A study presented at the ninth annual Gastrointestinal Cancers Symposium being held January 19-21, 2012, at The Moscone West Building in San Francisco, CA, USA, has identified new biomarkers that could eventually improve early detection of esophageal cancer in patients with Barrett’s esophagus (BE) or Barrett's Syndrome. BE refers to a metaplasia or abnormal change in the cells of the inferior portion of the esophagus and is known to significantly increases esophageal cancer risk.
Using a special type of high-powered microscope, researchers identified three “optical biomarkers,” specific nano-scale changes in cells of the lining of the esophagus, which enabled them to stratify patients’ risks of progressing to cancer.
Simple and Effective
“If subsequent testing proves successful, our approach could lead to simpler and more effective ways of monitoring for patients with Barrett’s esophagus. Such a monitoring program would identify a subset of high-risk Barrett’s patients who need more intensive surveillance, and who could also be candidates for therapy to destroy the precancerous tissue,” said lead researcher Randall Brand, MD, professor of medicine at the University of Pittsburgh.
The incidence of esophageal adenocarcinoma in the U.S. is increasing faster than any other type of cancer – approximately 400% in the last three decades. If detected early, 5-year survival can be as high as 90% - advanced esophageal adenocarcinoma has a 5-year survival rate of 13%. Barrett’s esophagus, which is estimated to affect about 1 to 2% of the U.S. population (approximately 3 to 6 million people), is a pre-malignant condition involving a change in the epithelium lining of the esophagus, also known as intestinal metaplasia. Individuals with longstanding gastroesophageal reflux disease (GERD) are at increased risk for BE.
Multiple random biopsies
Currently, patients with Barrett’s esophagus are monitored for the presence of dysplasia or early stage cancers through the use of endoscopy and biopsies. The recommended surveillance method consists of multiple random biopsies of the esophagus every one to two centimeters along the length of the area of the esophagus affected by BE every three years, if no abnormality is identified. However, this practice may miss abnormal cells (dysplastic cells) that indicate unseen high-grade dysplasia or an undetected small esophageal adenocarcinoma.
“Our ultimate goal is to identify all patients with high-grade dysplasia and early cancers to allow early treatment, when therapy is most effective and the least invasive,” said Brand. “The problem is that sometimes intestinal metaplasia from a patient with high-grade dysplasia looks normal under a traditional microscope.”
In the study, researchers retrospectively examined archived tissue from 60 patients with Barrett’s esophagus who underwent biopsies. Of these, 33 were known to have only intestinal metaplasia, meaning no dysplasia or cancer, while 27 patients had high-grade dysplasia or cancer. The investigators examined cells from biopsy specimens that only had intestinal metaplasia from both groups of patients: those who had no dysplasia and those who had high-grade dysplasia or cancer were diagnosed on a different biopsy specimen.
Using a special type of microscope, called spatial-domain low-coherence quantitative phase microscopy (SL-QPM), the researchers examined these samples for extremely small changes in the cell that cannot be seen by a conventional microscope.They found at least three new features that are based on the use of light to detect abnormalities in cells that distinguished patients with Barrett’s esophagus who had no cancer from those who had high-grade dysplasia/cancer. These include:
- Average optical path length of the cell nucleus, or the density of the cell nucleus
- Intra-nuclear entropy, or the random structure of the cell nucleus
- Intra-nuclear uniformity, or the texture uniformity of the cell nucleus
Using these biomarkers, the researchers developed a prediction model that resulted in 89% sensitivity (meaning they correctly detected 89% of cases of high grade dysplasia/adenocarcinoma), and 76% specificity (correctly identifying 76% of patients with non-cancer) in distinguishing Barrett’s patients with high-grade dysplasia/adenocarcinoma from those without dysplasia by only looking at cells that under a traditional microscope are non-cancerous.
Simpler and more sensitive
According to Brand, if a standard pathology examination identifies any form of dysplasia, the patient will immediately undergo treatment. These patients would not require this special imaging test. However, this test may be used for the majority of patients with Barrett’s esophagus whose pathology examination showed non-dysplastic intestinal metaplasia or was ambiguous for dysplasia. Ultimately, the researchers hope the new technique would be “a simpler, more sensitive and accurate approach,” requiring only two or three random biopsies and “may also allow for the identification of a subset of Barrett’s patients who require less frequent monitoring.”
The researchers plan to expand the study population and test additional optical biomarkers as well to improve on the current sensitivity and specificity. In the long-term, they plan on a multi-center trial using previously collected specimens at other centers to validate their results.
For more information:
Brand R, Rizvi S, Davison JM, Bista R, Staton K, Hartman D, Fasanella K, McGrath K, Liu Y. Use of optical biomarkers from nondysplastic metaplastic cells on the detection of high-grade dysplasia and adenocarcinoma from Barrett’s esophagus. 9th Annual Gastrointestinal Cancers Symposium. Abstract # 14
What: General Poster Session A
Who: Lead Author: Randall Brand, MD, University of Pittsburgh,Pittsburgh, PA
When: Thursday, January 19, 2012 - 11:45 PM - 01:45 PM PT / 05:15 PM – 06:45 PM PT
The 2012 Gastrointestinal Cancers Symposium is co-sponsored by the American Gastroenterological Association (AGA) Institute, the American Society of Clinical Oncology (ASCO), the American Society for Radiation Oncology (ASTRO) and the Society of Surgical Oncology (SSO).