Prevalence of cancer in the elderly: Discrepancies between self reported and registry data

In both large cohort and genetic studies, the absence of a population based cancer register for convenient identification of individuals with cancer often means that self-reported data are used. In such cases, only positive responses tend to be verified. However, relatively little attention has been focused on the real possibility of significant numbers of false-negative responses. In view of the high incidence of cancer in the elderly (Yancik and Ries, 1994; Coleman and Lutz, 1996), an increasing number of elderly people are likely to be included in future epidemiological studies. These considerations prompted us to examine the validity of information reported by a population of elderly persons with respect to the occurrence of cancer. Data from a cross-sectional epidemiological survey carried out in the French department of the Tarn (SW France) were cross-checked against data from a cancer registry of the same department used as reference.