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Original Investigation
June 2016

Artificial White Light vs Daylight Photodynamic Therapy for Actinic KeratosesA Randomized Clinical Trial

Author Affiliations
  • 1The Charles Center, Department of Dermatology, Saint Vincent’s University Hospital, Dublin, Ireland
  • 2Department of Medical Physics and Clinical Engineering, Saint Vincent’s University Hospital, Dublin, Ireland
JAMA Dermatol. 2016;152(6):638-644. doi:10.1001/jamadermatol.2015.5436

Importance  Daylight photodynamic therapy using topical methyl 5-aminolevulinic acid (MAL) for actinic keratoses (AKs) is as effective as conventional photodynamic therapy but has the advantage of being almost pain free. Daylight photodynamic therapy, however, requires dry and warm weather conditions.

Objective  To establish if topical MAL photodynamic therapy using a white light light-emitting diode (LED) lamp is as effective and well-tolerated as daylight photodynamic therapy for the treatment of AKs.

Design, Setting, and Participants  Overall, 22 men with significant photodamage and a high number of AKs were enrolled in this prospective, randomized, single-blind study, employing a split-scalp design, comparing the effectiveness and adverse effects of daylight photodynamic therapy and artificial white light (AWL) LED photodynamic therapy for the treatment of AKs on the forehead and scalp. Organ transplant recipients were excluded. Patients were treated and evaluated at an academic tertiary referral dermatology center. Treatment lasted from April 2014 to July 2014 and follow-up visits occurred for 9 months posttreatment.

Interventions  Two symmetrical treatment fields were defined and AKs counted, mapped, and photographed at baseline, 1, 3, 6, and 9 months. Patients had half of their scalp treated with daylight photodynamic therapy and the other half treated with AWL photodynamic therapy 1 week apart and randomly allocated. MAL was applied, and treatment commenced 30 minutes later and lasted 2 hours. Irradiance, illuminance, and light spectra measurements were performed. The integrated dose in J/cm2 was measured. The effective light dose, weighted to the absorption spectrum for protoporphyrin IX, was calculated.

Main Outcomes and Measures  The primary end point was the reduction in total AK count per treatment field. Secondary end points included adverse effects and patient satisfaction.

Results  We enrolled 22 men with a median age of 72 years (range, 47-85 years) at baseline, the total (median of AKs per field) were 469 (20.5) for the DPDT group and 496 (20.5) for the AWLPDT group (P = .34). The median number and percentage of reduction in AKs per field were 12 and 62.3% for DPDT and 14 and 67.7% for AWLPDT at 1 month (P = .21 and P = .13, respectively). There was no significant difference in the reduction percentage of AKs for either treatment at 1, 3, and 6 months. At 9 months, the median number and percentage of reduction in AKs per field was 9.0 and 48.4% for DPDT and 12.0 and 64.4% for AWLPDT (P = .13 and P = .05, respectively). Pain was reported by 14 patients with DPDT and 16 patients with AWLPDT (median maximum score [out of 100], 4 vs 6; P = .51). Moderate erythema was reported by 9 patients after DPDT and 14 patients after AWLPDT. On a scale of 0 (intolerable) to 10 (very tolerable) patients rated DPDT as 9.5 and AWLPDT as 9 (P = .37).

Conclusions and Relevance  Photodynamic therapy using an AWL source was as effective and well-tolerated as daylight photodynamic therapy.

Trial Registration  clinicaltrials.gov Identifier: NCT02520700