during treatment.

METHODS

SmartPDT® is a smartphone-based application and web-portal, developed by siHealth Ltd, enabling remote delivery of dPDT. It uses satellite imagery and computational algorithms to provide real-time determination of exposure to PpIX-effective solar radiation ("light dose"). The application also provides forecast of expected radiant exposures for 24- and 48-hs prior to the treatment period. Validation of the real-time and forecasted radiant exposure algorithms was performed against direct ground-based measurement under all weather conditions in Chilton, UK.

RESULTS

Agreement between direct ground measurements and satellite-determined radiant exposure for 2-h treatment was excellent at -0.1 % ± 5.1 % (mean ± standard deviation). There was also excellent agreement between weather forecasted radiant exposure and ground measurement, 1.8 % ± 17.7 % at 24-hs and 1.6 % ± 25.2 % at 48-hs. Relative Root Mean Square of the Error (RMSE_r) demonstrated that agreement improved as time to treatment reduced (RMSE_r = 22.5 % (48 -hs), 11.2 % (24-hs), 5.2 % (real-time)).

CONCLUSION

Agreement between satellite-determined, weather-forecasted and ground-measured radiant exposure was better than any existing published literature for dPDT. The SmartPDT® application and web-portal has excellent potential to assist with remote delivery of dPDT, an important factor in reducing risk in an elderly patient population during the Covid-19 pandemic.

Daylight photodynamic therapy is an option for the treatment of actinic keratosis in patients with xeroderma pigmentosum in Africa

BACKGROUND

Xeroderma pigmentosum (XP) is a very rare and severe genetic disorder with a DNA repair defect of ultraviolet (UV)-induced damage. Photodynamic therapy (PDT) has been successfully used in XP patients to treat actinic keratosis (AK) and daylight PDT (DL-PDT) has demonstrated similar efficacy to conventional PDT (C-PDT) for AK.

OBJECTIVES

To assess DL-PDT for the treatment of AK in patients with XP.

METHODS

Patients with XP were evaluated by a group of Spanish and African dermatologists. Clinical characteristics of the patients were assessed and divided in mild, severe or moderate affectation of AK in the face. A topical photosensitizer was extended on the patients' faces and after two hours of indoor light exposure, fluorescence was assessed and the cream was removed. Patients were examined two and seven days later to assess the reaction to PDT and followed up three months later.

RESULTS

A total of 13 patients were treated on the whole face. Three were classified as severe AK, six as moderate AK and four as mild AK. Fluorescence assessment showed a soft yellow-green colour and a pink-color delineating the AK. Two days after treatment patients presented a scaly reaction. After one week the reaction healed, there was improvement and after three months no adverse events were noticed.

CONCLUSIONS

PDT is an option for treatment of AK in patients with XP.

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.

[Chemical peeling in dermatology]

In this article, a comprehensive, yet introductory overview on chemexfoliation is given. The molecular mechanisms for selected indications are exemplified and the prerequisites, necessary precautions as well as potential complications are addressed. Finally, selected available superficial peeling substances are presented and the principal peeling procedure is outlined briefly.

Clinical utility of daylight photodynamic therapy in the treatment of actinic keratosis - a review of the literature

Actinic keratosis (AK) is an early in situ squamous cell carcinoma that results from UV light exposure and has the potential to evolve into invasive tumor. Therefore, it is crucial that AKs are monitored and treated appropriately. Photodynamic therapy (PDT) is a treatment option that is minimally invasive and leaves patients with cosmetically superior results. However, disadvantages of PDT include pain and lengthy clinic visits. Accordingly, there has been much interest in the use of daylight photodynamic therapy (daylight-PDT) as a more convenient and less painful alternative to conventional photodynamic therapy (c-PDT). Current evidence shows that daylight-PDT is noninferior to c-PDT in the short and long term. Patients reported decreased pain with daylight-PDT and were more satisfied with the procedure (P<0.001). Current evidence suggests that 2 hrs of daylight exposure was sufficient for treatment, and its efficacy does not appear to be limited by weather conditions. Given the decreased intensity of treatment, daylight-PDT is better for mild disease, as it is less effective in moderate-to-thick AKs. Though further studies are still needed to refine the technique, daylight-PDT is a potential alternative to c-PDT for thin-to-moderate AKs and should be offered to patients with lower pain tolerance or busy schedules.

