Background: Surveillance, Epidemiology, and End Results (SEER) cancer registries provide accurate information on cancer surgery and radiation, but the validity of registry data on chemotherapy and hormone therapy for breast cancer has not been well studied. We validated the registry data for chemotherapy and hormone therapy against an independent medical chart review.
Methods: We identified 1,228 women diagnosed with breast cancer at age > or = 65 in 1993-1999 in the New Mexico SEER Tumor Registry and completed medical chart reviews.
Results: Overall, there was moderate agreement between these two databases on chemotherapy that was received within 6 months of diagnosis. The observed agreement was 96.0%, with a kappa of 0.72 (95% confidence interval: 0.64-0.79). The sensitivity of the registry data for chemotherapy was 70.7% and the specificity was 98.2%. The positive predictive value of the registry data for chemotherapy was 77.8%. The sensitivity of the registry data for hormone therapy was 59.7%, and the specificity was 89.5%. The observed agreement for hormone therapy was 80.0%, with a kappa of 0.52 (0.46-0.57).
Conclusion: Agreement on chemotherapy and hormone therapy between the New Mexico SEER Tumor Registry and chart reviews was moderate. The preferred approach would be to combine data from different sources to obtain more complete information.