Daylight Photodynamic Therapy Research Articles

Exploring Patient Pain Experiences during and after Conventional Red Light and Simulated Daylight Photodynamic Therapy for Actinic Keratosis: A Qualitative Interview Study.

Simulated daylight photodynamic therapy is a relatively new and potentially less painful alternative to conventional red light photodynamic therapy for actinic keratosis. Qualitative research exploring patient experiences of pain and skin reactions during these treatments is scarce. To address this, semi-structured interviews were conducted of 10 patients aged 60-81 years with symmetrically distributed actinic keratoses 4 weeks after split-face treatment with conventional red light photodynamic therapy and simulated daylight photodynamic therapy. The participants were recruited from an ongoing clinical randomized trial. Interviews (median length 35 min) were conducted between June 2022 and January 2023, audio-recorded, transcribed verbatim, and analysed qualitatively using content analysis, as described by Graneheim and Lundman. Participants reported that conventional red light photodynamic therapy was very painful during illumination and transiently painful in the post-treatment period, while simulated daylight photodynamic therapy was almost painless during illumination and led to minor post-treatment pain. Also, skin reactions were more intense and longer-lasting with conventional red light photodynamic therapy than with simulated daylight photodynamic therapy. Most participants expressed a treatment preference for simulated daylight photodynamic therapy but had reservations about its unestablished long-term effectiveness. This study underscores the considerable pain associated with conventional red light photodynamic therapy, and the pivotal importance of shared decision-making when selecting the most appropriate treatment.

Pre-treatment with topical 5-fluorouracil increases the efficacy of daylight photodynamic therapy for actinic keratoses – A randomized controlled trial

BackgroundDaylight photodynamic therapy (dPDT) and topical 5-fluorouracil (5-FU) are each effective treatments for thin grade I actinic keratosis (AKs), but less so for thicker grade II-III AKs. Prolonged topical treatment regimens can be associated with severe skin reactions and low compliance.This study compares the efficacy of sequential 4 % 5-FU and dPDT with dPDT monotherapy for multiple actinic keratoses. MethodsSixty patients with a total of 1547 AKs (grade I: 1278; grade II: 246; grade III: 23) were treated in two symmetrical areas (mean size 75 cm2) of the face or scalp, which were randomized to (i) 4% 5-FU creme twice daily for 7 days before a single dPDT procedure and (ii) dPDT monotherapy. Daylight exposure was either outdoor or indoor daylight. ResultsTwelve weeks after treatment 87 % of all AKs cleared after 5-FU+dPDT compared to 74 % after dPDT alone (p<0.0001). For grade II AKs, the lesion response rate increased from 55 % with dPDT monotherapy to 79 % after 5-FU+dPDT (p<0.0056). Moderate/severe erythema was seen in 88 % 5-FU+dPDT areas compared to 41 % of dPDT areas two days after dPDT. Twelve weeks after treatment 75 % of the patients were very satisfied with both treatments. ConclusionsSequential 5-FU and dPDT was more effective than dPDT monotherapy in the treatment of AKs, especially for grade II AKs. Local skin reactions were more pronounced after combination treatment, but no patients discontinued the treatment. The combination of 5-FU and dPDT is an effective treatment of large treatment areas with high compliance and satisfaction.

The impact of occlusive vs non-occlusive application of methyl aminolevulinate on the efficacy and tolerability of daylight photodynamic therapy for actinic keratosis

