Study emphasizes value of giving annual PSA tests
■ Although the tests can result in more questions than answers, they still have an important role in cancer detection and treatment, according to some experts.
By Susan J. Landers — Posted Nov. 21, 2005
Washington -- A new study provides evidence that annual prostate-specific antigen screenings are a worthwhile enterprise, although the finding is unlikely to settle the controversy surrounding the test's value as a diagnostic tool.
The study, presented Oct. 19 at the annual meeting of the American Society for Therapeutic Radiology and Oncology, showed that annual PSA blood tests discover prostate cancer at a more curable time and could lower prostate cancer death, said lead author Jason Efstathiou, MD, a resident at the Harvard Radiation Oncology Program in Boston. Among the 1,492 men followed from 1988 to 2002, those who had an annual PSA test were three times less likely to die from prostate cancer than those who didn't have the test annually.
Although it's a simple blood test, PSA screening inspires complicated conversations between physicians and their male patients over what test results actually mean. While this study could tip the balance toward the value of annual PSA tests, it does not provide a definitive answer, Dr. Efstathiou said. "The jury is still out."
In this case, the jury consists of large randomized trials now under way to assess the predictive power of the tests. Data are not expected for at least three years. "The value of our study is that it may give us some indication or clues as to what those large studies will show," Dr. Efstathiou said.
No one would advocate using the PSA test alone as a diagnostic tool. The digital rectal exam should be performed also, and family history is important. But nonetheless, PSA is probably the most important biomarker available for prostate cancer, noted Stuart Holden, MD, medical director of the Prostate Cancer Foundation.
"I do them, and when I read a study like this, it sort of gives me comfort that I'm probably doing the right thing," Dr. Holden said.
The fact that the study examined annual screenings is important, he said. "If you get one [abnormal] test, it's likely to be influenced by things that would become normal over time." But a sudden large jump in score from one year to the next could signal trouble and should be looked at closely.