Results of an Investigator-Initiated Single-Blind Split-Face Comparison of Photodynamic Therapy and 5% Imiquimod Cream for the Treatment of Actinic Keratoses

BACKGROUND: Topical photodynamic therapy (PDT) with aminolevulinic acid (ALA) and 5% imiquimod cream are effective therapies for the treatment of actinic keratoses (AKs), but no split-face studies directly comparing these treatment options are available in the literature. OBJECTIVE: To compare the efficacy and tolerability of ALA-PDT and imiquimod 5% cream for the treatment of AKs. RESULTS: Sixty-one patients were enrolled from the Salt Lake City Veterans Affairs Hospital; 51 completed the study and were included in the analysis. All patients were randomized to receive half of a sachet of imiquimod 5% cream twice weekly on half of their face and two sessions of PDT with 20% solution of ALA applied for 1 hour to the other side of the face. The 75% AK clearance rate was 34.6% for ALA-PDT and 25% for imiquimod 5% cream (p = .30). The mean reduction in AK count was 59.2% for ALA-PDT and 41.4% for imiquimod 5% cream (p = .002). Dermatology Life Quality Index (DLQI) scores were assessed for each treatment modality at week 4 and were 1.95 and 1.38, respectively (p = .20). LIMITATIONS: The sample size was small, and patients applied a small amount of imiquimod 5% cream (half a sachet) to a large surface area. CONCLUSION: There was no statistically significant difference in treatment response when the 100% or 75% clearance rate cutoff was used, but our secondary outcome suggests that two sessions of ALA-PDT is superior to imiquimod 5% cream for the treatment of AKs. There was no statistically significant difference in effect on quality of life as assessed using the DLQI.