Novel Photodynamic Therapy Does Not Prevent New Skin Cancers—Randomized Controlled Trial

Abstract

To determine whether field photodynamic therapy (PDT) of actinic keratoses using a novel preparation of 5-aminolevulonic acid (novel ALA) results in fewer subsequent invasive skin cancers developing on the face of individuals with previous facial cutaneous malignancy in a prospective randomized controlled trial. Intervention patients received two treatments of novel ALA 2 weeks apart. Controls were observed. Patients were followed up with biopsy of any suspicious lesions for 3 years. The trial was suspended early because of problems with trial governance and the reporting of severe adverse events. Sixty-four patients who were recruited at that time at one center were monitored. Their average age was 71, and 57% were male. Patients were randomized to intervention (n = 34) or observation (n = 29). Over the subsequent 3 years, 13 intervention patients (38%) developed 30 new cutaneous malignancies in the field treated, and 11 control patients (38%) developed 22 new malignancies. Some intervention patients experienced prolonged adverse events, including permanent scarring. Novel ALA made no difference in the likelihood of new malignancies developing. The risks without benefit of this novel ALA are troubling. Lack of efficacy and safety of novel ALA cannot be extrapolated to other PDT products.