1. Department of Neurosurgery, General Hospital of Diseases - Guatemalan Institute of Social Security, Guatemala City, Guatemala.
2. Department of Neurosurgery, General Hospital of Accidents “Ceibal” - Guatemalan Institute of Social Security, Guatemala City, Guatemala.
3. Department of General Surgery, General Hospital of Accidents “Ceibal” - Guatemalan Institute of Social Security, Guatemala City, Guatemala.
4. Department of Radiation Oncology, HOPE International, Guatemala City, Guatemala.
5. Department of Epidemiology, Integra Cancer Institute, Guatemala City, Guatemala.