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

BACKGROUND

Conventional 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.

OBJECTIVE

To compare the efficacy and tolerability of occlusive and non-occlusive DL-PDT.

METHODS

We 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.

RESULTS

Lesions 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.

CONCLUSION

The occlusive application of MAL improves the efficacy of DL-PDT in clearing AKs and does not increase the incidence of side effects.

Modified red light 5-aminolevulinic acid photodynamic therapy versus low-dose isotretinoin therapy for moderate to severe acne vulgaris: A prospective, randomized, multicenter study

BACKGROUND

Modified 5-aminolevulinic acid photodynamic therapy (M-PDT) and isotretinoin (ISO) are effective treatments for moderate to severe acne vulgaris.

OBJECTIVE

To evaluate the efficacy and adverse effects of M-PDT and ISO for moderate to severe acne vulgaris.

METHODS

A multicenter, randomized clinical trial was conducted with participants randomly assigned to the M-PDT group (up to 5 weekly sessions following manual comedone extraction) or the ISO group (oral ISO, 0.5 mg/kg/d for 6 months) and followed up to 6-months after therapy.

RESULTS

A total of 152 patients were allocated. The overall effective rates in the M-PDT group were significantly higher than the ISO group at 1 month (67.74% vs 10.26%), whereas the opposite was the case 1 month after treatment (75.81% vs 97.44%). Time to achieve 50% lesion improvement in the M-PDT group was significantly less than the ISO group (1 vs 8 weeks). Overall, 70.67% of the ISO group patients experienced systemic side effects such as hepatotoxicity, whereas side effects were skin-limited in the M-PDT group.

LIMITATIONS

Limitations of this study included relatively low numbers of participants and high withdrawal rate.

CONCLUSION

M-PDT offers a more rapid onset of improvement, comparable overall efficacy, good tolerability, and comparable durability of response compared with ISO.

A Review of MAL-PDT for the Treatment Strategy of Actinic Keratosis: Broader Clinical Perspectives Beyond the Data and Guideline Recommendations

Methyl aminolevulinate (MAL) is a topical compound approved for use with photodynamic therapy (PDT) for the treatment of actinic keratosis (AK) and field cancerization in certain countries. There exists a high burden of disease for patients with AK: repeated treatments are required, there is a known risk of progression to keratinocyte carcinoma, and cosmetic appearance is affected. Delivery of PDT using MAL is a flexible treatment strategy available in many forms; red light, daylight, or artificial daylight can be used for illumination, all of which result in high AK clearance rates and low recurrence. MAL-PDT protocols continue to evolve to further improve adherence and treatment outcomes. Here, we used PubMed to search MEDLINE to identify guidelines, consensus recommendations, and studies describing the use of MAL for the treatment of AK. The aim of this targeted review is to consider various MAL-PDT treatment strategies on the basis of published literature, with a focus on personalizing treatment for the heterogeneous AK population.

Efficacy of two different methods of cold air analgesia for pain relief in PDT of actinic keratoses of the head region - a randomized controlled comparison study

BACKGROUND

Photodynamic therapy (PDT) is an effective method for treating actinic keratosis (AK) with pain during illumination representing the major side effect. The efficacy of two different cooling methods for pain relief in PDT of AK in the head region was compared.

METHODS

Randomized, assessor-blinded, half side comparison study in 20 patients with symmetrically distributed AK on the head. Conventional PDT was performed on both halves of the scalp or face by applying 20% aminolevulinic acid cream (ALA) and subsequent illumination with incoherent red light. During illumination one side was cooled with a cold air blower (CAB) and the other with a standard fan (FAN) in a randomized fashion. Pain and skin temperature were recorded during and after PDT. The phototoxic skin reaction was evaluated up to seven days after PDT. The clearance rate of AK was assessed at 3 and 6 months after PDT.

RESULTS

Mean pain (VASmean), maximum pain intensity (VASmax) and the mean skin temperature during PDT were significantly lower with CAB as compared to FAN (VASmean: 2.7 ± 1.4 vs. 3.7 ± 2.1, p = 0.003; VASmax: 3.8 ± 2.0 vs. 4.8 ± 2.5, p = 0.002; 26.8 ± 2.0 °C vs. 32.1 ± 1.7 °C; p=<0.001). The severity of the phototoxic skin reaction and the clearance rate of AK did not differ between the two cooling methods.

CONCLUSION

Cooling with CAB during PDT has a greater analgesic effect than cooling with FAN. Patients with a lower skin temperature during illumination tended to experience less pain, however, this effect did not reach the level of statistical significance.

Application of metalloporphyrin sensitizers for the treatment or diagnosis of tumors

At present, metalloporphyrin compounds demonstrate three main uses as anticancer sensitizers: (1) photosensitizers, (2) photothermal conversion agents, and (3) ultrasound sensitizers. Developing efficient sensitizers for cancer with excellent controllability and biocompatibility is an important goal of oncology medicine. Because of the different structural diversity of anticancer sensitizers, such sensitizers are used for treating cancers by employing a variety of tumor treatment methods such as mature photodynamic therapy, commonly used clinically photothermal therapy and promising sonodynamic therapy. Among the many sensitizers, metalloporphyrin-complex sensitizers attract wide attention due to their excellent performance in tumor treatment and diagnosis. This review briefly describes some metalloporphyrin anticancer drugs and diagnostic agents related to photodynamic, photothermal and sonodynamic therapy, and discusses the roles of metal atoms in these drugs.

