PHOTODYNAMIC THERAPY

Photodynamic therapy (PDT) is a medical treatment that utilizes a photosensitizing molecule (frequently a drug that becomes activated by light exposure) and a light source to activate the administered drug. Precancerous leisons called actinic keratoses and certain other types of cancer cells can be eliminated this way. Acne can also be treated as well. The procedure is easily performed in a physician’s office or outpatient setting. PDT is also referred to as blue light therapy.

Photodynamic therapy (PDT) is a medical treatment that utilizes a photosensitizing molecule (frequently a drug that becomes activated by light exposure) and a light source to activate the administered drug. Precancerous leisons called actinic keratoses and certain other types of cancer cells can be eliminated this way. Acne can also be treated as well. The procedure is easily performed in a physician’s office or outpatient setting. PDT is also referred to as blue light therapy.

PDT essentially has three steps. First, a light-sensitizing liquid or cream (photosensitizer) is applied to the area to be treated. Second, there is an incubation period of minutes to days. Finally, the target tissue is then exposed to a specific wavelength of light that then activates the photosensitizing medication.

In dermatology, PDT with the photosensitizer Levulan Kerastick (20% delta-aminolevulinic acid HCl) is used for the treatment of precancerous lesions called actinic keratoses (AK).

PDT works by direct injury to the target cells and tissues. This involves the production of an activated oxygen molecule that can injure or destroy nearby cells. Because the normal skin barrier is not present at the sites of the actinic keratoses, photosensitizing molecule is preferentially absorbed there and then activated by light. The activated oxygen destroys the adjacent abnormal tissue. Once the areas have healed following PDT, the areas are reexamined to see if additional treatments are needed.

With traditional cryosurgery (freezing with liquid nitrogen), only the visible actinic keratoses can be treated. Since many actinic keratoses are often not evident, PDT might be preferable since it presumably would destroy these “subclinical” lesions. PDT allows for treatment of an entire area of sun damage simultaneously, but subsequent treatments may be necessary.

No, PDT causes a temporary sensitivity to light, including natural sunlight and some indoor lights. The light sensitivity resolves with time, depending on both the photosensitizer drug and dosage used.

Light avoidance is generally required after PDT. The duration depends on the drug and dosage used.. Proper protection, including long sleeves and sunglasses, may be required. Topically applied aminolevulinic acid or methyl aminolevulinate may cause skin sensitivity only on the treatment areas for approximately 24-72 hours. These do not usually cause sensitivity on other body parts other than where the drug was directly applied. Your physician will need to discuss with you the required sun- and light-avoidance period required after your particular treatment.

The BLU-U treatment is covered by most insurances but a prior authorization will be done to determine if the patient has any out of pocket cost.