title: Photodynamic therapy in combination with CO2 laser for the treatment of Bowen's disease.
abstract: Photodynamic therapy (PDT) involves the activation of a previously administered photosensitizing agent by visible light to induce tumor necrosis. Photosensitizers are topically applied in the treatment of skin tumors to avoid systemic side effects. In this study, we evaluated the feasibility and efficacy of aminolevulinic acid (ALA) as a photosensitizer (ALA-PDT) in combination with CO2 laser in the treatment of Bowen's disease (BD; intraepithelial squamous cell carcinoma). Twenty-two lesions from 18 patients were randomized into two groups: 11 lesions were treated with topical ALA-PDT (180 J/cm(2) at 100 mW/cm(2)) + CO2 laser for one to three sessions. The remaining 11 lesions were treated with CO2 laser alone, serving as control group. All patients were reviewed at ≤1-week intervals. Biopsies were taken from BD lesions prior to treatment. The initial evaluation was undertaken 1 month after treatment, and biopsies were harvested for histological evaluation. Patients who did not respond to the three sessions of treatment were referred to surgical treatment. In the ALA-PDT + CO2 laser group, 72.73 % (8/11) of BD lesions showed complete remission, with an overall clearance of 90.91 %, and only one recurred (9 %) during follow-up. Local side effects included mild erythema, edema, erosion, and burning and/or stinging sensation. No systemic side effects were observed. In the control group, 63.63 % (7/11) of lesions had complete remission and the overall clearance was 54.55 %. However, five lesions (45.45 %) had recurrence. Local side effects included mild to moderate edema, erosion, ulceration, delayed healing, prolonged pain, and scarring. There existed a significant difference in recurrence rate between the two groups (P < 0.05). Moreover, after ALA-PDT plus CO2 laser treatment, complete necrosis was observed in responsive lesions, and 3 months later, the atypical BD cells were replaced by normal keratinocytes. Topical ALA-PDT in combination with CO2 laser is safe, effective, and is associated with low recurrence and reduced side effects.
authors.affiliation: Department of Dermatology, Air Force General Hospital, PLA, Beijing, 100142, People's Republic of China.
authors.forename: Hong
authors.initials: H
authors.lastname: Cai
authors.forename: Yi-xia
authors.initials: YX
authors.lastname: Wang
authors.forename: Ji-Chun
authors.initials: JC
authors.lastname: Zheng
authors.forename: Ping
authors.initials: P
authors.lastname: Sun
authors.forename: Zhi-yong
authors.initials: ZY
authors.lastname: Yang
authors.forename: Yuan-li
authors.initials: YL
authors.lastname: Li
authors.forename: Xiao-yong
authors.initials: XY
authors.lastname: Liu
authors.forename: Qiang
authors.initials: Q
authors.lastname: Li
authors.forename: Wei
authors.initials: W
authors.lastname: Liu
mesh_terms: D000287:Administration, Topical; D000328:Adult; D000368:Aged; D000622:Aminolevulinic Acid / Q000008:administration & dosage*; D001913:Bowen's Disease / Q000188:drug therapy* / Q000473:pathology; D002278:Carcinoma in Situ / Q000188:drug therapy* / Q000473:pathology; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D054020:Lasers, Gas / Q000627:therapeutic use; D008297:Male; D008875:Middle Aged; D010778:Photochemotherapy; D017319:Photosensitizing Agents / Q000008:administration & dosage*; D012878:Skin Neoplasms / Q000188:drug therapy* / Q000473:pathology; D016896:Treatment Outcome
chemical_list: D017319:Photosensitizing Agents; D000622:Aminolevulinic Acid