1. Department of Surgical Oncology, University of Texas MD Anderson Cancer Center, Houston, Texas, USA
2. Hepato-Biliary-Pancreatic Surgery Division, Department of Surgery, Graduate School of Medicine, the University of Tokyo, Tokyo, Japan
3. Department of Gastrointestinal Medical Oncology, University of Texas MD Anderson Cancer Center, Houston, Texas, USA
4. Hepatobiliary Surgery Unit, Foundation and Teaching Hospital IRCCS A. Gemelli, Rome, Italy
5. Department of Surgery, Division of General and Hepatobiliary Surgery, G. B. Rossi University Hospital, University of Verona, Verona, Italy
6. Department of Biostatistics, University of Texas MD Anderson Cancer Center, Houston, Texas, USA