Title, Authors and Institutions: / A randomised, single-blinded, prospective study of white-light LED topical methyl-5-aminolaevulinate photodynamic therapy; a novel treatment option that is as effective and well-tolerated as daylight photodynamic therapy for the treatment of actinic keratoses.S.M. O’Gorman1, J. Clowry1, M. Manley2, J. McCavana2, L. Gray2, A. Kavanagh1, A Lally1, P. Collins11 The Charles Centre, Department of Dermatology 2 Department of Medical Physics Saint Vincent’s University Hospital, Dublin, Ireland
Abstract:
(Your abstract must use Normal style and must fit in this space) / Our aim was to determine if photodynamic therapy using a white-light LED source (wlPDT) was as effective and well-tolerated as daylight PDT (dlPDT). Daylight PDT is recognised as being equally effective as conventional PDT (cPDT), while pain associated with the treatment is significantly reduced1. The drawback to dlPDT is that it requires acceptable weather conditions.
To achieve a power of 0.80 at a significance level of 0.05 we recruited 22 patients. Patients had two symmetrical treatment fields defined, each measuring 70 cm2. Actinic keratoses (AKs) were counted, mapped and photographed at baseline and at 1 month and 3 months post-treatment. Sunscreen was applied to all exposed areas and 30 minutes later Metvix© (methyl-5-aminolaevulinate cream) was applied. Following a 30-minute incubation period, treatment commenced and lasted 2 hours.
From April to July 2014, patients had one field treated with dlPDT and the opposite field treated with wlPDT, with one week between treatments and randomly allocated. A visual analogue scale was used at 30 minute intervals to assess pain. Calibrated instruments recorded the irradiance, illuminance and light spectra during dlPDT, from which the integrated dose (Jcm-2) and the effective light dose (Jeff), weighted to the absorption spectrum for protoporphyrin IX, were calculated. On the day following each treatment, patients were assessed for local and adverse effects.
All patients were male, and the median age was 72 years (range 47 – 85). At baseline, there was no significant difference in AK numbers between treatment groups (median(IQR) of 20.5(8.5) in the dlPDT fields and 20.5(12.5) in wlPDT fields, p= 0.3469). At one-month follow-up both treatments were equally effective, with a median reduction in AK number of 62.32% with dlPDT and 67.65% with wlPDT (p=0.135, Wilcoxon signed rank test). Again, at three months both treatments were equally effective. There was no significant difference in pain scores between groups (median pain score of 0/100 with dlPDT and 2/100 with wlPDT, p = 0.2887). Eleven of the patients preferred dlPDT, 10 preferred wlPDT and one patient found both equally tolerable. One patient, who had been unable to tolerate cPDT previously, developed severe erythema following both dlPDT and wlPDT, however he was able to complete both treatments successfully.
WlPDT is as effective as dlPDT, and represents a year-round treatment option.
1 Wiegell SR, Haedersdal M, Philipsen PA, Eriksen P, Enk CD, Wulf HC. Continuous activation of PpIX by daylight is as effective as and less painful than conventional photodynamic therapy for actinic keratoses; a randomized, controlled, single-blinded study. Br J Dermatol. 2008 Apr;158(4):740-6.

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