1 Department of Palliative Care, Rehabilitation and Integrative Medicine, University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA. Electronic address: dhui@mdanderson.org.
2 Department of Palliative Care, Rehabilitation and Integrative Medicine, University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA.
3 Department of Biostatistics, University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA.