Making cancer statistics more informative: measures of the quality of recorded diagnosis in a population-based registry.

The quality of the recorded diagnosis is a major limit to the usefulness of Cancer Registry statistics that is easily overlooked by users of the data. With data from a large population-based cancer registry as an example, we demonstrate how Registry statistics could be improved by wider use of three simple indices, namely (1) the proportion histologically verified (adjusted for age), (2) the proportion of verified cases with an uninformative diagnosis, and (3) the proportion of cases that are staged. We believe that greater awareness of the deficiencies of Cancer Registry statistics will lead to a more critical interpretation of them, and help stimulate efforts to rectify matters.