1 General Surgery Service, University Hospital Príncipe de Asturias, 28820 Alcalá de Henares, Spain.
2 Medical Oncology Service, University Hospital Príncipe de Asturias, 28820 Alcalá de Henares, Spain.
3 Department of Medicine and Medical Specialities, Faculty of Medicine and Health Sciences, University of Alcalá de Henares, 28880 Alcala de Henares, Spain.