BackgroundConventional photodynamic therapy (c-PDT) is an effective treatment for actinic keratoses (AKs) and nonmelanoma skin cancer which exploits the photosensitizing properties of methyl aminolaevulinate (MAL). Daylight photodynamic therapy (DL-PDT) is an alternative to c-PDT which does not require the application of MAL in occlusion and that is better tolerated by patients. The impact of occlusion on the efficacy of DL-PD has not been investigated by previous studies. ObjectiveTo compare the efficacy and tolerability of occlusive and non-occlusive DL-PDT. MethodsWe conducted a prospective intraindividual left/right comparison study. AKs of the face or scalp were marked in two symmetrical treatment areas. The two target areas were randomly assigned to DL-PDT with occlusive and non-occlusive application of MAL. The efficacy and cosmetic outcome were determined by a “blinded” investigator. ResultsLesions in occluded areas showed a better response in the clearance rate of the lesions (65.5% vs 35.0 %, p < 0.001 %), and cosmetic outcome (P < 0.001). There was no difference in phototoxicity or pain between occluded and non-occluded areas. ConclusionThe occlusive application of MAL improves the efficacy of DL-PDT in clearing AKs and does not increase the incidence of side effects.

Home- vs clinic-based daylight photodynamic therapy with 5-aminolevulinic acid nanoemulsion (BF-200 ALA) for actinic keratosis: A randomized, single-blind, prospective study

BackgroundDaylight photodynamic therapy (DL-PDT) has become one of the most effective treatments for the resolution of actinic keratosis (AK) of Olsen grade 1 and 2. Generally, PDT it is carried out in a clinic setting, which involves the patient's and their caregivers commuting to the hospital as well as a significant use of resources to carry it out within the clinic setting. ObjectivesTo determine the efficacy and safety of a home-based treatment of AK with DL-PDT with the BF-200 ALA gel compared to a clinic-based setting. MethodsThe study was performed as a randomized, single-center, non-inferiority clinical trial with two parallel groups. 9 patients received one clinic-based DL-PDT (group 1) and 11 patients received one session of home-based DL-PDT (group 2). The primary endpoints were the mean AK clearance per patient and the total AK lesion clearance rate 12 weeks after treatment. The secondary endpoints were the number of remaining AKs and new AKs appearing in the treatment field 12 weeks after one PDT session. The pain during and 24 h after PDT as well as the local skin reactions were also assessed. ResultsThe overall reduction of AK lesions per patient was similar in both groups with one PDT session. An overall AK clearance per patient of 10 ± 4.33 for group 1 versus 9.73 ± 2.9 for group 2 without statistically significant differences (p = 0.868). Regarding the clearance rate, although it was slightly higher in group 2 (71.58 ± 22.51 vs 82.1 ± 11.13), the analysis did not show statistically significant differences. The mild pain recorded during the treatment course and the mild local skin reactions were similar in both groups. Patient satisfaction was high for both groups without statistically significant differences. ConclusionSelf-performed home-based DL-PDT with BF-200 ALA gel is as effective as the one performed in a clinic-based setting, with a comparable safety profile, high levels of patient satisfaction and with advantages for the patients and their caregivers that can enhance patient´s adherence to the treatment

Development of novel holographic sensing technologies for accurate daylight photodynamic therapy (D-PDT) patient dosimetry

Development of novel holographic sensing technologies for accurate daylight photodynamic therapy (D-PDT) patient dosimetry

Assessment of reflectance confocal microscopy for monitoring treatment of actinic keratosis and field cancerization with daylight photodynamic therapy.

Actinic keratosis (AK) is the most common pre-malignant cutaneous lesion of the skin, often associated with field cancerization. Daylight photodynamic therapy (DL-PDT) is used as treatment, showing good histological results. Reflectance confocal microscopy (RCM) may be useful as a non-invasive, real-time approach to monitor treatment, however, there is a lack of data on the correlation between RCM and histopathological findings in AK patients treated with DL-PDT. To correlate histological and RCM findings and evaluate the efficacy of DL-PDT in patients with AK and field cancerization treated with DL-PDT. Patients with field cancerization and a minimum of six AK lesions on the face were included in the study. A single session combining methyl aminolevulinate followed by two-hour daylight exposure of the face was performed. RCM and biopsy were performed before and after three months of the intervention to compare efficacy between patients using the Wilcoxon test, and concordance of the findings based on the different methods was analysed using the Kappa test. Twenty-four patients completed the study. An improvement in photodamage and a decrease in the number of AK lesions (45.3% reduction) was observed. Regression in atypia and dysplasia was observed via histopathology and RCM, however, there was poor agreement between the methods. No changes were observed after treatment for inflammation, fibroplasia and acantholysis. Concordance between histological and RCM findings was poor, suggesting that RCM cannot replace the histopathological examination, however, it may be used as an adjuvant test for follow-up of patients. Despite this, DL-PDT proved to be an effective method for treating AK.

