THE VALIDITY OF HOSPITAL ADMINISTRATIVE DATA IN MONITORING VARIATIONSIN BREAST-CANCER SURGERY

To assess the validity of using hospital administrative data to measur e variations in surgery for early stage breast cancer, ICD-9-CM coded information was compared with corresponding tumor registry data for 12 93 breast cancer patients undergoing lumpectomy or mastectomy at a ter tiary referral center from January 1989 to October 1993. Relative to ' 'gold standard'' tumor registry data, the administrative data proved 8 3.4% sensitive and 80.4% specific in identifying women with localized disease who would be potential candidates for lumpectomy. The proporti on of women with localized disease under going lumpectomy in groups de fined by race and insurance status was nearly identical, whichever dat a were used. Administrative data, which is often readily and publicly available, may be useful in studying variations in breast cancer treat ment in key demographic groups.