1. Department of Family and Community Medicine, School of Medicine Pontificia Universidad Católica de Chile Santiago Chile
2. Department of Surgical Oncology, School of Medicine Pontificia Universidad Católica de Chile Santiago Chile
3. Department of Radiation Oncology, School of Medicine Pontificia Universidad Católica de Chile Santiago Chile
4. Resident in Radiation Oncology, School of Medicine Universidad Diego Portales Santiago Chile
5. Public Health Science Division Fred Hutchinson Cancer Research Center, Seattle Washington USA
6. Department of Surgery, College of Medicine University of Nebraska Omaha Nebraska USA