Our results suggested that an endoscopist with minimal experience in CEM can effectively use this technology to reduce the number to biopsies without decreasing the overall diagnostic yield when compared to the random biopsy protocol in BE surveillance. Several reports indicated high accuracy and inter-observer agreement among inexperienced endoscopists with CEM for the detection of BE and Barrett-associated neoplasm.17,18
These studies suggested that, although extensive training and experience will be required to tap the full potential of CEM, even with minimal experience, endoscopists can effectively use this technology to differentiate normal from neoplastic lesions.
The first prospective, randomized controlled trial showed that CEM was able to eliminate approximately 60% of biopsies in patients undergoing BE surveillance because no dysplasia was observed during CEM.18
Similar to our study, although Group A had 52% lower in number of biopsies compared to Group B, the overall diagnostic yield was similar between them. Also, Dunbar et al.18
reported, comparing to the random 4-quadrant biopsy protocol, the diagnostic yield of CEM-group was almost doubled for neoplasia (33% vs. 17%). However, our study did not demonstrate this difference likely because of a small number of patients. The above favorable results of using CEM in detecting
BE/Barrett-associated dysplasia were supported by Kiesslich et al.13
which showed that CEM-guided biopsy can identify these lesions with high sensitivity (92.9–98.4%) and specificity 94.1–98.4%). However, these studies were performed by endoscopists with extensive experience in CEM. So the results may not be representative of endoscopists with lesser experience. Our results were likely more “realistic” because the endoscopist (AD) had only minimal training in CEM prior to the study. It should be noted that our primary endpoint of this study was not to determine the performance characteristics of CEM but rather to examine the diagnostic yields of BE and BE-associated dysplasia between the CEM-guided biopsy technique and the standard 4-quadrant protocol.
Recent evidence suggests that narrow band and autofluorescence imaging can be used effectively in conjunction with CEM as “red-flag” techniques in BE surveillance because these techniques are able to evaluate the entire area of BE and their main limitation is low specificity.17
As a result, these optical methods can screen the mucosa for suspicious sites. Then the sites can be further examined by CEM for “smart,” targeted biopsies.
There are several limitations of the study should be mentioned. First, the sample size was small and uneven (11:7 instead of 1:1 ratio) due to relocation of the primary investigator (AD). Second, only one endoscopist performed all the procedures. Hence, generalization of our results is limited. Third, a crossover design was deemed to be not feasible in our clinical practice as most patients in a BE surveillance program were not required to have repeat endoscopies at 4–6 weeks intervals. However, to minimize bias, the same endoscopist performed the procedures in all patients included in this study using the same endoscope, and also, the pathologist was blinded. Fourth, we did not incorporate methylene blue based chromoendoscopy or even narrow band imaging in this study because these are currently not considered part of standard clinical practice in most centers. Fifth, differentiation between low grade dysplasia (LGD) and HGD was not possible in this study because nuclei were not readily visible by fluorescein. Other contrast agent such as acriflavin that stains nuclei selectively can overcome this problem, but acriflavin is currently not available in the USA for use in human beings.
In conclusion, limited data suggested that endoscopists with minimal experience in CEM can effectively use this technology for “smart,” targeted biopsy to decrease the need for intense tissue sampling but without lowering the diagnostic yield in detecting dysplasia. Further controlled studies with larger sample size are needed.