Daylight photodynamic therapy as a treatment for actinic field change in patients diagnosed with oculocutaneous albinism in sub-Saharan Africa.

Oculocutaneous albinism (OCA) is a genetically inherited condition, whereby melanin is reduced or absent in the skin. A lack of melanin predisposes people to actinic damage and skin malignancies. In Tanzania, a resource-limited country, the treatment of choice for precancerous skin lesions is cryotherapy. To investigate whether daylight photodynamic therapy (dPDT) is a safe and well-tolerated treatment for actinic field change in the OCA population in Tanzania. Twelve participants with actinic damage were recruited from a Standing Voice skin surveillance clinic and treated with dPDT. Study participants completed tolerability and acceptability questionnaires at day 5 and 3 months after treatment. A dermatologist assessed their clinical response to dPDT at 3 months. dPDT was well-tolerated and acceptable to the majority of patients. Actinic damage was reduced by 25-90%. No skin cancers developed during the treatment. This pilot study suggests that dPDT is a safe and tolerable treatment for actinic damage in people with OCA in Tanzania. Further work is required to compare the efficacy of dPDT against other topical therapies for actinic field change.

Photodynamic Therapy for Field Cancerization in the Skin: Where Do We Stand?

Photodynamic therapy (PDT) with a photosensitizer is available for the treatment of multiple actinic keratoses (AKs) in a restricted skin area or, as it is established, for the field-cancerized skin. Our review aims to present the up-to-date literature on skin field cancerization using PDT employing different topical photosensitizers, modified light delivery protocols and combination treatments to obtain excellent efficacy and safety in everyday clinical practice. We sought PubMed, MEDLINE, Scopus, OVID, Embase, Science Direct, Cochrane Library, Research Gate and Google Scholar for [(aminolevulinic acid OR aminolevulinate) AND photodynamic therapy] with (field-directed OR field cancerization, (actinic keratosis), and (efficacy OR effectiveness OR pain OR tolerability) for studies published until February 2023. Advantages of PDT compared to the other field treatments, including imiquimod, 5-fluorouracil, ingenol mebutate gel and diclofenac, reported better cosmetic outcomes and greater patient satisfaction. On the other hand, some drawbacks of field PDT include pain and treatment duration. Alternate illumination methods have also been investigated, including daylight as a light source. Pretreating the affected area may enhance photosensitizer absorption leading to better therapeutic results, while combinational treatments have also been tested. Patients prefer daylight PDT to traditional light sources since it is more well-tolerated and equally effective. Even as a preventive treatment, field PDT yields promising outcomes, especially for high-risk individuals, including organ transplant recipients. This review provides a thorough display of the field of PDT on cancerized skin, which will facilitate physicians in applying PDT more efficiently and intuitively.

Evaluation of Daylight Methylene Blue Photodynamic Therapy in Multiple Recurrent Molluscum Contagiosum

