SAN DIEGO — Two studies presented at the annual Digestive Disease Week indicate that confocal laser endoscopy increases diagnostic yield and is both accurate and safe.
The studies suggest that one day it may be possible to skip a step in the diagnosis and treatment of Barrett's esophagus, Dr. Kerry B. Dunbar said in a news conference. Dr. Dunbar was the senior author of the randomized study and a coauthor of the retrospective study.
In confocal laser endoscopy (CLE), an endoscope is equipped with a microscope that magnifies living cells close to the surface of the GI tract 1,000 times. When used in conjunction with intravenous contrast agents such as fluorescein, acriflavine, and cresyl violet, the microscope allows endoscopists to visualize the abnormal cell growth that is characteristic of cancerous lesions.
In one study, investigators retrospectively combined the results of 2,102 CLE examinations on 1,771 patients at three academic medical centers. They found the “optical biopsy” technique to be 91% accurate compared with standard biopsy. Moreover, the technique changed the initial diagnosis in 32% of the upper GI examinations and 22% of examinations of the lower GI tract.
Complications occurred in only 1% of patients. There were four perforations and four bleeding episodes, which are typical of any endoscopic procedure and not specifically related to CLE. The only CLE-specific complications—five cases of nausea and nine cases of decreased blood pressure—were related to the intravenous fluorescein.
The other study was a prospective, controlled, crossover trial in which 36 patients underwent both CLE and standard endoscopy (in random order and separated by 2–6 weeks) to identify areas of dysplasia in Barrett's esophagus. The two techniques uncovered about the same number of sites with high-grade dysplasia, but CLE required 60% fewer mucosal biopsies to do so.
Furthermore, 9 of 15 patients (60%) at high risk of high-grade dysplasia and 14 of 21 patients (67%) undergoing surveillance endoscopy following a Barrett's diagnosis required no mucosal biopsies at all during their CLE procedures, because the investigators detected no suspicious sites.
There were no fluorescein-related complications, but pneumonia developed in one patient who underwent CLE.
“Currently the biopsies go out to the pathologist [and] a week later I have to call the patient, discuss the results, do another invasive procedure, and then do a mucosal resection of the areas of dysplasia,” said Dr. Dunbar of Johns Hopkins University, Baltimore. “One of the great promises of confocal microscopy is that we instantly get a diagnosis.”
Dr. Dunbar said she had no relevant conflicts of interest, but disclosed that one of the investigators in the retrospective study received unrestricted research funding from Pentax, which manufactures a CLE system. The randomized study was funded by the National Institutes of Health and by a research award from the American Society of Gastrointestinal Endoscopy.