Return to Research+Publications Using Laser Light to Destroy Cancer For many cancer patients, the mere thought of enduring chemotherapy can be the most difficult part of their treatment. Varying degrees of nausea and hair loss are routinely the unpleasant hallmarks of traditional chemotherapy. For patients with esophageal cancer, the discomfort of chemotherapy is sometimes equal to the cancer's mere presence, since the act of simply swallowing becomes difficult or, in some cases, almost impossible.		Dr. Kenneth Chang with PDT laser image of esophageal cancer.
Esophageal cancer is one of the least curable forms of cancer, and in the majority of cases, the goal of therapy is for the patient to swallow again using the least invasive treatment, says Kenneth Chang, M.D., UCI Medical Center's head of Gastrointestinal Oncology. One ray of hope: the U.S. Food and Drug Administration’s clearance of a drug called Photofrin, which may give patients with completely or partially obstructive esophageal cancer an alternative to chemotherapy and the ability to swallow again. Photofrin is a light-sensitive drug that is given to patients intravenously. It travels through the bloodstream and concentrates in diseased cells. Photodynamic therapy (PDT) is then used by Chang and colleague Phuong Nguyen, M.D., to direct a laser light on the affected area, activating the drug and destroying the diseased cells. Although lasers have been used before by physicians to treat cancer, they destroy tissue only at the pinpoint area targeted by the laser beam which Chang likens to a precisely-directed flashlight. In contrast, the PDT laser shines in a cylindrical fashion, more like a lantern than a flashlight, says Chang. Because of this, and because the PDT laser only activates the Photofrin where it concentrates in cancer cells, the laser does not pass beyond a certain depth, thereby minimizing the risk of perforating or destroying adjacent tissue. This selective destruction of cancer cells is a great advantage, says Chang. It means that the patient receiving this light-activated chemotherapy can avoid wholebody side effects such as the nausea or hair loss experienced by most traditional chemotherapy patients. However, one side effect experienced by patients receiving Photofrin is extreme sensitivity to sunlight for approximately one month after the drug is administered. The benefits of PDT are very attractive to patients, says Chang, and with good reason. It's not as invasive as traditional surgery, the treatment confines itself to diseased tissue and the side effects are very manageable and well-tolerated cornpared to chemotherapy. Chang points out that the best use of PDT is with patients who have locally advanced esophageal cancer with partial or complete obstruction of the esophagus and trouble swallowing. And, he says, it is a very viable option for patients who are looking for alternatives to surgery or chemotherapy.

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