KISSIMMEE, FLA. – Fractional carbon dioxide laser resurfacing followed by 30 minutes of aminolevulinic acid plus blue light photodynamic therapy cleared 94% of actinic keratoses, significantly more than ALA-PDT alone, according to the findings of a randomized, single-blinded, split-face study of 20 patients.
Laser resurfacing was associated with worse short-term erythema, but erythema resolved in about 7 days and was not associated with other adverse events, Dr. Macrene Alexiades-Armenakas said at the annual meeting of the American Society for Laser Medicine and Surgery.
Historically, two sessions of 20% topical ALA and blue light PDT have yielded actinic keratosis cure rates of 78% to 89%, but only with ALA incubation times of 14-18 hours, said Dr. Alexiades-Armenakas, associate clinical professor at Yale University, New Haven, Conn.
“Increasing drug penetration may serve to enhance PDT efficacy and shorten incubation time,” she said.
To test that hypothesis, she compared the safety and efficacy of 15- and 30-minute incubations of ALA and blue light PDT, with or without CO2 laser resurfacing. After cleaning patients’ faces with acetone wipes and applying a topical anesthetic for 1 hour, she randomly selected one half of each patient’s face for pretreatment with fractional CO2 laser, using settings of 15-28 W, 500 mcm dot spacing, and 600-800 microsecond dwell time.
Next, she applied 5-ALA to the entire face, then performed blue light illumination for 1,000 seconds. Half of the 20 patients were randomly assigned ALA incubation times of 15 minutes, while the other half underwent 30-minute incubations. She rechecked patients at 1 week, 4 weeks, and 8 weeks, and took digital photographs at baseline and at each recheck using identical lighting conditions. A blinded evaluator scored each side of each face, defining clearance as complete regression of actinic keratosis.
At 8 weeks, the rate of complete clearance for the 10 patients who underwent 15-minute ALA incubations was 88% for laser resurfacing followed by ALA-PDT, compared with 74% for ALA-PDT alone (P < .05), Dr. Alexiades-Armenakas reported. Clearance rates for the 30-minute incubation group were 94% for laser followed by ALA-PDT and 82% for ALA-PDT alone (P < .05).
Skin treated only with ALA-PDT developed minimal to moderate erythema that resolved within 5-7 days for all patients, but the laser-resurfaced skin developed “moderate to significant” erythema that resolved within 5-7 days with home care, she said.
Taken together, the results indicate that fractional CO2 laser treatment yields safe and effective clearance of actinic keratoses with “ultra-short” incubation times, Dr. Alexiades-Armenakas said.
Deka manufactures the fractional CO2 laser tested in the study, and DUSA Pharmaceuticals manufactures the blue light PDT device and the ALA product. Dr. Alexiades-Armenakas reported receiving clinical research grants from Deka, DUSA Pharmaceuticals, Alma, and Syneron.