This prospective study includes patients with histologically proven cancer of the esophagogastric junction (Siewert Type II and III) and the stomach. Aim of the study is to evaluate the accuracy of PET-CT for the preoperative assessment of lymph node metastasis. The evaluation includes a combination with standard diagnostic tools (endoluminal ultrasound, CT and diagnostic laparoscopy prior to neoadjuvant therapy). Standardized D2-lymphadenectomy is performed and individual lymph node stations (Nr 1-12 according to the Japanese classification) are histopathologically examined. Furthermore we evaluate the role of the PET-CT for early metabolic response evaluation in patients receiving neoadjuvant chemotherapy.

• Trial with surgical intervention

Inclusion criteria:

• Histological prove of adenocarcinoma of the stomach.

Exclusion criteria:

• Recurrent gastric carcinoma
• No informed consent
• Previous malignancy (exception: thyroid, bladder in situ, Cervix in situ)