A recent prospective study (DA Katzka et al. Am J Gastroenterol 2017; 112: 1538-44 -thanks to Ben Gold for this reference) provided more information regarding the potential utility of the cytosponge for eosinophilic esophagitis (EoE); the cytosponge has been studied for Barrett’s esophagus.
Background: 86 adult patients were recruited; 6 could not swallow sponge. In the remainder, 105 procedures were performed comparing the cytosponge to standard endoscopic biopsies. The cytosponge technique can be completed in ~5 minutes without sedation. “All that is required is centrifuging the cytosponge specimen in its preservative to create a pellet followed by routine paraffin embedding and processing.”
- Cytosponge was considered to have adequate specimen in 102 of 105 cases, compared with 104 of 105 with endoscopic sampling
- Using a cutoff of <15 eos/hpf for inactive disease, the authors found that the cytosponge had a sensitivity of 75% and a specificity of 86%.
- Six patients had active EoE on cytosponge with negative endoscopic biopsies.
- 14 patients with active EoE with endoscopic biopsies had <15 eos/hpf with cytosponge
- No complications were noted with cytosponge.
The sensitivity of 75% is likely due to inadequate contact between cytosponge and esophageal wall which could be related to technique, especially in those with a normal caliber esophagus.
My take: The cytosponge appears to identify active EoE in the majority of adult patients. In those with abnormal cytosponge, the likelihood of active EoE would be very high; as such, it could be a useful biomarker. It is still probable that many with normal cytosponge result would need endoscopy due to suboptimal sensitivity.
Related blog posts: