Photodynamic Therapy (cont.)
In this Article
What photosensitizer drugs are available?
FDA-approved photosensitizers
include Photofrin (porfimer sodium), Levulan (5-aminolevulinic acid or ALA), and Metvix (methyl aminolevulinate
[MAOP]). More drugs may become available in the
near future. Photofrin is used intravenously for internal cancers while Levulan
and Metvix are applied topically for skin therapy.
What light sources are
available, and how are they applied?
PDT light sources include laser, intense pulsed light, light-emitting
diodes (LEDs), blue light, red light, and many other visible lights (including
natural sunlight). Photosensitizer drugs may become activated by one or several
types of light. The optimal light depends on the ideal wavelength for the
particular drug used and target tissue.
The light
source needs to be directly applied to the target tissue for a specific amount
of time. For surface skin treatments, the light is easily directly applied to
the area of the skin where the photosensitizer drug has been applied (such as
face, scalp, arms, etc.). For internal cancers, delivering the light to the
desired area is more challenging. The light may be delivered through small
fiber-optic cables into the body cavity or area being treated. Sometimes, endoscopes (a
thin, lighted, elongated tube that is inserted into a body space) are used to
deliver the light into the lungs, stomach, or bladder.
How does PDT work?
PDT
works by direct injury to the target cells and tissues. This involves an
activated oxygen molecule that can injure or destroy nearby cells. By
preferentially attacking the active or abnormal cells, PDT combines a very high
success rate with good preservation of normal skin without significant risks for
scarring. Once the areas have healed following PDT, the areas are reexamined
to see if additional treatments or biopsies are needed.
PDT is a targeted treatment aimed at more rapidly dividing cells and atypical
skin growths. With regular or traditional cryosurgery (freezing with liquid
nitrogen) or burning, only the visible pre-skin cancers can be treated,
potentially leaving behind cancers that are hidden. PDT allows for treatment of
an entire area of sun damage, thereby reducing the chance that undetected pre-skin cancer cells will be left untreated.
Next: Does PDT make me permanently more sensitive to light? »
- imiquimod-topical, Aldara - Consumer information about the medication IMIQUIMOD - TOPICAL (Aldara), includes side effects, drug interactions, recommended dosages, and storage information. Read more about the prescription drug IMIQUIMOD - TOPICAL.
- Lung Cancer - Get the facts on lung cancer treatment, diagnosis, staging, causes (smoking), types (adenocarcinoma, squamous cell), prevention, symptoms, warning signs and survival rates.
- fluorouracil topical, Carac, Efudex, Fluoroplex -
Latest Medical News
Cancer RSS