Photodynamic therapy with a 5-ALA patch does not increase the risk of conversion of actinic keratoses into squamous cell carcinoma: Results of a multicentre non-interventional study.

Background: It is important to collect data about the risk of transformation of an actinic keratosis (AK) lesion into squamous cell carcinoma (SCC) after a single photodynamic therapy (PDT) with 5-ALA patch for a longer follow-up period under daily routine.

Questions Addressed: The purpose of this non-interventional study (NIS) was to collect data on the frequency of occurrence of SCCs in the treated area during an interval of 2 years after a single 5-ALA patch-PDT.

Experimental Design: This prospective observational case-only study included patients with mild AK lesions on the head and face treated with 5-ALA patch-PDT according to the Summary of Product Characteristics (SPC).