Cancer registries: their interest and practical problems.

Cancer registries record all new cases of cancer within the population they survey. Thus they provide accurate regional measurements of cancer morbidity and mortality and their geographical distribution. This form of epidemiology allows the study of regional variations and alterations with the passage of time. It also allows the study of environmental factors that might cause cancer. The work of the French regional cancer registries is described to illustrate these points. The problems of running a cancer registry are also set out and suggestions are made for future organization. The statistics gathered by such registries indicate possible methods for the early detection and treatment of some cancers and provide evidence of the long-term effects of all kinds of therapy. The socio-economic aspects of cancer can also be measured by the registry, thus providing valuable data for use in the planning of health care in any community.