Photodynamic therapy for actinic keratosis of the forehead and scalp with the Aktilite CL 128: Is there a cut-off value for PpIX-weighted irradiance for effective treatment?

Self-Applied Daylight Photodynamic Therapy: A Paradigm Shift?

Photodynamic therapy (PDT) involves the topical application of a photosensitizer and its activation by visible light, leading to the generation of protoporphyrin IX (PpIX) and reactive oxygen species. Daylight photodynamic therapy (dPDT), a variant utilizing natural sunlight as the energy source, enhances procedural flexibility by eliminating the need for specialized equipment. dPDT has been effectively used in dermatology to treat various cutaneous disorders, including neoplastic and infectious diseases. Traditionally, skin preparation and photosensitizer application are performed by trained practitioners, limiting the accessibility of dPDT for broader populations. However, recent studies suggest that these preparatory steps can be managed by patients or caregivers, enabling fully self-applied, home-based dPDT protocols. This review systematically examines the current evidence on self-applied dPDT (SA-dPDT), emphasizing molecular mechanisms and its efficacy in managing premalignant and other cutaneous conditions.

Impact of light dose and fluence rate on the efficacy and tolerability of topical 5-ALA photodynamic therapy for actinic keratoses: A randomized, controlled, observer-blinded intrapatient comparison study

BACKGROUND

Conventional photodynamic therapy (cPDT) is an effective treatment option for field cancerization and multiple actinic keratoses (AK). The main side effect of cPDT is pain during illumination which in severe cases might necessitate early termination of treatment. Modification of treatment parameters such as light dose and fluence rate is a promising approach to mitigate PDT-associated pain.

OBJECTIVES

The aim of this study was to compare the efficacy and tolerability of four different cPDT illumination protocols in the treatment of AK in the head region.

METHODS

Prospective, investigator-blinded, within-patient study on 67 patients with multiple AK in the head region. PDT treatment was performed on comparable target areas with four different settings of illumination: (A) standard light dose and standard fluence rate, (B) standard light dose and halved fluence rate, (C) halved standard light dose and standard fluence rate and (D) halved standard light dose and halved fluence rate. Pain and the intensity of the phototoxic skin reaction was recorded during and after illumination. The clearance rate of the target areas and target lesions was assessed at 12 weeks after PDT. Target areas with incomplete clearance were retreated, those with complete clearance were reassessed at 24 weeks after PDT.

RESULTS

The mean and maximum pain level during illumination was significantly decreased at the lower fluence rates. The phototoxic skin reaction was most pronounced with the standard illumination setting. The overall clearance rate of AK and the clearance rate of the target lesions at 3 months after PDT as well as the number of recurrent or new AK at 6 months after PDT did not differ between four treatment protocols.

CONCLUSIONS

Reduction of the fluence rate and/or light dose was associated with less PDT-induced pain and/or shorter exposures times without compromising the therapeutic efficacy of cPDT for AK in the head region.

Safety of topical interventions for the treatment of actinic keratosis

Introduction: Actinic keratosis (AK) are proliferations of atypical keratinocytes that may eventually progress to cutaneous squamous cell carcinoma. Therefore, AK requires consequent and early treatment. Areas covered: A variety of effective approaches is currently available for the clearance of AK. These interventions may be applied either in a lesion-directed or field-directed mode as AK can occur as single or multiple lesions. Field-directed approaches typically comprise topical drug-mediated interventions which aim at eliminating all visible lesions and also at clearing subclinical changes of the actinically damaged field. However, most treatment options are associated with local adverse events such as erythema, scaling, pain, and rarely with systemic symptoms. This expert review provides a comprehensive and up-to-date overview of the safety considerations of the commonly prescribed topical treatment agents cyclooxygenase inhibitors, 5-fluorouracil, imiquimod, ingenol mebutate, and photodynamic therapy. All these therapies have been proven efficient, yet they differ considerably regarding their safety profile. Expert opinion: In the future, safety concerns will relate to long-term and irreversible adverse drug events instead of application site reactions. In particular, the rate of treatment-associated non-melanoma skin cancers will increasingly come into focus and warrant investigation in postmarketing surveillance trials with a long-term follow-up.

The conventional protocol vs. a protocol including illumination with a fabric-based biophotonic device (the Phosistos protocol) in photodynamic therapy for actinic keratosis: a randomized, controlled, noninferiority clinical study

BACKGROUND

Topical photodynamic therapy (PDT) using methyl aminolaevulinate is a noninvasive treatment option suitable to treat clinical and subclinical actinic keratosis (AK) over a large area (field cancerization). The most widely used, conventional protocol in Europe includes illumination with a red-light lamp. This illumination commonly causes pain, and patients often cannot complete the treatment.

OBJECTIVES

The aims of this paper are twofold. The first aim is to introduce a novel protocol, the Phosistos protocol (P-PDT), which includes illumination with a fabric-based biophotonic device. The second and major aim is to assess the noninferiority, in terms of efficacy for PDT of AK, of P-PDT compared with the conventional protocol (C-PDT).

METHODS

A randomized, controlled, multicentre, intraindividual clinical study was conducted. Forty-six patients with grade I-II AK of the forehead and scalp were treated with P-PDT on one area (280 AK lesions) and with C-PDT on the contralateral area (280 AK lesions). The primary end point was the lesion complete response (CR) rate at 3 months, with an absolute noninferiority margin of -10%. Secondary end points included pain scores, incidence of adverse effects and cosmetic outcome.

RESULTS

Three months following treatment, the lesion CR rate of P-PDT was noninferior to that of C-PDT (79·3% vs. 80·7%, respectively; absolute difference -1·6%; one-sided 95% confidence interval -4·5% to infinity). The noninferiority of P-PDT to C-PDT in terms of the lesion CR rate remained at the 6-month follow-up (94·2% vs. 94·9%, respectively; absolute difference -0·6%; one-sided 95% confidence interval -2·7% to infinity). Moreover, the pain score at the end of illumination was significantly lower for P-PDT than for C-PDT (mean ± SD 0·3 ± 0·6 vs. 7·4 ± 2·3; P < 0·001).

CONCLUSIONS

P-PDT is noninferior to C-PDT in terms of efficacy for treating AK of the forehead and scalp and resulted in much lower pain scores and fewer adverse effects. What's already known about this topic? Topical photodynamic therapy using methyl aminolaevulinate is effective for treating actinic keratosis. In Europe, the conventional protocol involves illumination with a red-light lamp. Unfortunately, pain is often experienced by patients undergoing this protocol. An alternative protocol that uses daylight illumination has recently been shown to be as effective as the conventional protocol while being nearly painless. However, this alternative protocol can be conducted only in suitable weather conditions. What does this study add? The Phosistos protocol is demonstrated to be as effective as the conventional protocol, nearly as painless as the daylight protocols and suitable year round for treatment of actinic keratosis.