1. Department of Palliative, Rehabilitation, Integrative Medicine, University of Texas MD Anderson Cancer Center, Houston, Texas, USA.
2. Department of Pain Medicine, University of Texas MD Anderson Cancer Center, Houston, Texas, USA.
3. Department of Biostatistics, University of Texas MD Anderson Cancer Center, Houston, Texas, USA.
4. Department of Hospital Medicine, University of Texas MD Anderson Cancer Center, Houston, Texas, USA.
5. Department of Psychiatry, University of Texas MD Anderson Cancer Center, Houston, Texas, USA.