Combination of ablative fractional laser and daylight-mediated photodynamic therapy for actinic keratosis in organ transplant recipients - a randomized controlled trial

Background Topical photodynamic therapy (PDT) for actinic keratoses (AK) is hampered by pain during illumination and inferior efficacy in organ-transplant recipients (OTR). Objectives We assessed ablative fractional laser (AFL)-assisted daylight photodynamic therapy (PDT) (AFL-dPDT) compared with daylight PDT (dPDT), conventional PDT (cPDT) and AFL alone (AFL) in field treatment of AK in OTR. Methods In each patient, four areas in the same region were randomized to one treatment with AFL-dPDT, dPDT, cPDT and AFL. AFL was delivered with a 2940-nm AFL at 2.3 mJ per pulse, 1.15 W, two stacks, 50-mu s pulse-duration, 2.4% density. In dPDT and AFL-dPDT, methyl aminolaevulinate (MAL) was applied for 2.5 h without occlusion during daylight exposure. For cPDT, MAL was occluded for 3 h followed by red-light (630 nm) irradiation at 37 J cm(-2). The primary end-point was complete response (CR) 3 months post-treatment. Results Sixteen patients with 542 AK (grades I-III) in field-cancerized skin of the scalp, chest and extremities were treated during August and September 2012. After 3 months, CR (AK I-III) rates were 74% after AFL-dPDT, 46% after dPDT, 50% after cPDT and 5% after AFL (P < 0.001). CR rates in AFL-dPDT, dPDT and cPDT were also significantly different (P = 0.004). Median maximal pain scores differed significantly during AFL-dPDT (0), dPDT (0), AFL (0) and cPDT (5) (P < 0.001). Erythema and crusting were more intense following AFL-dPDT than dPDT and cPDT, but only transient hypopigmentation was observed. Conclusions AFL-dPDT is a novel PDT modality that enhances CR with excellent tolerability compared with dPDT and cPDT in difficult-to-treat AK in OTR.