Abstract Background Molluscum contagiosum is a common viral infection caused by DNA Poxvirus. Daylight-photodynamic therapy (DL-PDT) is defined as a photochemical reaction used to selectively destroy tissue. Objectives To evaluate the efficacy and safety of daylight methylene blue photodynamic therapy in treatment of multiple recurrent molluscum contagiosum. Subject and methods This is a single blinded controlled prospective interventional clinical study including 20 patients with molluscum contagiosum diagnosed clinically and by dermoscopy. Patients subjected to daylight methylene blue-mediated photodynamic therapy. Topical MB liposomal loaded 10% cream was applied over the lesions area with occlusion and left for 15 minutes. Two leisons were left as control in each studied patient. Patients were instructed to stay outdoors exposing their lesions and the adjacent area to daylight continuously for at least 90 minutes (if it was a sunny day) or 120 minutes (if it was an overcast or partially sunny day) between 11:00 am to 02:00 pm. Treatment sessions were done weekly for 10 weeks or till complete clearance. Follow up of the patients for 6 months after end of study to detect recurrence or appearance of new lesions. Results Daylight MB Mediated PDT response in a total of 20 (100%) studied patients showed Excellent response to treatment shown as complete clearance in 65%( no.=13) of patients, very good response to treatment in 15.0%( no.=3), good response to treatment in 10.0%( no.=2) and poor response to treatment in 10.0%( no.=2). The total number of lesions was 313. Response of the lesions in studied patents to MB-PDT was monitored by dermoscopic follow up of lesions. Lesions showed complete response in 66.5% (no. = 208) of lesions, partial response in 25.2% (no. = 79) of lesions and no response in 8.3% (no. = 26) of lesions. No serious side effects and also MB-DL/PDT is a painless treatment. No relapse was detected at the site of cleared MC or at a near site during the follow-up period of 6 months following the procedure. Conclusion Daylight-PDT using MB is effective in clearing MC lesions, also is safe, easy to carry out, economic, acceptable cosmetic results with no recurrence, convenient especially for children as it is a painless treatment.

Ablative Fractional Laser Enhances Artificial or Natural Daylight Photodynamic Therapy of Actinic Field Cancerization: A Randomized and Investigator-initiated Half-side Comparative Study.

Artificial daylight photodynamic therapy is a near-painless treatment for actinic keratoses, which can be performed indoors using a controlled light dose. Daylight photodynamic therapy is approved only for treatment of grade I-II actinic keratoses. The aim of this study was to evaluate whether fractional laser pre-treatment improves the outcomes of daylight photodynamic therapy for actinic keratoses of all grades. In addition, the study compared the outcomes of artificial and natural daylight photodynamic therapy. This randomized single-blinded split-side comparative study included 60 patients with ≥ 2 actinic keratoses of the head. Fractional laser pre-treatment was assigned randomly for actinic keratoses on 1 side of the head and, subsequently, the entire treatment area was treated with artificial or natural daylight photodynamic therapy. Fractional laser-mediated daylight photodynamic therapy achieved significantly higher complete clearance (50.0% vs 30.3%, p = 0.04), partial clearance (78.6% vs 50.0%, p < 0.01) and lesion-specific clearance (86.2% vs 70.2%, p < 0.01) than daylight photodynamic therapy alone at the 6-month follow-up. No significant differences were found in the outcomes of artificial vs natural daylight photodynamic therapy or grade I lesions vs grade II-III lesions. Thus, fractional laser pre-treatment appears to significantly increase the efficacy of artificial and natural daylight photodynamic therapy, and to be suitable for treatment of actinic keratoses of all grades.

