title: Primary clinical response and long-term follow-up of solar keratoses treated with topically applied 5-aminolevulinic acid and irradiation by different wave bands of light.
abstract: Photodynamic therapy with 5-aminolevulinic acid (ALA-PDT) is based on photosensitization by endogenous synthesis of protoporphyrin IX and its transient accumulation especially in malignant epithelially derived tissues. Recent studies have indicated that ALA-PDT is effective for the treatment of solar keratoses (SK), but there has been a lack of long-term clinical follow-up. The goal of the present study was to investigate the immediate and long-term effect of ALA-PDT on SK. Twenty-eight patients with a total of 251 SK were enrolled in the study. Standard treatment involved the topical application of 20% ALA, under occlusive and light-shielding dressing for 4 hours before exposure to UVA and/or different wave bands or wave band combinations of polychromatic visible light (full-spectrum visible light, and/or different wave bands of filtered visible light > 515, > 530, > 570, or > 610 nm) in one or two treatment sessions. The primary complete response rate of SK to ALA-PDT was 64% after one treatment, but 85% when the responses to a second treatment were included. Taken all treatments together, the complete response rate for lesions on face, scalp and neck was 93% for full-spectrum visible light, 96% for the combination of full-spectrum visible light and filtered light, 91% for different wave bands of filtered visible light, and 100% for the combination of long wave UVA and full-spectrum visible light, respectively. The complete response rate for lesions on forearms and hands was 51% for full-spectrum visible light and 33% for the combination of full-spectrum visible light and filtered light. The greater response rate for SK on the face, scalp, and neck was associated with a higher surface fluorescence and immediate response rate after ALA photosensitization at these sites (chi 2; p = 0.0001). However, due to the treatment protocol the mean light dose applied to lesions on the face, scalp and neck (50 J cm-2) was substantially higher than that for lesions on forearms and hands (35 J cm-2). In the long term follow-up of SK on face scalp and neck, the projected disease-free rate at 36 months after therapy was 71% for lesions treated with full-spectrum visible light versus 23% for lesions treated with different wave bands of filtered light (Log rank-Mantel Cox; p = 0.0001). These results indicate that treatment with full-spectrum visible light at higher light doses may be the most effective and promising form of light exposure in ALA-PDT of SK.
authors.affiliation: Department of Dermatology, University of Graz, Austria.
authors.forename: R
authors.initials: R
authors.lastname: Fink-Puches
authors.forename: A
authors.initials: A
authors.lastname: Hofer
authors.forename: J
authors.initials: J
authors.lastname: Smolle
authors.forename: H
authors.initials: H
authors.lastname: Kerl
authors.forename: P
authors.initials: P
authors.lastname: Wolf
mesh_terms: D000287:Administration, Topical; D000368:Aged; D000369:Aged, 80 and over; D000622:Aminolevulinic Acid / Q000009:adverse effects / Q000627:therapeutic use*; D004890:Erythema; D005260:Female; D005453:Fluorescence; D005500:Follow-Up Studies; D006801:Humans; D007642:Keratosis / Q000188:drug therapy* / Q000503:physiopathology; D008027:Light; D008297:Male; D008875:Middle Aged; D010146:Pain; D017319:Photosensitizing Agents / Q000009:adverse effects / Q000627:therapeutic use*; D013472:Sunlight; D013997:Time Factors
chemical_list: D017319:Photosensitizing Agents; D000622:Aminolevulinic Acid