1. Department of Abdominal Surgery, Instituto Nacional de Enfermedades Neoplásicas , 2520 E Angamos Ave. Of. 216. Surquillo, Lima 15038, Peru
2. Department of Surgical Clinics, Universidad Peruana Cayetano Heredia , 430 Honorio Delgado Ave. San Martín de Porres, Lima 15102, Peru