Following reflux control, intestinal metaplasia can still persist in Barrett's mucosa. Of most concern in such an incidence is the risk of uncontrolled cellular proliferation and adenocarcinoma formation.
A total of 45 patients with Barrett's esophagus were therefore followed up (mean follow-up of 4 years) after undergoing Collis-Nissen gastroplasty, with the objective of comparing proliferation in the columnar-lined esophageal mucosa before and after antireflux surgery.
Proliferative activity was assayed using immunohistochemistry for Ki-67 expression in 73 pre-operative and 176 post-operative biopsies. Correlation with manometric and 24 hour results was also obtained.
Following Collis-Nissen gastroplasty, the researchers found that lower esophageal sphincter gradient was restored from 5.5 mmHg before surgery to 14.5 mmHg at 24 months and 12.9 mmHg at 48 months after surgery.
The median esophageal acid exposure was reduced from 8% to 1% of recording time, when tested 24 months after surgery, and remained at 1% of recording time when retested a year later.
The median Ki-67 labeling index increased from 29% before surgery to 36% at 12 to 23 months. It returned to a preoperative level (27%) at 24 to 47 months.
After surgery, abnormal intra-esophageal acid exposure was documented in 12 patients but could not be correlated with sphincter pressure.
The pattern of proliferation after surgery in patients with acid exposure less than 4% in their esophagus showed significant differences when compared with the proliferation pattern of patients where abnormal intraesophageal acid exposure was recorded.
|Abnormal esophageal acid exposure:
more proliferation and dysplasia
|Annals of Surgery|
New present dysplasia was only observed in those patients with abnormal acid exposure.
The researchers conclude that in Barrett's mucosa proliferation peaks early after surgery, but does then decrease back to pre-operative levels.
However, it is patients with abnormal esophageal acid exposure who are liable to display greater proliferation and more dysplasia.