Treatment of Bowen's disease with photodynamic therapy. Observational study in 171 patients with 5-aminolaevulinic acid (BF-200 ALA) and methyl aminolaevulinate (MAL).

• Bowen´s disease (BD) is an intraepidermal squamous cell carcinoma (SCC). • There are several alternatives for treatment of BD, including photodynamic therapy (PDT). • Photosensitizer precursors used in Europe include methyl-5-aminolaevulinate (MAL) and 5-aminolaevulinic acid (BF-200 ALA). • We designed a study with 171 patients to investigate the efficacy and safety of PDT in BD. • PDT is an effective and safe treatment option in BD. Our analysis suggests a higher rate of healing with ALA-PDT over MAL-PDT. An observational study was carried out in the photodynamic therapy (PDT) section of Fuenlabrada's hospital (Madrid, Spain). Our goal was to investigate the efficacy and safety of PDT in Bowen's disease (BD). Between June 2011-June 2017 171 patients (191 lesions) with diagnosis of BD were enrolled in the study (95 women and 76 men; average age of 74.31 years). Lesions were treated with one 5-aminolaevulinic acid (BF-200 ALA)-PDT or methyl-5-aminolaevulinate (MAL)-PDT cycle of two sessions in one week. A second treatment cycle was performed in cases of clinical persistence at 12 weeks. Our results showed that 47/55 lesions were resolved (84.75%) after one or two ALA-PDT cycle and 75/136 lesions (55.15%) after one or two MAL-PDT cycles, in the 12-month follow-up. In conclusion PDT is a safe and non-invasive treatment option in BD. In addition, our results suggest a better response with ALA-PDT over MAL-PDT. Limits: observational study with a limited number of patients. [ABSTRACT FROM AUTHOR]