1. Departments of Pulmonary Medicine, Houston, Texas, USA
2. Departments of Head & Neck Surgery, Houston, Texas, USA
3. Departments of Biostatistics, Houston, Texas, USA
4. Departments of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA
5. Thoracic/Head & Neck Medical Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA