A Quantitative Comparison of 5-Aminolaevulinic Acid- and Methyl Aminolevulinate-Induced Fluorescence, Photobleaching and Pain During Photodynamic Therapy

TY - JOUR

T1 - A Quantitative Comparison of 5-Aminolaevulinic Acid- and Methyl Aminolevulinate-Induced Fluorescence, Photobleaching and Pain During Photodynamic Therapy

AU - Valentine, Ronan M.

AU - Ibbotson, Sally H.

AU - Brown, C. Tom A.

AU - Wood, Kenny

AU - Moseley, Harry

PY - 2011

Y1 - 2011

N2 - The characteristics of protoporphyrin IX (PPIX) fluorescence in superficial basal cell carcinoma (sBCC) and carcinoma in situ (Bowen's Disease, BD) following application of 5-aminolaevulinic acid (5-ALA) and its methyl ester (methyl aminolevulinate [MAL]) before, during and after photodynamic therapy (PDT) were investigated in 40 patients. Photosensitizer prodrug penetration can limit PDT efficacy and understanding the characteristics of PPIX fluorescence through fluorescence spectroscopy, may improve knowledge of photosensitizer delivery. Fluorescence intensity was assessed quantitatively, and the rate of photobleaching was determined by fitting an exponential decay. As a secondary end-point, PDT-induced pain was also measured continuously during treatment using a novel hand-held device, known as a pain logger. In vivo PPIX fluorescence was shown to decrease during irradiation, allowing the in vivo photobleaching of PPIX to be monitored. No significant difference was found between ALA- or MAL-induced PPIX fluorescence in lesions of sBCC and BD (P > 0.05), indicating no detectable difference in PPIX kinetics for the two prodrugs as assessed by these measures. Pain, as assessed by the logger device, showed high interindividual variability and pain levels tended to be higher initially, decreasing during treatment. No difference was seen in pain experienced during ALA-or MAL-PDT (P > 0.05).

AB - The characteristics of protoporphyrin IX (PPIX) fluorescence in superficial basal cell carcinoma (sBCC) and carcinoma in situ (Bowen's Disease, BD) following application of 5-aminolaevulinic acid (5-ALA) and its methyl ester (methyl aminolevulinate [MAL]) before, during and after photodynamic therapy (PDT) were investigated in 40 patients. Photosensitizer prodrug penetration can limit PDT efficacy and understanding the characteristics of PPIX fluorescence through fluorescence spectroscopy, may improve knowledge of photosensitizer delivery. Fluorescence intensity was assessed quantitatively, and the rate of photobleaching was determined by fitting an exponential decay. As a secondary end-point, PDT-induced pain was also measured continuously during treatment using a novel hand-held device, known as a pain logger. In vivo PPIX fluorescence was shown to decrease during irradiation, allowing the in vivo photobleaching of PPIX to be monitored. No significant difference was found between ALA- or MAL-induced PPIX fluorescence in lesions of sBCC and BD (P > 0.05), indicating no detectable difference in PPIX kinetics for the two prodrugs as assessed by these measures. Pain, as assessed by the logger device, showed high interindividual variability and pain levels tended to be higher initially, decreasing during treatment. No difference was seen in pain experienced during ALA-or MAL-PDT (P > 0.05).

KW - BASAL-CELL CARCINOMA

KW - INDUCED PROTOPORPHYRIN-IX

KW - NONMELANOMA SKIN-CANCER

KW - ACTINIC KERATOSIS

KW - PHOTOSENSITIZER FLUORESCENCE

KW - TOPICAL APPLICATION

KW - LIGHT

KW - IRRADIANCE

KW - GUIDELINES

KW - DOSIMETRY

U2 - 10.1111/j.1751-1097.2010.00829.x

DO - 10.1111/j.1751-1097.2010.00829.x

M3 - Article

C2 - 21077899

SN - 0031-8655

VL - 87

SP - 242

EP - 249

JO - Photochemistry and Photobiology

JF - Photochemistry and Photobiology

IS - 1

ER -