The contribution of subclinical cancer to Denver's high prostatic cancer incidence rate.

In order to quantitate the contribution of latent prostatic cancer to the very high prostatic cancer incidence rate in Denver, we conducted a population-based study. In 1979, 33% of 402 incidence cases were discovered incidentally, 4% at autopsy and 29% because of surgery for presumably benign prostatic disease. Of the unsuspected cases, 43% were stage A1, i.e. low grade and focal. The rest were high grade, more extensive, or both. It is expected that unsuspected cancers are a highly variable component of reported rates of prostatic cancer from other areas since their frequency of discovery depends upon urological and pathological practices that have been demonstrated to vary greatly from region to region.