Dynamic phototherapy

Dynamic phototherapy is a new technique in France associating active substance and luminous irradiation of the skin. Dynamic phototherapy enables us to treat some precancereous lesions and also some superficial cancers.

Historically, at the beginning of the 20th century, Oscar Raab is the one who discovered the action of some colorants such as acrinidin orange upon paramecium culture exposed to the sun.

Oscar Raab’s master, Professor Hermann Von Tappeiner, finds out the same effects with methylen blue and soudan 3 (Magdala red). He realises that in order to obtain a cytotoxic effect of cell destruction, such a substance associated with light is required.

Free oxygen is also necessary. The vocabulary ‘photodynamic effect’ and its thereapeutical use ‘dynamic phototherapy’ emerge in 1904 in Germany.

That same year, Albert Jesionek, a dermatologist from Munich, performs the first therapeutical tests in order to treat skin cancers.

About a hundred years were necessary for the technique to be proven valid and for dynamic therapy to be used on a day to day basis.

Dynamic phototherapy (DPT) does not engender skin cancers. Its action upon precancereous or cancereous cells does never enter the nuclear membrane. Many studies have demonstrated the absence of mutagenicity.

The 5-ala or acid-5-delta-aminolevulinic, but also the methyl-5-ala or Metvix are the photosensitiser agents used in dermatology. They are comercialised in several european countries by the Galderma laboratory.

The source of light chosen depends on the target to reach. We usually use a red orangish light with an absorption pic to 630 nm which allows a 3mm penetration into the skin.

A luminous source with homogeneous intensity is required on the entire area treated.

Indications

Scientific studies carried out in many countries show a good indication for actinic keratosis, which are precancereous lesions occurring essentially on white skins, but also superficial basla cell carcinoma, difficult to treat on the surgical level.

Side effects

The patient may feel a painful burning sensation, in particular when forehead and scalp are being treated.

2 or 3 days following the treatment, oedema, healing scabs, vesicules and itching sensation may emerge.

It is advised to avoid sun exposure the week following the treatment.

Treatment Procedure

A prior consultation is scheduled in order to inform the patient about the technique. Before the treatment is being performed, the skin must be prepared in order to reduce visible scabs: the dermatologist scratches the largest lesions. Then, the photosensitive preparation containing the 5-ala or the methyl-5-ala is being applicated and an occlusive dressing is being applied. The patient comes back for a check up 3 to 4 hours following the first cream application.

The cutaneous area is illuminated with a specific red orangeish light for about 15 to 20 minutes. (Waldmann Lamp PDT 1200). A red mark comparable to sunburn appears and remains between 24 and 48 hours. Usually, there is a control check up within the month following the session.

One or two treatments may be necessary in function of the degree of the actinic phenomenon linked to the sun.

Dynamic phototherapy gives birth to a new approach for the treatment of pre-cancereous and superficial cancereous lesions. It is no longer one lesion at a time which is treated but an entire area.

This medical treatment obtains a very good cosmetic result without leaving any scars.

However, it is recommended to perform check ups after treatment in order to detect other lesions which could emerge on other areas of the body.