Natural daylight photodynamic therapy (DL-PDT) is as effective as conventional photodynamic therapy with blue light (c-PDT) for the treatment of actinic keratosis (AK), study research results published in the Journal of the European Academy of Dermatology and Venereology suggests. Despite their equal efficacy profiles, natural DL-PDT may be less painful than c-PDT in patients with AK, the study investigators reported.

A total of 26 patients with mild and possibly moderate AK (mean age, 75 years; range, 47 to 88 years) with ≥2 comparable target areas on the face or scalp and ≥5 AKs in each area were enrolled in the study. As the study featured a split-face and split-scalp design, patients acted as their own controls. The researchers randomly assigned patients with regard to which side of the face or scalp was exposed to daylight and blue light.

Only 1 treatment was performed on AKs of the face and scalp, using DL-PDT on 1 side and c-PDT on the contralateral side. Prior to therapy, a 16% methyl aminolevulinate cream was applied to the entire treatment area. The cream was uncovered on the side of the face or scalp that was exposed to daylight and kept covered for 3 hours on the side exposed to blue light. The primary study end points included efficacy, which was defined as clearance of AKs at 12 weeks, as well as safety, which was assessed by reported pain. In addition, the investigators assessed lesions’ 12-week complete response rates after 1 treatment and until week 24.

In total, 563 lesions were treated with DL-PDT and 556 lesions with c-PDT. At 3-month follow-up, the numbers of cleared AK lesions for DL-PDT and c-PDT were 19.6 and 20.0, respectively (90.5% vs 94.2%; P =.8460). The response rates for DL-PDT and c-PDT were maintained at 6 months (90.0% and 94.6%, respectively). Lesion recurrence was observed more often after DL-PDT than after c-PDT at 3 months (difference, 0.6±0.8; P =.0007) and at 6 months (difference, 1.3±0.9; P <.0001). Treatment with DL-PDT was reported by patients as being less painful than c-PDT with light blue (mean pain score, 1.2 vs 5.1, respectively; P <.0001).


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A potential study limitation was the lack of an investigator- and participant-blinded design.

The study researchers concluded that their findings “suggest a higher risk of relapse for DL-PDT patients, which suggests that these patients should be closely monitored or even re-treated earlier.”

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Disclosure: This clinical trial was supported by Galderma. Please see the original reference for a full list of authors’ disclosures.

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Reference

Assikar S, Labrunie A, Kerob D, Couraud A, Bédane C. Daylight photodynamic therapy with methyl aminolevulinate cream is as effective as conventional photodynamic therapy with blue light in the treatment of actinic keratosis: a controlled randomized intra-individual study [published online January 19, 2020]. J Eur Acad Dermatol Venereol. doi:10.1111/jdv.16208