Return to Research+Publications Experimental PDT to Prevent Esophageal Cancer This Spring, the Institute became the first site on the West Coast to perform a new laser treatment for an increasingly common malady of the esophagus. Dr. Kenneth Chang of UC Irvine’s Chao Family Clinical Cancer Research Center used an experimental application of photodynamic therapy (PDT) to treat a patient suffering from Barrett's Esophagus. This was the first procedure in a series of clinical trials to be conducted jointly between the Institute and the Cancer Center.		Dr. Kenneth Chang performs photodynamic therapy to treat Barrett's Esophagus.
Affecting approximately 70,000 people in California and between 800,000 and two million nationwide, Barrett's Esophagus is a disease caused by long-standing acid reflux that converts the esophageal lining into stomach-type tissue. When stomach acid splashes up into the esophagus, it causes heartburn. If this condition persists over time, the acid can severely damage or destroy the normal lining of the lower esophagus. Stomach or intestine like cells then grow into the esophagus to replace the acid damaged lining there. These abnormal cells can develop a dysplasia that may be a prelude to cancer. Heartburn and Cancer About 24 percent of all cancer deaths in the United States are due to cancers of the gastrointestinal tract. Barrett's Esophagus is a major cause of these cancers, and the likelihood of Barrett's patients developing esophageal cancer is 30 to 40 times that of the normal population. Between 1976 and 1990, the annual incidence of Barrett's-associated cancer tripled, making it one of the fastest growing cancers in the country. Diagnosis a Challenge Heartburn is the most common symptom of acid reflux. Patients with long-standing heartburn are at risk for Barrett's Esophagus and should consult their physician about possible testing for the condition. Those patients diagnosed with the condition may need to undergo endoscopy on a routine basis. Any suspicious areas can then be examined through biopsy for signs of precancerous dysplasia or cancer itself. "Early diagnosis is key," Dr. Chang notes. "In general, 95% of patients with advanced esophageal cancer die within 5 years. Early diagnosis of potentially precancerous dysplasia can allow us to prevent the cancer from ever starting." Treatment Options Most patients with severe dysplasia must undergo surgery for the removal of part of the esophagus to eliminate the Barrett's mucosa. This surgical procedure, called esophagectomy, is a major cutting operation requiring full anesthetic and long hospitalization. Patients can suffer prolonged pain during recovery. Afterwards, patients will have to make major lifestyle changes and may have to endure continuing medical problems. Esophagectomy also carries a relatively high mortality rate. In contrast, PDT can be considered an office procedure because it requires no cutting and only a local anesthetic. A minimally invasive procedure, PDT is also very cost effective and offers encouraging results to eliminate Barrett's tissue without lingering side effects. PDT to treat Barrett's Esophagus involves the use of the photosensitizing drug Photofrin (manufactured by QLT Phototherapeutics, Inc., in Vancouver, and distributed in the U.S. by Sanofi Winthrop) in combination with an argon dye laser. The drug is administered systemically, but it concentrates mainly in abnormal tissue, in this case, located in the esophagus. When the laser light shines on the photosensitized diseased tissue, the drug produces a chemical reaction that kills only the target cells, leaving healthy tissue relatively unaffected. Although PDT is less invasive than esophagectomy, complications can occur, including stricture formation. PDT patients must also bear with the inconvenience of staying out of the sun for thirty days. So far the results are promising. The patient returned for a follow up treatment a couple weeks after the initial PDT. "Now," Dr. Chang explains, "he is recovering nicely. We expect his condition to return from almost malignant to nearly normal." Institute Clinical Research Director Dr. Yona Tadir, himself a minimally invasive surgery specialist, is enthusiastic about the project. "Esophageal PDT," he feels, "is a promising new application of a laser treatment that we have studied to treat conditions ranging from dysfunctional uterine bleeding to skin cancer. This project could result in great medical benefit."

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