In a study that could dramatically reduce the need for surgery to prevent esophageal cancer, doctors reported on Wednesday that they can significantly cut the risk of a tumor by using radio waves to scorch suspicious-looking cells.

Barrett's esophagus, in which repeated bouts of acid reflux have caused the cells just above the entrance to the stomach to become abnormal, is found in one of every 62 Americans, although most do not have pre-cancerous cells.

When it causes a tumor, the five-year survival rate is less than 15 percent. Esophageal cancer kills about 14,000 people in the United States annually.

Dr. Nicholas Shaheen of the University of North Carolina School of Medicine and colleagues tested 127 patients with Barrett's, giving them either the heat treatment, known as radiofrequency ablation, or a sham procedure.

Abnormal cells disappeared in nearly 78 percent of the patients who received the heat treatment compared to 2 percent of people in a control group given fake surgery, they reported in the New England Journal of Medicine.

After a year, 9.3 percent who received the sham therapy developed esophageal cancer, compared to only 1.2 percent of those whose suspicious cells were seared.

The researchers, who will present their two-year results at a medical meeting next week, cautioned that because only five patients in the study developed cancer, the results are not completely reliable.

"The study was really designed to look to see if we could get rid of the Barrett's, not to look and see if we could get rid of the cancer," Shaheen said in a telephone interview.

"The fact that we did find a cancer difference between the groups was a little surprising and unexpected. It certainly has us hopeful that this may be a way to decrease the chance of cancer in these patients," he said.

The technique is performed as outpatient surgery after precancerous cells are discovered in a Barrett's patient. The cell-destroying radio waves are applied by inserting probes to the base of the feeding tube. A video showing the technique is posted at www.nejm.org.

The work was sponsored by privately held BARRX Medical of Sunnyvale, California, which makes the device.

The work should change treatment recommendations for high-grade Barrett's, where the pre-cancerous cells pose a 10 percent annual risk of cancer, Dr. Jacques Bergman of the Academic Medical Center in Amsterdam wrote in a commentary.

The results "suggest that surgery for high-grade dysplasia should no longer be offered routinely" and the results are better than for another alternative, photodynamic therapy, which uses a light-sensitive chemical and a laser to burn away the suspicious cells.

The 45-minute procedure has some side effects. The most common was chest pain that usually disappeared after a week. There was one case of bleeding. Six percent of the patients needed repeat surgery because the esophagus closed up.