OAK BROOK, Ill. July 31, 2008 A multicenter U.S. registry study examining the treatment of Barrett's esophagus (BE) with high-grade dysplasia (HGD) showed that in 92 patients treated with endoscopic circumferential ablation who had at least one follow-up biopsy session, 90.2 percent were free of HGD at an average of one-year follow-up. This registry is the first to report on the use of circumferential ablation for BE HGD. The study appears in the July issue of GIE: Gastrointestinal Endoscopy, the monthly peer-reviewed scientific journal of the American Society for Gastrointestinal Endoscopy (ASGE).
Barrett's esophagus is a condition where the lining of the esophagus changes because of chronic inflammation, generally due to gastroesophageal reflux disease (GERD). Definitive diagnosis requires a biopsy, taken at upper endoscopy, demonstrating replacement of the normal cell lining with one more like the cell lining of the small intestine. This is also known as intestinal metaplasia (IM). Barrett's esophagus itself has no specific symptoms, but this change can increase the risk of esophageal adenocarcinoma (a type of esophageal cancer). Barrett's esophagus can be readily detected during an upper endoscopy, but must be confirmed by biopsies. The intent is to diagnose this condition, treat it medically, and follow it over time before a cancer has a chance to develop. If biopsies detect dysplasia (a precancerous change in tissue), then either surgery, close endoscopic surveillance (doing endoscopies at regular intervals with biopsies) or other treatments will be recommended. Once high-grade dysplasia is present, the risk of developing adenocarcinoma is two percent to 10 percent per patient, per year. Given the rising incidence of esophageal adenocarcinoma and the poor prognosis once cancer develops, aggressive therapy of the precancerous changes may be beneficial.
"This patient registry assessed the safety and effectiveness of endoscopic circumferential balloon-based ablation using radiofrequency energy for the treatment of BE HGD at 16 U.S. academic and community institutions," said study lead author Robert A. Ganz, MD, FASGE, Minnesota Gastroenterology, Minneapolis. "Results were promising, showing that 90.2 percent of patients were free of high-grade dysplasia at an average of one-year follow-up and avoided many of the adverse events associated with other modalities currently used with this disease."
Patients who have BE with HGD have historically been referred for surgical removal of the esophagus. However, over the last several years alternative therapies for these patients have been pursued given the risks of surgery. These therapies include endoscopic mucosal resection (EMR), endoscopic ablation by using photodynamic therapy (PDT), and a myriad of other thermal and nonthermal modalities. Each therapeutic strategy has specific limitations, such as technical complexity of the procedure itself, stricture formation leaving behind buried Barrett's esophagus, photosensitivity, and stricture formation.
The primary benefit shared by the endoscopic techniques is esophageal preservation, whereas esophagectomy has merit because of resection of the entire organ, which allows for complete histologic assessment and removal of all the at-risk tissue. Circumferential ablation with a balloon-based radiofrequency device is a more recently available endoscopic ablation technique for BE HGD. This procedure burns away the abnormal cells with radiofrequency energy.
Patients and Methods
A total of 142 patients (median age 66 years) at 16 academic and community centers in the U.S. were enrolled in the registry from September 2004 to March 2007. Patients had histologic evidence of IM that contained HGD confirmed by at least two expert pathologists. A prior EMR was permitted provided that residual HGD remained in the BE region for ablation.
The endoscopic circumferential ablations were performed with a balloon-based radiofrequency energy electrode array catheter introduced in a side-by-side manner with an endoscope. The procedures were performed on an outpatient basis. After the primary ablation session, patients underwent an endoscopy at three-month intervals. If persistent BE was evident, then another circumferential ablation was performed. The outcomes were histology based and derived from the last available endoscopy with a biopsy session. Three separate outcomes were measured: presence/absence of HGD, presence/absence of any dysplasia, presence/absence of IM, including IM buried beneath the normal esophageal lining.
In these 142 patients treated with circumferential ablation for BE with HGD, 92 patients had at least one follow-up biopsy session (median follow-up twelve months) and were evaluated for effectiveness. 90.2 percent were free of HGD; 80.4 percent were free of any dysplasia; and 54.3 percent were free of IM. No serious adverse events occurred in the safety analysis cohort. Esophageal stricture occurred in one patient (.4 percent).
The authors concluded that circumferential ablation is a promising modality for the treatment of Barrett's esophagus with high-grade dysplasia and the technique compares favorably with PDT, wide-field EMR, and esophagectomy, with respect to safety, patient tolerability, and the histologic complete response outcomes tracked. Further, there may also be an adjunctive role for circumferential ablation and EMR, with EMR used to remove visible abnormalities for staging followed by circumferential ablation to eliminate all remaining dysplastic and metaplastic disease.
The study acknowledges some limitations, including a nonrandomized study design, but demonstrates a real-life experience on the use of this ablative modality in the management of BE HGD. Researchers also noted that additional studies are underway to confirm these registry results.
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American Society for Gastrointestinal Endoscopy