The purpose of this study is to determine the diagnostic value of various nitrogen components in oral gas for esophagus cancer (ESCA) .

Less effective diagnostic markers for ESCA can be used in present. Nitrogen elements include a variety of nitrogen components (each corresponding to a specific mass-charge ratio [m/z] value). Stable nitrogen isotope ratios 15 Nitrogen/14 Nitrogen (15 N/14 N) are of particular advantage to understand the metabolic state of cancer cells, since most biochemical reactions involve transfer of nitrogen. Cancerous cells can recycle metabolic ammonium for their growth . The recycling of this ammonium with a low nitrogen isotope ratio (15 N/14 N) may cause cancer tissue to have lower 15 N/14 N than surrounding healthy tissue, and it could diagnose malignancy as well as an avenue for investigation of cancer metabolism.

However, the relationship and diagnostic value between nitrogen excretion from oral gas and ESCA remains unclear. The purpose of this study is to analyze the diagnostic value of various mass nitrogen components excreting for oral gas for ESCA.

Inclusion Criteria:

• Esophageal cancer patients (Case): Subject diagnosed with ESCA based on typical clinical symptoms, endoscopic observation of esophageal lesions, and histopathological examination of biopsy specimens obtained from the lesion sites.
• Reflux esophagitis patients (Case control): Subject diagnosed diagnosed with reflux esophagitis based on typical clinical symptoms (e.g., heartburn and acid regurgitation) and endoscopic evidence of esophageal mucosal injury classified according to the Los Angeles classification system (Grade A: mucosal breaks ≤5 mm in length; Grade B: mucosal breaks >5 mm in length but not confluent; Grade C: confluent mucosal breaks involving <75% of the esophageal circumference; Grade D: confluent mucosal breaks involving ≥75% of the esophageal circumference).
• Health people: (Healthy control): no history of malignant tumors within the past five years, normal findings on gastroscopy, with no evidence of esophageal or gastric lesions, no history of gastrointestinal diseases such as gastroesophageal reflux disease (GERD) or Barrett's esophagus, blood counts, tumor biomarkers, and liver and kidney function tests within normal ranges.

Exclusion Criteria:

• Esophageal or gastric surgery
• History of previous upper abdominal surgery
• History of previous gastrectomy, endoscopic mucosal resection or endoscopic submucosal dissection
• History of other malignant disease within past five years
• History of previous neoadjuvant chemotherapy or radiotherapy
• History of unstable angina or myocardial infarction within past six months
• History of cerebrovascular accident within past six months
• Requirement of simultaneous surgery for other disease
• Emergency surgery due to complication (bleeding, obstruction or perforation) caused by cancer
• Pregnant women or breastfeeding
• Unwillingness or inability to consent for the study
• Severe mental disorder
• Unstable vital signs Coagulation dysfunction (INR>1.5)
• Low peripheral blood platelet or using anti coagulation drugs
• Long-term Chinese medicine treatment of unknown drug nature

40 esophageal cancer patients; 40 reflux esophagitis patients; 40 health volunteers

Individuals may be reluctant to divulge health information