1. Department of Coloproctology, Hospital Universitario de la Princesa, 28006 Madrid, Spain
2. Department of Coloproctology, Clínica Santa Elena, 28003 Madrid, Spain
3. Angelita and Joaquim Gama Institute, São Paulo 01329-020, Brazil
4. Department of Coloproctology, Hospital Alemão Oswaldo Cruz, São Paulo 01323-020, Brazil
5. Department of Surgical Oncology, Hospital Beneficencia Portuguesa, São Paulo 01323-001, Brazil