LARGE PATCHES OF BOWENS-DISEASE TREATED BY TOPICAL AMINOLEVULINIC ACID PHOTODYNAMIC THERAPY

Large patches of Bowen's disease (intraepidermal carcinoma in situ) ca n be difficult to treat by conventional methods. Photodynamic therapy (PDT) uses the combination of a photosensitizer, which preferentially accumulates in malignant cells, and photoactivation by visible light t o kill the malignant cells. 5-aminolaevulinic acid (ALA) PDT uses exce ss exogenous ALA, which produces, via the haem synthesis pathway, a bu ild up of the photosensitizer protoporphyrin IX. We describe the use o f topical ALA PDT to treat three patients with three especially large patches of Bowen's disease. Following two treatments all three lesions achieved a complete clinical and histological response with a good co smetic result. ALA PDT is a simple, effective and well tolerated treat ment for large patches of Bowen's disease.