FROM GASTROENTEROLOGY
Patients with Barrett’s esophagus have about a 0.2% annual chance of developing esophageal adenocarcinoma in the 5 years after initial diagnosis, but the likelihood then rises so that about 9% of all patients will develop cancer by 20 years out, according to a study in the September issue of Gastroenterology.
The modeled rates of progression for the early years after diagnosis are substantially lower than are those reported by prospective studies, which involve more intensive surveillance and therefore suffer from detection bias, said Dr. Sonja Kroep of Erasmus Medical Center, Rotterdam, the Netherlands, and her associates. “Clinicians informing their patients about their cancer risk can best use this clinical progression rate, which is not influenced by surveillance-detected cancers,” they wrote.
Past analyses have yielded varying results for the rate at which Barrett’s esophagus with low-grade dysplasia progresses to high-grade dysplasia and esophageal carcinoma. For their study, Dr. Kroep and her associates calibrated a model based on the annual rate of 0.18% reported by population-level studies, and used it to simulate prospective studies and to predict results from both population-based and prospective studies for various follow-up periods ( Gastroenterology 2015 Apr 29. pii: S0016-5085(15)00601-0 ).
For the first 5 years of follow-up, the model predicted a 0.19% annual rate of transformation to esophageal adenocarcinoma for population-based studies and a 0.36% annual rate for prospective studies, the researchers reported. At 20 years, these rates rose to 0.63% and 0.65% annually, for a cumulative incidence rate of 9.1% to 9.5%. Between the 5-year and 20-year thresholds, the gap between rates of progression for the two types of studies narrowed from 91% to 5%. Taken together, the findings suggest that for the first 5 years after a diagnosis of Barrett’s esophagus, rates of progression to esophageal adenocarcinoma reflect those from population-level studies instead of surveillance-based prospective studies, the investigators said. “Clinicians should use this information to explain to patients their short-term and long-term risks if no action is taken, and then discuss the risks and benefits of surveillance,” they added.
In a separate retrospective study, radiofrequency ablation of low-grade esophageal dysplasia was linked to substantially lower rates of progression compared with watchful waiting in the form of endoscopic surveillance, said Dr. Aaron Small of the University of Pennsylvania, Philadelphia, and his associates. Their study included 125 patients with Barrett’s esophagus and low-grade dysplasia who underwent surveillance only, and 45 patients who underwent radiofrequency ablation at three university medical centers.
Over median follow-up periods of more than 2 years, the risk of progression with radiofrequency ablation was significantly lower than with endoscopic surveillance only, even after the researchers controlled for year of diagnosis (adjusted hazard ratio, 0.06; 95% confidence interval, 0.008-0.48; P = .008). The ablation group also had fewer visible macroscopic lesions, although the difference was not significant. “We estimate that for every three patients treated with radiofrequency ablation, one additional patient with low-grade dysplasia will avoid progression to high-grade dysplasia or esophageal adenocarcinoma within 3 years,” the researchers wrote. “Although selection bias cannot be excluded, these findings provide additional evidence for the use of endoscopic ablation therapy for low-grade dysplasia” ( Gastroenterology 2015 Apr 24. pii: S0016-5085(15)00569-7 ).
The study by Dr. Kroep and her associates was funded by grant U01 CA152926, and the investigators reported having no conflicts of interest. The study by Dr. Small and his associates was supported by the National Institutes of Health/National Institute of Diabetes and Digestive and Kidney Diseases and by institutional funds. Dr. Small reported no conflicts of interest, but seven coauthors reported ties with a number of pharmaceutical companies.
