1. Department of Internal Medicine; Section of Medical Oncology; Attikon University Hospital; National and Kapodistrian University of Athens; School of Medicine; Athens Greece
2. Radiation Oncology Department; University of Thessaly; School of Health Sciences; Faculty of Medicine; Larissa Greece
3. First Department of Surgery; National and Kapodistrian University of Athens; School of Medicine; Athens Greece
4. Department of Medicine; Division of Medical Oncology; Princess Margaret Cancer Centre; University of Toronto; Toronto Ontario Canada
5. Department of Gastrointestinal Medical Oncology; The University of Texas MD Anderson Cancer Center; Houston Texas