Validity of cancer registry data for measuring the quality of breast cancer care

Abstract

Background: Various groups have called for a national system to monitor the quality of cancer care. The validity of cancer registry data for quality of cancer care has not been well studied. We investigated the validity of such information in the California Cancer Registry. Methods: We compared registry data associated with care with data abstracted from the medical records of patients diagnosed with breast cancer. We also calculated a quality score for each subject by determining the proportion of four evidence-based quality indicators that were met and then compared overall quality scores obtained from registry and medical record data. All statistical tests were two-sided. Results: Records of 304 patients were studied. Compared with the medical record data gold standard, the accuracy of registry data was higher for hospital-based services (sensitivity = 95.0% for mastectomy, 94.9% for lumpectomy, and 95.9% for lymph node dissection) than for ambulatory services (sensitivity = 9.8% for biopsy, 72.2% for radiation therapy, 55.6% for chemotherapy, and 36.2% for hormone therapy). On average, quality scores calculated from registry data were 11 percentage points (95% confidence interval [CI] = 9 to 13 percentage points, P