Long-term follow-up of metil aminolevulinate (MAL)-PDT in difficult-to-treat cutaneous Bowen's disease

Bowen's disease (BD) is a form of intraepidermal squamous cell carcinoma, which is clinically characterized by gradually enlarging, well-demarcated erythematous plaques with irregular borders and surface crusting or scaling, affecting primarily the elderly. BD often presents with lesions difficult to treat with standard therapy as surgery, cryosurgery, or 5-fluorouracil (5-FU) for the risk of significantly poor cosmetic outcome, failure rate, and adverse events, related mainly to the age of the patients. Topical PDT with methyl aminolevulinate (MAL) represents a valid and approved therapy for BD lesions in many cases, especially for lesions located at poor healing sites or for large patches of disease, due to its high efficacy coupled with good tolerability and tissue-sparing attitude. In this study, we sought to investigate the efficacy, safety, and cosmetic outcome of MAL-PDT in a series of patients with BD lesions which were challenging to treat for clinical, surgical, and patient-related reasons, such as size of the lesion, difficult surgical approach for anatomical sites, or age of patients and request of the best cosmetic result. We also performed a long-term follow-up to assess recurrence rates and eventual late-onset adverse events.