Summary 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.

Background Actinic keratosis (AK) is a common early in situ skin carcinoma caused by long-term sun exposure and usually develops on sun-exposed skin areas. Left untreated, AK may progress to squamous cell carcinoma. To prevent such risk, most clinicians routinely treat AK. Therapy options for AK include cryotherapy, topical treatments, curettage, excision surgery, and photodynamic therapy (PDT). Objective The aim of this study is to assess the noninferiority, in terms of efficacy at 3 months, of a PDT protocol involving a new light-emitting device (PDT using the Phosistos protocol [P-PDT]) compared with the conventional protocol (PDT using the conventional protocol [C-PDT]) in the treatment of AK. Methods In this randomized, controlled, multicenter, intra-individual, phase II noninferiority clinical study, subjects with AK of the forehead and scalp are treated with P-PDT on one area and with C-PDT on the contralateral area. In both areas, lesions are prepared and methyl aminolevulinate (MAL) is applied. Thirty minutes after MAL application, the P-PDT area is exposed to red light at low irradiance (1.3 mW/cm 2 ) for 2.5 hours so that a light dose of 12 J/cm 2 is achieved. In the control area (C-PDT area), a 37 J/cm 2 red light irradiation is performed 3 hours after MAL application. Recurrent AK at 3 months is retreated. The primary end point is the lesion complete response rate at 3 months. Secondary end points include pain scores at 1 day, local tolerance at 7 days, lesion complete response rate at 6 months, cosmetic outcome at 3 and 6 months, and patient-reported quality of life and satisfaction throughout the study. A total of 45 patients needs to be recruited. Results Clinical investigations are complete: 46 patients were treated with P-PDT on one area (n=285 AK) and with C-PDT on the contralateral area (n=285 AK). Data analysis is ongoing, and statistical results will be available in the first half of 2019. Conclusions In case of noninferiority in efficacy and superiority in tolerability of P-PDT compared with C-PDT, P-PDT could become the treatment of choice for AK. Trial Registration ClinicalTrials.gov NCT03076892; https://clinicaltrials.gov/ct2/show/NCT03076892 (Archived by WebCite at http://www.webcitation.org/779qqVKek) International Registered Report Identifier (IRRID) DERR1-10.2196/12990

Actinic keratosis (AK) is a very common skin diagnosis in office-based dermatology. Due to the demographic changes with increasing numbers of elderly people, the proportion of patients with AK is expected rise. In order to avoid progression into squamous cell carcinoma, early treatment is recommended. Numerous treatment options are currently available for this purpose. In addition to targeted therapies for isolated AK many field-directed treatment modalities are available. However, the treatment option that is finally chosen depends on a variety of factors (e.g., age of the patient, the extent of the clinical findings) and the patient's needs and therefore has to be customized.

Summary An actinic keratosis (AK) is an area (lesion) of sun‐damaged skin, mainly found on sun‐exposed parts of the body, particularly the forearms, backs of the hands, face, ears, bald scalp and the lower legs. Left untreated, there is a small risk that an AK could progress into a form of skin cancer called squamous cell carcinoma. One way of treating AK is called photodynamic therapy (PDT). The usual, or conventional, protocol for using PDT to treat AK is called C‐PDT. It involves applying a light‐sensitising cream to the skin which is activated by a high‐intensity red light about 2.5 hours later. This causes intense inflammation in the skin which destroys abnormal, but not normal, skin tissue. The main drawback of C‐PDT is the pain experienced by patients during the treatment. Due to this pain, many patients cannot complete the treatment. The authors of this study, based in France and Germany, proposed a new protocol for PDT of AK, called P‐PDT. P‐PDT involves a revised red light activation: the light intensity has been considerably reduced and the activation begins only 30 minutes after the molecule (cream) application. This revision was expected to increase the patient's tolerance. The primary aim of the study was to assess whether P‐PDT is at least as effective as C‐PDT in destroying AK. One of the secondary aims was to compare pain levels between P‐PDT and C‐PDT. Forty‐six patients with AKs of the head were included. These patients were treated with P‐PDT on one side of the head and with C‐PDT on the other side. With 94.2% disappearance of AKs six months after the treatment, P‐PDT was found to be at least as effective as C‐PDT, which had a disappearance rate of 94.9%. Moreover, from the pain levels reported by the patients for each protocol, P‐PDT is much less painful, or even painless, compared to C‐PDT. This summary relates to the study: 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

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