BOSTON, June 14 (UPI) -- A blood test at midlife can accurately predict a man's risk for more deadly forms of prostate cancer, according to a review of medical data.
Prostate specific antigen, or PSA, tests correctly predicted whether a man would have lethal prostate cancer later in life more than three-quarters of the time, researchers at Harvard University report in a new study.
Although studies have suggested PSA tests give false positives too often and can miss tumors, the tests have been used to detect or predict prostate cancer since the early 1990s.
Researchers at Harvard looked at data on men in their 40s, finding the blood test indicated whether they would go on to develop the disease. They recommend men with high PSA levels undergo increased screening, because of the higher risk they found.
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"Our study does not imply prostate biopsy or definitive treatment is immediately required in younger men with higher PSA levels at baseline, as this could lead to over diagnosis," Dr. Lorelei Mucci, an associate professor of epidemiology at Harvard's T.H. Chan School of Public Health, said in a press release. "Rather, these men should undergo more intensive PSA screening to enable earlier identification of cancer and potential cure while still possible."
For the study, published in the Journal of Clinical Oncology, researchers reviewed medical data on 945 men who participated in the Physician's Health Study, 234 of whom developed prostate cancer and 711 who did not. Of the 234 with cancer, 71 developed lethal prostate cancer.
Among the men with PSA levels above the median, 82 percent of those between age 40 and 49 developed lethal cancer, 71 percent of men between age 50 and 54 developed the disease and 86 percent of those between 55 and 59 developed cancer. Men with a PSA below median at age 60 also were less likely to develop lethal prostate cancer, the researchers reported.
With better screening methods available, the researchers say their results suggest increased screening for patients with indications they may have lethal cancer later in life, despite not having it at the time of the test.
"We found a single baseline PSA-level measurement during midlife could accurately predict future risk of lethal prostate cancer," said Dr. Mark Preston, a physician in the Division of Urology at Brigham and Women's Hospital. "These data identify subgroups of men, based on their PSA levels at a given age, who could benefit from screening intervals tailored to their actual magnitude of risk."
