The potential and limitations of data from population-based state cancer registries.

Cancer incidence varies markedly among states because of population heterogeneity regarding risk, genetic, and demographic factors. Population-based cancer registries are essential to monitoring cancer trends and control. The Centers for Disease Control and Prevention and the North American Association of Central Cancer Registries, through the National Program of Cancer Registries, are helping state registries generate more and better data nationwide. The National Program of Cancer Registries has supported the enhancement of 36 registries and the creation of 13 new registries in 45 states, 3 territories, and the District of Columbia, providing national standards for completeness, timeliness, and quality; financial support; and technical assistance. Users must be aware of diverse issues that influence collection and interpretation of cancer registry data, such as multiple cancer diagnoses, duplicate reports, reporting delays, misclassification of race/ethnicity, and pitfalls in estimations of cancer incidence rates. Attention to these issues and intense use of the available data for cancer surveillance will enable maximum societal benefit from the emerging network of population-based state cancer registries.