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Photodynamic therapy, a new treatment now being used in patients with certain types of cancer, uses a combination of a photoactive drug ( a drug that is activated by light), and light from a laser. Both work to allow the doctor to specifically target and destroy cancer cells while limiting damage to surrounding health tissue.
First, you will be given an injection of the photoactive drug Photofrin (porfimer sodium). Photofrin will be absorbed by your body's tissues, including cancer tissue. Over the next couple of days, the drug will largely be eliminated from most healthy tissue, but will remain in cancer cells. (It also will remain for a while longer in skin).
Approximately 40 to 50 hours after the Photofrin injection, light from a laser will be directed at the cancer cells. The application of light takes approximately 5 to 40 minutes depending on the amount of tumor your doctor wants to treat. For many patients the entire procedure takes under one hour. The light will activate the drug present within those cells and destroy them.
Because Photofrin is retained to a greater degree by cancer cells than by healthy cells, most of the healthy tissue surrounding the tumor will not be affected.
Neither the drug nor the laser light alone can destroy the cancer cells - they must be used in combination. That's because the drug must be activated by the laser light before it can destroy the cancer cells.
Low-powered light from a laser is used, which is not the kind that is used for cutting in surgery. The light used in photodynamic therapy is nonthermal, meaning it does not burn.
The doctor will direct the laser light to its target through a fiber optic. Fiber optics are thin, flexible, transparent strands, something like fishing lines, that are specially designed to conduct laser light.
In treating esophageal cancer the fiber optic is passed down the throat through and endoscope (a thin tube that is placed down your throat). If the treatment is for lung cancer the fiber optic is passed through a bronchoscope.
With this procedure, a sedative is given along with local or general anesthesia, so you should feel little or no discomfort during the procedure.
There are two major side effects associated with photodynamic therapy: Local swelling and inflammation occurring in and around the treated area may cause physical discomfort including pain in the chest, back, or abdomen and breathing difficulties. Photosensitivity will surely occur, due to the continued presence of the drug in the skin.
This means that from the moment you receive your Photofrin injection--and for approximately 30 days thereafter--your skin and eyes will be very sensitive to bright light. Exposure to bright light or direct sunlight should therefore be avoided to prevent sunburn, redness and swelling. Photosensitivity reactions can occur in minutes, so it is important to take precautions to shield your skin and eyes from exposure.
Other fairly common side effects include the following if your esophagus is being treated: nausea, vomiting, fever, constipation, difficulty swallowing and sleeping, infection, and shortness of breath. They include the following if your lung is being treated: fever, bronchitis, and shortness of breath. Talk with your doctor about what you can expect.
You must be careful during the first 30 days after your injection to avoid bright lights and direct sunlight. You don't have to limit yourself to dark rooms, however, either in the hospital or once you are back home. In fact, its important to get some indoor light, because low levels of light will help break down the drug in your skin and make you less photosensitive.
The lighting in your home should not be a problem, but do stay away from direct sunlight from skylights or undraped windows. Most indoor activities, including watching television, are fine. You can also go to the movies or live theater. When reading, do not expose your skin to the light from reading lamp--keep your skin covered.
If at all possible, wait until sundown to do daily chores like shopping. If you go out during daylight hours, you must cover as much skin as possible. That means wearing a long-sleeved shirt, slacks, gloves, socks, shoes and a wide-brimmed hat. Wear tightly woven, light-colored fabrics, if possible. You should also protect your eyes by wearing dark sunglasses (less than 4% white light transmittance). It is important for you to wear protective clothing and sunglasses even on cloudy days and while in a care.
For at least 30 days after the injection, stay away from bright examination lights such as those found in a dentist's office, and "helmet" type hair dryers like those found in beauty salons, as they can cause skin burns. Hand-held hair dryers at low settings are a safer option.
No. Sunscreens will not protect against photosensitivity, no matter how high the SPF, because sunscreens protect against ultraviolet (UV) light. Photoactivation is caused by visible light, not UV light, which is invisible.
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©2007, Division of Thoracic Surgery at Brigham and Women's Hospital. All rights reserved.
Division of Thoracic Surgery
Brigham and Women's Hospital
75 Francis Street
Boston, MA 02115
Phone: (617) 732-6824