Terapia fotodinámica en queratosis actínicas y nuevas indicaciones

Abstract

The objective of this work is to report the results of PDT in actinic keratosis ( AK) and other dermatosis, as well as their correlation with fluorescence diagnosis. A total of 57 patients were treated in the face, scalp and back of the hands, which are the typical sites of AK presentation. PDT is a welltolerated treatment, with good response rates both in the lenght and clearance of the lesions. However, treatment must be planned according to the location of the lesions. Results are excellent in the face with a 92.5% of clearance rates and good tolerability. Consequently, it may be more effective to apply three sessions instead of two on the scalp and the back of the hand. For this locations, three sessions could be planning at the beginning of the treatment, and they could be interrupted if the clearance is achieved before. AK exhibit red fluorescence under a Wood light after occlusion with methyl aminolaevulinic acid ( MAL). Fluorescence diagnosis allows detection of the lesions and has also been correlated with higher treatment response. The fluorescence area was measured in our group of patients before and after the PDT treatment, in order to confirm if it is related with treatment response. It was found that fluorescence is higher in the face than in the other locations, and that the fluorescence of the lesions previous to treatment and its decrease after the PDT session is signivicantly correlated with treatment response. Fluorescence is observed as parameter that can predict treatment response before begining the sessions of PDT. Among other dermatosis, patients affected of cutaneous T cell lymphoma in plaques, viral warts and Bowen disease were treated with PDT with good results. Moderate results have been obtaned in Paget disease, lichen sclerosus et atrophicus, localized scleroderma, Hailey-Hailey disease, hidradenitis suppurativa, and actinic disseminated porokeratosis. Partial responses have been achieved in these cutaneous disorders, but not completely cure. No response has been achieved in the treatment of alopecia areata and necrobiosis lipoidica with PDT. We also have applied PDT in dermatosis not yet published in the literature. Good results have been obtanied in primary follicular mucinosis, pitiriasis lichenoides chronica and cutaneous lupus erythematosus. We have applied PDT in vitiligo without any result. Plaque psoriasis is one of the diseases most studied, but our results were bad because of the low tolerability. None of the patient could be treated because of the discomfort during the light exposure. Nevertheless, these results are in direct contrast with the results of PDT in nail psoriasis ( NPs), with both treatments, PDT and PDL, an improvement is observed, without statistically significant differences. This means that topical MAL could not play any role in the improvement of NPs, and this effect is due to the PDL therapeutic effect. To the best of our knowelge, this is the first study that evaluates retrospectively PDT treatment in AK in clinical practise. It is also the first study that has evaluated and demonstrated, the efficacy of fluorescence diagnosis in predicting treatment response. PDT is at present been developed, with multiple studies evaluating its efficacy in new indications. Its potential is huge and exciting, and this work achieve new conclusions about these new indications. Nevertheless, further studies are necessary to determine its role and implement PDT in these new dermatosis.