Right Versus Left Thoracic Surgical Approaches for Siewert II Gastroesophageal Junction Adenocarcinoma

Inclusion Criteria: 1. Histologically confirmed gastroesophageal adenocarcinoma; 2. R0 resectable Siewert Ⅱ, cT2-3N0-3M0 (AJCC V8 TNM classification); 3. Have a performance status of 0 or 1 on the ECOG Performance Scale; 4. Age 18-80 years old, both men and women; 5. Estimated survival ≥6 months; 6. Be willing and able to provide written informed consent/assent for the trial; 7. Demonstrate adequate organ function ; 8. Female subject of childbearing potential should have a negative urine or serum pregnancy within 7 days before enrollment. If the urine test is positive or cannot be confirmed as negative, a serum pregnancy test will be required; 9. Have not received systemic or local treatment for esophageal cancer in the past. Exclusion Criteria: 1. Have a history of other malignant tumors in the past or at the same time; 2. Previous upper abdominal surgery (excluding cholecystectomy); 3. Bleeding, perforation and obstruction requiring emergency surgical treatment; 4. Severe heart, lung, liver and kidney dysfunction, which the researcher thinks is not suitable for operation; 5. Hydrothorax and ascites with clinical symptoms need therapeutic puncture or drainage; 6. Participate in other clinical studies or less than 1 month from the end of the previous clinical study; 7. Have a history of psychoactive drug abuse, alcoholism or drug abuse; 8. Be unable or do not agree to bear the inspection and treatment expenses at their own expense; 9. The researcher thinks that it should be excluded from this study.