PD02 Home daylight photodynamic therapy

Abstract Actinic keratoses (AK) on the face and scalp are often extensive and are a major cause of morbidity and associated with increased risk of skin cancer. Field-directed treatment approaches, such as daylight photodynamic therapy (DPDT) are required, and this has been shown to be effective, well-tolerated and feasible in the UK between April and September. We have used DPDT since 2013, with good outcomes. Patient engagement indicated that convenience and tolerability were rated as highly as efficacy, and we therefore developed an entirely home-based approach ‘home DPDT (H-DPDT)’ in 2021. Working with an art-and-design student, we developed a fully recyclable home kit to enable patients to self-treat with H-DPDT entirely in their home environment. Patients were selected by a dermatologist and then received nurse-led training prior to treatment. In-person review after the second treatment was undertaken to assess response and decide if further treatment was needed, and telephone follow-up was undertaken after the first and third treatments. Final clinician review was undertaken 3–6 months after the last treatment. We reported on implementation in 2021 and introduced this into our routine PDT service options, and we now wish to report our findings from 2021–22. Seventeen patients (82% male) were treated in 2021–2022 for AK on the head and neck. Each patient completed an average of four (range 2–5) treatments. Clinical response was good (≥ 75% response) in nine of 15 (60%) patients assessed. Response was moderate in one (7%) patient (50–75% response) and the remaining five (33%) had a poor response (&amp;lt; 50% response). Treatment success correlated with grade of disease. Patients with more hyperkeratotic disease had poorer outcomes. In 2022, five patients responded to the routine daylight PDT questionnaire. Of these, two rated the H-DPDT as Excellent and the other three rated it as Good. Four patients stated that they had tried other AK treatments, two of which thought that H-PDT was better. One patient felt alternative treatments were more effective but they tolerated H-PDT better. Three of the five patients expressed a preference for H-DPDT for repeat treatment and would recommend it. This innovative H-DPDT service enables patients to self-treat in their home environment, and the initial results showed high rates of patient satisfaction. Treatment outcomes were better for those with milder disease, highlighting the need for careful patient selection and good surface preparation. As a proof of concept, H-DPDT is a feasible therapeutic option and empowers patients, but it may have more of a place in the treatment of milder AK disease, and further work to optimize this approach is indicated.

647 Combination treatment of daylight photodynamic therapy (DL-PDT) and alpha-hydroxy acid(AHA) 30% chemical peels as a novel effective treatment for severe papulopustular rosacea

647 Combination treatment of daylight photodynamic therapy (DL-PDT) and alpha-hydroxy acid(AHA) 30% chemical peels as a novel effective treatment for severe papulopustular rosacea

Improved Simulated-Daylight Photodynamic Therapy and Possible Mechanism of Ag-Modified TiO2 on Melanoma.

Simulated-daylight photodynamic therapy (SD-PDT) may be an efficacious strategy for treating melanoma because it can overcome the severe stinging pain, erythema, and edema experienced during conventional PDT. However, the poor daylight response of existing common photosensitizers leads to unsatisfactory anti-tumor therapeutic effects and limits the development of daylight PDT. Hence, in this study, we utilized Ag nanoparticles to adjust the daylight response of TiO2, acquire efficient photochemical activity, and then enhance the anti-tumor therapeutic effect of SD-PDT on melanoma. The synthesized Ag-doped TiO2 showed an optimal enhanced effect compared to Ag-core TiO2. Doping Ag into TiO2 produced a new shallow acceptor impurity level in the energy band structure, which expanded optical absorption in the range of 400-800 nm, and finally improved the photodamage effect of TiO2 under SD irradiation. Plasmonic near-field distributions were enhanced due to the high refractive index of TiO2 at the Ag-TiO2 interface, and then the amount of light captured by TiO2 was increased to induce the enhanced SD-PDT effect of Ag-core TiO2. Hence, Ag could effectively improve the photochemical activity and SD-PDT effect of TiO2 through the change in the energy band structure. Generally, Ag-doped TiO2 is a promising photosensitizer agent for treating melanoma via SD-PDT.

Equivalent efficacy of indoor daylight and lamp-based 5-aminolevulinic acid photodynamic therapy for treatment of actinic keratosis.

