1. Department of Medical Oncology, Hospital 12 de Octubre, 28041 Madrid, Spain
2. Department of Geriatrics, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Mexico City 14080, Mexico
3. School of Medicine, University of Toronto, Toronto, ON M5S 3G5, Canada
4. Department of Palliative Care, Hospital Gea González, Mexico City 14080, Mexico