This means making progress in early detection in places where access to screening equipment is not available.
Lesions of the esophagus caused by cancer. Photo: shutterstock.
The researchers found that esophageal squamous cell carcinomas can be detected by analyzing a panel of methylated DNA biomarkers in cytology samples obtained through a swallowable sponge capsule device.
This approach may be particularly useful in under-resourced settings where endoscopy is not available, they say in a report in Gastroenterology.
Squamous cell carcinoma of the esophagus accounts for 90% of esophageal cancers worldwide. It can be diagnosed by esophagogastroduodenoscopy with biopsy, but this procedure is not widely available in developing countries.
“Inexpensive, safe, and easily accessible diagnostic alternatives are likely to improve prognosis and outcomes,” write Dr. Stephen Meltzer of Johns Hopkins University School of Medicine in Baltimore, Maryland, and colleagues.
They tested sponge-based sampling with a panel of predictive biomarkers as a screening method for esophageal squamous cell carcinoma in developing countries.
In paired samples of esophageal squamous cell carcinoma tissue and normal tissue, they identified five biomarkers (cg20655070, SLC35F1, TAC1, ZNF132, and ZNF542) that were hypermethylated in esophageal squamous cell carcinoma tissue.
In cellular samples obtained by ingestion of the spongy capsule apparatus, these five biomarkers showed significantly higher methylation levels in patients with esophageal squamous cell carcinoma than in controls.
In the training set, age paired with the three biomarker algorithm demonstrated high accuracy in detecting this type of cancer, with a variable scale of 0.94.
They reported that in a separate set of tests, the algorithm successfully classified 90% of patients with esophageal squamous cell carcinoma, with a specificity of 0.87 and a sensitivity of 0.92, with two false-positive and one false-positive score. A value (PPV) of 0.86 and a negative predictive value (NPV) of 0.93.
Meltzer and colleagues report that the model was “remarkably” accurate, particularly in early-stage esophageal squamous cell carcinoma.
“Therefore, we present a systematic application of a stepwise approach to identify and validate distinct methylation-specific biomarkers for the diagnosis of esophageal squamous cell carcinoma in patient samples obtained using a minimally invasive and non-endoscopic approach,” they wrote.
“This method and model, with the possibility of generalization to populations at risk, fills the potential need for screening for squamous cell carcinoma of the esophagus, because endoscopy of the esophagus, stomach and duodenum is not widely available in countries prone to this type of cancer. Application of this screening strategy may lead in Ultimately improving early diagnosis of the condition, therapeutic intervention, and survival.”
Consistent with previous studies, there have been no adverse events from ingestion of the sponge capsule device, “which indicates its safety, convenience, ease of use, and efficacy,” they say.
They concluded, “This strategy represents a low-risk, cost-effective esophageal diagnosis and sampling strategy that merits further study in larger, prospective, high-risk population screening trials.”
Consulting resource here.