In patients with actinic keratosis (AK), ablative fractional laser (AFL) photodynamic therapy (PDT) with higher laser density (22%) and with methyl aminolevulinate is associated with a better complete response (CR) rate and a potentially reduced recurrence rate compared with AFL-PDT with lower laser densities. This is according to study data published in the Journal of the American Academy of Dermatology.

A total of 47 patients from Korea who had AK lesions were randomly assigned to 3 different AFL density groups: 5.5% (n=16), 11% (n=15), and 22% (n=16). Lesions were photographed and graded. Protoporphyrin IX accumulation was assessed by measuring fluorescence intensity approximately 3 hours after application of methyl aminolevulinate. Each area was then irradiated with red light-emitting diode lamp, with a peak emission of 630 and a total light dose of 37 J/cm2.

There was no difference among groups with regard to sex, age, Fitzpatrick score, number of lesions, or Olsen grade. At month 3, patients who received AFL-PDT with a 22% density had a significantly higher CR rate compared with patients who received the 5.5% density (88.7% vs 80.0%, respectively; P =.037). An even higher proportion of patients in the 22% density group achieved a CR at 12 months compared with the 5.5% density group (81.1% vs 60.9%, respectively; P =.003). In Olsen grade 3 AK lesions, the CR rate was higher in the 22% vs the 5.5% density group at 3 months (81.3% vs 55.9%, respectively) and 12 months (68.8% vs 38.2%, respectively; P =.043).

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Limitations of the study included its small sample size and the single ethnic group, which may reduce the findings’ generalizability.

Taken together, these findings “recommend pretreatment with AFL at a higher laser density when AFL-PDT is used to treat AK with severe hyperkeratosis.”

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Reference

Cho YR, Seo JW, Kim HJ, Song KH. A comparison of the efficacy of ablative fractional laser-assisted photodynamic therapy according to the density of ablative laser channel in the treatment of actinic keratosis: a prospective, randomized, controlled trial [published online October 25, 2019]. J Am Acad Dermatol. doi:10.1016/j.jaad.2019.10.037