Photo Dynamic Therapy – PDT
Photo Dynamic Therapy (PDT) is a simple non-invasive procedure used to treat Actinic Keratosis (AK) & superficial Basal Cell Carcinomas (sBCC). It involves the application of a photosensitizing solution Metvix (16% methyl aminolevulinate) to the lesions as prescribed by Dr. Kirsten. The photosensitizing solution is activated by illumination from an Aktilite light source (red light, a wavelength of 630 nm). Metvix solution is related to naturally occurring substances found in the body. The depth of light penetration into the skin is dependent on the wavelength of the light itself, the longer the wavelength the greater the depth of penetration. To treat sBCC’s that occur deeper in the skin Metvix is required as it is activated with the longer wavelength.
How does it work?
Metvix can be applied to either Ak ’s or sBCC’s. The solution is preferentially absorbed by the tumor cells where it accumulates and sensitizes them to red light (by increasing the number of photoactive porphyrins in the cells). Once the red light is activated the lesions are destroyed by a phototoxic reaction while leaving healthy tissue surrounding the tumor cells relatively undamaged. This PDT therapy is approved by Health Canada for the treatment of sBCC’s. It is non-invasive and minimizes the risk of scarring that would occur if the sBCC was to be removed surgically or by cryotherapy.
What to expect during treatment?
Treatment begins with a light microdermabrasion to aid the skin in the absorption of the Metvix.
The Metvix solution stays on the skin for 1.5 to 3 hours to incubate depending on the area(s) treated and the severity of the lesions. After incubation, the area(s) are exposed to Aktilite CL 128 red light for 7-10 minutes. BBL (Broad Band Light) treatment may be used next to help activate theMetvix and treat pigmentation and vascular irregularities before being exposed to red light for 10-16 minutes.
How much downtime?
Redness and peeling of AK and sBCC sites should resolve after 1-2 weeks. The skin needs to be protected from sun exposure for 48 hours after treatment.
Skin will be sensitive to sun exposure for up to 6 weeks.
What areas can be treated?
Face, ears, scalp, neck, chest, back, arms, hands, and legs.
How many treatments are required?
Metvix PDT: 2 treatments are required 7 days apart. After 3 months the lesions need to be re-evaluated and possibly the second session of 2 treatments may be necessary.
Maintenance treatments will depend on the recurrence of AK and sBCC lesions. A yearly check-up of the affected area is advised.
Cost of the Metvix cream is usually covered by extended health care.