In the first, researchers from Kansas City, Missouri, USA, compared the confirmation of intestinal metaplasia in patients with suspected short-segment Barrett's esophagus (SSBE) by using methylene blue-directed versus random biopsies.
A total of 75 consecutive patients (mean age 64 years) undergoing EGD, in whom columnar-appearing mucosa less than 3 cm in length was visualized, underwent methylene blue (MB) staining.
Stained areas within suspected SSBE segments were targeted for biopsies.
A historical control group consisted of 83 patients (mean age 61 years), with less than 3 cm of columnar-appearing mucosa, in whom biopsy specimens were obtained randomly without MB staining.
Within the MB and control groups, the mean lengths of columnar-appearing mucosa were 1.2 and 1.16 cm, respectively.
Intestinal metaplasia was detected in 61% of the MB group vs 42% of the control group.
Patients in the MB group required significantly fewer biopsies (4.3 vs 5.1).
Confirmation of intestinal metaplasia by length was as follows: less than 1 cm (irregular Z line), MB 17.4% vs control 25%; 1 to less than 2 cm, MB 77% vs control 45%; 2 to less than 3 cm, MB 90% vs control 58%.
Dr Prateek Sharma, of the University of Kansas and Veterans Affairs Medical Center, concluded on behalf of the group, "MB chromoendoscopy significantly increases the detection of intestinal metaplasia. It also requires fewer biopsies in patients with suspected SSBE with greater than 1 cm of columnar-appearing mucosa.
"It does not appear to be beneficial in patients with irregular Z lines (<1 cm)."
In the second study, a team from Louisville, Kentucky, USA, enrolled 47 patients with columnar-lined esophagus (CLE) into a randomized crossover trial of MB-directed biopsy vs conventional biopsy. Of these, 19 had long-segment and 28 had short-segment CLE.
|Results conflict as to whether MB chromoendoscopy increases detection of intestinal metaplasia.|
Sensitivity and specificity of MB for specialized intestinal metaplasia were found to be 53% and 51%, respectively.
Sensitivity and specificity of MB for dysplasia were 51% and 48%, respectively.
Some 35 patients (15 long-segment CLE; 20 short-segment CLE) completed the crossover trial.
Relative frequencies for specialized intestinal metaplasia were 73% and 71% from MB-directed and conventional biopsy specimens, respectively. The relative frequencies for dysplasia were 20% and 18%, respectively.
In patients with long-segment CLE, dysplasia was diagnosed in 10 patients with MB and 7 patients with conventional biopsy methods.
The number of biopsy specimens per EGD was greater with MB, which may have influenced the diagnosis.
Histologically, the grade of dysplasia was indefinite/low in nearly all of the dysplastic specimens.
Dr John M. Wo and colleagues from the University of Louisville School of Medicine and VA Medical Center, concluded, "Results of MB-directed biopsy were similar to conventional biopsy in detecting specialized intestinal metaplasia and indefinite/low-grade dysplasia.
"MB was not useful in short-segment Barrett's esophagus."