Dusa® - Innovation in Photodynamic Therapy for Actinic Keratoses
What are actinic keratoses?
Actinic keratoses (AKs) are rough, scaly patches on the skin, caused by excessive exposure to the sun. They can sometimes progress into dangerous skin cancers. More than 5 million Americans live with these lesions, and far too many people ignore them, leaving them untreated. This can have serious consequences. Doctors estimate that 40% of squamous cell carcinomas, the second leading cause of skin cancer deaths in the United States, begin as AKs. And without performing a skin biopsy, it can be almost impossible for a doctor to distinguish an AK from a squamous cell carcinoma.
For this reason, 3 major medical groups – the American Cancer Society, The Skin Cancer Foundation, and the American Academy of Dermatology – all recommend that people with AKs seek treatment for them immediately.
How do AKs become squamous cell carcinomas?
AKs sometimes can become larger and thicker. Doctors call this "hyperkeratotic." These enlarged lesions may then progress to squamous cell carcinomas. Patients may notice increased redness, tenderness, itching, and burning. However, these symptoms can be the same for either AKs or squamous cell carcinomas. This is what makes distinguishing between the two so difficult without a biopsy.
Left untreated, squamous cell carcinomas may become larger, go deeper into the skin, and eventually spread to other parts of the body. This results in thousands of skin cancer deaths each year, many of which could be prevented by prompt diagnosis and skin care treatments.
How likely are AKs to become squamous cell carcinomas?
It is impossible to predict if an AK will evolve into a squamous cell carcinoma, or at which point it will happen. Many doctors believe that AKs and squamous cell carcinomas are really the same condition at different stages of a continuing process. This process begins with minor cell damage and, over time, ultimately results in the cell become cancerous. These doctors believe that AKs occur in the early stages of the process, and that squamous cell carcinomas occur in the final stage.
One thing, however, is certain: a significant percentage of AKs develop into squamous cell carcinomas. Estimates range from 10% to as high as 20% over a 10-year period.
Is there anything I can do to prevent AKs in the future?
Long-term exposure to the sun is the single most significant cause of AKs, so the best defense against them is a comprehensive sun protection program. This includes wearing protective clothing and a wide-brimmed hat, avoiding the sun at midday when ultraviolet rays are strongest, staying in the shade as much as possible, and wearing a broad-spectrum sunscreen with a sun protection factor (SPF) of at least 15.
The Levulan® PDT System
How does the Levulan PDT system work?
Step 1
The first step in the Levulan PDT system is when your dermatologist applies Levulan Kerastick® (aminolevulinic acid HCL) for Topical Solution, 20% to individual AKs on your skin. This unique solution is an acid that occurs naturally in your body; it makes the AKs more sensitive to light. This application prepares them for step 2 in the Levulan treatment.
Step 2
After 1 hour, the Levulanic Acid will be washed off. The esthetician then exposes the AKs treated in step 1 to a special blue light. This light destroys these AKs, whether they are precancerous or not.
Are there any precautions I should take after the treatment?
Because step 1 makes the treated areas more sensitive to light, it is important that you avoid bright light during the 24 to 36 hours immediately following one of these skin care treatments. Sunscreens alone will not protect these treated areas. Stay out of sunlight or bright indoor light, wear light-shielding clothing such as a wide-brimmed hat, and use a sunblock with an SPF of 30 or higher, with titanium or zinc.
What will I experience during treatment?
During step 2 (the blue light therapy), at least half of the patients in the clinical studies felt a stinging and/or burning in the treated areas. Usually, this improved immediately after treatment and ended within 24 hours. (Less than 3% of patients discontinued therapy because of this discomfort.)
After treatment, a small number of patients experienced some temporary reddening and swelling of the AKs and surrounding skin, which generally was completely gone by 4 weeks after treatment.
