Sigrid Karrer, Rolf-Markus Szeimies, Wolfgang G. Philipp-Dormston, Peter A. Gerber, Welf Prager, Elisabeth Datz, Florian Zeman, Karolina Müller, Michael Koller
DOI: 10.2340/00015555-3717

Actinic keratoses are a chronic condition in ultraviolet-damaged skin, with a risk of progressing to invasive skin cancer. The aim of this study was to investigate the preventive potential of field-directed repetitive daylight photodynamic therapy for actinic keratoses. A randomized trial was performed, including 58 patients with ≥5 actinic keratoses on photodamaged facial skin, who received either 5 full-face sessions of daylight photodynamic therapy within a period of 2 years or lesion-directed cryosurgery. Primary outcome was the mean cumulative number of new actinic keratoses developed between visits 2 and 6 (visit 6 being a follow-up). This outcome was lower after daylight photo­dynamic therapy (7.7) compared with cryosurgery (10.2), but the difference did not reach significance (–2.5, 95% confidence interval –6.2 to 1.2; p=0.18). Several signs of photoageing (fine lines, pigmentation, roughness, erythema, sebaceous gland hyperplasia) were significantly reduced after daylight photodynamic therapy, but not after cryosurgery. Significantly less pain and fewer side-effects were reported during daylight photodynamic therapy than during cryosurgery. This study found that repetitive daylight photodynamic therapy had photo-rejuvenating effects. However, the prevention of actinic keratoses by this therapy could not be proven in a statistically reliable manner.

Actinic keratoses are a chronic-progressive condition in ultraviolet-damaged skin, with the risk of progression to invasive skin cancer. Effective therapies are available, but the best treatment would be prophylaxis. This trial was based on the hypothesis that daylight photodynamic therapy, applied to the whole face on a regular basis, might prevent the development of new actinic keratoses, by treating not only visible lesions, but also subclinical lesions in sun-damaged skin. Repetitive daylight photodynamic therapy was found to be superior to cryosurgery in preventing the development of new actinic keratoses, although this trend was not statistically significant. Photodynamic therapy was found to improve several signs of photoageing and was better tolerated than cryosurgery.

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