Single versus two-treatment schedule of methyl aminolevulinate daylight photodynamic therapy for actinic keratosis of the face and scalp: An intra-patient randomized trial

Background: Efficacy of daylight-photodynamic therapy (DL-PDT) with methyl aminolaevulinate (MAL) has been reported to gradually decrease as the severity of actinic keratosis (AK) lesions increases. Repeated treatments have been suggested to increase the efficacy of DL-PDT. Aim of our pilot study was to evaluate the efficacy and tolerability of a single versus two-treatment schedule of MAL DL-PDT for the treatment of multiple AKs of the face/scalp in a prospective, intra-patient, comparison study. Methods: Patients with multiple AKs of the face/scalp received a single treatment of MAL DL-PDT or 2 treatments, 1 week apart, on either half-side. Weather conditions and outdoor temperature were recorded during daylight exposure. Visual analog scale for pain was assessed immediately after each session, and severity of local skin reactions after 2 days. Treatment efficacy was evaluated at 3 months. Results: Thirty-one patients with multiple AKs of the face/scalp were enrolled and completed the study. No significant difference was observed between single and two-treatment schedule in the lesion complete response rate for total AKs (80.7% vs 85.6%, p = 0.28) and for AKs divided by grade (grade I: 88.5% vs 89.2%, p = 0.79; grade II: 67.3% vs 71.0%, p = 0.71; grade III: 50.0% vs 55.6%, p≈1.00). Pain was significantly higher during the second session (p = 0.04). Local skin reactions were generally mild, but more severe after the first treatment (p < 0.01). Conclusions: The two-treatment schedule did not improve significantly the efficacy of MAL DL-PDT for AKs of the face and scalp as compared to the single-treatment. Alternative strategies might be recommended to optimize the efficacy of DL-PDT.