women—those with early, favorable breast cancer who are having primary conservation and women with metastatic disease who are getting a biopsy only to establish the diagnosis and test for hormone receptors. Adequate staging data are needed not only for fully interpreting studies of practice variations but also for investigating outcomes, especially those with strong quality-of-life components.
Nevertheless, the administrative data sets even now can provide information on several important topics, such as the site of service, shifts in the proportions of procedures (e.g., from radical mastectomy to modified and/ or simple mastectomy), and geographic variations in broad patterns of care. They can also be used to look at in-hospital survival, time-based survival, readmissions, some complications, and other simple outcome measures when one is unable to measure functional status, mental health, or other health status outcomes directly. Thus, although the discussion emphasized the necessity of obtaining richer clinical and patient outcome data through Medicare PROs, linkages with local SEER registries, and (most important) primary data collection, the potential of the existing data sets was also acknowledged.