National trends in the epidemiology of prostate cancer, 1973 to 1994: evidence for the effectiveness of prostate-specific antigen screening.

OBJECTIVES

The use of prostate-specific antigen (PSA) to screen for prostate cancer remains controversial. Although it is still too early to measure directly the effects of PSA screening on mortality, we examined changes in the epidemiology of prostate cancer to determine if there is other evidence of the effectiveness of PSA as a screening tool.

METHODS

We examined trends in age at diagnosis, and age-adjusted trends in stage and grade at diagnosis, for 140,936 white and 15,662 African American men diagnosed with prostate cancer from 1973 to 1994 in the National Cancer Institute's Surveillance Epidemiology and End Results data base.

RESULTS

We found a significant downward trend in age at diagnosis, concomitant with a downward shift in stage of disease at diagnosis, starting with the advent of the PSA era in the late 1980s. We noted most cancers detected since the PSA era to be moderately well differentiated (International Classification of Diseases of the World Health Organization grade 2; Gleason score 5, 6, 7) and organ confined. Although findings were similar for both whites and African Americans, African Americans experienced a greater increase in poorly differentiated disease than did whites.

CONCLUSIONS

Changes in the epidemiology of prostate cancer since the advent of the PSA era are consistent with the introduction of an effective screening test. This is evidenced by an increase in detection of significant prostate cancer in individuals who will likely benefit from treatment.