Photodynamic Therapy (PDT)
Over the last few years, there have been great strides made in the use of a novel approach to cancer treatment called photodynamic therapy, available at the Jefferson Digestive Disease Institute.
PDT utilizes the administration of a light-sensitive drug, which is then exposed to a visible light beam, to destroy cancerous cells. This treatment is FDA approved for palliation of esophageal cancer and for other esophageal cancers which fail to respond to standard treatment. It is also approved for obstructing bronchogenic carcinoma.
What Does Photodynamic Therapy Involve?
The treatment involves administering a nontoxic photosensitizing drug intravenously, which then is selectively retained by precancerous and cancerous cells rather than normal cells. Under conscious sedation, the lesion is exposed to red light at 630 nanometers, which then triggers a chemical reaction releasing singlet oxygen and other chemical mediators; dysplastic and neoplastic tissue are then destroyed.
Other than the above two FDA-approved indications, it is now being utilized for high-grade dysplasia in Barrett's esophagus, early esophageal cancer, Barrett's esophagus without dysplasia (in hopes of reversing this precancerous area), nonsmall cell carcinoma of the lung, intra-peritoneal malignancies, mesothelioma, malignant pleural effusions, colon/rectal cancer and other head and neck lesions.
Jefferson is at the forefront of cancer research and treatment, and we are pleased to offer this therapy as an option to more invasive treatments.
Treating Precancerous Changes in the Skin
PDT, combined with a photosensitizing agent called ALA (aminolevulinic acid), can treat precancerous changes of the skin. Offered at the Jefferson Laser Surgery and Cosmetic Dermatology Center, the ALA medication is applied to the skin for at least an hour in the office, followed by exposure light for 15 to 20 minutes. Once the ALA on the skin is exposed to the light, this photosensitive drug starts to react by attacking the diseased precancerous cells.
The reaction of the light and sensitized skin leads to a sunburn-like effect that exfoliates the superficial damaged layers of the skin. The process takes about five to seven days to heal, and the usual end result is mild to moderate rejuvenation of the skin and improvement or resolution of the precancerous growths. This process is FDA approved for treatment of precancerous growths when the sensitizer is preapplied for 14 to 18 hours, however, we have found that more practical shorter incubation are just as effective. The cosmetic indication of photodynamic therapy, or any other indication including treatment of skin cancer, is considered an "off-label use" of this technique.
A nurse or medical assistant will apply the medicine. After 1 hour, you will be treated with the light or laser. You will be given special goggles to wear to protect your eyes. You may feel stinging, tingling, prickling or burning of the lesions, but this should go away after the treatment.
After Photodynamic Therapy Treatment of the Skin
After treatment, you should stay out of the sun or bright light as much as possible. Wear sunglasses and protective clothing when going outside.
The skin will turn red and swollen in the following three to seven days. Some crusting may be noted. There may be some discomfort but no significant pain. After one week, there might be some residual redness that will subside after a few days and can be covered with makeup.