Background: Photodynamic therapy with a self-adhesive 5-aminolaevulinic acid (5-ALA) patch shows high efficacy rates in the treatment of mild to moderate actinic keratosis (AK) in short term trials.
Objectives: The purpose of the trial was to follow up patients after successful 5-ALA patch-PDT at 3 month intervals over a total period of 12 months. Patients who had received placebo-PDT or cryosurgery served for comparison.
Patients/methods: Three months after therapy, 360 patients from two separate randomized parallel group phase III studies (one superiority trial vs. placebo-PDT, one noninferiority trial vs. cryosurgery) were suitable for the follow-up study. Patients had to show at least one successfully treated AK lesion after initial therapy. A total of 316 patients completed the follow-up.
Results: Twelve months after a single treatment, 5-ALA patch-PDT still proved superior to placebo-PDT and cryosurgery (P < 0.001 for all tests). On a lesion basis, efficacy rates were 63% and 79% for PDT, 63% for cryosurgery and 9% and 25% for placebo-PDT. Recurrence rates of patch-PDT proved superior to those of cryosurgery (per protocol set: P = 0.011, full analysis set: P = 0.049). While 31% of cryosurgery lesions were still hypopigmented after 1 year, the 5-ALA patch-PDT groups showed hypopigmentation in 0% (superiority trial) and 3% (noninferiority trial) of the treated lesions.
Conclusion: Twelve months after a single 5-ALA patch-PDT the majority of lesions were still cleared with an excellent cosmetic outcome. 5-ALA patch-PDT proved to be superior to cryosurgery in the noninferiority study setting.