1. Department of Gastroenterological Oncology, The Oncology Center, Maria Curie Institute, Warsaw, Poland
2. Department of Gastroenterology, Hepatology and Clinical Oncology, Medical Center for Postgraduate Education, Warsaw, Poland
3. Department of Cancer Prevention, The Oncology Center, Maria Curie Institute, Warsaw, Poland
4. Department of Health Management and Health Economics, University of Oslo, Oslo, Norway