1. Institute of Oncology Ljubljana , Slovenia
2. Institute for Oncology and Radiology of Serbia, Medical Faculty , University of Belgrade , Serbia
3. Department of Oncology , Medical Faculty University of Niš ; Clinic of Oncology , University Clinical Centre Niš , Serbia
4. University Hospital Centre Zagreb, School of Medicine , University of Zagreb , Croatia
5. National Cancer Hospital , Sofia , Bulgaria
6. Oncology Institute of Vojvodina, Faculty of Medicine , University Novi Sad , Novi Sad , Serbia
7. Medical University Pleven , Bulgaria
8. University Hospital of Split, University of Split - School of Medicine , Croatia