Prostate cancer: who to screen, and what the results mean.

Long-term survival of patients with prostate cancer is inversely proportional to the extent of disease at diagnosis. Patients with known risk factors for the development of prostate cancer may be particularly well-suited for screening. The combination of digital rectal exam and serum prostate specific antigen (PSA) level results in higher cancer detection rates and positive predictive values than either test alone. PSA levels < 4 ng/ml are unlikely to reflect cancer, whereas patients with PSA levels > 10 ng/ml are presumed to have prostate cancer until proven otherwise. Using PSA density or PSA rate of change can increase the diagnostic accuracy of the serum PSA level in the 4 to 10 ng/ml range. Despite the ability of screening tests to detect prostate cancer, no trial has tested the impact of screening on survival.