A Controlled Comparison Study of Topical Fluourouracil 5% Cream Pre-Treatment of Aminolevulinic Acid/Photodynamic Therapy for Actinic Keratosis

Abstract

Introduction: Topical Fluorouracil 5% cream (5-FU) and 20% aminolevulinic acid (ALA)/ photodynamic therapy (PDT) are both FDA approved for the treatment of Actinic Keratosis (AK). We have studied the use of these 2 agents alone and in a sequential manner. We have also used a 5-FU re-challenge 3 months after treatment to highlight the efficacy of these treatments.

Methods: This was an investigator-blinded randomized study in which 30 patients were randomized 1:1:1 into the following groups: Group 1 patients pretreated for 6-7 days with 5-FU, ALA applied with incubation of 2 hours, ALA removed with wet gauze, illuminated treated areas with 10 J/cm(2) with Blu-U device; Group 2 patients treated with 5-FU BID for 6-7 days and no ALA/PDT; Group 3 patients received no pretreatment, ALA applied with incubation of 2 hours, ALA removed with wet gauze, illuminated treated areas with 10 J.cm2 with Blu-U device. Patients were seen at screening/baseline, treatment for ALA/PDT, 24 hours post treatment, 1 week post treatment and 3 months post treatment. All subjects were then given a re-challenge course of 5-FU for 6 days and reassessed.

Results: AK counts in all groups were dramatically decreased and similar at 1 and 3 months post treatment. The re-challenge brought a significant difference with many subclinical lesions in the area of activity in the ALA and 5-FU alone groups.

Conclusions: All three arms appeared equal in treating visible AKs. These data strongly suggests a synergistic role of 5-FU with ALA/PDT over ALA/PDT or 5-FU alone in treating the subclinical lesions demonstrated on a 5-FU re-challenge. Treatment of these subclinical lesions should result in a longer remission. The data also suggests that a 5-FU re-challenge could be a clinical tool to judge the efficacy of treatment for AK if these subclinical lesions are proven to be an AK precursor.