Therapeutic Revolution in Dermatology
What are PDT's indications and advantages?
Professor Lasse Braathen: Today, PDT is the treatment of choice fornon-melanoma skin cancers. Euro-PDT's recommendations specify that topicalPDT could be one of the treatments of choice for actinic keratoses, Bowen'sdisease, and superficial and even nodular baso-cellular skin cancers, whichare the most common skin cancers and are caused by exposure to the sun (1).
PDT avoids recourse to surgery and its scarring after effects. Hence itsadvantages are obvious: this treatment allows recovery in five years in morethan 80% of cases with no visible scar; this is an essential advantage incosmetic terms for lesions in open areas of the skin, especially those on theface and neckline. This represents undeniable therapeutic progress that isalso very simple to apply. This treatment is also very specific in that itdestroys only cancerous cells. It also makes it possible to treat large areasof skin in a single session with excellent tolerance and perfect cosmeticresults, which is especially appreciated by patients.
Can several PDT sessions be applied if lesions recur?
Professor Lasse Braathen: Yes, because phototherapy involves no ionizingtoxicity. When lesions reappear, the patient can again be offered treatmentby PDT, and the treatment can be repeated as many times as necessary. In rarecases of failure, all therapeutic options are available because of theabsence of local or general toxicity from PDT, with no loss of the patient'schances. When skin lesions are extensive, treatment by PDT makes it possibleto pinpoint the "PDT-resistant" lesions that require some other therapeuticapproach.
Are there other possible uses of PDT?
Professor Lasse Braathen: Yes, but they have not been validated by theAMM; some skin lymphomas can benefit from it, with remarkable effectiveness.PDT can also be used preventively in transplant patients, in whom skin cancerappears in 15% of cases after the transplant.
Cosmetic use of PDT is also practiced outside AMM for its "rejuvenating"effect. Patients presenting an actinic keratosis also benefit from thispositive secondary effect of PDT.
The relatively recent concept of "field cancerization" could become anindication for PDT. A field cancerization around actinic keratosis lesionsforms an area with pre-neoplastic anomalies and infra-clinical and multifocalgenetic mutations that can evolve into primitive new tumours and localrecurrences. It seems logical to treat all of this area preventively ratherthan to treat an isolated lesion. Applying Metvix makes it possible to moreeasily see the non-visible lesions, which glow under black light. This methodis very much appreciated by patients, who can use it to see their skin riskand easily understand the need for treatment.
With regard to the development of PDT, what are Euro PDT's mainactivities?
Professor Lasse Braathen: The European Society for Photodynamic Therapy(Euro PDT) is a clearinghouse for practitioners and researchers; itsobjective is to promote research, development and clinical applications forphotodynamic therapy in Europe. Every year for the past 10 years, Euro PDThas held an international conference to inform specialists about the resultsof international research on the use of PDT in dermatology. Euro PDT alsoparticipates in most international and national dermatology conferences. EuroPDT holds regular training sessions in order to teach practitioners how toproperly use photodynamic therapy. This instruction with certification takesan entire day. In particular, we stress optimal management of the painassociated with the treatment, which the patient must be informed of. Thistraining has led to the creation of excellent PDT research and treatmentcenters, for example at Saint Louis Hospital in Paris.
With photodynamic therapy being used worldwide, in 2007 Euro PDTpublished international recommendations in order to define its instructionsand standardize its clinical application in treating non-melanoma skincancers (1). Finally, Euro PDT creates many partnerships with universityresearch labs, the pharmaceutical industry and clinical research teams.
(1) Braathen L, Szeimies RM, Basset-Seguin N, et coll.: Guidelines on theuse of photodynamic therapy for nonmelanoma skin cancer: An internationalconsensus. J AM Acad Dermatol 2007; 125-143.
10th Congress of the European Society for Photodynamic Therapy (Euro PDT)(Nice): March 12 -13, 2010
SOURCE European Society for Photodynamic Therapy (Euro PDT)
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