Preoperative optimization of diagnostic work-up and physical fitness predicts and improves outcome of patients with colorectal cancer

In colorectal cancer, surgical resection of the tumor remains the foundation of curative treatment. This involves a major treatment, which can have a considerable impact on a patient. Approximately one-third of the patients who undergo colorectal resection experience postoperative complications. In elderly, frail, and unfit patients, this percentage is even higher, with percentages well above 50%. The aim of this thesis was to improve the preoperatively identification of patients at risk for postoperative complications (high-risk patients), by looking at the role and risks of a patient’s physical fitness. In addition, it was investigated whether the postoperative outcomes in these high-risk patients could be improved with a physical exercise training program (prehabilitation) prior to surgery. Within a relatively short 3-week period of prehabilitation, physical fitness improved by approximately 10% and the incidence of postoperative complications decreased by more than 40% compared to usual care without prehabilitation.