Distribution of 5‐aminolevulinic Acid‐induced Porphyrins in Noduloulcerative Basal Cell Carcinoma

Abstract

Abstract— Microscopic fluorescence photometry incorporating a light‐sensitive thermo‐electrically cooled charge‐coupled device (CCD) camera was employed to investigate the fluorescence distribution of 5‐aminolevulinic acid (ALA)‐induced porphyrins in 22 patients with a total number of 52 noduloul‐cerative basal cell carcinomas (BCC) after topical ALA application with or without dimethylsulfoxide (DMSO)/ethylenediaminetetraacetic acid (EDTA) or after intravenous administration of ALA. Both localization patterns and amounts of ALA‐induced porphyrins in the BCC were studied. The ALA‐induced porphyrins were localized only in the superficial layers of the noduloulcerative BCC lesions after topical application of 20% ALA alone for 3 h. However, both the penetration of ALA into deep lesions and the production of the ALA‐induced porphyrin fluorescence were increased after topical administration of 20% ALA and 20% DMSO/4% EDTA for 3 h. Prior treatment with 99% DMSO for 15 min further enhanced the ALA penetration into the BCC lesions after topical application of the ALA/DMSO/EDTA mixture and produced more ALA‐induced porphyrins by a factor of about three compared with those treated with ALA alone. The penetration of ALA into the deep BCC lesions could also be increased by prolonging the time of topical application of 20% ALA/4% EDTA to 29–48 h (without DMSO). Intravenous injection of ALA led to a more homogeneous distribution of the ALA‐derived porphyrins in the whole noduloulcerative BCC lesions.

Spatial Laser Induced Fluorescence Imaging (SLIFIMG) Analysis to Assess Tissue Photosensitizer Uptake

“…They used a very sensitive, cryogenically cooled CCD camera allows for acquiring a fluorescence image which showed the contrast of fluorescence intensities of the tumor (T) to those of normal tissue (N). This conform what obtained from the present study [30].…”

The Use of Dipeptide Derivatives of 5-Aminolaevulinic Acid Promotes Their Entry to Tumor Cells and Improves Tumor Selectivity of Photodynamic Therapy

“…Although ALA-PDT has already shown great potential both for the treatment of cancer and infectious diseases (11,12), its efficacy is somewhat limited by the hydrophilic nature of the molecule, leading to poor penetration through certain malignant tissues. At physiologic pH, ALA is a zwitterion, which severely impairs its ability to cross cell membranes via passive uptake, and may result in poor penetration and nonhomogeneous distribution in target tissues (13). In addition, saturation of heme synthesis as well as photobleaching of PpIX are also factors limiting the outcome of ALA-PDT (14,15).…”

The time-dependent accumulation of protoporphyrin IX fluorescence in nodular basal cell carcinoma following application of methyl aminolevulinate with an oxygen pressure injection device

“…Therefore the ester derivative, MAL, with greater lipophilicity (provided by the additional alkyl chain), can be utilised as it is expected to cross the stratum corneum more easily than ALA [13]. Past studies by Peng et al have reported that in lesions of up to 2 mm thickness the application of MAL for 3 hours showed the highest ratio of PpIX fluorescence depth to tumor depth [7], in contrast to the more limited penetration with ALA [8]. A review of the use of MAL-PDT for the treatment of nBCC found clearance rates ranging from 75-82% at 3 months to 77% at 60 months [14].…”