Internet-based Perioperative Exercise Program in Patients With Barrett's Carcinoma Scheduled for Esophagectomy

Inclusion Criteria: * Histologically proven adenocarcinoma of the esophagus or adenocarcinoma of the esophagogastric junction type I according to Siewert's classification, clinical stages IIB-IIIC (T3/T4 and/or N+; M0) according to Union Internationale Contre le Cancer (UICC), 7th Edition * Resectable stage according to discussion in the local multidisciplinary tumor board (MDT) of the participating centers and patient medically fit for multimodality therapy (ECOG performance status at least 1 or better, no severe impairment of cardiac, renal, hepatic, endocrine, bone marrow and cerebral functions) * Planned abdominal-thoracic esophagectomy with gastric pull-up and intrathoracic or cervical anastomosis * Cognitive ability of the patient to understand the perioperative program and to participate actively Exclusion Criteria: * Presence of a second malignant tumor (unless curatively treated \> 5 years ago) * Chemotherapy or radiochemotherapy in patient's history * Orthopedic, rheumatologic, cardiovascular or neurologic (epilepsy, stroke, Parkinson's disease, muscle wasting diseases such as amyotrophic lateral sclerosis or multiple sclerosis) contraindications for the sports program * Inability to use the internet or no internet Access * Inability to communicate in German * Each active disease, which hinders completion of the study * Active alcoholism or illegal drug consumption within the last six months before study entry