Daylight photodynamic therapy for actinic keratoses in São Paulo, Brazil

Abstract

Fourteen patients (10 women and 4 men) with multiple AKs on the face (at least six lesions) were selected. The patients selected had AKS of grades I (thin lesions, slightly palpable) or II (moderately thick, easily felt) according to Olsen et al. (1). Patients with thicker lesions (grade III) were excluded. None of the selected patients had received any treatment in the previous 6 months. The study was approved by the local ethical committee at the University of São Paulo.After informed consent, patients were photographed, and the lesions were mapped and counted.As recommended by the international consensus on D-PDT published in 2011 by Wiegell et al. (2), the treatment method consisted of light curettage and application of a non-physical SPF30 sunscreen (3). Fifteen minutes later, 16% methyl ester of 5-aminolaevulinic acid (MAL) in a cream base (Metvix®, Galderma S.A., Hortolândia, Brazil) was applied in a thick layer over the lesions and a thinner one on the whole face. The cream was left on the face with no occlusion for 30 min, and after that, the patients were instructed to expose themselves to sunlight in the hospital garden for 60 to 90 min.Immediately after exposure, the patients returned to the department of dermatology, where their faces were wiped clean and the sunscreen reapplied. They also answered a questionnaire about pain during the treatment.The patients were evaluated 1 month after treatment; the remaining lesions were counted and photodocumented.The patients who did not achieve a good response were submitted to repeated D-PDT sessions with monthly follow-up, with a maximum of three treatments.This study was conducted between August 2012 (winter in Brazil) and May 2013 (autumn), and all of the patients were exposed to natural daylight between 8:30 AM and noon.The measurement of incoming solar radiation during the daylight exposure was made at surface level (horizontal). The 5-min average values of this radiation were integrated for the exposure time. Environmental radiation was measured at the micrometeorological platform located on top of a four-story building in the University of São Paulo campus in the western part of São Paulo city (23.4°S, 46.7°W, 742 meters above the mean sea level). The Photodermatology, Photoimmunology & Photomedicine

A consensus on the use of daylight photodynamic therapy in the UK

“…One way to deliver very low irradiance PDT is by the use of daylight to activate PpIX. It has been demonstrated that for patients with AKs and in particular field AKs, PDT using daylight can have a similar efficacy to c-PDT, is almost pain free and produces excellent cosmetic results (22)(23)(24)(25)(26)(27)(28)(29)(30). However, it is important to note that in these studies, the efficacy of d-PDT was only followed up over 3-6 months, although with high efficacy rates still apparent at six months (31,32) and this is also typical of the follow-up interval used in most studies of most treatments for AK.…”

“…Subsequently, studies were conducted in central and southern Europe, Brazil and Australia (27,(29)(30)(31). Patients in these studies mostly had mild-to-moderate AKs on the face and scalp and duration of exposure varied between studies (90-240 min).…”

“…In Europe, the mean rate of clearance of AKs was 75-83% after one treatment for patients with Grade I/II AKs (22)(23)(24)(25)(26)(27)29). In Australia and Brazil, the response was greater, at 89% and 88%, respectively, for patients with mild AKs (30,31). Pain scores were generally low with some studies demonstrating that d-PDT was almost pain free (24,27).…”

Feasibility of daylight‐mediated photodynamic therapy for actinic keratosis throughout the year in Central and South America: a meteorological study

“…Although several studies have demonstrated the efficacy and advantages of this treatment, no previous study has examined weather conditions in Central and South America. Grinblat et al 15 previously confirmed that there is no relationship between irradiance and treatment efficacy. The average irradiance levels reported in this meteorological study conducted in Central and South America exceeded the MICB reported in the Australian DL-PDT clinical study.…”

“…Results showed high cure rates irrespective of the light dose received, with good responses observed even in patients treated during the winter. 15 Weather conditions and abundance of daylight vary among locations throughout the year. An important shortcoming of the European and Australian DL-PDT studies refers to the limited period of the year during which they were conducted, and thus these studies do not provide information on the feasibility of treatment throughout the year.…”