1. Department of Surgery, University Clinical Hospital of Valencia , Valencia , Spain
2. INCLIVA Biomedical Research Institute , Valencia , Spain
3. Department of Surgery, University General Hospital of Valencia , Valencia , Spain
4. Department of Surgery, University General Hospital of Alicante , Alicante , Spain
5. Department of Surgery, Valencian Institute of Oncology (IVO) , Valencia , Spain
6. Department of Surgery, University Clinical Hospital of Santiago de Compostela , A Coruña , Spain
7. Department of Surgery, La Fe University and Polytechnic Hospital , Valencia , Spain
8. Department of Surgery, Hospital of Antequera , Málaga , Spain
9. Department of Surgery, General Hospital of Requena , Valencia , Spain
10. Department of Surgery, Hospital of San Pedro , Logroño , Spain
11. Department of Surgery, University Clinical Hospital of Marques de Valdecilla , Santander , Spain