N E Samalavicius1,2, P Kavaliauskas2,3, D Simcikas1, A Dulskas2,3,4. 1. Department of Surgery, Klaipeda University Hospital, Klaipeda, Lithuania. 2. Institute of Clinical Medicine, Faculty of Medicine, Vilnius University, Vilnius, Lithuania. 3. Departament of General and Abdominal Surgery and Oncology, National Cancer Institute, Vilnius, Lithuania. 4. Faculty of Health Care, University of Applied Sciences, Vilnius, Lithuania.