Trends in the treatment and prevention of keratinocyte carcinoma (non-melanoma skin cancer)

Keratinocyte carcinoma (KC), previously also known as non-melanoma skin cancer, is the most common malignancy worldwide. It comprises basal cell carcinoma, squamous cell carcinoma (SCC), and actinic keratoses as carcinoma in situ or precursors of SCC. With solar ultraviolet radiation being the main risk factor, several countries have accepted KC as an occupational disease of outdoor professions. The prevalence in these high-risk groups is substantial, but awareness and preventive behavior remains inadequate. Parallel to the development of improved treatments, such as daylight photodynamic therapy and PD1 inhibitors for progressive KC, target-oriented prevention strategies are requisite if the global burden of KC is to be lowered. Health-related communication, internet search analysis, and telemedicine could be the key to addressing this issue.

Daylight Photodynamic Therapy for Actinic Keratoses

Topical photodynamic therapy (PDT) using daylight is effective in the treatment of actinic keratoses (AKs), offering the potential for treatment of large fields such as full face and balding scalp, but with minimal therapy-associated pain. Comparison with conventional PDT indicates similar efficacy for thin and moderate-thickness AKs, but with significantly less discomfort/pain, driving a patient preference for daylight-mediated PDT (DL-PDT) compared with conventional PDT using high-intensity office/hospital-based light sources. Treatment protocol involves the application of a photosensitizing agent without occlusion and subsequent exposure to ambient daylight within 30 min, with patients exposed to daylight for 1.5-2.0 h. Pivotal randomized controlled trials in Europe and Australia have confirmed the efficacy of methyl aminolevulinic acid (MAL) DL-PDT in comparison with conventional MAL-PDT for mild and moderate-thickness lesions on the face and scalp. Initial clearance rates of 70-89% are reported. DL-PDT using a nanoemulsion aminolevulinic acid (ALA) has recently been shown to be at least as effective as MAL DL-PDT in treating mild and moderate-thickness AKs. DL-PDT may offer a better-tolerated method for treating patients with extensive AK disease. There is emerging literature on the potential for field PDT to reduce the number of new AKs developing, potentially preventing/slowing skin cancer development. Conventional PDT remains established as a therapy for Bowen's disease (squamous cell carcinoma in situ), superficial and certain thin basal cell carcinomas (BCCs), and AKs. The evidence for the use of DL-PDT beyond AK is limited, although has been reported in actinic cheilitis, superficial BCC, and acne and cutaneous leishmaniasis. There is emerging interest in combination therapy for AK, using one or more field therapies such as DL-PDT as an option to complement with localized treatment for residual lesions. We review current recommendations and consider the appropriate place for DL-PDT in our treatment armamentarium.

Photodynamic therapy for aesthetic-cosmetic indications

Photodynamic therapy (PDT) is a well-established, non-invasive treatment for a variety of dermatologic disorders, including actinic keratosis. Furthermore, PDT results in marked improvements in the signs of skin aging, although currently there are no standardized guidelines for PDT in skin rejuvenation. Two types of PDT are available: conventional-PDT (c-PDT) and the newly introduced daylight-PDT (DL-PDT). Both require a topical photosensitizer, a light source and oxygen, and both are comparable regarding safety and efficacy for treatment of photo-induced skin aging. Treatment is particularly effective for improvement of fine wrinkles, skin roughness, actinic elastosis and mottled hyperpigmentation. The most widely studied topical sensitizers used in PDT are 5-aminolevulinic acid (ALA) and methyl aminolevulinate (MAL). A range of pre-treatment procedures help improve skin absorption of the photosensitizer and lead to significantly improved efficacy. A variety of activating light sources can be used for c-PDT, while DL-PDT uses natural daylight, making it easier to treat larger areas of photodamaged skin. A major limitation of c-PDT is significant treatment-related pain, but DL-PDT has proved to be an almost pain-free procedure. Treatment duration is based on individual patient need but most patients receive 2 to 3 treatment cycles, with results fully evident 3-6 months post-treatment. PDT for aesthetic-cosmetic treatments has established its value in modern procedural dermatology as mono- or combination therapy. A major, unique advantage of PDT is that it is a non-invasive treatment that effectively rejuvenates photodamaged skin, while successfully treating a range of dermatologic conditions, including prevention and therapy of pre-cancerous actinic keratosis.

