The Diagnostic Value of Nitrogen Element (N) in Esophagus Cancer

Inclusion Criteria:

• Esophageal cancer patients (Case): Subject diagnosed with ESCA based on typicalclinical symptoms, endoscopic observation of esophageal lesions, andhistopathological examination of biopsy specimens obtained from the lesion sites.

• Reflux esophagitis patients (Case control): Subject diagnosed diagnosed with refluxesophagitis based on typical clinical symptoms (e.g., heartburn and acidregurgitation) and endoscopic evidence of esophageal mucosal injury classifiedaccording to the Los Angeles classification system (Grade A: mucosal breaks ≤5 mm inlength; 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 pastfive years, normal findings on gastroscopy, with no evidence of esophageal orgastric lesions, no history of gastrointestinal diseases such as gastroesophagealreflux disease (GERD) or Barrett's esophagus, blood counts, tumor biomarkers, andliver 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 endoscopicsubmucosal 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) causedby 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