Zapping precancerous tissue reduces number of people who get disease, study finds
People who have abnormal cell growth in the esophagus due to damage from acid reflux might benefit from a searing of the esophageal lining. Researchers find that promptly zapping aberrant tissue with a technique called radiofrequency ablation could forestall many cases from progressing to esophageal cancer.
Heartburn, or gastroesophageal reflux disease, can lead to changes in the tissues of the lower esophagus, a condition called Barrett’s esophagus. Doctors monitor Barrett’s patients because in some cases, precancerous cell growth called dysplasia results and sometimes dysplasia turns cancerous. The National Cancer Institute estimates about 18,000 new cases of esophageal cancer will be diagnosed in the United States this year. The five-year survival rate for esophageal cancer patients is 17 percent in the United States.
Radiofrequency ablation sears off abnormal cells on the surface of the inner esophagus without damaging the muscle cells beneath them, says study coauthor Jacques Bergman, a gastroenterologist at the University of Amsterdam. He likens it to frying a steak in a hot pan for only a moment on each side. The inside is unaffected.
Doctors typically use radiofrequency ablation only on Barrett’s patients with high-grade dysplasia, but Bergman and his colleagues wondered whether some with low-grade abnormalities would also benefit. Low-grade dysplasia denotes cell abnormalities beyond those seen in Barrett’s patients and sometimes excess mucus secretion; high-grade dysplasia is marked by greater distortion of cell architecture and changes in cell nuclei, steps further down the road to cancer.
The researchers randomly assigned 68 patients with low-grade dysplasia to get the treatment while 68 others didn’t. The plan was to see if ablation improved patients’ prospects after three years. But before all the patients reached the three-year mark, it became clear that those getting ablation were faring better. In the March 26 JAMA, the researchers report that while one person who had the treatment developed high-grade dysplasia and esophageal cancer, 18 people in the no-treatment group progressed to high-grade dysplasia and six of them had cancer. Three-fifths of the patients were monitored for three years; the rest were tracked for at least two years. All were ultimately offered the procedure.
“This is a significant study,” says Chin Hur, a gastroenterologist at Harvard Medical School. Professional groups’ guidelines don’t call for using radiofrequency ablation in low-grade dysplasia patients, he says, but some doctors treat patients if a pathology report suggests dysplasia. “A study like this can make an impact” in such cases, he says. While Hur leans toward caution before recommending ablative therapy, he allows that it has few serious side effects. In the study, people getting ablation were treated a median of three times each. Two patients had serious side effects linked to ablation: pain in one and fever and chills in the other.
Some doctors compare radiofrequency ablation in the esophagus to polyp removal in the colon, in which precancerous growths are snipped off to prevent cancer. But dysplasia is different, says gastroenterologist Klaus Mönkemüller of the University of Alabama at Birmingham, writing in the same issue of JAMA. Abnormal growths can show up dispersed in the esophagus and most don’t progress to cancer.
Nevertheless, the study “provides a strong argument to shift the current approach” toward earlier intervention, he says. To optimize radiofrequency ablation in Barrett’s patients, he says, doctors will need accurate dysplasia diagnoses, which require a skilled pathologist.
K.N. Phoa et al.Radiofrequency ablation vs endoscopic surveillance for patients with Barrett esophagus and low-grade dysplasia: a randomized clinical trial. JAMA. Vol. 311, March 26, 2014, p. 1209. doi: 10.1001/jama.2014.2511.
K. Mönkemüller. Radiofrequency ablation for Barrett esophagus with confirmed low-grade dysplasia. JAMA. Vol. 311, March 26, 2014, p. 1206. doi:10.1001/jama.2014.2512.
N.J. Shaheen et al. Radiofrequency ablation in Barrett’s esophagus with dysplasia. New England Journal of Medicine. Vol. 360, May 28, 2009, p. 2277. doi:10.1056/NEJMoa0808145.
An explanation of low-grade and high-grade dysplasia from the University of Washington