P69 Does the fluence rate influence clinical outcome and pain experienced by the patients with actinic keratosis treated with PDT?

Abstract

Background Topical 5-aminolevulinic acid-based photodynamic therapy (ALA-PDT) has been established in recent years as an effective treatment for non-melanoma skin cancers, including actinic keratosis (AKs). Available literature data suggest that low fluence rates are preferable in terms of efficacy and tolerability for treating patients suffering from disseminated AKs. Aims To identify factors contributing to pain induction during PDT, and to detect the optimal fluence rate, in conjunction with the clinical outcome. Methods Fifty adults, with an overall of 150 histologically confirmed lesions of AKs were recruited in the study. Inclusion criteria were the presence of at least 3 discrete AKs, located on face or scalp, and age over 18. Treatment protocol for each lesion included two therapeutic sessions of topical PDT, one week apart. Each lesion was randomly allocated to 25, 50 or 75 mW/cm2. The total light dose was equal to 75 J/cm2 and was maintained the same during all treatment sessions. A 20% 5-aminolevulinic acid (ALA) cream was applied over the lesion, and after 4 h of light-impenetrable occlusion dressing, the lesion was illuminated with red light (570–670 nm) by a non-coherent light source (Waldmann PDT 1200, Waldmann-Medizin-Technik, Villingen-Schwenningen, Germany). Pain experienced by patients during illumination was recorded using a visual analogue scale (VAS) graded from 0 (no pain) to 10 (unbearable pain). Follow-up visits were held at months 3, 6 and 12 after treatment. Clinical outcome was defined as complete response (CR; complete absence of any clinical sign indicative of AKs) or as non-complete response (non-CR; remaining clinical signs indicative of AKs). Results Mean VAS score did not significantly differ between the groups of 25 and 50 mW/cm2. However, mean VAS was significantly higher at the group of 75 mW/cm2. With respect to the clinical outcome and the rate of recurrences during the first year of follow-up, no differences were observed. Conclusion According to our observations a fluence rate of 50 mW/cm2 is equally effective and better tolerated by patients treated with topical 5-ALA PDT for AKs.