Photodynamic therapy (PDT) is widely used as a treatment for actinic keratoses (AK), with new sunlight-based regimens proposed as alternatives to lamp-based treatments. Prescribing indoor daylight activation could help address the seasonal temperature, clinical supervision, and access variability associated with outdoor treatments. To compare the AK lesion clearance efficacy of indoor daylight PDT treatment (30min of 5-aminolevulinic acid (ALA) pre-incubation, followed by 2h of indoor sunlight) versus a lamp-based PDT treatment (30min of ALA preincubation, followed by 10min of red light). A prospective clinical trial was conducted with 41 patients. Topical 10% ALA was applied to the entire treatment site (face, forehead, scalp). Patients were assigned to either the lamp-based or indoor daylight treatment. Actinic keratosis lesion counts were determined by clinical examination and recorded for pre-treatment, 1-month, and 6-month follow-up visits. There was no statistical difference in the efficacy of AK lesion clearance between the red-lamp (1-month clearance=57±17%, 6-month clearance=57±20%) and indoor daylight treatment (1-month clearance=61±19%, 6-month clearance=67±20%). A 95% confidence interval of the difference of the means was measured between -4.4% and 13.4% for 1-month, and -2.2% and +23.6% for 6-month timepoints when comparing the indoor daylight to the red-lamp treatment, with a priori interval of equivalence of ±20%. Ensuring an equivalent dose between the indoor and lamp treatment cohorts limited randomisation since it required performing indoor daylight treatments only during sunny days. Indoor-daylight PDT provided equivalent AK treatment efficacy to a lamp-based regimen while overcoming temperature limitations and UV-block sunscreen issues associated with outdoor sunlight treatments in the winter. Clinicaltrials.gov listing: NCT03805737.

Clinical practice Guidelines for 5-Aminolevulinic acid photodynamic therapy for acne vulgaris in China.

A variety of evidence suggest that 5-Aminolevulinic acid-based photodynamic therapy (ALA-PDT) is clinically effective in management of acne vulgaris. Several clinical guidelines for acne recommend PDT as an alternative treatment modality for severe acne. However, there is a lack of detailed clinical guideline for PDT in acne treatment. To propose up-to-date, evidence-based and practical recommendations on application of ALA-PDT for acne vulgaris, dermatologists and PDT experts from the Photodynamic Therapy Research Center of the CMA and Photodynamic Therapy Rehabilitation Training Center of CARD achieved consensus and guidelines based on careful evaluation of published literature, expert opinions and experience. ALA-PDT plays a therapeutic role in all four major pathogenesis of acne, and is suitable for moderate to severe acne and scar-prone acne, especially for patients who cannot tolerate or refused systemic antibiotics and isotretinoin. The efficacy and adverse reactions of ALA-PDT are closely related to therapeutic parameters including ALA concentration, incubation time, light source and dosage. Proper pretreatment helps to improve transdermal absorption of ALA and enhances its efficacy. We reviewed and proposed recommended protocols for four PDT procedures including conventional PDT (C-PDT), modified painless PDT (M-PDT), intense pulsed light PDT (IPL-PDT) and daylight PDT (DL-PDT). M-PDT with lower ALA concentration (3-5%), shorter incubation time (30 mins), and lower dose but prolonged illumination (630nm, 40-60 mW/cm2, 150 J/cm2) can improve lesions of moderate to severe acne vulgaris effectively with minimal pain and easier manipulation, and thus was recommended by Chinese dermatologists. Lastly, management of adverse reactions were addressed.

Wearable devices for photodynamic therapy – A systematic review

Wearable devices for photodynamic therapy – A systematic review

Advances in Photodynamic Therapy for the Treatment of Actinic Keratosis and Nonmelanoma Skin Cancer: A Narrative Review.