Quantifying the radiant exposure and effective dose in patients treated for actinic keratoses with topical photodynamic therapy using daylight and LED white light

Daylight photodynamic therapy (dl-PDT) is as effective as conventional PDT (c-PDT) for treating actinic keratoses but has the advantage of reducing patient discomfort significantly. Topical dl-PDT and white light-PDT (wl-PDT) differ from c-PDT by way of light sources and methodology. We measured the variables associated with light dose delivery to skin surface and influence of geometry using a radiometer, a spectral radiometer and an illuminance meter. The associated errors of the measurement methods were assessed. The spectral and spatial distribution of the radiant energy from the LED white light source was evaluated in order to define the maximum treatment area, setup and treatment protocol for wl-PDT. We compared the data with two red LED light sources we use for c-PDT. The calculated effective light dose is the product of the normalised absorption spectrum of the photosensitizer, protoporphyrin IX (PpIX), the irradiance spectrum and the treatment time. The effective light dose from daylight ranged from 3  ±  0.4 to 44  ±  6 J cm^-2due to varying weather conditions. The effective light dose for wl-PDT was reproducible for treatments but it varied across the treatment area between 4  ±  0.1 J cm^-2 at the edge and 9  ±  0.1 J cm^-2 centrally. The effective light dose for the red waveband (615-645 nm) was 0.42  ±  0.05 J cm^-2 on a clear day, 0.05  ±  0.01 J cm^-2 on an overcast day and 0.9  ±  0.01 J cm^-2 using the white light. This compares with 0.95  ±  0.01 and 0.84  ±  0.01 J cm^-2 for c-PDT devices. Estimated errors associated with indirect determination of daylight effective light dose were very significant, particularly for effective light doses less than 5 J cm^-2 (up to 83% for irradiance calculations). The primary source of error is in establishment of the relationship between irradiance or illuminance and effective dose. Use of the O'Mahoney model is recommended using a calibrated logging illuminance meter with the detector in the plane of the treatment area.

Daylight photodynamic therapy: experience in the treatment of actinic keratosis in the San Gallicano Institute (Rome) and a review of literature

BACKGROUND

Actinic keratosis (AK) is a photo-induced skin lesion. It has been considered by several authors as in-situ squamous cell carcinoma (SCC), that can evolve to invasive SCC (iSCC). Given the malignant potential and because it is impossible predict which AK will evolve in iSCC, it is necessary to treat each lesion. Multiple therapeutic approaches have been described to treat AKs. In addition to the topical drugs, photodynamic therapy (PDT) has become an established therapeutic modality for grade I and II of AKs of face and scalp. Recently the daylight photo-dynamic therapy (DL-PDT) has found extensive use in the care of the AK and in the field cancerization.

METHODS

The study included 101 patients, 90 males and 11 females, mean age 71, phototype I-II, with multiple AK I and II of the face and the scalp, treated with DL-PDT. Patients were clinically evaluated for 3 months. The aim of this study was to show our experience in Daylight Photodynamic Therapy, to confirm the validity in term of efficacy and safety of DL-PDT for I and II AK of face and scalp and to underline the patient's higher satisfaction for this type of treatment and his availability to be retreated with the DL-PDT.

RESULTS

The efficacy was complete in 16 patients (15.8%), in 71 patients (70.3%) was much improved or improved and only in 14 (13.9%) subjects were minimal, while nobody had worsened or changed. The majority of patients (84.2%) patients were satisfied of the efficacy as well of the cosmetic results, only 15 (14.9%) were low satisfied and one patient was not satisfied.

CONCLUSIONS

This study confirms that the DL-PDT is a good alternative to c-PDT for the treatment of grade I and II AK of the face and scalp and in Rome, as in Southern Europe, it is possible to perform the DL-PDT in almost every month of year.

High Patient Satisfaction with Daylight-Activated Methyl Aminolevulinate Cream in the Treatment of Multiple Actinic Keratoses: Results of an Observational Study in Australia

Introduction

Actinic keratoses (AK) are treated to reduce the risk of progression to squamous cell carcinoma and for symptomatic and cosmetic benefits. The objective of this observational study was to generate real-life data on the use of daylight photodynamic therapy with methyl aminolevulinate cream (MAL DL-PDT) in treating mild to moderate facial/scalp AK.

Methods

A multicenter, prospective, observational study was conducted in Australia in patients receiving a single treatment of MAL DL-PDT for mild to moderate AK. Efficacy was assessed 3 months after treatment by investigator-assessed improvement and patient- and physician-completed satisfaction questionnaires. Adverse events were recorded throughout the study.

Results

Overall, 81 patients were enrolled of mean age 62.7 years, mostly men (76.5%) with skin phototype I (64.2%) or II (35.8%) and a long history of AK (mean duration 16.8 years). Most had multiple lesions (82.7% had >10 lesions) of predominantly grade I (75.3%). At 3 months after treatment, almost half the patients (46.8%) required no further treatment. The proportions of patients and physicians satisfied to very satisfied with the MAL DL-PDT treatment were 79.7% and 83.3%, respectively. After receiving the treatment, 74.1% of patients indicated via the questionnaire that they were not bothered at all by the pain. Related AEs were reported in 48.1% of patients, mainly mild erythema (44.4%).

