Funding for this research was provided by:
National Cancer Institute (P30CA016672)
Received: 17 June 2019
Accepted: 24 January 2020
First Online: 31 January 2020
Ethics approval and consent to participate
: This study was approved by the Ethics committee and Institutional Review Board number DR10–0385 at the University of Texas MD Anderson Cancer Center; which determined that consent to participate could be waived because the subjects of the study were not exposed to any interventions. The study consisted purely on retrospective data collection and analysis.
: Not applicable.
: The authors declare that they have no competing interests.