Comparative Efficacy and Tolerability of Imiquimod 3.75% Cream vs 5-Fluorouracil 4% cream in the Treatment of Actinic Keratosis: A Split-Face Study

Introduction: Actinic keratosis (AK) is a common precancerous skin lesion that arises on chronically UV-exposed skin and that can progress to keratinocyte carcinoma. Objective: The aim of this study was to compare the efficacy, safety, local skin reaction, time to wound healing, and patient preference of imiquimod (IMQ) 3.75% vs 5-fluorouracil (5-FU) 4% cream treatment for AKs. Methods: Two symmetrical contralateral areas of approximately 25 cm2 harboring a similar (≥5) number of AKs were selected and randomly assigned to IMQ 3.75% or 5-FU 4% cream treatment. The total number of AKs for each patient was evaluated at baseline (T0) and 90 days after the end of treatments (T1). Local skin reaction (LSR) score was registered the day after the end of both treatments. Complete remission rate of lesions, cosmetic outcome, and patient preference of treatment were assessed after 90 days (T1). Results: The mean variation (ΔT0-T1) of AKs was not significantly different in patients treated with IMQ 3.75% vs 5-FU 4% (P = 0.35). The mean LSR was not significantly different between patients treated with IMQ 3.75% and those with 5-FU 4% (p=0.63). No difference in cosmetic outcome was observed in the two groups. Patient preference was equally distributed between the treatments. The mean time to wound healing after the end of the treatment was similar with IMQ 3.75% and with 5-FU 4% (P = 0.83). Conclusions: This study reports a non-superiority of efficacy, tolerability, wound-healing time, and cosmetic outcome of topical IMQ 3.75% treatment compared to topical 5-FU 4% treatment in AK management.