Conclusions

In clinical practice in Australia, the use of MAL DL-PDT in treating multiple mild to moderate non-hyperkeratotic AK of the face and/or scalp results in high levels of patient and physician satisfaction reflecting the good efficacy and tolerability of this almost painless, convenient procedure.

Trial Registration

ClinicalTrials.gov identifier, NCT02674048.

Funding

Galderma R&D.

COMPARATIVE STUDIES OF EFFICACY OF PHOTODYNAMIC THERAPY AND CRYOTHERAPY FOR TREATMENT OF ACTINIC KERATOSIS

The results of a study on the effectiveness of photodynamic therapy with a photosensitizer fotoditazin and cryotherapy for actinic keratosis are represented in the article. The study included 80 patients with 215 lesions, among them erythematous form of actinic keratosis was diagnosed in 151 (70.2%) cases, hyperkeratotic form – in 46 (21.4%) cases, a pigmented form – in 12 (5.6%) and an atypical variant of the disease – in 6 (2.8%) cases. According to histological type the distribution of tumor was as follows: 19 (54.3%) cases were diagnosed as hypertrophic type, 6 (17.1%) – atrophic, 8 (22.9%) – bowenoid and 2 (5.7% ) – pigmented type. Patients from the study group received one session of photodynamic therapy using laser unit "LAMI" (662 nm) after 2 hours of application of fotoditazin 0.5% gel at dose of 0,2-0,3 ml per 1 cm2 of actinic keratosis focus with the following parameters: the energy density of the laser radiation – 200 J/cm2, power density – 0.14–0.48 W/cm2. In the control group patients underwent cryotherapy with liquid nitrogen with an exposure of 30-60 sec. The comparative analysis of the immediate results showed a tendency for the efficacy of photodynamic therapy to increase (the rate of complete regression was 92.5%) compared with cryotherapy (85.0%) (p>0,05). There were also a tendency for long-term results after photodynamic therapy to improve: three-year recurrence-free survival was 94.6% and 88.2%, respectively. For the photodynamic therapy there were significantly fewer adverse reactions, the epithelization time in lesions was significantly shorter. Compared with cryotherapy the photodynamic therapy provided significantly better cosmetic results (p <0.01), and can be used for out-patient treatment of patients with actinic keratosis.><0.01) and can be used for out-patient treatment of patients with actinic keratosis.

Photodynamic Therapy and Non-Melanoma Skin Cancer

Non-melanoma skin cancer (NMSC) is the most common malignancy among the Caucasian population. Photodynamic therapy (PDT) is gaining popularity for the treatment of basal cell carcinoma (BCC), Bowen's disease (BD) and actinic keratosis (AK). A topical or systemic exogenous photosensitiser, results in selective uptake by malignant cells. Protoporphyrin IX (PpIX) is produced then activated by the introduction of a light source. Daylight-mediated MAL (methyl aminolaevulinate) PDT for AKs has the advantage of decreased pain and better patient tolerance. PDT is an effective treatment for superficial BCC, BD and both individual and field treatment of AKs. Excellent cosmesis can be achieved with high patient satisfaction. Variable results have been reported for nodular BCC, with improved outcomes following pretreatment and repeated PDT cycles. The more aggressive basisquamous, morphoeic infiltrating subtypes of BCC and invasive squamous cell carcinoma (SCC) are not suitable for PDT. Prevention of "field cancerization" in organ transplant recipients on long-term immunosuppression and patients with Gorlin syndrome (naevoid basal cell carcinoma syndrome) is a promising development. The optimisation of PDT techniques with improved photosensitiser delivery to target tissues, new generation photosensitisers and novel light sources may expand the future role of PDT in NMSC management.

Use of Lesion Response Rate in Actinic Keratosis Trials

Complete patient clearance is often required by regulatory agencies for the approval of treatments for actinic keratosis (AK). However, an increasing number of clinicians have challenged the use of this measure in clinical practice and its interpretation. It has been argued that complete patient clearance often underestimates the clinical benefit of a drug and is influenced by a number of key confounding factors, such as number and distribution of lesions, at baseline. Lesions response rate is one alternative which has been suggested as more relevant due to its applicability to clinical practice and closer reflection of the clinical value of the drug. This paper provides an updated perspective on the topic and details the current thinking on the role of complete clearance and lesion response rate in the context of AK.

Funding: Galderma.

PDT and emerging therapies for Actinic Keratosis-A resource letter

Aktinic Keratosis is common and if left untreated may develop into life threatening squamous cell carcinoma. Therefore early intervention is the standard of care. While many treatments are available PDT continues to move to the for - front for this indication (Brito et al., 2016 [31]). Topical PS is commercially available that are able to reliably ablate these lesions. Innovative protocols including sunlight, large volume LED arrays and maneuvers to improve treatment parameters and cosmesis continue to make this a worldwide treatment of choice for AK.

In situ production of ROS in the skin by photodynamic therapy as a powerful tool in clinical dermatology

Photodynamic therapy (PDT) is a clinical modality of photochemotherapy based on the accumulation of a photosensitizer in target cells and subsequent irradiation of the tissue with light of adequate wavelength promoting reactive oxygen species (ROS) formation and cell death. PDT is used in several medical specialties as an organ-specific therapy for different entities. In this review we focus on the current dermatological procedure of PDT. In the most widely used PDT protocol in dermatology, ROS production occurs by accumulation of the endogenous photosensitizer protoporphyrin IX after treatment with the metabolic precursors 5-methylaminolevulinic acid (MAL) or 5-aminolevulinic acid (ALA). To date, current approved dermatological indications of PDT include actinic keratoses (AK), basal cell carcinoma (BCC) and in situ squamous cell carcinoma (SCC) also known as Bowen disease (BD). With regards to AKs, PDT can also treat the cancerization field carrying an oncogenic risk. In addition, an increasing number of pathologies, such as other skin cancers, infectious, inflammatory or pilosebaceous diseases are being considered as potentially treatable entities with PDT. Besides the known therapeutic properties of PDT, there is a modality used for skin rejuvenation and aesthetic purposes defined as photodynamic photorejuvenation. This technique enables the remodelling of collagen, which in turn prevents and treats photoaging stygmata. Finally we explore a new potential treatment field for PDT determined by the activation of follicular bulge stem cells caused by in situ ROS formation.

MAL Daylight Photodynamic Therapy for Actinic Keratosis: Clinical and Imaging Evaluation by 3D Camera

Non-melanoma skin cancer is the most common skin cancer with an incidence that varies widely worldwide. Among them, actinic keratosis (AK), considered by some authors as in situ squamous cell carcinoma (SCC), are the most common and reflect an abnormal multistep skin cell development due to the chronic ultraviolet (UV) light exposure. No ideal treatment exists, but the potential risk of their development in a more invasive form requires prompt treatment. As patients usually present with multiple AK on fields of actinic damage, there is a need for effective, safe, simple and short treatments which allow the treatment of large areas. To achieve this, daylight photodynamic therapy (DL-PDT) is an innovative treatment for multiple mild actinic keratosis, well tolerated by patients. Patients allocated to the PDT unit, affected by multiple mild-moderate and severe actinic keratosis on sun-exposed areas treated with DL-PDT, were clinically evaluated at baseline and every three months with an Antera 3D, Miravex(©) camera. Clinical and 3D images were performed at each clinical check almost every three months. In this retrospective study, 331 patients (56.7% male, 43.3% female) were treated with DL-PDT. We observed a full clearance in more than two-thirds of patients with one or two treatments. Different responses depend on the number of lesions and on their severity; for patients with 1-3 lesions and with grade I or II AK, a full clearance was reached in 85% of cases with a maximum of two treatments. DL-PDT in general improved skin tone and erased sun damage. Evaluating each Antera 3D images, hemoglobin concentration and pigmentation, a skin color and tone improvement in 310 patients was observed. DL-PDT appears as a promising, effective, simple, tolerable and practical treatment for actinic damage associated with AK, and even treatment of large areas can be with little or no pain. The 3D imaging allowed for quantifying in real time the aesthetic benefits of DL-PDT's increasing compliance.

[Skin aging and evidence-based topical strategies]

Anti-aging in dermatology primarily focuses on the prevention of skin aging with UV protection (clothing and sunsceens), free radical scavengers (synthetic or botanic), and cell-protecting agents such as vitamin B3. For the correction of signs of early skin aging, retinoic acid derivatives in dermatological prescriptions are the best studied substances. Topical hormonal prescriptions are also an option if UV damage has not been the leading culprit for aging. Chemical peeling leads to a marked increase in collagen formation, the deaper the better. Ingredients in cream preparations can reduce superficial skin folds (polyphenols, amino acid peptides). Modulators of regular pigmentation are important for anti-aging preparations. Growth factors (plant extracts, recombinant growth factors) are not thoroughly studied regarding the cost-benefit and risk ratio. Complex precedures such as photodynamic therapy have an impact on the appearance of aged skin.