Clinical results of photodynamic therapy for superficial skin malignancies or actinic keratosis using topical 5-aminolaevulinic acid

Abstract

Photodynamic therapy (PDT) with topical application of 5-aminolaevulinic acid (ALA, 20% w/w) was used to treat superficial basal cell carcinoma (BCC, 16 patients), Morbus Bowen (one patient), basal cell naevus syndrome (BCNS, three patients), actinic keratosis (AK, two patients), chronic inflammation (CI, one patient), and metastasized BCC (one patient). The interval between ALA application and illumination was 3–6 h. The incident light dose was 50–100 J cm−2, mostly 75 J cm−2, at 633 nm wavelength. This was based on the fluorescence excitation spectrum, measured on the skin of human volunteers. In a few cases, 514.5 nm light was used. A complete response (CR) rate of 79% (median follow-up 13 months) was obtained with 42 BCC lesions. The treatment of five areas with AK, two areas with CI and one area with M. Bowen yielded three CR for AK and five partial remissions (PR). Photodynamic therapy of metastasized BCC, after either topical or oral ALA, was not successful. Treatment of BCNS was satisfactory with 100% CR in one patient (22 lesions), PR in a second patient (20 lesions), and good palliation in a third patient (>250 lesions). The treatment was well tolerated, although the illumination had to be interrupted occasionally due to pain. Healing usually occurred in 2 weeks. Cosmetic results were good to excellent. 5-Aminolaevulinic acid application over 16–19 h and repeated treatments made it possible to obtain CR of non-superficial lesions. The selective tumour fluorescence was then lost, however, due to fluorescence of normal skin, but the cosmetic outcome did not deteriorate. 5-Aminolaevulinic acid PDT may be a good alternative outpatient treatment, especially in elderly patients and for large treatment areas. The excellent cosmetic outcome warrants further study in younger patients. More work is necessary to establish optimal ALA-treatment schemes.