What is Photodynamic Therapy and what is it used for?
Photodynamic therapy (PDT) is a procedure that uses a photosensitizing drug to selectively apply light therapy to target pre-skin cancerous lesions and treat sun damaged skin. PDT helps to clear the skin of these pre-cancerous growths (actinic keratoses) to prevent progression into skin cancer over time. It is most commonly used on the face and scalp. Photodynamic therapy is also known as phototherapy, photochemotherapy, or photoradiation therapy. The prevalence of the word “photo” in all of the names refers to the involvement of light, that is used to activate the special drugs that target the cancer cells.
Pros and cons of PDT
The American Cancer society cites some of the major advantages of PDT in treating pre-cancerous lesions, including: it can be targeted very precisely, it has no long-term side effects when used properly, and there’s little to no scarring after the site heals.
There are also important limitations to keep in mind, including that PDT can’t be used to treat cancers that have grown deeply into the skin or spread to other organs and it can’t be used to treat individuals who have specific blood diseases or certain types of allergies. More information on PDT from the American Cancer Society can be found here.
What to expect during and after the procedure.
The skin will be cleansed thoroughly and your provider will use a special astringent immediately before application of the medication to increase penetration. The aminolevulinic acid, a clear liquid, will be applied to the entire surface of the skin that is to be treated. This will incubate, or be absorbed, for approximately 2 hours. At this point, you will be able to leave our office and return at the designated time. Be aware that you will have to wear a large hat, provided to you, to prevent any sun exposure to the treatment area.
Upon return to our office, you will be seated under a blue light device for approximately 15 minutes. This light activates the previously applied medication and selectively destroys the sun damaged skin cells. While sitting under the light you may feel some burning discomfort which is lessened by using a fan. After the treatment the skin involved will be extremely light sensitive for 48 hours until the medication is completely metabolized. Hats, scarves, a broad spectrum sun screen, and light avoidance are required to protect the skin during that time. Most of the time, some redness and mild peeling occur over the first two to three days. Occasionally, there can be a burning discomfort for 24 hours and a more prolonged peeling and redness for 5 to 14 days can occur. We typically have you return to the office 6 weeks after treatment to re-evaulate the treated area.