PHOTODYNAMIC THERAPY
Photodynamic Therapy (PDT) is a relatively new method of treatment for pre-cancerous and cancerous diseases. It has been used in experimental studies for the last decade and recently has been approved by the FDA for treatment of early and advanced lung cancer and also for advanced esophageal cancer. We are currently using PDT to treat patients with Barrett’s esophagus and pre-cancerous dysplasia as well as early cancer patients that are not amenable to mucosal resection or HALO ablation.
What is PDT and how does it work?
PDT involves the intravenous injection of a light-sensitive drug (Photofrin® or Levulan®). The drug is distributed to all tissues including lungs, brain, skin, esophagus, etc. In PDT with Photofrin, 48 to 72 hours after the drug has been injected, the physician performs an endoscopy and treats the diseased area of the esophagus using a high intensity, powerful red laser light. In contrast, Levulan (Levulan-PDT, a.k.a. ALA-PDT) is given orally and endoscopic laser treatment is carried out within four to six hours. The laser light is delivered through the endoscope using special equipment including sausage-shaped balloons and linear diffuser probes so that the physician can target the exact area of the diseased esophagus for treatment.
The light stimulates the drug, which has been absorbed into the lining of the esophagus, to produce a chemical that destroys the cells. An endoscopy is performed again 48 hours after the first light exposure to observe the effect of the initial treatment. If there are any areas that do not fully respond to the treatment, re-treatment of the area may be needed.
The effect of the treatment is profound. Commonly, there will be destruction of the lining of the treated area of the esophagus. Associated with this will be symptoms, including chest pain which most patients describe as moderate. Some patients become nauseated and experience loss of appetite. Indeed, patients do not eat well because of the marked inflammation in their esophagus. Medication for pain and nausea are prescribed on an as-needed basis.
The treatment is performed on an outpatient basis at the Thompson Cancer Survival Center, which is the leading cancer center of excellence for photodynamic therapy. The home health care team will visit the patient at the Fellowship Center and provide intravenous fluids if needed for a day after the treatment in order to help maintain hydration. Typically, patients begin to resume liquids and soft foods such as puddings and mashed potatoes in two to three days, but occasionally a longer recovery time is necessary. After patients are able to drink adequately and achieve enough oral intake to maintain nutrition, they are ready to return home. Usually this is three to five days after treatment with Photofrin®-PDT and two days after Levulan-PDT®. The time will vary from patient to patient.
Photosensitivity
Photosensitivity is an issue that all patients must address. Photofrin® remains in the skin for about one month. The drug is light-sensitive and is in all tissues, including the skin. The patient must be covered up when exposed to direct sunlight during the first month after injection of Photofrin®. Covering should be complete and involve a hat, ski mask, long sleeves, gloves, long pants, dark glasses to protect eyes, etc. We recommend that our patients begin very brief exposures to direct sunlight immediately after receiving Photofrin® as this will "bleach" the drug from the skin. Indirect sunlight or room light is fine and should not cause any problems. Lights can be on and windows can be open and not shaded. Do not expose skin to direct sunlight except as mentioned below. Also, avoid sitting in reflected sunlight (such as a mirror or car window) or close to a fire.
Days One to Two (day of Photofrin® injection)
For brief exposure to sunlight, it’s recommended the patient wear shorts and a T-shirt and walk quickly through an area of direct sunlight, for example that beaming in through a window or even a quick two to three seconds in direct sunlight, three to four times a day.
Days Three to Four
If there is no sunburn in two days, walk through the sunlight at a slower pace. The patient should again do this three to four times a day.
Days Five to Seven
If there is no sunburn, we suggest increasing the exposures into direct sunlight outside lasting no more than 10-15 seconds, three to four times per day.
Day Six to Seven
Exposures can be increased to 30 seconds several times a day, gradually increasing the time interval but not to exceed one minute during the first week.
The time intervals can be gradually increased during the second week at home, providing sunburn does not occur. At one month we recommend the patient expose one hand to direct sunlight for 10-15 minutes and if there is no sunburn, the next day the other hand for a longer period up to 20-25 minutes. If the patient has followed these instructions and there is no sunburn, the patient can enter the sunlight without being covered up for periods beginning with 15 minutes and then increasing. It is important to understand that areas unexposed to sunlight (for example, legs) may become hypersensitive to sunburn even two to three months after the drug injection. All areas of skin must be gradually re-exposed to sunlight. To ignore this advice and go directly into sunlight is to invite severe sunburn, even to a point of blistering. Several patients ignore this advice and get into a car and drive home into the western sun. Unfortunately, the patient calls the next morning to say they have extreme swelling of the exposed skin, such as hands and face.
For Levulan®-PDT, light sensitivity is much less of an issue, since the drug remains in the body for only approximately 48 hours. It is best to remain in a room with reduced lighting during the first 48 hours. For those who must go outside into sunlight, covering the entire skin as described before is essential. The light sensitivity should be gone in 48 hours.
Possible complications
In more than 350 patients treated with Photofrin®-PDT, we have had to hospitalize fewer than a dozen. The treatment for the others has been completely outpatient. We have had no deaths, stroke or heart attack in our first 350 patients. The major complication seen following Photofrin®-PDT is esophageal stricture, which occurs in 15-20 percent of patients.
The intense inflammation in the esophagus created by PDT heals in some patients as a scar which can narrow and restrict the esophagus, producing difficulty in swallowing. If this occurs, your gastroenterologist will dilate your esophagus using rubber tubes or balloons to stretch the scar. Typically, two to four dilations are required, but occasionally patients with severe stricture require a large number of repeated procedures. In that case, we may ask the patient to return to GIA to perform the dilations. All patients who have had dilation are swallowing essentially normally.
Esophageal strictures are not a problem with Levulan®-PDT, as the treatment does not produce tissue injury as deep as Photofrin®. Many patients, however, will experience rather intense nausea for six to 12 hours after administration of the drug. Also, hypotension (low blood pressure) occurs after ingestion of Levulan®, sometimes requiring treatment with intravenous medications to correct the hypotension.
If you come visit GIA for photodynamic therapy, we will assist you in arranging living quarters at the Fellowship Center. This center is the result of an outstanding effort by local benefactors to provide pleasant efficiency apartments for patients visiting Knoxville for treatment. The apartments are large enough for the patient and a caregiver or two. Additional information regarding the Fellowship Center is available upon request. Please call (865) 521-6729 to make reservations.
As you will soon find out, you will become part of our team of excellence during your stay. We take pride in you and hope you take pride in us.
If you have any questions regarding PDT, will will be glad to answer them. Please contact us at (865) 588-5121 or e-mail our Clinical Coordinator Karen Abbott, L.P.N., at kabbottlpn@aol.com. You may also visit our Web site at giahealthcare.com for additional information.
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