Doctors at the University of Maryland Medical Center are using a new cryotherapy technique to treat cancerous and precancerous conditions of the esophagus.
The medical center is one of only a handful of facilities in the world to offer the CryoSpray ablation procedure and one of three centers conducting clinical research to determine its effectiveness.
In this novel outpatient treatment, doctors spray liquid nitrogen onto abnormal or cancerous tissue using specially designed equipment threaded into the esophagus through an endoscope. An endoscope is a thin, fiber-optic instrument inserted through the mouth to enable a doctor to see inside the digestive tract. The liquid nitrogen freezes the tissue, which then thaws and ultimately sloughs off, providing an opportunity for normal tissue to grow back in its place.
Bruce D. Greenwald, M.D., a gastroenterologist at the medical center and an associate professor of medicine at the University of Maryland School of Medicine, is leading this pilot study. He has treated 22 patients since April 2006. The majority were diagnosed with a precancerous condition known as Barrett?s esophagus with high-grade dysplasia (significant abnormalities in the esophageal lining). Other patients in the study had esophageal cancer in its early stages and were not candidates for conventional medical or surgical treatment.
?The early results are very promising. The patients diagnosed with high-grade dysplasia and early-stage cancer are responding well to the treatment,? says Dr. Greenwald, adding that it is too early to draw any definite conclusions about the long-term effectiveness of the procedure. ?We want to follow these patients for a longer period of time, at least a year for the cancer patients and two years for those with high-grade dysplasia.? The CryoSpray ablation system is approved by the U.S. Food and Drug Administration.
The treatment sessions take an average of 10 to 15 minutes, and patients receive moderate sedation for the procedure, which is performed on an outpatient basis in the gastrointestinal endoscopy suite. Typically, several abnormal areas of the esophagus are treated during each session. Each area is frozen and thawed multiple times. Sessions are repeated every two to six weeks, depending on the extent of the disease and the patient?s response to treatment. Patients so far have required an average of three treatments.
In Barrett?s esophagus, the normal lining of the esophagus (the muscular tube leading from the mouth to the stomach) is replaced by tissue similar to that found in the intestine. The condition is associated with chronic heartburn, or gastroesophageal reflux disease, that has damaged the esophagus. Doctors examine the tissue under the microscope to determine the extent of the disease. In high-grade dysplasia, the tissue is severely abnormal and may develop into esophageal cancer.