Standard Versus Super-extended Lymphadenectomy After Neo-adjuvant Chemotherapy for Gastric Cancer

Inclusion Criteria: * Age equal or greater than 18 years * IIA-IIIC histologically proven primary gastric adenocarcinoma, before the treatment with NAC. Not including gastro-oesophageal junction/cardia carcinoma but only Siewert 3, without any previous treatment (surgery and / or chemotherapy) for this diagnosis * Lack in CT scan of following: 1. Mediastinal lymph nodes 2. Lung metastases 3. Peritoneal metastases 4. Liver metastases 5. Pleural effusion, ascites 6. Metastases to para-aortic lymph nodes No 16a2/b1 7. Metastases to lymph nodes located in the "posterior" area (8p, 12 b/p, 13) 8. Extra-regional lymph node metastases * ECOG performance status ≤ 2 * No prior radio- or chemotherapy conflicting with the treatment of gastric cancer * No oesophageal invasion, or invasion \<=3cm * Negative peritoneal washing cytology findings and no peritoneal metastases in staging laparoscopy * No gastric stump cancer * No signs of cervical and subclavear lymph nodes or distal metastases * Patient's consent form obtained, signed and dated before beginning specific protocol procedures * Absence of any psychological, familial, sociological or geographical condition potentially hampering compliance with the study protocol and follow-up schedule; those conditions should be discussed with the patient before registration in the trial Exclusion Criteria: * Contraindications for any sort of appropriate chemotherapy according to local standards * Linitis plastica * Second uncontrolled malignant tumour (synchronous or metachronous (last 5 years) other than Cis or mucosal cancer * Neoplasms involving the esophago-gastric junction (Siewert types I and II) * Expected unresectability after neo-adjuvant treatment or progression in metastases * Emergency surgery due to bleeding or perforation * Uncontrolled infections * Other serious underlying medical conditions that could impair the ability of the patient to participate in the study * Pregnant or lactating women * Significant neurologic or psychiatric disorders * Severe cardiac illness (NYHA class IV) * Under treatment of systemic steroids * Participation in any other clinical trial that might interfere with the results of this trial * Lack of compliance * Inability to fill in questionnaires (insufficient command of language, dementia, lack of time)