Comparison of Endoscopic Resection and Surgery for Early Gastric Cancer With Undifferentiated Histological Type

This study is comparing two treatments for early-stage stomach cancer with a specific cell type (undifferentiated, such as signet ring cell carcinoma): endoscopic submucosal dissection (a non-surgical procedure that removes the tumor through a scope) versus standard stomach surgery. Researchers want to know if the less invasive procedure is just as safe and effective. **You may be eligible if...** - You are between 19 and 75 years old - You have been diagnosed with early undifferentiated gastric cancer (signet ring cell, poorly differentiated, or poorly cohesive type) - Your tumor is confined to the inner lining of the stomach, has no ulcer, and is 2 cm or smaller - Imaging shows no spread to lymph nodes or distant organs - You are willing and able to give consent **You may NOT be eligible if...** - You are under 19 or over 75 years old - You have had another cancer (other than skin cancer in remission) treated within the past 5 years - You have previously had stomach or esophageal surgery - You have multiple stomach cancers - You have serious heart, liver, kidney, or lung conditions Talk to your doctor to see if this trial is right for you.