Update on PSA testing.

The use of prostate-specific antigen (PSA) testing for prostate cancer screening has increased dramatically over the past decade. Determining the most efficient way to use PSA testing and how to interpret total PSA levels and changes in PSA values over time remain challenging. Guidelines for early detection of prostate cancer have a direct impact on the number of unnecessary tests performed and are critical for developing a successful screening approach for prostate cancer. The age at which PSA screening should begin, PSA testing intervals, and the importance of understanding fluctuations in PSA values over time are discussed in the framework of recent discoveries in the field. Results from ongoing randomized trials will confirm whether prostate cancer screening is an effective method for reducing deaths from prostate cancer and what approaches will provide the most cost-effective screening strategies.