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In vitro and in vivo comparison of two different light sources for topical photodynamic therapy
Author(s) -
Babilas P.,
Kohl E.,
Maisch T.,
Bäcker H.,
Groß B.,
Branzan A.L.,
Bäumler W.,
Landthaler M.,
Karrer S.,
Szeimies RM.
Publication year - 2006
Publication title -
british journal of dermatology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.304
H-Index - 179
eISSN - 1365-2133
pISSN - 0007-0963
DOI - 10.1111/j.1365-2133.2006.07143.x
Subject(s) - university hospital , dermatology , medicine , art , library science , computer science , surgery
Summary Background Photodynamic therapy (PDT) with 5‐aminolaevulinic acid (ALA) is an effective and safe treatment option for the treatment of actinic keratosis (AK). Incoherent lamps are often used, matching the absorption maxima of ALA. Objectives A comparative trial was performed to evaluate the efficacy of recently developed light‐emitting diodes (LEDs). Methods Human epidermal keratinocytes were incubated for 24 h with ALA (100, 200, 300, 400 or 500 μ mol L −1 ) and irradiated consecutively using either an incoherent halogen lamp ( λ em = 580–750 nm; 24 J cm −2 ; 40 mW cm −2 ) or an LED system ( λ em = 633 ± 3 nm; 3, 6, 12 or 24 J cm −2 ; 40 mW cm −2 ). Topical ALA‐PDT was performed on 40 patients with AK ( n = 584) in a symmetrical distribution suitable for two‐sided comparison. After incubation with ALA (20% in cream base) irradiation was performed with the incoherent lamp (100 J cm −2 ; 160 mW cm −2 ) on one side and the LED system (40 J cm −2 ; 80 mW cm −2 ) on the opposite side followed by re‐evaluation up to 6 months. Results No significant differences between the LED system (3, 6, 12 or 24 J cm −2 ) and the incoherent light source (24 J cm −2 ) regarding cytotoxicity was found in vitro . The complete remission rate yielded in the in vivo investigation was also not significantly different at 6 weeks ( P = 0·95), 3 months ( P = 0·75) and 6 months ( P = 0·61) following therapy. Six weeks following therapy complete remission rates of 84·3% (LED system) and 82·8% (incoherent lamp) were achieved. There was also no significant difference between both light sources regarding pain during light treatment ( P = 0·67), patient satisfaction ( P = 1·0) or cosmesis ( P = 1·0) following therapy. Conclusions These results show the efficacy of an LED system for ALA‐PDT both in vitro and in vivo . ALA‐PDT with the LED system showed a noninferiority regarding the clinical outcome in the treatment of AK compared with the incoherent lamp.