PREHAB - Improving Condition Before Surgery

Inclusion Criteria: * radically operable locally advanced cancer of the esophagus, esophagogastric junction, stomach * radically operable locally advanced carcinoma of the rectum * the patient is able to handle the planned surgical resection procedure * planned preoperative neoadjuvant therapy * age \> 18 years * the ability to complete a spiroergometric examination * the ability to carry out a prehabilitation program consent to participate in the study confirmed by signing the informed consent Exclusion Criteria: * contraindications for spiroergometric examination * limitation on the part of the locomotor system to spiroergometric examination or daily exercise (e.g. amputation, severe gonarthrosis, coxarthrosis) * inoperability determined by the interdisciplinary team * inability to manage the planned operational performance * acute surgical performance * synchronous malignant disease * multivisceral resection * planned non-surgical therapeutic procedure * incomplete data