Laser-assisted vs. conventional daylight photodynamic therapy for actinic keratosis: a 2-year randomized evaluator-blinded half-side comparative trial

BACKGROUND: Actinic field cancerization is considered a chronic and relapsing condition. Thus, long‐term clearance and prevention of cutaneous squamous cell carcinoma should be the fundamental goal of treatment. OBJECTIVES: This trial aims to compare long‐term outcomes of two novel field treatments for actinic keratoses. METHODS: The investigator‐initiated intraindividual randomised controlled and evaluator‐blinded trial compared fractional laser‐assisted artificial‐ or natural daylight photodynamic therapy to daylight photodynamic therapy alone, as a split‐head comparison of 60 patients with ≥ two actinic keratoses of the head, on a two‐year follow‐up. RESULTS: The intention‐to‐treat analysis showed a significantly higher lesion‐specific two‐year sustained clearance with the laser‐assisted treatment (p=0.003, 56.3% (147/261)) vs. 43.0% (108/251) for daylight photodynamic therapy alone. Additionally, 45.6% (26/57) of patients achieved two‐year sustained partial clearance in the laser‐assisted treatment compared to 31.6% (18/57) in daylight photodynamic therapy alone (p=0.064). Correspondingly, 15.8% (9/57) compared to 7.0% (4/57) of patients achieved sustained complete clearance (p=0.070). No squamous cell carcinomas developed on the treatment field, and in total three Bowen's diseases. CONCLUSIONS: Laser‐assisted daylight photodynamic therapy seems to achieve a higher long‐term sustained clearance and may be superior also on long‐term compared to daylight photodynamic therapy alone in the treatment of actinic keratosis of all grades.