Novel Water-Soluble Chlorin-Based Photosensitizer for Low-Fluence Photodynamic Therapy

Photodynamic therapy (PDT), performed with low-fluence rates, can improve antitumor responses and prevent adverse effects. However, photosensitizers (PSs) for low-fluence PDT treatment are rarely reported. Herein, we exploited an amphiphilic chlorin-based PS, named DYSP-C34, which has a variety of beneficial biological properties, such as improved water solubility, better cellular permeability, specific localization and enhanced phototoxicity under low light dose irradiation. In addition, DYSP-C34 could effectively accumulate in a mouse subcutaneous xenograft tumor and exhibit substantial tumor regression after irradiation with an extremely low light fluence (6 J/cm²). Meanwhile, the excellent phototoxicity could stimulate the host immune system and lead to a strong inhibition of tumor growth synergistically. These results indicated the potential value of DYSP-C34 as a chlorin-type PS for low-fluence PDT application.

A randomized split-face clinical trial of conventional vs indoor-daylight photodynamic therapy for the treatment of multiple actinic keratosis of the face and scalp and photoaging

BACKGROUND

Recently, indoor daylight photodynamic therapy (idl-PDT) has been developed; however, its efficacy and tolerability remain to be assessed.

OBJECTIVE

This is a not-inferiority study to compare treatment outcomes of cPDT with a red LED lamp and idlPDT with a polychromatic white LED lamp in adult patients affected by symmetrical AKs of face and/or scalp.

METHODS

In this comparative, intra-patient, split-face, randomized clinical trial forty-three adult patients were enrolled. Two contralateral and symmetrical target areas of the face and/or scalp harboring at least 5 AKs were selected and randomized 1:1 to treatment with cPDT and idlPDT. The AKs number and cumulative area were assessed at baseline (T0). Efficacy and cosmetic outcome were assessed 3 months after treatment (T1).

RESULTS

Total AKs number and area reduced significantly with both idlPDT (p < .0001) and cPDT (p < .0001) in comparison to baseline. cPDT was more painful (p < .0001) and induced a more severe inflammation (p < .0001). Twenty-nine patients (70.7%) gave their overall preference to idlPDT (p < .001).

CONCLUSION

idlPDT may represent an alternative treatment protocol to cPDT for in-office treatment of AKs patients with better tolerability and a not inferior efficacy.

Review of the European Society for Photodynamic Therapy (Euro-PDT) Annual Congress 2020

This article reviews the 2020 European Society for Photodynamic Therapy (Euro-PDT) Annual Congress. Cutting edge studies included assessment of immunohistochemical variables influencing response of basal cell carcinomas and Bowen's disease to PDT with p53, the only biomarker associated with good response in both conditions. A further study indicated that analysis of molecular markers, such as PIK3R1, could help select patients with actinic keratoses who demonstrate the best response to daylight PDT. Novel delivery protocols include artificial daylight, and laser-assisted and textile PDT. The meeting learnt of novel indications including antimicrobial PDT, as well as methods to optimise daylight PDT, including combination therapy for actinic keratoses. Adverse events were reviewed and options for painless and efficient PDT assessed, including the effect of reduced drug-light interval. A smartphone application was also evaluated which may be used to assist clinicians and patients in effective dosing and timing of daylight PDT via computational algorithms using data from earth observation satellites, to send light and ultraviolet dose information directly to patients' smart phones.

[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.

Modified photodynamic therapy to minimize pain in the treatment of condylomata acuminata: A prospective, randomized, self-controlled study

BACKGROUND

Pain is a major concern associated with conventional photodynamic therapy (C-PDT).

OBJECTIVE

To evaluate the efficacy, pain and safety of modified photodynamic therapy(M-PDT) for the treatment of condylomata acuminata.

METHODS

A prospective, randomized, self-controlled study was conducted. Warts were randomized to the M-PDT or C-PDT side. 5-aminolevulinic acid (ALA; 20 %) was incubated for 3 h before patients were exposed to LED red light (100 J/cm2) on the C-PDT side and for 30 min before being exposed to LED red light (300 J/cm2) on the M-PDT side. Treatment was administered with 1-week interval for three weeks. The clearance rates were determined at one week and the recurrence rates at 4, 8, and 12 weeks after treatment. The pain and other side effects were also investigated.

RESULTS

A total of 24 patients with condylomata acuminata were enrolled in this trial. Twenty patients completed the trial. The clearance rates were 98.17 % in the M-PDT side and 98.20 % in the C-PDT side(P > 0.05). The recurrence rates were 11.11 % and 10.53 % (P > 0.05). However, M-PDT was almost painless (mean score 0.3 ± 0.47, range 0∼1), which was significantly less than that on the C-PDT side (mean score 3.6 ± 0.94, range 0∼1) (P < 0.05). Local erythema, mild edema and erosion were observed on both sides.

CONCLUSION

The modified PDT is basically painless with similar efficacy to conventional PDT, which is a major breakthrough of pain management in PDT.

[Actinic keratoses : Current guideline and practical recommendations]

The S3 guideline "Actinic keratosis and squamous cell carcinoma of the skin" was published on 30 June 2019. Subsequently, publications, reviews and meta-analyses appeared with new questions regarding the comparability of study data and heterogeneity of the evaluations, which are caused, among other things, by divergent measurement parameters as well as insufficient consideration of pretreatments and combined treatments. This concise overview was written in the context of criticism and in view of necessary developments and research. Topics include epidemiology, pathogenesis, prevention, clinical presentation, therapy and BK5103. Therapy is divided into local destructive procedures and topical applications. Recommendations with quotation marks are based on the actual guideline. Corresponding evidence levels are given. For the implementation in daily routine basic data, side effects and features of therapeutic options are mentioned. The current developments and questions concerning actinic keratoses become clear.

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.