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Photodynamic therapy is a new specialized treatment for patients with certain types of cancer. The treatment kills cancer cells by combining a light sensitive (photo-active) drug with light from a laser. The treatment enables your doctor to target and destroy cancer cells, while limiting damage to surrounding healthy tissues.
To begin the treatment, patients are given an injection of a photo-active drug called Photofrin. The generic name of this drug is porfimer sodium. Photofrin is absorbed by all of the tissues in your body, including the cancerous tissues. Over the next 24-48 hours, the healthy tissues will eliminate much of the drug, but the drug will remain concentrated in the cancerous tissues.
The drug is inactive at this point. Approximately 40 to 50 hours after Photofrin injection, your doctor will activate the drug in the area of your tumor by directing light from a laser directly on the cancer cells. The application of light takes between 5 and 40 minutes depending on the size of the tumor. For most patients, the entire treatment takes less than one hour.
Although Photofrin is retained in cancer cells to a greater degree than normal healthy tissues, your skin will be light sensitive for approximately one month after the treatment, and you must take precautions to cover your skin and prevent exposure to direct sunlight.
Neither the drug nor the laser light will destroy cancer cells alone. They must be used in combination.
The type of laser used for this treatment is different from the laser light used for cutting in surgery. Photodynamic therapy uses nonthermal, low-powered light, which means it does not burn. However, your skin will remain sensitive to light for about 30 days after treatment and during that period you are susceptible to sunburn, redness, and swelling if you do not cover your skin and avoid direct exposure to sunlight.
The doctor will direct the laser light to its target through a fiber optic. Fiber optics are thin, flexible, transparent strands, that are specially designed to conduct laser light.
In treating esophageal cancer, the fiber optic strand is passed down the throat through an endoscope (a thin tube that is placed in your throat). If the treatment is for lung cancer, the fiber optic is passed through a bronchoscope.
You should experience little or no discomfort during the procedure, as it is performed under sedation along with local or general anesthesia.
The two major side effects are local swelling and inflammation around the treated area, which may cause some physical discomfort in the chest, abdomen, or back, and possibly breathing difficulties depending on the location of your tumor. The second common side effect is photosensitivity.
From the moment you receive the Photofrin injection, and for approximately 30 days thereafter, your skin and eyes will be very sensitive to bright light. Exposure to bright lights or direct sunlight therefore should be avoided to prevent sunburn, redness, and swelling. It only takes several minutes of exposure to notice a reaction. Therefore it is extremely important to shield your eyes and skin at all times.
For patients undergoing treatment for esophageal cancer, other fairly common side effects include nausea, vomiting, fever, constipation, difficulty swallowing and sleeping, injection, and shortness of breath. For lung cancer, patients may experience fever, bronchitis, and shortness of breath. It is important to speak with your doctor before treatment about what to expect.
Although your skin and eyes will be sensitive to light for about a month after the treatment, it is not necessary to live in a darkened room. In fact, it is important to get some indoor light, because low levels of light will help the drug to break down in your skin and make you less photosensitive.
Room light is generally well tolerated as long as you avoid direct sunlight from a skylight or an undraped sunny window. Most indoor activities are safe, including watching television. It also is perfectly fine to go to a movie theater or live concert or play. When reading, however, do not expose your skin to close light from a reading lamp.
If you can avoid going out during the day, try to do outside chores and shopping after sundown. If you must go outside during daylight hours, it is extremely important to cover your skin by wearing long-sleeved garments, gloves, socks, shoes, a wide-brimmed hat, and dark sun glasses (less than 4% white light transmittance). Wear tightly woven, light colored fabrics. Since visible light travels through clouds, these precautions also apply to overcast days.
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. A sunscreen will not protect against photosensitivity because sunscreens filter out ultraviolet (UV), which is invisible, and Photofrin is activated only by visible light.
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Division of Thoracic Surgery
Brigham and Women's Hospital
75 Francis Street
Boston, MA 02115