Nutritional Risk Factors and Colorectal Surgery

This observational study aims to learn about the relationship between the nutritional status of patients with colorectal cancer and clinical outcome after colorectal surgery.
The main question[s] it aims to answer are:
* which anthropometric, laboratory and specific parameters best define that patient is at nutritional risk
* will patients that are at nutritional risk stay longer in the hospital after surgery than those who are not at nutritional risk Patients will be preoperatively examined anthropometrically, radiologically and laboratoryally. Postoperatively, the course of their treatment will be monitored, as well as the monitoring of postoperative complications. A group of patients with and without malnutrition will be compared.