A very large, retrospective study analyzing the 10-year health records of almost 220,000 men over age 45 years suggests that measuring levels of prostate-specific antigen (PSA) can help improve detection of aggressive prostate cancer.
PSA is made by the prostate and is found in the blood. Generally, higher PSA levels suggest something is wrong with prostate function, but specific PSA levels depend on a man’s age, conditions, race, and other factors. A PSA screening test is currently the most common way to screen for prostate cancer and to monitor patients who have been diagnosed with the disease. But, this screening is controversial.
Prostate cancer mortality data suggest that there is not enough benefit from PSA screening to justify it. Prostate cancer screening guidelines from the American Society of Clinical Oncology (ASCO) say that men with life expectancies of over 10 years should receive PSA tests, but that those with life expectancies of less than 10 years do not benefit from screening. These guidelines are based on PSA screening trials in both the U.S. and Europe including the Prostate, Lung, Colorectal, and Ovarian (PLCO) Cancer Screening Trial. In July of 2012, the U.S. Preventive Services Task Force also reviewed the evidence and released a statement against PSA-based screening for all men in the U.S., as long as a patient has no prostate cancer symptoms. Although the overall message is not to screen, the task force recommendation does include a statement that a man should discuss PSA screening with his clinician to make an individual decision.
The new retrospective study aimed to determine whether tracking PSA levels could better detect prostate cancer compared to just a single PSA measurement. Previous research has suggested that this type of tracking may be more informative and improve detection of prostate cancer, particularly of aggressive forms of the disease.
Researchers from Kaiser Permanente, the University of Southern California, and Yale University found that the annual average change in PSA levels was 2.9% and that the rate increased with age, but modestly. The percent change in PSA predicted the presence of prostate cancer and was more accurate in predicting aggressive cancer compared to just a single PSA measurement. None of the men initially enrolled in the trial had a history of prostate cancer.
The researchers’ conclusion: “Longitudinal measures of PSA improve the accuracy of aggressive prostate cancer detection when compared with a single measurement of PSA alone.”
Although there are no recommendations that suggest men should now have more frequent PSA level tracking as part of their normal checkups, men who have had several PSA tests over time might benefit from looking back and discussing the changes with their doctors.
The study is published in the British Journal of Urology International (DOI: 10.1111/j.1464-410X.2012.11651.x)