PSA for outcome prediction and posttreatment evaluation following radiation for prostate cancer: do we know how to use it?

Pretreatment prostate-specific antigen (PSA) has been shown to be a powerful predictor of expected outcome after radiation for prostate cancer. Additional measures such as recursive partitioning analysis and PSA Cancer Volume calculations are further refining this useful tool to provide the greatest degree of prognostic information. The post-treatment PSA level is also being used as a means to assess therapeutic efficacy rapidly and objectively. Although no single PSA value has been shown to equate to long-term clinical tumor control consistently, consensus has been reached regarding the value of a rising PSA level as an early surrogate for tumor recurrence. Since the first introduction of PSA as a tumor marker, we have become much more comfortable with what it means, the ways it can help us, and how to use it.