A Randomized Multicenter Study to Compare Two Treatment Regimens of Topical Methyl Aminolevulinate (Metvix ® )‐PDT in Actinic Keratosis of the Face and Scalp

Abstract

Photodynamic therapy (PDT) with topical methyl aminolevulinate (MAL) administered in two treatment sessions separated by 1 week is an effective treatment for actinic keratoses. This open prospective study compared the efficacy and safety of MAL-PDT given as a single treatment with two treatments of MAL-PDT 1 week apart. Two hundred and eleven patients with 413 thin to moderately thick actinic keratoses were randomized to either a single treatment with PDT using topical MAL (regimen I; n=105) or two treatments 1 week apart (regimen II; n=106). Each treatment involved surface debridement, application of Metvix cream (160 mg/g) for 3 h, followed by illumination with red light using a light-emitting diode system (peak wavelength 634+/-3 nm, light dose 37 J/cm2). Thirty-seven lesions (19%) with a non-complete response 3 months after a single treatment were re-treated. All patients were followed up 3 months after the last treatment. A total of 400 lesions, 198 initially treated once and 202 treated twice, were evaluable. Complete response rate for thin lesions after a single treatment was 93% (95% CI=87-97%), which was similar to 89% (82-96%) after repeated treatment. Response rates were lower after single treatment of thicker lesions (70% (60-78%) vs 84% (77-91%)), but improved after repeated treatment (88% (82-94%)). The conclusion of this study is that single treatment with topical MAL-PDT is effective for thin actinic keratosis lesions; however, repeated treatment is recommended for thicker or non-responding lesions.

Treatment plan evaluation for interstitial photodynamic therapy in a mouse model by Monte Carlo simulation with FullMonte

“…The relative uncertainty, measured by coefficient of variation ( σ /μ), therefore scales inversely with the square of the energy absorbed in an element The absorbed energy integrated over volume is not directly useful for calculating photodynamic dose because it does not separate photosensitizer absorption from other chromophores; that requires knowledge of photosensitizer concentration (outside the scope of the optical simulator), absorption cross-section (a material property), and fluence (derived from optical simulation). Conversion of absorbed energy into fluence requires simply multiplication by a constant (k = i /Ei = V −1 μ −1 a ) if we assume homogeneous fluence and absorption coefficient over the volume element in Equation (1). That multiplication changes the values of mean (kμ) and variance (k 2 σ 2 ) but not the coefficient of variation due to algebraic cancelation.…”

“…It is widely used for indications which are superficial in terms of both the method of light application and the lesion depth, so currently mostly actinic keratosis [1] and skin cancer [2]. For more difficult interstitial applications, it shows both great promise [3] and ongoing challenges with inconsistent outcomes [4,5].…”

Efficacy of Photodynamic Therapy in the Short and Medium Term in the Treatment of Actinic Keratosis, Basal Cell Carcinoma, Acne Vulgaris and Photoaging: Results From Four Clinical Trials

“…Previous studies have proven PDT to be very effective in the treatment of non-hypertrophic AK 2,3,11) . Tshen et al, recommend one or two treatment sessions, according to the case, reporting full healing in 86% of lesions four months after treatment 11) .…”

“…The importance and objective of treatment for AK and BCC are focused on their malignant transformation potential; intervention therefore must be geared towards eradication of the lesion and prevention of recurrence [2][3][4][5][6] . In AV and PA cases, the aim is the maximum reduction in number of lesions and to achieve an aesthetic improvement [7][8][9] .…”

Terapia fotodinâmica em dermatologia: princípios básicos e aplicações

“…25,26,34,35,37,38 Em recente publicação, Tarstedt e cols, observaram que apenas uma sessão de MAL-TFD, repetida 3 meses após se necessário, era igualmente eficaz e com índice de cura de 92%, semelhante ao protocolo inicial. 38 Assim, para o tratamento das QAs com MAL, preconiza-se apenas uma sessão e, se necessário, nova sessão após 3 meses, nos casos de resposta parcial. Cabe ressaltar que sempre se faz o preparo das lesões antes da aplicação do MAL, ou seja, uma leve curetagem das lesões com o intuito de remover as camadas mais superficiais de queratina.…”