Glossary

Esophagus – The tube that carries food from the mouth to the stomach

Gastrointestinal tract (GI tract) – The entire digestive system

Gastroesophageal reflux – When acid flows from the stomach back into the esophagus. Also known as acid reflux. 

Gastroesophageal reflux disease (GERD) – A chronic condition where acid repeatedly flows from the stomach back into the esophagus

Barrett’s esophagus (BE) – A condition where the lining of the esophagus changes to resemble the lining of the intestine. Barrett’s esophagus is the only known precursor to esophageal adenocarcinoma.

Esophageal adenocarcinoma (EAC) – A highly lethal esophageal cancer that has been increasing in incidence since 1970.

Pathologist –  A specialist who uses laboratory techniques to study disease. For example, a pathologist assesses tissue biopsies under a microscope in order to make an official diagnosis of Barrett’s esophagus and looks for signs of cancer.

Gastroenterologist – A physician who specializes in diseases of the digestive system and liver. In the case of  Barrett’s esophagus, a gastroenterologist will conduct endoscopies and recommend treatment and management of the condition.

Barrett’s esophagus segment length – Barrett’s esophagus segment length is based on how far up the esophagus the longest tongue of Barrett’s tissue extends. Segment length is classified as either long- or short-segment, and is considered a risk factor of progression from Barrett’s esophagus to cancer. Those with long-segment Barrett’s esophagus may receive follow-up screenings more frequently than those with short-segment Barrett’s esophagus. 

Metaplasia – A change in cell type. For example, Barrett’s esophagus tissue is metaplastic because cells normally found in the esophageal cells (squamous cells) have been replaced by cells normally found in the intestine (columnar cells).

Dysplasia – Cell development is abnormal, and cells appear irregular in size, shape or organization. In Barrett’s esophagus, metaplastic cells (in this case, intestine-like cells where there should be esophageal cells) become increasingly dysplastic before they progress to cancer. 

Morphological change – A change in cell size, shape or organization, often identifiable through a microscope

Molecular change – A change in the DNA, RNA or protein signatures of a cell

Columnar cells – Cells normally found in the intestine

Squamous cells – Cells normally found in the esophagus

Precancerous – Something that is likely to become cancerous in the future, but is not cancerous at present

Stage – Used to describe cancers and distinguish them by tumor size and extent of spread. Precancerous conditions like Barrett’s esophagus are not staged.

Grade – Used to describe the appearance of cancerous or dysplastic cells in comparison to healthy cells, with higher grades indicating greater cell abnormalities.

Risk factor – A factor that increases the chance that something undesirable will happen in the future. For example, dysplasia is a risk-factor for Barrett’s esophagus progressing to cancer because if a Barrett’s esophagus patient has highly dysplastic cells, the chances that they will progress to cancer are much higher than someone whose cells are not dysplastic. 

Risk of progression – In the case of Barrett’s esophagus, “risk of progression” often refers to the risk that Barrett’s esophagus, a precancerous condition, will progress to esophageal cancer. When specified, “risk of progression” may also refer to the risk that Barrett’s esophagus will progress to either high-grade dysplasia or esophageal cancer.

Proton pump inhibitor (PPI) – A medication used to control acid reflux 

Esophagogastroduodenoscopy (EGD) – Also known as upper endoscopy, this procedure is conducted so that a clinician can inspect the upper part of the gastrointestinal tract. 

Endoscope – The endoscope is a small, flexible tube with a light and a camera at the tip, which is inserted through the nose or mouth and into the esophagus. Small surgical tools can be inserted through the endoscope to take tissue samples from the esophagus. 

Prague classification – A method of measuring Barrett’s esophagus segment length which accounts for the length of undisrupted Barrett’s tissue and the maximum length that tongues of Barrett’s tissue extend upward from the stomach. 

Seattle protocol – The current method of biopsy collection for Barrett’s esophagus. This method requires a clinician to take four biopsy samples for every 1-2 cm of Barrett’s esophagus tissue – to increase the chances of detecting dysplasia. However, because the Seattle protocol biopsies only a small percentage (~5%) of Barrett's tissue, it is vulnerable to sampling and human error. 

Endoscopic Eradication Therapy (EET) – An effective, minimally invasive treatment for Barrett’s esophagus, which is a combination of two therapies, endoscopic mucosal resection, and ablation, intended to remove any worrisome areas of Barrett’s esophagus tissue and prevent progression to cancer. Some patients may undergo only ablation if there are no visible areas of concern. 

Ablation – A treatment for Barrett’s esophogus that involves controlled injury through burning or freezing which destroys Barrett’s esophagus tissue, and allows the esophagus to heal with normal, healthy tissue. 

Spatialomics – An analysis method that is able to combine molecular analysis with spatial information from tissue.