A modified photodynamic therapy (PDT) for actinic keratoses (AK) can reduce pain during treatment while obtaining similar clinical efficacy to conventional therapy, according to study results published in the Journal of the American Academy of Dermatology.

As evidence has suggested that reducing 5-aminolevulinic acid (ALA) incubation times before PDT may reduce pain while still maintaining effective clearance of lesions, researchers sought to determine whether immediate PDT after ALA application could provide good clinical efficacy for clearance of AK lesions on the face and scalp while minimizing pain during treatment.

A total of 23 patients (2 women) recruited from the Dermatology Department at the Cleveland Clinic in Ohio were included in the prospective, randomized clinical trial, which was bilaterally controlled using a contralateral split-body design. Side A was randomly chosen using a computer-generated, block randomization scheme and received the experimental treatment (simultaneous PDT) of 20% ALA followed by immediate blue light treatment. A dose escalation scheme was employed, with the first cohort (7 patients) receiving a 30-minute dose of blue light after ALA application and subsequent cohorts receiving 45-minute (8 patients) and 60-minute (8 patients) doses. Side B received conventional treatment, which included illumination with blue light for 1000 seconds after 60 minutes of ALA preincubation.

The primary endpoint for the study was clinical efficacy, defined as percentage reduction in the number of AK lesions after 3 months. Secondary endpoints included assessment of pain during illumination, using a visual analog scale, measurement of erythema, and assessment of adverse effects using a daily home questionnaire.

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The total number of lesions observed per patient on the face and scalp ranged from 23 to 70 and 0 to 123, respectively. Clinical efficacy was approximately equal between simultaneous and conventional treatment on the face (57.7% and 59.1%, respectively) and scalp (43.8% and 41.9%, respectively). Simultaneous treatment was statistically noninferior to conventional treatment. There was no difference in clinical efficacy observed among the 30-, 45-, and 60-minute experimental doses. Spotty erythema and major inflammatory parameters were also approximately equal for both treatments. However, the mean pain score was significantly lower on Side A (0.52; 95% CI, 0-1.09) compared with Side B (3.57; 95% CI, 2.97-4.16; P <.001).

The investigators noted the relatively small cohort size as a limitation of the study, as well as the bilateral design, which may present problems for resolution in the event of systemic effects mediating clearance of lesions.

“ALA-PDT of extensive AK of the face and scalp, using a new simultaneous incubation-illumination regimen, causes minimal pain yet provides clinical efficacy comparable to traditional PDT regimens,” the researchers concluded. “This new simultaneous approach should significantly improve patient care by reducing pain, discomfort, and patient anxiety.”

Disclosure: Funding for the study was partially provided by Sun/DUSA Pharmaceuticals. Please see the original reference for a full list of disclosures.

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Reference

Kaw U, Ilyas M, Bullock T, et al. A regimen to minimize pain during blue light photodynamic therapy of actinic keratoses: Bilaterally controlled, randomized trial of simultaneous versus conventional illumination [published online September 13, 2019]. J Am Acad Dermat. doi:10.1016/j.jaad.2019.09.010