Conventional vs. daylight methyl aminolevulinate photodynamic therapy for actinic keratosis of the face and scalp: an intra-patient, prospective, comparison study in Italy

Introduction Daylight photodynamic therapy (DL-PDT) with methyl aminolevulinate (MAL) is a simplified PDT procedure that was recently shown in a few trials to be effective for grade I actinic keratosis (AK), with improved tolerability and reduced time of clinical attendance as compared to conventional PDT (c-PDT). Objective To evaluate the efficacy and tolerability of DL-PDT vs. c-PDT with MAL in the treatment of grade I AK on the face and scalp in Italy. Methods Thirty-five patients with AKs on the face (n = 17) or scalp (n = 18) were prospectively enrolled in an intrapatient, left-right, prospective, comparison study between DL-PDT and c-PDT at a single centre between September and October 2013. Weather conditions and outdoor temperature during daylight exposure were recorded for each DL-PDT session. Pain was assessed after the PDT session and local adverse events 2 days after treatment. Lesion response rate was evaluated on both sides at 3 months. AKs with complete regression were followed until 6 months. Patient's preference for either treatment was recorded. Results There was no difference in complete response (CR) rate of AK I at 3 months between DL-PDT and c-PDT (87% vs. 91%; RR = 0.96; P = 0.16). A lower CR rate was observed with DL-PDT than with c-PDT for AK II (36% vs. 61%; RR = 0.58, P = 0.06) and III (25% vs. 46%; RR = 0.50, P = 0.20). Recurrence rate at 6 months was slightly higher for cleared AK I after DL-PDT than after c-PDT (17% vs. 12%, RR = 1.50, P < 0.05). DL-PDT was associated with lower pain (DVAS = -2.2, P < 0.01) and reduced severity of local adverse events (Delta LSR = -1.4, P < 0.01) than c-PDT. Increasing outdoor temperature was associated with the efficacy of DL-PDT and the severity of adverse events. DL-PDT was preferred by 88% of the patients. Conclusion MAL DL-PDT showed similar efficacy to c-PDT in the treatment of AK I of the face/scalp but was less effective than c-PDT for AKs II and III. DL-PDT was better tolerated being associated with lower pain and occurrence of fewer adverse events. Clinical response to DL-PDT was significantly moderated by outdoor temperature, increasing at higher temperatures.