Department of Gynecologic Oncology and Reproductive Medicine, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA; Department of General Internal Medicine, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA; Department of Biostatistics, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA. The University of Texas School of Public Health, Houston, TX 77030, USA; Department of Clinical Education, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA.