Qualitative mapping of Barrett's metaplasia: a prerequisite for intervention trials

Barrett's esophagus may present as a cellular mosaic with irregular longitudinal extensions of intestinal epithelium, spotty areas of dysplasia and other intermediate markers for cancer risk. It may not be possible to detect and reproducibly localize these findings with routine endoscopic biopsies. A more systematic biopsy protocol is necessary for chemopreventive studies to be feasible.

Utilizing an adapted upper endoscope that allows accurate evaluation of distance from the incisors and rotatory position, chromoendoscopy with toluidine blue and systematic mapping (4 quadrant jumbo biopsies at 1 cm intervals) were performed twice on 18 patients with Barrett's esophagus (second procedure 1 to 3 months after baseline study). All biopsy specimens were subjected to routine and immunohistochemical staining and flow cytometry to create baseline and follow-up maps for each patient. Eight of the 18 patients also underwent standard surveillance biopsies within 6 months of the systematic mapping procedures.

Epithelium type was reproducibly identified with 94% accuracy on second endoscopic maps. Ploidy, p53, and Ki-67 status were also reproducibly identified on second endoscopic maps (97%, 89%, and 85%, respectively). Dysplasia was found in 7 of 18 patients at similar sites at each mapping procedure (3 patients with high-grade dysplasia, 4 with low-grade dysplasia). Five of the patients who had dysplasia on mapping had also undergone standard surveillance. Low-grade dysplasia was missed in 2 of 3 patients and 1 patient with high-grade dysplasia had only low-grade dysplasia detected with standard biopsies.

Utilizing a modified gastroscope and this methodology, we reliably located sites of dysplasia and other biomarkers within a field of Barrett's esophagus. Patients had variable areas of dysplasia that were missed on standard endoscopic surveillance.