CHICAGO, Aug. 9 -- Surgeons at Rush-Presbyterian-St. Luke's Medical Center are treating patients unable to breath or swallow as a result of cancerous tumors in their esophagi or lungs with a laser treatment that enables them to regain these functions. William Warren, a cardiovascular-thoracic surgeon, uses a laser technique called photodynamic therapy (PDT) in a three-step process that takes several days. Patients receive an injection of Photofrin, a photosensitizing drug, which selectively remains in cancer cells. Physicians then use a laser placed in a flexible scope to target the light-sensitized tumor in the patient's throat. PDT has been approved by the US Food and Drug Administration for use on tumors in the esophagus and on lung cancers blocking the windpipe. Warren cautioned that PDT is not a cure for many patients whose cancer has spread, but asserted that it can improve the quality of life significantly for those who are having trouble breathing, eating or swallowing. Other alternatives available to ease breathing or swallowing include stent surgery, in which a device is implanted into the windpipe or esophagus to prop open the passageway. Such options can be used in conjunction with PDT and conventional laser therapy.