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KM Surgical & Dermatology Associates

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PDT (photo-dynamic therapy)

Photo-chemo-surgery is an effective treatment for some non-melanoma skin cancers as well as certain types of pre-cancerous lesions. These are known medically as actinic keratoses (or solar keratoses), superficial or nodular basal cell carcinomas and squamous cell carcinoma in situ.

How does it work?

It is simple, non-invasive treatment that consists of the application of a Metvix® cream to the lesion(s) followed by its exposure to light from the specially designed lamp.  The cells in the lesion absorb the active ingredient from the Metvix® cream.  When exposed to the red light from the lamp, a chemical reaction occurs which destroys the lesion, minimising side effects and potential for scarring.

Treatment of skin lesions using Metvix® consists of the following steps.  You may have more than one lesion treated at one time.

1.  Lesion preparation

Before the Metvix® cream is applied, the lesion(s) will be prepared by removing scales and crusts and roughening the skin surface.  This preparation helps the cream be absorbed by the abnormal cells that cause the lesions.

2.  Application of Metvix® cream

Metvix® cream will be applied to the lesion and around the surrounding area.  The area will then be covered with a dressing, which must remain in place for 3 hours.  You must not remove this dressing.  During this time you are free to leave the surgery, however you should ensure that the lesion is not exposed to very cold air or direct sunlight.

3.  Exposure to the lamp

After 3 hours, the dressing will be removed, the treated area cleansed with normal saline, and then immediately exposed to light from the lamp for a short period - approximately 10 minutes.  This process is called illumination.  Due to the selective nature of Metvix® cream, healthy skin surrounding the lesion does not need to be protected during illumination.  As a safety precaution, you will be given goggles to wear during the illumination to protect your eyes from the intense light.  The number of treatments you will need depends on the type of lesion you have.  You will be asked to return for a further check-up after 3 months.

Is it painful?

Not everyone experiences pain, however you may experience a stinging or burning sensation during the illumination.  If the treatment becomes too uncomfortable, we can pause the light for a short while to relieve your discomfort.  Metvix® cream selectively targets abnormal cells.  This level of accuracy means that while the lesion is destroyed, the potential for scarring and disfigurement often associated with other treatments is significantly minimised with Metvix® PDT.

What should I expect after treatment?

After your treatment, you are advised to keep the treated area clean.  It is also recommended that you protect the treated skin from direct sunlight for a couple of days.  Local discomfort around the lesion site immediately after the treatment is the most common side effect with Metvix® PDT.  Mild to moderate redness, swelling and inflammation are normal after-treatment responses, which usually resolve rapidly.

This page was last updated at 3:08PM on October 8, 2019.