1. Beth Israel Deaconess Medical Center; Boston Massachusetts
2. Department of Radiation Oncology; Massachusetts General Hospital; Harvard Medical School; Boston Massachusetts
3. Division of Biostatistics; Department of Radiation Oncology; Massachusetts General Hospital; Boston Massachusetts
4. Department of Medical Oncology; Continuum Cancer Centers of New York; New York New York
5. Center for Health Quality Outcomes and Economic Research; Edith Nourse Rogers Memorial Veterans Hospital; Bedford Massachusetts