Selection, follow-up, and analysis in the Birmingham Study.

The Birmingham, England, Cancer Registry is so organized that every case of cancer in its territory of 5,200,000 persons is included. This coverage allows the staff to detail every epidemiologic aspect of the cancer experience of a whole population. For example, this registry system made it possible for us not only to demonstrate that the Birmingham region had four times the incidence of scrotal cancer as another region had but to identify the locations and the specific practices in the workplace responsible for the excess. The result was the successful adoption of protective measures. Other instances are presented of the inestimable value of a population-based registry to cancer epidemiology.