Cancer is the second leading cause of death in Poland after cardiovascular disease. Disorders of nutritional status are very common in patients with cancer. 80% of cancer patients suffer from malnutrition. Phatophysiology of malnutrition in patients with cancer is complex. The most common cause of eating disorders in those patients is poor oral nutrition brought about by many factors. Primary and secondary consequences are very dangerous for patients. Determining methods which would allow to early identify the risk of malnutrition or the degree of its severity is very important for a patient care, treatment and nutrition in oncology. In order to identify state of malnutrition in patients, screening and comprehensive evaluation by nutritional status are carried out. Screening evaluation uses simple methods. It is performed by means of such tools as forms for screening evaluation of nutritional status. In-depth comprehensive analysis, on the other hand, is done by using objective methods based on the analysis of anthropometric results, additional biochemical and immunological tests. In the case of the risk of malnutrition, institutions take appropriate steps for further development of patient’s treatment plan.

Key words: cancer, malnutrition, nutritional status evaluation.