Efficacy of 4% 5-Fluorouracil Cream in the Treatment of Actinic Keratoses: A Single-Center Experience

<b>Background/Objectives:</b> Actinic keratoses (AKs), also known as solar keratoses, are considered premalignant skin lesions that can evolve into squamous cell carcinoma (SCC). Among the available options, 5-fluorouracil (5-FU) remains a cornerstone. <b>Methods:</b> This study is a retrospective analysis of our database of the non-melanoma skin cancer outpatient clinic. The main objective was to evaluate patients treated with 4% 5-FU cream for AK lesions. The efficacy of 4% 5-FU was evaluated retrospectively by measuring the percentage of patients who achieved complete clearance. A secondary efficacy measure was the percentage of partial clearance, defined as at least a 75% reduction in lesion count. Additionally, the study aimed to assess the safety of 4% 5-FU cream. <b>Results:</b> We included 150 patients clinically diagnosed with AK, treated with 4% 5-FU cream and evaluated 432 lesions. Complete clearance of lesions was observed in 138 patients (92%) with partial clearance in 12 patients (8%). At 12 months, the recurrence rate was 11%. <b>Conclusions:</b> Based on our analysis, 4% 5-FU cream is an effective and well-tolerated treatment for AKs, particularly in patients with extensive field cancerization. While local skin reactions are a natural part of its mechanism, they are manageable and do not outweigh clinical benefits.