Sponge Cytology “Moderately Successful” at Guiding Food Reintroduction in EoE

A new report suggests the use of a noninvasive esophageal sponge device can be successful in guiding dietary therapy among patients with eosinophilic esophagitis (EoE).

However, the authors added there was some variance between their sponge results and biopsy findings, suggesting a need for further study. The report was published Clinical Gastroenterology & Hepatology.

For some patients EoE, a food antigen–mediated chronic inflammatory disease, pharmacologic therapy is used to control the disease. However, the authors said most patients (about 70%) will respond to a food elimination diet known as the Six Food Elimination Diet (SFED). The diet calls for the elimination of common allergy-associated foods like dairy, wheat, soy, and eggs. If symptoms improve, patients then re-introduce the foods individually to see which foods trigger symptom return.

The problem, the authors said, is that tracking EoE activity typically requires multiple endoscopies, which is both invasive and costly. Thus, the investigators sought to evaluate a new tool, an esophageal sponge-on-a-string device (Cytosponge) that can be used in an outpatient setting without sedation. Previous research has suggested the method can achieve greater than 80% accuracy in assessing EoE histologic activity compared with endoscopy and biopsy, the authors said.

To evaluate the method as a tool to direct diet-elimination therapy, the investigators recruited 22 patients who responded to the SFED. The patients underwent food reintroduction followed by esophageal sponge cytology. Foods were classified as “triggers” if sponge cytology revealed an eosinophil count greater than 15 eosinophil cells per high-powered field (eos/hpf). Patients were also assessed using the EoE symptom activity index (EEsAI), endoscopic reference scores (EREFS), and biopsy histology prior to dietary therapy, after dietary therapy, and 4 weeks following food reintroduction, to see whether the results matched the expectations based on sponge-directed therapy.

The investigators found that both the EEsAI scores and the endoscopic scores were similar at the postdietary therapy timepoint and following food reintroduction. However, biopsy histology showed peak eosinophil counts were higher post food reintroduction compared with post dietary therapy: 20.0 (range, 5.0-51.5) vs 2.0 (range, 1.0-4.0; P < .001). The authors said this suggests some food triggers were missed. At the same time, they said peak eosinophil count was still lower post food reintroduction vs before dietary therapy was started, suggesting a benefit.

“At the post food reintroduction evaluation, sponge cytology and biopsy histology were in agreement in 59% of cases, using a cut off of < 15 eos/hpf, and 68% of cases, using a cut off of < 6 eos/hpf,” they wrote.

The authors said the sponge method led to a significant reduction in mucosal eosinophil counts in all patients and identified food antigen triggers in most patients.

“Unfortunately, on an individual-patient level, the correlation of Cytosponge eosinophil count and other measures of EoE activity, including biopsy histology, were not consistent,” they said.

Still, patients preferred the sponge-directed method, which the investigators said cost just 15% of what it costs to use endoscopy to guide food reintroduction.

“The sponge study is conducted without sedation during a routine 30-minute office visit without the need for a driver or missing work or school,” they wrote. “There may also be safety benefits to the sponge, as patients are not subjected to the small but quantifiable risks of sedated upper endoscopy.”

The authors said in their practice, they use the Cytosponge when patients have well-controlled symptoms and a lumen diameter of greater than 13 mm. They said the new technique might be a strong selling point to induce patients to use dietary elimination therapy.

“Our data also suggest that similar to biopsy histology, levels of esophageal eosinophilia measured with the Cytosponge are unlikely to be a solitary end point but complementary to other measures of EoE activity such as EREFS and symptom scoring systems,” they concluded.

Reference

Alexander JA, Ravi K, Symrk TC, et al. Use of the esophageal sponge in directing food reintroduction in eosinophilic esophagitis. Clin Gastroenterol Hepatol. Published online June 10, 2022. doi:10.1016/j.cgh.2022.05.029