Deeper Intubation Make Effects on Cervical Esophageal ESD

This study is testing a specialized endoscopy technique for removing precancerous or early cancerous tissue from the upper part of the esophagus (the food pipe near the throat). Researchers are looking at how the depth of breathing tube placement during sedation affects the procedure's success. **You may be eligible if...** - You have early-stage esophageal cancer or high-grade precancerous changes in the cervical (upper) esophagus - Scans show no spread to lymph nodes or distant organs - You understand the study and can give written consent **You may NOT be eligible if...** - You have already had chemotherapy or radiation therapy before this procedure - You have serious other health conditions that make endoscopic surgery unsafe Talk to your doctor to see if this trial is right for you.