Accuracy of Cancer Registry Data When Treatment Is in the Ambulatory Setting

Because there is an interest in using cancer registry data to monitor the quality of cancer care, the authors evaluated the validity of information on cancer treatment in the California Cancer Registry. The authors compared data in the registry with data abstracted from the medical records of patients diagnosed with breast cancer. The authors calculated the percent agreement, kappa statistic, sensitivity, and specificity of the registry data as compared with data from the medical record. Records of 304 patients were studied. Compared with the medical record, registry data were more accurate 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). CONCLUSION: Cancer registry data are less accurate for ambulatory-based services than hospital-based services. Since cancer treatment is increasingly provided in the ambulatory setting, modifications to registry data collection methods are needed to ensure accurate data collection regardless of the treatment setting.