Go through these in order and stop at the first one that applies. If you are reading this for someone else, answer for them.
These concerns should not wait for the next planned surveillance appointment.
Follow-up plans are based on biopsy results and the quality of the endoscopic examination.
Contact the treating clinic between routine visits for progressive swallowing difficulty, pain with swallowing, unexplained weight loss, persistent vomiting, signs of bleeding, or a major change in reflux symptoms.
The article also says
When no dysplasia is found, surveillance endoscopy is usually performed at intervals measured in years.
Current guidance uses the length of the Barrett segment as one factor: shorter segments may be monitored less often than longer ones.
The exact schedule should come from the treating gastroenterologist because recommendations may change and individual findings matter.
Indefinite or abnormal biopsy results generally require earlier reassessment.
This may include improving control of esophageal inflammation, repeating the endoscopy, and obtaining expert pathology review.
Confirmed dysplasia requires a focused discussion about eradication therapy or close surveillance.
After ablation or removal of abnormal tissue, scheduled endoscopies check whether Barrett tissue has cleared and whether it has returned.
Keeping these appointments is important even when reflux symptoms are absent.
It can be helpful to keep copies of endoscopy and pathology reports.
Important details include the length of the Barrett segment, whether dysplasia was found, whether an expert pathologist reviewed the samples, and the recommended timing of the next procedure.
Every sign above is quoted from the sofidex article on Barrett esophagus. If you are not sure, err upward — it is always reasonable to be checked.