Efficacy and tolerability of 1.6% phenol-croton peeling vs. topical 5% imiquimod in the treatment of actinic cheilitis: a randomized controlled trial

Background Trials evaluating the effectiveness of topical treatments for actinic cheilitis (AC) are scarce. Despite no comparative data, phenol-croton peeling has been reported as effective in treating this condition. Objective To assess for the treatment of AC the efficacy and tolerability of a single session of 1.6% phenol-croton peeling vs. topical 5% imiquimod cream applied for 30 days for the treatment of AC. Methods An open, randomized controlled trial was conducted to compare the effectiveness and tolerability of 1.6% phenol-croton peeling vs. topical 5% imiquimod for the treatment of AC [protocol registered at ReBEC (Brazilian Registry of Clinical Trials) - RBR-1044sz68]. Thirty-six patients with biopsy-proven AC were allocated into two groups (1 : 1): the imiquimod group received 5% topical imiquimod three times a week for 30 days, and the croton group underwent one session of 1.6% phenol-croton peeling. The primary outcome was the clearance of AC after 56 days. Secondary outcomes included clinical and histological parameters, adverse effects and clinical results after 180 days. Results Complete clinical clearance of AC (defined as clearance of both leukoplakia and hyperkeratosis) at day 56 and day 180 occurred in 17 of 18 (94%) participants from the croton group but in none of the 18 participants in the imiquimod group (P < 0.01). Improvement in all clinical parameters was more prominent in the croton group (P <= 0.01). Complete histological normalization at day 56 occurred in 72% of the croton group and only 17% in the imiquimod group (P < 0.01). Histological parameters such as atypia (keratinocyte intraepithelial neoplasia score), solar elastosis and hyperkeratosis reduced in intensity only in the croton group (P < 0.05). Adverse effects were most intense on day 7 in the croton group and persisted until day 21 in the imiquimod group. The study was prematurely terminated at the interim analysis. Conclusions A single session of 1.6% phenol-croton peeling produced clinically and histologically superior results with a shorter recovery period compared with imiquimod for treating AC.