Prospective, single-center, nonrandomized, explorative imaging study evaluating the value of PET as a predictor of histopathological response in metabolic non-responders Patients with resectable AEG (adenocarcinoma of the esophagogastric junction) type I and II (cT3/4 and/or cN+ and cM0)

Metabolic non-responders, showing a <35% decrease of SUV (standardized uptake value) two weeks after the start of neoadjuvant chemotherapy are eligible for the study and are taken to intensified taxane-based RCT (radiochemotherapy) before surgery. 18FDG-PET scans will be performed before (=Baseline) and after 14 days of standard neoadjuvant therapy as well after the first cycle of Taxotere/Cisplatin chemotherapy (=PET1) and at the end of intensified radiochemotherapy (PET2).

Tracer uptake will be assessed semiquantitatively using standardized uptake values (SUV). The percentage difference Delta SUV=100(SUVBaseline-SUVPET1)/ SUVBaseline will be calculated and assessed as an early predictor of histopathological response. In a secondary analysis, the association between the difference SUVPET1 - SUVPET2 and histopathological response will be evaluated.

The HICON trial is a prospective, single-center, nonrandomized, explorative imaging study evaluating the value of PET (Positron emission tomography) as a predictor of histopathological response in metabolic non-responders Patients with resectable AEG (adenocarcinoma of the esophagogastric junction) type I and II, staged cT3/4 and/or cN+ and cM0 by endoscopic ultrasound, spiral CT or MRI and FDG-PET are eligible. Tumors must be potentially R0 resectable and must have a sufficient FDG-baseline uptake. Only metabolic non-responders, showing a <35% decrease of SUV (standardized uptake value) two weeks after the start of neoadjuvant chemotherapy are eligible for the study and are taken to intensified taxane-based RCT (chemoradiotherapy (45 Gy) before surgery. 18FDG-PET scans will be performed before (=Baseline) and after 14 days of standard neoadjuvant therapy as well after the first cycle of Taxotere/Cisplatin chemotherapy (=PET1) and at the end of intensified radiochemotherapy (PET2). Tracer uptake will be assessed semiquantitatively using standardized uptake values (SUV). The percentage difference Delta SUV=100(SUVBaseline-SUVPET1)/ SUVBaseline will be calculated and assessed as an early predictor of histopathological response. In a secondary analysis, the association between the difference SUVPET1 - SUVPET2 and histopathological response will be evaluated..

Inclusion Criteria:

• Biopsy-proven adenocarcinoma of the distal oesophagus (AEG type I) or cardia (AEG type II) with or without metastases in local lymph nodes (tumor stage cT3/T4, cNX, and cM0 in the tumor-node-metastasis classification)
• Staging procedures include endoscopy, endoscopic ultrasound and computed tomography (CT) of the chest and abdomen.
• Eligible patients have to be fit for platin-containing chemotherapy
• Tumors must be potentially R0 resectable tumors during consecutive operation.
• Tumors must have demonstrated a minimal amount of FDG-uptake in the baseline PET-CT, defined as 18FDG-uptake in tumor at first examination > 1,35 x hepatic-SUV + 2 x standard-deviation of hepatic-SUV, and must be a metabolic non-responder under EOX, defined as a decrease of the SUVmax of <35% in a second PET on day 14 of chemotherapy.

Exclusion Criteria:

• Eastern Cooperative Oncology Group score >1
• Previous or secondary malignancy
• Life expectancy of less than 3 months
• Uncontrolled bleeding from the tumor
• Tumor infiltration of the airways
• Pregnancy
• Uncontrolled diabetes
• Patients are also ineligible if they have undergone previous chemotherapy, radiotherapy, or endoscopic laser therapy.