1. Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, Massachusetts.
2. Survey and Data Management Core, Dana-Farber Cancer Institute, Boston, Massachusetts.
3. Department of Medicine, Columbia University College of Physicians and Surgeons, New York, New York.
4. Department of Community Health Sciences, Boston University School of Public Health, Boston, Massachusetts.
5. Department of Health Care Policy, Harvard Medical School, Boston, Massachusetts.
6. Division of General Internal Medicine, Brigham and Women's Hospital, Boston, Massachusetts.