1. Department of Clinical General Surgery, Endocrine Surgery, and Gastroenterological Oncology, Poznan University of Medical Sciences, Poland
2. 2nd Department of Gastroenterology, Centre of Postgraduate Medical Education, Warsaw, Poland, Department of Gastroenterology, Bielanski Hospital, Warsaw, Poland
3. Department of Colorectal, General and Oncological Surgery, Medical Centre of Postgraduate Education in Warsaw, Bielański Hospital in Warsaw, Poland
4. Department of General and Oncological Surgery, St. Padre Pio Provincial Hospital in Przemysl, Poland