1. Department of Radiation Oncology; Memorial Sloan Kettering Cancer Center; New York New York
2. Department of Radiation Oncology; Princess Margaret Hospital/University of Toronto; Toronto Ontario Canada
3. Department of Biostatistics and Epidemiology; Memorial Sloan Kettering Cancer Center; New York New York
4. Department of Radiation Oncology; The University of Texas MD Anderson Cancer Center; Houston Texas
5. Department of Head and Neck Surgery, Section of Speech Pathology; The University of Texas MD Anderson Cancer Center; Houston Texas