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Cellvizio detects Barrett’s esophagus better than current methods
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Probe-based confocal laser endomicroscopy with Mauna Kea Technologies’ Cellvizio platform was superior for detecting Barrett’s esophagus compared with the standard Seattle protocol, according to new research presented at the Society of American Gastrointestinal and Endoscopic Surgeons 2018 Annual Meeting and World Congress of Endoscopic Surgery.
“pCLE with Cellvizio is considerably more sensitive in the detection of Barrett’s esophagus than the conventional diagnostic standard (Seattle Protocol), which leaves a majority of epithelium unexamined,” Paul Severson, MD, FACS, co-director of the Minnesota Institute for Minimally Invasive Surgery, told Healio Gastroenterology and Liver Disease. “This effect is seen even in novice users and increases with experience.”
pCLE is an advanced imaging modality that provides microscopic views of the GI mucosa, enables real-time evaluation of entire segments of columnar lined esophagus, and rapidly captures digital images for optical biopsy.
To evaluate the role of pCLE in screening and surveillance for Barrett’s esophagus, Severson and colleagues assessed its ability to identify intestinal metaplasia in 172 patients at eight non-academic centers in the U.S. compared with standard histological analysis of random four quadrant biopsies. The performing endoscopists were all novice pCLE users, with an average of 6.6 months experience. pCLE images were interpreted in real-time and after the procedure.
pCLE detected intestinal metaplasia in 99 patients (57.6%), whereas tissue biopsy detected intestinal metaplasia in 46 (27%). This represents an increase of more than 100%, according to a press release from the manufacturer (P < .0001).
Additionally, a blinded expert who reviewed pCLE images after the procedure confirmed intestinal metaplasia in 56 of 61 patients who had tissue biopsies that tested negative, per the press release.
“Overall, pCLE provides a promising advance in Barrett’s detection, which will likely result in superior identification of individuals at risk for esophageal adenocarcinoma,” Severson said. – by Adam Leitenberger
Reference:
Richardson C, et al. Abstract S071. Presented at: Society of American Gastrointestinal and Endoscopic Surgeons 2018 Annual Meeting and World Congress of Endoscopic Surgery; April 11-14; Seattle, WA.
Disclosures: Severson reports serving as a preceptor, speaker and consultant for Ethicon/Torax, and as a consultant for Mauna Kea Technologies outside of the current study.
Perspective
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Zachary L. Smith, DO
The incidence of esophageal cancer in the U.S. continues to rise at a rate disproportionately higher than other cancers. The predominant subtype of esophageal cancer in the U.S. is adenocarcinoma and the major precursor condition to developing this devastating disease is Barrett’s esophagus (BE). Despite our best efforts, pre-existing BE continues to go unrecognized in a large number of patients who, only after developing symptoms such as dysphagia, end up presenting with invasive esophageal cancer.
Once identified, surveillance of BE is imperative to detect low- and high-grade dysplasia, as well as early cancer when it is still treatable. Endoscopic eradication therapy for dysplastic BE has evolved greatly over the last decade. With the advent of radiofrequency ablation (RFA), cryotherapy, and endoscopic resection techniques like mucosal resection (EMR) and submucosal dissection (ESD), fewer patients are undergoing surgical esophagectomy for dysplastic BE and early cancer. Despite this, more asymptomatic patients at risk for developing BE need to be screened before an appreciable impact can be made on the rising incidence of esophageal cancer.
At the 2018 annual meeting of the Society for American Gastrointestinal and Endoscopic Surgeons (SAGES), Richardson et al. presented data evaluating the use of probe-based confocal laser endomicroscopy (pCLE) vs. 4-quadrant random biopsies every 1 cm to 2 cm (so-called “Seattle protocol”) in the detection of BE. The authors conclude that “pCLE is considerably more sensitive in the detection of Barrett’s Esophagus than the Seattle Protocol.” A subsequent press release from Mauna Kea technologies, the maker of Cellvizio, claims “this large multi-center study confirms that endoscopists can more than double their detection rate of patients with intestinal metaplasia (IM) and dysplasia when using Cellvizio.” While the results of this study sound promising at face value, there is more than meets the eye as this study appears to have significant methodologic flaws.
The Seattle protocol, developed more than 20 years ago, is used in the surveillance of known long-segment BE (≥3 cm). In the U.S., a diagnosis of BE requires both the presence of columnar-lined esophageal mucosa above the gastroesophageal junction (GEJ) and histologic evidence of specialized-IM. In other words, there is no role for the Seattle protocol in patients without known IM or visible columnar-lined esophagus. In the present study, 78 of 172 patients (45%) had no visible columnar-lined esophagus and therefore, employing the Seattle protocol in these 78 patients is of no use. It also makes little sense that IM was seen on tissue biopsy in only 47 patients if in fact 94 patients in total had visible columnar-lined esophagus. If true columnar-lined esophageal mucosa (above the GEJ) was adequately biopsied, detecting IM at a rate of 50% is not believable. These numbers could suggest an over-estimation of true columnar-lined esophageal mucosa in the study group as well as other possible technical errors.
Intestinal metaplasia of the gastric cardia (IM-GC) is a common phenomenon, described in up to 20% of asymptomatic individuals presenting for upper endoscopy. The prevalence of IM-GC is much higher than that of BE and further data suggest that IM-GC is not more common in BE patients compared with healthy controls. IM-GC is commonly associated with Helicobacter pylori infection and not with the development of esophageal adenocarcinoma. It is because of this that numerous guidelines actively recommend against the endoscopic surveillance of IM-GC and against tissue biopsy of an irregular Z-line to assess for BE. Because the authors appear to have used pCLE in patients with very little, if any visible columnar-lined esophagus, it is likely that the majority of IM detected in these cases that was “missed” histologically was that from the gastric cardia and not from the esophagus. Therefore, the positive impact on the increased detection of IM with pCLE and its possible role in preventing esophageal cancer in these patients is highly questionable.
The use of pCLE for detecting dysplasia and early cancer in patients with known BE has been promising, as suggested by a 2016 systematic review and meta-analysis by the ASGE Technology Committee. The use of pCLE in other clinical applications like the classification of cystic neoplasms of the pancreas has also been exciting. Despite this however, to claim that the results of this study “confirm” that pCLE can “more than double” the detection of Barrett’s esophagus is problematic and a striking over-reach based on the inherent flaws of the study as performed.
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