1. Division of Gastrointestinal Medical Oncology and Neuroendocrine Tumors, European Institute of Oncology IRCCS, Milan, Italy
2. Division of Gastrointestinal Medical Oncology and Neuroendocrine Tumors, European Institute of Oncology IRCCS, Via Ripamonti 435, Milan 20141, Italy
3. Department of Statistics and Quantitative Methods, University of Milan-Bicocca, Milan, Lombardia, Italy
4. Division of Radiotherapy, European Institute of Oncology IRCCS, Milan, Lombardia, Italy
5. Division of Endoscopy, European Institute of Oncology IRCCS, Milan, Lombardia, Italy
6. Division of Pathology, European Institute of Oncology IRCCS, Milan, Lombardia, Italy
7. Division of Gastrointestinal Surgery, European Institute of Oncology IRCCS, Milan, Italy