PSA Tests Miss Over Half of All Prostate Cancers, Study Says
The study evaluated 6,691 volunteers and found that the prostate-specific antigen (PSA) test missed 82 percent of tumors in men under 60 and 65 percent of tumors in older men.
In their study, Dr. Rinaa Punglia of Harvard Medical School and her team said the test’s accuracy has been overestimated because doctors do not routinely confirm what seems to be a healthy reading on the test.
The PSA test measures levels of prostate-specific antigen, a protein produced by prostate cells and over-produced by prostate tumors. About 75 percent of men in the U.S. who are 50 and over have had the screening test. Currently, a PSA level of 4.1 or under is considered healthy.
Many doctors champion the test, which gives men the chance to treat prostate cancer before it spreads. Others have been more critical and are awaiting the results of large studies investigating whether using the PSA test to screen for prostate cancer decreases men’s likelihood of dying from the disease.
”If these studies are all negative, showing no advantage, it may turn out that we are over-treating prostate cancer and aggressive screening is no longer necessary,” Dr. Daniel George of the Dana Farber Cancer Institute’s Lank Center for Genitourinary Oncology told The Boston Globe.
Punglia’s team raised further questions about PSA testing, recommending that the test results be interpreted differently. They suggested lowering the threshold for a “healthy” reading from 4.1 to 2.6, particularly for younger men, even though this would mean that many more men who do not have prostate cancer would have to undergo painful biopsies to verify they do not have cancer.
According to the researchers, using 2.6 as the cutoff would double the tumor detection rate to 36 percent for men under 60. The number of healthy men who would undergo an unnecessary biopsy would rise from 2 to 6 percent.
But in an editorial in the Journal, Fritz Schroder and Ries Kranse of the Erasmus Medical Center in Rotterdam, Netherlands, cautioned the findings are “difficult to apply clinically.”
“This recommendation is not ready for routine clinical practice. New recommendations for screening should arise from ongoing, randomized studies that are designed to show whether screening indeed reduces mortality from prostate cancer without unacceptably reducing the quality of life,” Schroder and Kranse wrote.
Treatment options for prostate cancer can cause side effects such as impotence and incontinence. Prostate cancer is the second most common type of cancer found in American men and kills about 29,000 Americans each year.