1 Department of Radiation Oncology, University of Colorado Denver, Anschutz Medical Campus, Aurora, Colorado. Electronic address: sana.karam@cuanschutz.edu.
2 Department of Radiation Oncology, University of Iowa Hospitals & Clinics, Iowa City, Iowa.
3 Department of Radiation Oncology, Mayo Clinic, Rochester, Minnesota.
4 Divisions of Radiation Oncology and Medical Sciences, National Cancer Centre Singapore, Duke-NUS Medical School, Singapore, Singapore.
5 Department of Human Oncology and UW Carbone Cancer Center - University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin. Electronic address: rkimple@humonc.wisc.edu.