Photodynamic therapy (PDT) with photosensitization using 5-aminolevulinic acid (ALA) [including a nanoemulsion (BF-200 ALA)] is approved in the USA for the treatment of actinic keratoses (AKs); another derivative, methyl aminolevulinate, is not approved in the USA but is used in Europe. For AK treatment, the photosensitizer may be applied to individual AK lesions or, depending on treatment regimen, to broader areas of sun-damaged skin to manage field cancerization, although not all products are approved for field treatment. ALA-PDT and photosensitizers have also been used off-label for the treatment of nonmelanoma skin cancers, primarily basal cell carcinomas (BCCs) and cutaneous squamous cell carcinomas (cSCC). Advantages of PDT include potentially improved cosmesis and patient satisfaction; disadvantages include pain and duration of treatment. Alternative illumination approaches, including intense pulsed light as well as pulsed-dye lasers, have also been used successfully. Pretreating the affected tissue or warming during incubation can help to increase photosensitizer absorption and improve therapeutic efficacy. Combinations of multiple treatments are also under exploration. Reducing incubation time between photosensitizer application and illumination may significantly reduce pain scores without affecting treatment efficacy. Substituting daylight PDT for a conventional illumination source can also reduce pain without compromising efficacy. The objective of this narrative review is to describe current and ongoing research in the use of topical photosensitizers and modified light delivery regimens to achieve improved therapeutic outcomes with less toxicity in patients with AK, cSCC, BCC, and field cancerization.

Refractory facial Darier's disease treated with daylight photodynamic therapy.

Refractory facial Darier's disease treated with daylight photodynamic therapy.

Fully home-based methyl aminolevulinate daylight photodynamic therapy for actinic keratosis of the face or scalp: A real life open study.

Methyl aminolevulinate daylight photodynamic therapy (MAL DL-PDT) is highly efficacious for the treatment of nonhyperkeratotic actinic keratosis (AK), even when partially performed at home. To evaluate the long-term effectiveness, safety, and patient-reported outcomes of MAL DL-PDT performed completely by the patient in real life conditions. An open prospective study was conducted in Spain among patients diagnosed with at least five AK lesions on the face or the scalp. Patients received instruction and information in infographic format to perform MAL DL-PDT at home. All had been treated with 30% urea daily for 7 days before the day of MAL DL-PDT. Meteorological conditions on the day of the treatment and adverse effects were recorded. Patients underwent follow-up, and a second session of home-based MAL DL-PDT if deemed necessary, 3, 6, and 12 months after the initial treatment session. The study population consisted of 22 patients (19 men and three women, mean [standard deviation, SD] age, 72.05 [6.96] years). A complete response was observed in 47.7% of AK lesions at 3months (p < 0.001) and 65.9% (n=199) at 12 months (p < 0.001). Olsen grade II lesions showed the highest rate of response (76.07% at 12 months). The mean (SD) actinic keratosis area and severity index score decreased significantly from 4.99 (2.43) at baseline to 2.33 (1.01) at 12 months (p=0.0234). Adverse effects were mild and expected. A majority of patients were "satisfied" or "very satisfied" with the treatment instruction provided (90.9%) and the treatment outcome (72.7%). MAL DL-PDT can be applied at home like any other topical treatment for AK. Our results indicate good long-term effectiveness, a high level of patient satisfaction, and no significant side effects.

Counteracting Side-effects of Photodynamic Therapy for Actinic Keratoses.

Actinic keratoses (AKs) are precursors of squamous cell carcinomas and early intervention is important. Photodynamic therapy (PDT) is often first-choice treatment for widespread AKs. Classic PDT consists of: Superficial curettage, application of 5-aminolevulinic acid or methyl aminolevulinate, incubation and protoporphyrin IX (PpIX) accumulation under occlusion for 3 hours, followed by illumination with red light-emitting diode light (37 J/cm2). Classic PDT is effective in treating AKs, but side-effects include unpleasant pretreatment, severe pain during illumination, inflammation after treatment, and long waiting time in the clinic. This targeted mini review describes efforts to counteract side-effects and simplify the procedure considering the clinic capacity. Changes are only acceptable if treatment effect is maintained. We introduce the following procedure changes: (i) reducing pre-treatment pain, bleeding, and oozing by omitting curettage; (ii) long-term illumination for 2 hours during PpIX formation (already in use as daylight PDT) and shortening of incubation time from 3 hours to 30 minutes to minimize pain and inflammation risk. In addition, options of timing, incubation, and illumination indoors and outdoors are discussed, focusing on advantages and disadvantages for patients and clinics. We report several options to counteract side-effects of classic PDT.