1. Gastrointestinal Unit, A. Manzoni Hospital, Lecco, Italy
2. Oncology Department, A. Manzoni Hospital, Lecco, Italy
3. Department of Surgery, A. Manzoni Hospital, Lecco, Italy
4. Division of General Surgery, Merate Hospital, Merate, Italy
5. Community Health Care Centre, Lecco, Italy
6. Community Health Care Centre, Bergamo, Italy
7. Faculty of Economics, Catholic University, Milan, Italy
8. Regional Reference Centre for Screening, Milan, Italy