The evidence discussed in this article supports the current recommendation of GI societies that screening endoscopy for Barrett’s esophagus be performed only in well-defined, high-risk populations. Alternative tests for screening are not now recommended; however, some of the alternative tests show great promise, and it is expected that they will soon find a useful place in clinical practice. At the same time, there should be a complementary focus on using demographic and clinical factors as well as noninvasive tools to further define populations for screening. All tests and tools should be balanced with the cost and potential risks of the screening proposed.
Stuart Spechler, MD, of the University of Texas and his colleagues looked at a variety of techniques, both conventional and novel, as well as the cost effectiveness of these strategies in a commentary published in the May issue of Gastroenterology.
Some studies have shown that endoscopic surveillance programs have identified early-stage cancer and provided better outcomes, compared with patients presenting after they already have cancer symptoms. One meta-analysis included 51 studies with 11,028 subjects and demonstrated that patients who had surveillance-detected esophageal adenocarcinoma (EAC) had a 61% reduction in their mortality risk. Other studies have shown similar results, but are susceptible to certain biases. Still other studies have refuted that the surveillance programs help at all. In fact, those with Barrett’s esophagus who died of EAC underwent similar surveillance, compared with controls, in those studies, showing that surveillance did very little to improve their outcomes.
Perhaps one of the most intriguing and cost-effective strategies is to identify patients with Barrett’s esophagus and develop a tool based on demographic and historical information. Tools like this have been developed, but have shown lukewarm results, with areas under the receiver operating characteristic curve (AUROC) ranging from 0.61 to 0.75. One study used information concerning obesity, smoking history, and increasing age, combined with weekly symptoms of gastroesophageal reflux and found that this improved results by nearly 25%. Modified versions of this model have also shown improved detection. When Thrift et al. added additional factors like education level, body mass index, smoking status, and more serious alarm symptoms like unexplained weight loss, the model was able to improve AUROC scores to 0.85 (95% confidence interval, 0.78-0.91). Of course, the clinical utility of these models is still unclear. Nonetheless, these models have influenced certain GI societies that only believe in endoscopic screening of patients with additional risk factors.
Although predictive models may assist in identifying at-risk patients, endoscopes are still needed to diagnose. Transnasal endoscopes (TNEs), the thinner cousins of the regular endoscope, tend to be better tolerated by patients and result in less gagging. One study showed that TNEs (45.7%) improved participation, compared with standard endoscopy (40.7%), and almost 80% of TNE patients were willing to undergo the procedure again. Despite the positives, TNEs provided significantly lower biopsy acquisitions than standard endoscopes (83% vs. 100%, P = .001) because of the sheathing on the endoscope. Other studies have demonstrated the strengths of TNEs, including a study in which 38% of patients had a finding that changed management of their disease. TNEs should be considered a reliable screening tool for Barrett’s esophagus.
Other advances in imaging technology like the advent of the high-resolution complementary metal oxide semiconductor (CMOS), which is small enough to fit into a pill capsule, have led researchers to look into its effectiveness as a screening tool for Barrett’s esophagus. One meta-analysis of 618 patients found that the pooled sensitivity and specificity for diagnosis were 77% and 86%, respectively. Despite its ability to produce high-quality images, the device remains difficult to control and lacks the ability to obtain biopsy samples.
Another example of a swallowed medical device, the Cytosponge-TFF3 is an ingestible capsule that degrades in stomach acid. After 5 minutes, the capsule dissolves and releases a mesh sponge that will be withdrawn through the mouth, scraping the esophagus and gathering a sample. The Cytosponge has proven effective in the Barrett’s Esophagus Screening Trials (BEST) 1. The BEST 2 looked at 463 control and 647 patients with Barrett’s esophagus across 11 United Kingdom hospitals. The trial showed that the Cytosponge exhibited sensitivity of 79.9%, which increased to 87.2% in patients with more than 3 cm of circumferential Barrett’s metaplasia.