Photodynamic therapy, also known as PDT, uses a photosensitizing agent and particular types of light to treat cancer. The photosensitizing agent produces a form oxygen when it is exposed to certain wavelengths of light. The oxygen then kills the nearby cancer cells. The specific photosensitizing agent and wavelength of light determine how deeply the light travels into the body and varies depending on the part of the body being treated.
How Does PDT Work?
PDT is typically an outpatient procedure in our Orange County dermatology office, and may be used in conjunction with other cancer therapies, including radiation, surgery, and chemotherapy. The doctor starts by injecting the photosensitizing agent into your bloodstream. In some instances, a machine may be used to collect the blood cells so they can be treated and exposed to light outside of the body and then returned to the patient.
After about 24 to 72 hours, the agent will have left the normal cells and will only remain in the cancerous cells. Light from a laser or LED is directed at the cancerous area. This causes the photosensitizing agent to produce an active form of oxygen that can destroy the cancer cells. In the case of tumors, the photosensitizing agent may help by destroying blood vessels that feed the tumor. PDT may also activate the body’s natural immune system to attack the cancer.
What Types of Cancer are Treated with Photodynamic Therapy?
The lights used in PDT can only pass through about one centimeter of tissue. This means that the therapy is most effective for tumors on or just below the skin or on the linings of internal organs. PDT is not effective on large tumors since the light cannot penetrate far enough into the mass. PDT is also not typically used for cancers that have metastasized. The U.S. Food and Drug Administration has approved PDT for esophageal and non-small cell lung cancer. Clinical trials are currently underway to expand the use of PDT to other types of cancer, including cancer of the skin, brain, prostate, and cervix.
Are There Risks to PDT?
The photosensitizing agent can make your eyes and skin more sensitive to sunlight. You should avoid bright lights or direct sunlight for approximately six weeks following treatment. PDT is a localized treatment, so damage to nearby healthy tissue is usually minimal; however, there is a slight risk of burns near the treatment area.
OC Skin Institutes offers a variety of treatments for different types of skin cancer. Call us today to arrange a consultation to discuss your options.