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Photodynamic therapy for actinic keratosis of the forehead and scalp with the Aktilite CL 128: Is there a cut‐off value for Pp IX ‐weighted irradiance for effective treatment?
Author(s) -
Vicentini Claire,
VignionDewalle AnneSophie,
Thecua Elise,
Lecomte Fabienne,
Béhal Hélène,
Maire Cyril,
Tylcz JeanBaptiste,
AbiRached Henry,
Mortier Laurent,
Mordon Serge
Publication year - 2019
Publication title -
photodermatology, photoimmunology and photomedicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.736
H-Index - 60
eISSN - 1600-0781
pISSN - 0905-4383
DOI - 10.1111/phpp.12457
Subject(s) - actinic keratosis , irradiance , protoporphyrin ix , forehead , photodynamic therapy , confidence interval , nuclear medicine , medicine , scalp , dermatology , ophthalmology , optics , chemistry , surgery , basal cell , physics , organic chemistry
Summary Background/purpose Photodynamic therapy ( PDT ) is an established treatment for actinic keratosis ( AK ). Among the approved protocols in Europe, the most widely used involves irradiation with the Aktilite CL 128 (C‐ PDT ). We aimed to assess the heterogeneity of irradiance over the treatment area when using C‐ PDT . We also investigated whether there is a cut‐off value for protoporphyrin IX (Pp IX )‐weighted irradiance that may predict the treatment outcome of C‐ PDT . Methods An Ophir PD 300 photodiode sensor connected to an Ophir Laser Star power meter was used to measure the irradiance delivered to 114 AK s of the scalp and forehead of 19 patients treated with C‐ PDT . The Pp IX ‐weighted irradiances were deduced and cross‐referenced with the complete responses at 3 months. Results From the measured irradiances ranging from 0.25 to 60 mW/cm 2 (average: 31.94 mW/cm 2 ), a standard deviation of 17.17 mW/cm 2 was computed. Irradiance heterogeneity over the treatment area during C‐ PDT was demonstrated. The 66/114 AK s with a complete response at 3 months (57.89%) received a mean Pp IX ‐weighted irradiance of 0.52 mW /cm 2 vs 0.56 mW /cm 2 for the resistant 48/114 AK s (42.11%). No significant effect of Pp IX ‐weighted irradiance on the complete response at 3 months was found (odds ratio for a 0.1‐unit change, 0.96; 95% confidence interval, 0.83 to 1.10; P = 0.53). Therefore, no cut‐off value for Pp IX ‐weighted irradiance that predicts treatment outcome could be identified. Conclusions A device enabling homogeneous irradiation at a lower irradiance than the Aktilite CL 128 may therefore be suitable. This lower irradiance may further increase the treatment tolerance by patients.