1. Center of Oncosurgery, Institute of Oncology, Vilnius University, Clinic of Internal, Family Medicine and Oncology, Faculty of Medicine, Vilnius, Lithuania.
2. Department of Surgery, Gastrointestinal Unit, B.P. Koirala Institute of Health Sciences, Dharan, Nepal.
3. Vilnius University, Institute of Oncology, Vilnius, Lithuania.
4. Aintree University Hospitals NHS Foundation Trust, University Hospital Aintree, Liverpool, UK.