Efficacy, Tolerability, and Patient Preference of Indoor, Simulated, or Artificial Daylight Photodynamic Therapy Versus Conventional Lamp-Based Photodynamic Therapy for Actinic Keratosis: A Systematic Review and Meta-analysis

BACKGROUND:Actinic keratosis (AK) is a common ultraviolet-induced keratinocyte lesion. Conventional photodynamic therapy (C-PDT) is effective as a field-directed treatment, but pain and treatment burden may limit acceptability. Indoor, simulated, or artificial daylight PDT (Indoor/SDL-PDT) may offer a more tolerable and controllable alternative. This systematic review and meta-analysis compared the efficacy, tolerability, and patient preference of Indoor/SDL-PDT versus C-PDT for AK. METHODS:Four major databases were searched from their establishment to 30 June 2026. Eligible studies enrolled adults with AK and compared Indoor/SDL-PDT with conventional lamp-based PDT using aminolevulinic acid or methyl aminolevulinate. For continuous variables, combined effects were documented as mean differences with corresponding 95% confidence intervals, whereas binary outcomes were summarized using risk ratios with 95% confidence intervals. For split-face, split-site, and intra-patient studies, the main analysis assumed a within-participant correlation coefficient of 0.5. RESULTS:Four studies including 171 treated or analyzed participants were included. Indoor/SDL-PDT was associated with lower lesion complete response or clearance at 3 months than C-PDT (RR = 0.86, 95% CI 0.83 to 0.89, p < 0.001). Continuous lesion response or clearance rate did not differ significantly across groups. Indoor/SDL-PDT significantly reduced pain during illumination (MD = -4.44 points, 95% CI -7.18 to -1.71, p = 0.001) and was more frequently preferred by patients. No significant difference was found in erythema or local skin reaction score. CONCLUSION:Indoor/SDL-PDT is better tolerated and more acceptable than C-PDT, but complete lesion clearance favored C-PDT. It may be useful for selected patients when tolerability is a priority.